[From the U.S. Government Printing Office, www.gpo.gov]





 4












                                       CZ-214


                                  Final Report-Task 15






                     THE EFFECTS OF ANTHROPOGENIC ACTIVITIES AND
                     '@UTURAL EVENTS ON A FRESHWATER TIDAL MARS/

                                      Final Report


                                      submitted to





                        Maryland Department of Natural Resources





                              Humaira Khan and Grace Brush

                Department of Geography and Environmental  Engineering
                              The Johns Hopkins University
                                 Baltimore, MD, 21218.


                                   4 February, 1991.









           Q11
           541.5
           'M'
           K63
           1991












             TABLE OF CONTENTS



                                                                                      page

             List of Tab  les and Figures   ...........................                i
             Introduction   .....................................                      1
             Approach  .........................................                       2
               Paleoecological indicators used
               in the study..                                                          4
             Description of t@;*R*;;;arch Site      ............................       6
               Location and history     ......................................         6
               Soils and plants    .................   o .......................       7
             Methods  ....................................................             8
               Collection and dating of cores       ........ o ......o ..........  o   8
               Pollen and seeds   ..............................       -   ........    9
               Total and organic carbon,
               nitrogen and phosphorus     .........  o....... o ...... o.........    10
             Results ..........................     o ......             o ........   11
               Analysis of Core JUG I    .... o  .................  o-   ......  -    13
               Analysis of Core JUG 3    ...................................          16
               Analysis of Core JUG 5    ...............    o..... o.............     18
               Analysis of Core JUG 7    ...................................          21
             Discussion an(i Conclusions    ........  ..... o................    -    23
             References  .............................      o..... o.............     29
             Appendix 1 ... o...............   o  ..... oo ....................       45








 4j








          ACKNOWLEDGEMENTS


          This study was partially funded by the Coastal Resources Division,
          Maryland Department of Natural Resources, through a grant provided
          by the Coastal Zone Management Act of 1972, as amended, by the
          Office of Ocean and Coastal Resource Management, National Oceanic
          and Atmospheric Administration.














          TABLES AND FIGURES



                                                                              page


          Table 1. Pollen and seed taxa identified in JUG 1                    32

          Table 2. Pollen and. seed taxa identified. in JUG 3                  33

          Table 3. Pollen and seed taxa identified in JUG 5                    34

          Table 4. Pollen and seed taxa identified in JUG 7                    35

          Table  5. Nutrient data for JUG 1                                    36

          Table  6. Nutrient data for JUG 3                                    36

          Table  7. Nutrient data for JUG 5                                    37

          Table  8. Nutrient data for JUG 7                                    37

          Fig.l. Oak/Ragweed pollen ratio for JUG 1                            38

          Fig.2.  Nutrient profile of JUG 1                                    39
          Fig.3.  Oak/Ragweed pollen ratio for JUG 3                           40

          Fig.4.  Nutrient profile of JUG 3                                    39
          Fig.5.  % Nuphar pollen in JUG 1 and JUG 5                           41
          Fig.6.  Oak/Ragweed pollen ratio for JUG 5                           42
          Fig.7.  Nutrient profile for JUG 5                                   43

          Fig.8.  Oak/Ragweed pollen ratio for JUG 7                           44
          Fig.9.  Nutrient profile'for JUG 7                                   43








          INTRODUCTION


          This study was conducted at the Jug Bay Wetlands Sanctuary in order

          to investigate the impacts of historical changes in land use and

          climate (storms) on sedimentation rates and vegetation composition

          in a tidal freshwater wetland, and on its ability to protect

          estuarine water quality through time.


          Increased research in the 1970s and 80s led to a recognition of wet-

          land values. Tidal freshwater wetlands are now known-to-be important

          fish and wildlife habitats (Odum, 1988), help curb shoreline erosion

          and control potentially damaging runoff from storms or floods

          (Tiner, 1985). One of the supposed values most often debated by

          wetland researchers and managers is their role in the maintenance of

          water quality in rivers and estuaries.


          Research of the past twenty years or so suggests that wetlands

          maintain water quality 'in adjacent rivers, lakes and estuaries by

          removing and retaining nutrients, sediment, organic wastes and heavy

          metals (Grant and Patrick, 1970; Whigham and Simpson, 1976; Klopatek

          1978; Sloey et al, 1978; Tilton and Kadlec, 1979; Simpson et al,

          1981, 1983b). Retention of nut rients may take place in two ways. One

          is through plant uptake by wh ich they are stored temporarily or per-

          manently (see below). The other is by deposition of water-borne

          sediments on the marsh surface. Many sediment particles, especially

          clay, have nutrients adsorbed on their surfaces so that nutrient re-

          tention occurs when these particles are deposited on the.marsh (Boto

          and Patrick, 1979).


          Many workers, through measurements on surface sediments of both salt






                                         -2-


         and freshwater marshes, believe that the largest and longest term

         retention of nutrients such as nitrogen and phosphorus, occurs in

         peaty and organic substrate where they are either immobilized in

         peat or their reactive forms are sorbed on organic material (Farnham

         and Boelter, 1976; DeLaune et al, 1981; Dolan et al, 1981; Howard-

         Williams, 1985). Nitrogen may also be removed by denitrification.

         Other studies indicate that nutrients are taken up by marsh plants--------

         during the growing season but are exported out into the estuary when

         dieback of vegetation takes place so that nutrient retention occurs

         only on a seasonal basis (Simpson et al, 1978; Whigham and Simpson,

         1980; Richardson, 1985). Therefore the question of whether tidal

         freshwater marshes act as net sinks for incoming nutrients on a long

         term or only on a seasonal basis can be answered by conducting hist-

         orical studies of nutrient fluxes in these marshes. Previous work

         is confined to only one or two years of data (Simpson et al, 1983a).


         APPROACH.

         A stratigraphic study was carried out to test the hypothesis that

         historical changes in regional land use and natural events have

         impact on sedimentation rates,. vegetation dynamics and nutrient up-

         take capabilities of a tidal freshwater marsh.


         Environmental changes, both due to natural (storms, water level) and

         anthropog'enic (cultural eutrophication, land use) causes, and their

         effects on the vegetation structure, sedimentation rates and

         nutrient uptake ability of the marsh were investigated. Since

         anthropogenic influence came largely after European settlement in

         the region, environmental conditions-in-thie-pr-e- and post-European

         periods and their effects-on                   III P Ci.L A-- U, ni-b-wa-s -done






                                         -3-


          by using the information contained in the sedimentary record. There

          are various organic and inorganic substances preserved in the

          sediment that reflect environmental conditions at the time of their

          deposition (Birks and Birks, 1980), stretching from the present to

          thousands of years in the past.


          Cores were collected in the high and low marsh and in the estuary

          upstream and downstream from it. The purpose of estuarine cores was

          to compare sediment fluxes and nutrient content in portions of the

          estuary just above and below the marsh during different time

          periods. Fluxes of these materials were measured in the marsh cores

          as well.



          Flux changes seen in the estuarine cores were time-correlated and

          compared with those in the marsh cores. Inferences about the influe-

          nce of the marsh on downstream water quality were based on statisti-

          cally significant differences in nutrient con-tent observed in the

          marsh and estuarine cores. For example, lower nutrient levels in the

          marsh cores during pre-European but higher levels in post-European

          era would show that the marsh was affected by upstream pollution and

          trapped some of the nutrients on a permanent basis. If an increase

          in nutrient content was seen in the upstream core but no significant

          increase occurred concurrently in the marsh then it was not a long-

          term sink for the nutrients. Elevated levels, if detected in the

          downstream core for the same time intervals, were further evide-
          nce that the marsh did not affect downstream water,quality.






                                         -4-


          Paleoecological indicators used in the study:


          Substances found in the sediment that are used in constructing past

          environments are - pollen, macrofossils such as seeds, rhizomes and

          roots, peat, parts of insects or other animals, chlorophyll degra-

          dation products, nutrients, total organ ic carbon, heavy metals and

          PCBs. In this study, total and organic carbon, nitrogen, and

          phosphorus, and pollen and seeds of aquatic and terrestrial plants

          were used to investigate environmental changes in the Jug Bay

          marsh/estuarine system since European settlement in the region.


          1) Pollen and Seeds - Pollen grains are easily retrieved and

          studied. Their resistant outer layer, the exine, enables them to be

          well-preserved, especially in acidic sediments. They are also

          produced in enormous quantities. Pollen can tell us much about the

          vegetational and environmental history of a region. Close correspon-

          dence between pollen assemblages and vegetation has been found in

          all part's of the world (Davis, 1969). A similar conclusion is

          reached by studies of surface sediment pollen assemblages and modern

          vegetational regions in eastern North America (Davis and Webb, 1975;

          Brush and DeFries, 1981). Knowing the plant species and their

          ecologic requirements enables. one to infer past climatic and

          ecologic conditions. It is also possible to attribute temporal

          changes in vegetation to changing

        .influences (Faegri and Iversen, 1989).


          Another measure of temporal vegetational change in response to nat-

          ural and man-induced changes areplant macro-fossils such as seeds.

          Seeds have been used to determine long-term trends in macrophyte






                                         -5-


          populations (Watts and Winter, 1966; Birks et al, 1976; Brush and
          Davis, 1984; Davis, 1985). They also give a more local record of
          vegetation since in many plants, seeds are not dispersed very far
          from the parent plant (Davis, 1985). Research has shown that seed

          bank species in tidal fres-ho7ater marshes strongly reflect those of

          the standing vegetation (Leck and Graveline, 1979; Parker and Leck,

          1985). My previous work at Jug Bay in 1989 also showed that about

          75% of the observed species along a marsh transect are represented

          in surface sediment (Khan, unpublished Final Repo-r-t-to- _tS6_DNR,_

          1989). Therefore seeds of emergent and submerged plants were used to

          trace the history of water level in different parts of the marsh.

          This showed us if conditions in these areas have changed from low to

          high marsh or vice versa due to changing sedimentation rates.



          2) Total and organic carbon, nitrogen and phosphorus - Elevated

          levels of nitrogen and phosphorus in sediments are considered good

          indicators of nutrient loading in estuaries and lakes; total organic

          carbon is an indicator of primary productivityand organic content

          of sediments.


          Several workers have found that concentration of P and TOC stays

          more or less constant in.the pre-cultural period but increases sign-

          ificantly in post-cultural periods (Shapiro et al, 1971; Bortleson

          and Lee, 1972; Jaworski, 1979). Bortleson and Lee (1972) attribute

          the increased P level to a combination of.greater supply of P to the

          lake and a higher efficiency of P precipitation and retention due to

          more Fe, Al and Mn oxides and clay                          These

          nutrients show higher concentrations in marsh surface sediments too






                                         -6-


          when the watershed has experienced heavy agriculture and urbaniza-

          tion (Kadlec and Tilton, 1978; Simpson et al, 1983b). Dolan et al

          (1981) found that a Florida freshwater marsh receiving effluent

          assimilated over 97% of the phosphorus and of this, 69.2% was taken

          up by the soil. Incoming nitrogen is mainly removed by marsh plants.

          On the higher marsh a large part of the organic detritus from

          primary production is retained (DeLaune and Patrick, 1980) and so is

          the nitrogen immobilized in it. Most of this nitrogen is recycled

          internally through mineralization and plant uptake. In comparison to

          this, hydrologic exports and denitrification of sedimentary N are

          much smaller for most marshes (Bowden, 1987).




          DESCRIPTION OF THE RESEARCH SITE



          Location and History:

          Jug Bay is a tidal freshwater marsh on the Patuxent River estuary,

          about 70 km upstream from its mouth at the Chesapeake Bay. It covers

          an area of over 133 ha and is located on the Coastal Plain of

          Maryland in a heavily populated region, with the metropolitan area

          of Washington, D.C., 45 km to the west. The surrounding land has

          been settled for centuries, first by the Indians and then by the

          Europeans. Evidence of human habitation along the Patuxent goes back

          8000 years. However, from the 17th century to mid 19th century,

          European settlers cleared individual plots for tobacco growing. The

          area under cultivation during this time was about 1.4-3% of the

          total land (Froomer, 1978). In early 19th century, agriculture

          expanded so that by 1840, 40-50% of the land had been cleared

          (Craven, 1925). In the past few decades, however, agricultural






                                         -7-


          activities in the region have been diminishing, giving way to
          second.-growth forests and urbanization. Thus, in 1930 50% of

          the land was under cultivation, 10% urban and 40% forested. In 1982,

          these land uses were 37%, 12% and 51% respectively (Maryland Dept.

          of State Planning, MAGI data, 1982).


          Nutrient input into the estuary has increased over time, first from

          fertilizers which came into general use in the 19th century (non-

          point sources) and then from the dischargeof wastewater treatment

          plants (point sources), concentrated around and upstream from Jug

          Bay. A large plant, the Western Branch Treatment Plant, is located

          about 3 km upstream from Jug Bay on a tributary of the Patuxent and

          has been discharging effluent into the river since the early 1970s.

          However, from mid-80s onward, it has been removing phosphorus from

          the effluent and in the spring of 1991 it will start removing

          nitrogen also (Western Branch Treatment Plant staff, pers. comm.).



          Soils and Plants:


          The soils at this site range from sandy and silty along the main

          channel to clayey and very peaty in the actual marsh (Soil Survey of
          Anne Arundel County, MD, 1973). 0'rganic content of soils increases

          from low to high marsh.


          Jug Bay is typical of tidal freshwater marshes along the mid-

          Atlantic coast of the US. It supports a large variety of plants,

          both emergent and submergent, and is very productive. The dominant

          plants are grasses and sedges-, whlcich- IU-J*-s-t@-ii-i-&ui-s-'cc--i@t-frori-L-o-t'L-Lei@- types

          of wetlands such as swamps, bogs and fens. Arboreal species like





                                          -8-


          maple, ash, sweetgum, alder, oak, beech and birch are found on the

          fringes of the high marsh while floating and submerged plants occur

          in and around the main channel.




          METHODS



          Collection and dating of cores:


          The location of the cores is shown on the map. They were collected

          with a piston Vibrocorer which can penetrate the marsh sediments

          easily, resulting in minimum compaction. Preliminary work at Jug Bay

          in the summer of 1989 showed that, due to high sedimenta- tion

          rates, pre-European time is not represented in cores less than 70cm

          long. Therefore all the cores were one meter or more in length. They

          were extruded from the corer in the laboratory, cut into half

          lengthwise and examined for sedimentological features. Each half was

          then cut into one centimeter intervals, sealed in plastic bags an(i

          stored at 4 C. Four representative cores from high and low marsh and

          upstream and downstream from the marsh were selected for fos sil and

          chemical analysis.


          These cores were dated by pollen analysis (Brush and Davis, 1984).

          This method entails the recognition of datable horizons in the core

          and the assignment of chronologies to each interval. One of these

          horizons,is 1650 A.D. in the Jug Bay area. It is called the

        --agricultural horizon and occurs where the oak to ragweed ratio drops
          sharply, from >15 or 20 to between 5 and 10. Another horizon is 1840

          A.D. where the oak/ragweed ratio drops again to <5 and percentage of

          ragweed in the pollen sum becomes >10. Recognition of datable





                                               -9-


            horizons in the core enables average sedimentation rates to be

            calculated by dividing the depth of the dated horizon by the number

            of years represented from the @.ate the core was taken to the date of

            that horizon. Total pollen concentration in all the levels above the

            dated horizon and the average number of pollen grains-per interval

            was computed and sedimentation rates for each interval found by the

            following equation:

                                    n
                                         R
                      0-1           n
                                     0-1



            where   R
                      0-1    = sedimentation rate for interval 0-1

                    n        = average no. of pollen grains per interval

                    n        = number of pollen grains in interval 0-1
                      0-1

                    R        = average sedimentation rate (d/t)

                    d        = depth of dated horizon in the core

                    t            time in years


            The years represented by each interval,A t, were then determined by

            dividing the depth of the interval, (in this case 1 cm) by its sedim-

            entation rate. Below the 1650 horizon, sedimentation rates were

            calculated by C-14 dating the lowest level of the core.



            Pollen and Seeds:


            Pollen was extracted from sediments by standard procedures (Faegri
            and Iv@rsen, 1_98@,),. -1.5-ml- of wet sedi,ment--f@rom_e.a_qh interval were

            oven-dried, treated with hydrochloric and hydrofluoric acids, an

            acetolysis mixture of sulfuric acid and acetic anhydride,        then






                                           _10-


          washed with glacial acetic acid, distilled water, ethanol and tert-

          iary butanol. The residue was stored in 25 ml of tertiary butanol.

          Aliquots from e ach subsample were examined for pollen with a

          light microscope at 400x. All grains were counted and identified

          with the help of reference slides and texts.


          Seeds were extracted by soaking about 20 g of sediment from each

          interval in 10% nitric acid. The acid helps break down the organic

          matter (Birks and Birks, 1980). After washing the sediment with

          water into a sieve, seeds were examined under a binocular microscope

          and identified to the species level using reference material and

          texts. All the seeds were stored in a mixture of distilled water and

          formalin.


          Since sediment deposition is very variable temporally and spatially

          in an estuarine environment, concentrations were converted to fluxes

          for a meaningful comparison between different time intervals in and

          among cores (Brush, 1989). Thus pollen and seed fluxes (no./cml/yr)

          for individual intervals in the cores were obtained by multiplying
          their concentration (no./ cm 3 )"by the appropriate sedimentation

          rates (cm/yr).



          Total and organic carbon, nitrogen and phosphorus:


          TOC was measured by the method of Krom and Berner (1983). Samples

                                             0
          were first dried overnight at 105 C and then finely ground with mor-

          tar and pestel. A portion (1-2 g) from the ground sample was ashed

                                                                t; Ii rl -r- o A a
          for 16 hours at 450 C in a muffle furnacan_-                      nd the

          ashed samples were run for percent total carbon on    a Carlo Erba CNS







           analyzer at the Maryland Geological Survey. The difference between

           the two measurements gave-percent total organic carbon. Total and

           total organic nitrogen were obtained in a similar way.


           Total phosphorus was measured by first digesting the sediment with

           70% perchloric acid on a digestion block for 75 minutes (Sommers and

           Nelson, 1972) and then analyzing the digestant for total P on a

           spectrophotometer using the.Murphy and Riley (1962) method. This--------.--

           method is also recommended for total P analysis by Standard. Methods,

           1989 edition. Total organic phosphorus-was determined-by-treating

           ashed and unashed portions of the sediment sample with sulfuric acid

           and analyzing both for orthophosphate. organic P is the difference

           between orthophosphate in the ashed and. unashed samples.





           RESULTS



           Sedimentation rates in this area since European settlement are not

           only high but also vary considerably over short distances (Appendix

           1). Calculations of sedimentation rates for individual intervals
           show that Jug Bay has experienced Variable sediment influx over

           time. Big storm events increase sediment influx into the marsh and

           estuary by many fold. This is reflected in the cores where sediment-

           ation rates in this period increase to as high as 1.3 cm/yr

           (Appendix 1).

           reported in a Delaware freshwater tidal marsh during the increased

           storm activity of 1954-65 (Orson et al, 1990).


           Arboreal pollen, especially oak,--hicI-cr--,-                       pine





                                         -12-


          is well represented in the cores and reflects the species growing in

          and around Jug Bay. However, there are some species such as

          Liriodendron tulipifera (tulip poplar) which, although present in

          the area, do not leave any pollen record in the sediment. The same

          is true of marsh plants like Peltandra virginica and Sagittaria

          latifolia. Also, pollen of SAV, except forPotamogeton, was not

          detected in the cores. Other marsh plants like Typha, Impatiens,

          Nuphar and Gramineae are well-represented in the pollen record.


          Arboreal pollen, as a percentage of total pollen sum, decreases

          above the 1650 agricultural horizon and increases below it. This

          reflects forest clearings by settlers for agriculture. It reaches a

          minimum in the nineteenth century when between 40 to 50% of the land

          was cleared and then increases a-ain in the twentieth century.

          Pollen of Ambrosia and other composites which colonize open,

          disturbed habitats (Bazzaz, 1974) also increases in the l3th and

          19th centuries. The ratio of oak to ragweed pollen, which is a

          measure of land clearance (Brush and Davis, 19S4), reaches a minimum

          value in mid-nineteenth century, reflecting large tracts of

          previously forested. areas brought under cultivation. at that time.


          Seeds in all four cores are generally well preserved. The most

          frequently found seeds are Cyperaceae and Gramineae, followed by

          Polygonum arifolium, Peltandra virginica, Bidens laevis and Acnida

          cannabina. There were very few seeds of Pontederia cordata in the

          cores even though this species grows abundantly in the marsh. This

          may be because its seeds disintegrate more easily than those of

          other species. Seeds of Zizania aquatica and Leersia oryzoides were

          also present in small numbers in all the cores.




                                          _13-




          In contrast to the pollen record, SAV was well represented in the

          seed profile. The most abundant were Zanichellia palustris, Potamo-

          geton diversifolius, Elodea canadensis and Najas guadalupensis.


          Nutrient data for the cores indicate that there has been an increase

          in sedimentary nitrogen and phosphorus at Jug Bay in post-cultural

          period. This increase is closely related to the total organic carbon

          content of the sediment in the marsh cores (r=0.61).



          Analysis of Core JUG I


          Sedimentation rates - JUG 1 is a high marsh core and. 149 cm long.

          The 1650 horizon is found at 83 cm and the 1840 horizon at 66 cm.

          Average sedimentation rate for this core in the post-European era

          are - from 1840 to the present 0.44 cm/yr and from 1650 to 1840,

          0.09 cm/yr. The lowest portion of the core (148-149 cm) has a C-14

          date of 1,540 ï¿½ 100 yr B.P. However, sedimentation rates for

          individual intervals vary considerably around these averages. For

          example, rates as high as 1.30 cm/yr are recorded in this core and

          appear to be related to storm activity in the area around 1954-55,

          as determined from historical'records. They rise to 0.55-0.61 cm/yr

          during the inid-lFOOs when agricultural activity in the area was at

          its maximum. Another maximum is seen during the mid-1900s when the

          Patuxent watershed was und-e r-goi-n.-g- - ur-ba-niz-ation
                                          L>

          Wolman (1967) found that areas experiencing construction yield

          several hundre,1 times more sediment than those that are forested or

          farmed, but after completion of development and construction,

          sediment yields decline to low values-.-4e-c-@-ase in seriimentation






                                         -14-



          rates,toware@s the top of this core may be partly explained by

          urbanization and partly by the presence of second growth forests.


          Pollen - All pollen types identified. in this core are shown in

          Table 1. The most abundant and persistent pollen in this core is of

          the grasses, mostly Zizania and Phragmites. It occurs down to the

          lowest level but increases in abundance from about 95 cm upward,

          comprising >15% of total pollen in succeeding intervals, and >20% in

          the top 70 cm. This increase suggests two things. First, the marsh

          had come into existence around 300 years ago and second, ecoloSic-

          ally disturbed habitat due to human activities in the area

          encouraged the establishment of Phragmites (reedgrass) in the marsh,

          which contributed to the significant increase in grass pollen in the

          upper 55-60 cm. Other numerically significant ( >5% of total nollen)

          species is Typha, though it is absent from about 90 cm doT..7n. It

          reaches its greatest abundance   >10% of total pollen) in the top 30

          cm. Pollen of Impatiens is present sporadically from the top of the

          core to 85 cm. These are all high marsh species (Odum et al, 1984)
          which sug-ests that this site has been high marsh for the past 300@

          years or so. Smaller numbers, < 3% of total, of Nuphar pollen are

          also found in the upper 80 cm but increase in the lower part of the

          core (Fig.5) . Cyperaceae pollen shows a reciprocal relationship

          with Gramineae, increasing in the lower 30 cm and decreasing upward

          in the core. Such trends indicate higher water levels at this site

          in precultural times.


          Changes in vegetation and land use taking place in the watershed are

          also reflected in the pollen profile, with Ambrosia and other

          composites like Chenopodium increasing and arboreal taxa decreasing






                                           -15-


          sharply with the advent of agriculture in the region. Towards the

          top, there is a slight relative decrease in Ambrosia and increase in

          arboreal, especially Quercus, Carya and Pinus, pollen influx, again

          reflecting declining agricultural activities in the region in recent

          decades. Oak/ragweed pollen ratio depicts this trend (Fig. 1).



          Seeds - All the seed species found in JUG 1 are shown in Table 1.

          The most abundant seeds were those of Gramineae, Polygonum arifolium.

          and Bidens laevis (over 25 per 100 ml). Arboreal seeds were few and

          sporadic. The number of all SAV seeds was small, under 10 per 100

          ml, except from 115 cm to the bottom of the core, where there is a

          slight increase in their number (ï¿½ 10-per 100 ml). Almost no SAV

          seeds are found in the upper few intervals.


          The seed record of JUG 1 indicates that this site has been high

          marsh for the past three centuries or so and thus supports the

          pollen record. The increase in LSAV.seeds in the lower part of the

          core was found statistically significant (p<0.05), using the Mann-

          Whitney test (Snedecor and Cochran, 1967). This su.-gests, like the

          pollen record, that water level was higher here in the pre-cultural

          period. Thus low marsh, or even open water, may have existed

          previously at the present high marsh site. Froomer (1980) reports

          that in many Chesapeake estuaries, post-European sed-im,@@nt deposit-

          ional rates have created new marshes in previously open water

          areas. This is the most likely-cause of change from low to high

          marsh at this site. Decrease of SAV seeds in the upper intervals is

          probably due to the onset of eutrophication and reduction of SAV

          population in the region.





                                             -16-


          Nutrients - Variation of % TOC, N and P with depth in JUG.1 is

          shown in Fig. 2 and Table 5. Before mid nineteenth century, ie,

          below 50 cm, all three parameters are more or less constant, with

          the exception of an increase around 94-96 cm. The reason for this is

          not known, but there may have been allochthonous input of organic

          matter and associated N and P due to increased runoff from a storm

          or flood. There is an increase in their value between 50cm ana the

          surface layer, most probably resulting from increased enrichment of

          the estuary by farming and urbanization in the watershed. A-higher

          value for TOC in the upper 2-3 centimeters is most likely due to the

          freshness of organic matter in surface layers. However, P decreases

          in the top 0-5 cm, reflecting a decrease in the amount of nutrients,

          especially phosphorus, entering the estuary. One of- the reductions

          comes from the removal of P from the effluent discharged by the

          nearby wastewater treatment plant since the early 1980s (Western

          Branch Wastewater Treatment Plant staff, pers. comm.)



          Analysis of core JUG 3


          Sedimentation rates      This is  a low marsh core, 107 cm long, fron

          the north side of the railroad    bed. The 1650 A.D. horizon occurs at

          88 cm and the 1340 horizon at 70 cm. So the average sedimentation

          rate from 1840 to the present is 0.47 cm/yr and from 1650 to 1840 it

          is 0.10 cm/yr. Individual se imentation rates vary, being lower in

          the upper intervals of the core and higher in the lower intervals.

          (Appendix 1).


          These values again clearly reflecc charigiffk@-I-@@nd--use-in r-he-Jug Bay

          area, with low rates when the land was forested and high rates when


                                                -17-

it was cleared for agriculture. A sharp increase in sediment input rate around 8-9 cm(0.61 cm/yr) may have been caused by 
heavy runoff following three hurricanes in 1954-55 (Ashbaugh and Brancato, 1958).Pollen- The pollen taxa identified here 
are similar to those of JUG 1(see Tables 1 & 2). However, the relative abundances of the taxa are different.Grasses 
comprimise a significant percentage of total pollen, but Nuphar and Nymphea pollen is much more abundant than JUG 1.
Arboreal pollen of Quercus, Pinus,Carya,Alnus,Betula,Acer,Juglans and Liquiambar is also present but exept for Quercus, no 
pattern is seen.Ambrosia, Chenopodium, Dryopteris ans Solidago are among the more abundant non-arboreals (5-10%of total pollen).
Typha percentage in much lower (5%) than JUG 1 and is virtuall absent in lower 30 cm or so.This, and a high percentage (15%)
of Nuphar and Nymphea pollen throughout the core indicates that low marsh or open, shallow water conditions have existed 
here in the last 1000 years represented by the core.Minimum oak/ragweed ratio occurs from 60 upto 30 cm (Fig. 3), reflecting 
height of agriculture activities in the region.Decline in agricultural land is shown by increasing pollen arboreal pollen and 
oak/ragweed ratio  in the upper part of the core.Seeds- Seed record in this core also shows a low marsh/open water environment
in the past three centuries.Most abundant seeds are Potamogeton, Peltandra virinica and Gamineae (>30 per 100ml).A few sporadic
seeds of Bidens laevis and Acnida cannabina are also present.SAV seeds are abundant(>25 per 100 ml)until the upper 5 cm where
they become very rare.Aroreal seeds occur infrequently (approx.1-2 seeds per 10 cm).very few seeds are preserved below 90

                                           -18-


cm, so it is hard to interpert conditions in pre-European times.However, judging by the pollen record of lower marsh/open water
habitat at that time, one would expect to find  more SAV seeds here.The reason for their absence is not known.A list of all seed
specimens recovered from JUG 3 given in Table 2.Nutrients-The nutrient profile for JUG 2 (Fig.4 and Table 6) shows a decrease 
in TOC, N and P in the sediment between 30 and 50 cm. This decrease occurs in spite of increasing euthrophication in the area.Apart
from this, no other clear pattern is discernible.The levels of TOC and total n in this core are consistently lower than JUG 1.

Analysis of core JUG 

Sedimentation rates-This core was taken at the influence of Western Branch and Patuxent rivers.It is 127 cm long and its 1650 
horizon id located at 86 cm and the 1840 horizon at 62 cm. The average sedimentation rate for that period 1840-1990 is 0.41 cm/yr
and for the period 1650-1840 it is 0.13 cm/yr.Before 1650 sedimentation rates are assumed even lower. Changing land use patterns 
are reflected in thge individual sedimentation rates.Very high rates are attained in the mid 1800s during maximum land clearence 
for agriculture and in the mid 1900s when heavy urbinisation of the watershed was taking place.They decline in the last three
decades due to less land under agriculture,regrowth of forests and completion of urbanisation in the region (Appendix 1).  





                                           _19-


           Pollen    The pollen taxa found in JUG 5 are given in Table 3. All

           the taxa in this core are similar to those in JUG 1, which is a high

           marsh core (see Table 1). However, relative abundances of various

           pollen species are more like those of JUG 3 than of JUG 1. In JUG 5,

           very little Typha pollen is found (< 5% of total pollen); many

           intervals do not have any Typha pollen at all. On the other hand,

           pollen of Nuphar in this core is much more numerous than in JUG l.-

           It increases steadily from the bottom of the core to about 70 cm and

           then remains a significant part of total po_llen_(13_l60fl)__to th@e_ top

           of the core. Fig. 5 shows the difference between JUG I and JUG 5.


           More Cyperaceae pollen isfound in this core than in JUG 1.

           Gramineae are also represented here but they do not comprise more

           than 10% of the total pollen in-any interval, in contrast to the

           marsh core. There is no significant difference in the abundance of

           arboreal pollen between JUG 5 and JUG 1 (p=0.17), although Quercus

           and Pinus pollen increases significantly around 95-100 cm. Ambrosia

           and Chenopodium pollen increases in the 19th century and decreases

           slightly in recent decades.


           The oak/ragweed ratio of JUG 5, like that of the marsh cores,   shows

           land use changes taking place in the region since European

           settlement, from limited land clearance in the 17th century to

           maximum in the 19th and adecl-iffe-iri- cu ivate                   mid

           20th century onward (Fig.6).


           Greater abundance of deeper water species like Cyperaceae and Nuphar

           throughout this core suggests                                   open

           water since the precultural era. A C-14 date on the lowest interval






                                         -20-



          of this core is not available, but it is reasonable to assume,

          judging from the C-14 date on JUG 1, that JUG 5 represents at least

          1000 years of environmental record. The small number of grass pollen

          found in this core most likely was blown in from the nearby marsh,

          as was the pollen of high marsh taxa like Impatiens, Typha, Rosa and

          Dryopteris. Increase in Quercus and Pinus pollen around 900 B.P.

          suggests a drier period in this area and may be associated with the

          Medieval Warming Period of 1000-140O.A.D. (Ingram et al, 1981).



          Seeds - Taxa represented by seeds in this core are the same as

          those in JUG 1 and JUG 3. However, there are more streambank emer-

          gents and SAV seeds in JUG 5 than in JUG 1. The most abundant seeds

           >20 per 100 ml) through most of the core are those of Potamogeton,

          Cyperaceae spp., Elodea canadensis, Zanichellia palustris'and N@,@

          guadalupensis. In the 19th century, species that grow in moderately

          eutrophic waters such as Zanichellia palustris and Potamogeton

          diversifolius (Hellquist, 1975), appear in the record. But in the

          top layers even these species disappear. This reflects increased

          eutrophication of waters around Jug Bay with the introduction of

          sewage treatment facilities in the area'in the late 1960s to early

          1970s. Further reduction in the SAV population occurred after the

          tropical storm Agnes passed through in 1972. There are very few

          seeds in the top 3-4 cm, and none of Najas and Elodea.


          Nutrients - The P profile presents a good record of environ-

          mental conditions in this part of the estuary through time'. Fig. 7

          and Table 7 show a rise in P around late 19th century (50-40 cm) and

          then again in the 1960s and 70s (10-5 cm). The first increase is the






                                         -21-



          result of fertilizer runoff from the watershed, where they were in

          common useage at this time. The second rise reflects enrichment of

          the tributary from wastewater effluent and from domestic and

          industrial sources further up the estuary. The slight decrease in

          nutrients, notably phosphorus, in the upper few cm of the core

          resulted from controls on the use of P, in the early 1980s, in

          domestic products like detergents and also its removal from treated

          effluent of the Western Branch treatment plant since the mid-80s.

          TOC variation corresponds closely with that of P and is most likely

          due to increased algal productivity in the estuary. Nitrogen values

          are small and do not show a clear trend.




          Analysis of Core JUG 7


          Sedimentation rates - This core, taken downstream from Jug Bay in

          the estuary, is 190 cm long. The 1650 horizon is located at 92 cm

          and the 1840 horizon at 73 cm. Average sedimentation rate@from 1840

          to the present is 0.49 cm/yr and from 1650 to 1840 this rate i-s 0.11

          cm/yr. As in the other cores, individual sedimentation rates are

          variable, and are affected by chaiiing land use and storms.
                                            IN


          Pollen - The pollen taxa of JUG 7 (Table 4) are similar to those of

          JUG 5 in that among the non-arboreal taxa, the most common are

          Cyperaceae, Nuphar and Nymphaceae, with fewer but persistent grains

          of Gramineae, Dryopteris and Polypodiaceae. High marsh species like

          Typha, Impatiens, Rosa and Bidens are found sporadically and in

          small numbers (< 5% of total pollen). Representation of arboreal

          pollen is similar to other cores, with oak, pine and hickory

          constituting the largest portion. There is a considerable increase






                                          -22-


          (from,- 10% to >25% of total pollen) in oak and pine pollen at 115

          cm which persists upto 120 cm.


          The pollen record shows that the site has been under shalllow water

          continually for the length of time represented by the core. This

          time will be known as soon as a C-14 date on the lowest part of the

          core-is available. There is no evidence, such as abundant pollen of

          higher ground species, that this site was ever a supratidal zone. it

          is hard to say however, from the pollen record, whetherthe-water

          was deeper at any time in the past than it is now. The increase in

          oak and pine pollen at 115-120 cm, about 1000 years ago, points to

          drier conditions in the region at that time. This is similar to the

          trend seen in JUG 5.


          Seeds - Seeds (Table 4) of Najas guadalupensis, Potamogeton

          diversifolius and Elodea canadensis are abundant in JUG 7 in

          intervals covering the time be-fore European settlement and up until

          early 20th century. Zanichellia palustris appears in late 19th

          century and persists in. considerable numbers until the 1970s.

          Towards the top 5 cm, very few seeds of any SAV species are present.

          A moderate number (10-20 per 100 ml) of grass seeds are also present

          which were presumably carried and deposited here by tidal waters.

          The few seeds of Acnida cannabina, Alnus serrulata, Polygonum

          punctatum, Pontederia cord-ata afi'd _'_Z_iza_n_i_a___a_q dati c a----f ou -nd- -I--n---s-d-m--e-

          intervals also seem to be deposited here by tidal currents.


          The seed record of JUG 7 indicates, like that of JUG 5, that there

          has been a sharp reduction 'in SAV              ju-Bay - in rer-ent

          decades. The abundance of SAV seeds deeper down in the core supp-






                                         -23-


          orts evidence from the pollen profile that this site has been sub-

          merged for the entire time period represented by the core.


          Nutrients - N and P in this core show an interesting pattern

          (Fig.9 and Table 8). Their % values are low before mid 19th century.

          Thereafter they begin to rise steadily between 50 and 30 cm and

          then decrease between 20 to 5 cm. In the top 4 cm their fluxes

          slightly increase again. This increase is significant (p<0.05). TOC

          variation corresponds closely with those of total N and-Palthough

          its value is much lower compared to JUG 1 and JUG 3. The nutrient

          record more or less reflects the history of eutrophication in the

          region, except for the 5-20 cm interval. This trend appears to be

          related to marsh influence and will be discussed next.




          DISCUSSION AND CONCLUSIONS


          All the cores show a well-preserved pollen and seed record, except

          in the lower 15 cm of JUG 3 where almost no seeds are found.

          Sedimentation rates andpollen and seed assemblages in these cores

          reflect changing environmental conditions in the Jug Bay region,

          particularly land use and varying water levels and storms. However,

          effects of all the historical'ly recorded storms and hurricanes on

          sediment influx in Jug Bay were not found in the sedimentary record.

          The clearest effect of

          for the heavy storms of 1954-55 in JUG 1 and JUG 3.


          Such heavy influxes of sediment in a short period of time are accom-

          panied by a decrease in the

          substrate, like the one at 10 cm (Fig. 2 an(i Table 5). This is due






                                         -24-



          to the dilution of organic content of marsh substrate by large

          amounts of mineral sediment brought in with storm runoff and

          deposited on the marsh surface. Such an effect is not seen in the

          estuarine cores where the organic content of sediments is already

          low compared to those of the marsh.


          High sedimentation rates in the post-cultural period have given rise

          to infilling of marshes and open water areas. The tendency of

          marshes to progress from low to high elevations over time is well

          documented (Redfield, 1972). This trend is visible at Jug Bay also.

          Here, previously low marsh or open, shallow water areas have turned

          into high marsh. It is quite likely, judging from the stratigraphic

          record, that the present low marsh will be raised and become a high

          marsh environment in the next couple of hundred years. The high

          marsh may eventually turn into forested floodplain. The time for

          this transformation will be shortened if sedimentation rates rise

          again in the future; if not, this time will be lengthened, provided

          factors such as sea level or precipitation do not vary much.


          Other environmental changes induced by man, namely eutrophication of

          the Patuxent estuary, can be seen more clearly in the high marsh

          (JUG 1) and the estuarine cores (JUG 5 and JUG 7) than in the low

          marsh core (JUG 3). Moreover, TOC and P show a -clearer trend in

          the estuarine cores than does N. This may be because, in estuaries,

          some nitrogen is inevitably lost via denit'rification (Smith and

          DeLaune, 1983). However, eutrophication of incoming waters in the

          last 60-70 years have resulted in elevated levels of nitrogen in the

          high marsh core. In the marsh, a large proportion of incoming

          inorganic nitrogen is incorporated in the organic matter and gets


                                                      -25-


recycled internally. Phosphorous fkuxes show a corresponding increase.TOC also rises, most likely due to the increased primary
productivity in the marsh has been affected by upstream pollution, experiencing an increase in biomass and acting as a long term 
sink for at least a portion of the incoming N and P.The low marsh core does not show any clear pattern (Fig. 4). TOC, N and P
are consistenty low and do not increase in responce to cultural eutrophication in the region.In the low marsh, decomposition 
rates and flushing of litter are greater than in high marsh (Odum, 1988) so that very little becomes incorprated into the 
sediment, resulting in low organic and peat content. Reaserch, on the other hand, has shown that a greater amount of nutrients,
especially P, are retained by organic and peatry sediments than by  largely inorganic sediments (Zoltek et al; Dolan et al, 1981).
This may explain why no change in nutrients was observed in JUG 3 when the estuary became eutrophic. Another possibility is that 
this part of the marsh may be a sick for nutrients only on a seasonal basis, with uptake by plants occuring in the growing deason 
and export during dieback af vegitation in the winter.But this cannot be confirmed by the sedimentary record.JUG 5 has preserved 
the best record of anthropogenic eutrophication.The strongest correspondence with historical record of eutrophication is 
shown by TOC and P. No trend is observed for nitrogen. Comparing its profile with that of JUG 1, it can be seen that both 
cores can register a rise in P at about the same time.Thus nutrient pollution in the region affected both the marsh and the estuary.
  





                                         -26-



          upstream from it.


          It is also interesting to compare nutrient profiles of JUG 1 and JUG

          7. There is a rise in TOC, P and N in JUG 7 around late 1800s (40

          cm), when a similar rise occurs in JUG 1 and JUG 5. This increase

          continues for a few years (40 to 30 cm) and then begins to decline

          (20-5 cm). Such trends indicate that the marsh did not protect

          downstream water quality throughout its history. However, its

          nutrient retaining capacity increased with time so that finally the

          downstream water quality seems to improve. This may be a result of

          increasing biomass from elevated levels of nutrients in the marsh

          leading to sediment richer in organic and peaty material (Fig.2) and.

          of greater quantities of Fe, Al and Mn oxides in the sediment as a

          result of upland erosion and increased sedimentation. These three

          substances bind P very well (Patrick and Khalid, 1974; Richardson,

          1985). Hence it seems that higher nutrient and sediment influx into

          the marsh initially enhances its ability to protect estuarine water

          quality.


          Towards the top of JUG 7, nutrient values show an increase, in spite

          of the fact that efforts have been made in recent years to control

          nutrient input into the estuary. A possible explanation for this is

          that the marsh is no longer acting as a long term sink for nutrients

          so that all of the upstream nutrient discharge (albeit smaller than

          before) is going downstream past the marsh. This may be because the

          marsh is no longer nutrient limited, its organic proOuction has

          levelled off or perhaps even the chemical nature of the soil has

          changed, ie, the P binding substances in the soil have diminished

          through leaching or other chemical processes. All these factors may





                                          -27-


          have exhausted the marsh's capacity to assimilate additional

          nutrients on a permanent basis. The marsh vegetation may also be

          trapping less nutrients than before since nutrient limitation in the
          marsh does not exist anymore. Therefore.' at present there appears to

          be no significant'difference in water quality upstream and down-

          stream from the marsh.


          The effect of vegetation on nutrient trapping ability of the marsh

          seems to exist only insofar as higher marsh plants produce a peatier

          sediment than do low marsh plants. It is not possible to conclude,

          from the sedimentary record, if individual plant-species differ in

          their nutrient entrapment abilities, which may well be the case.


          The results of this study indicate that the stratigraphic record can

          be used to study the effects of changing environmental conditions on

          the marsh through a longer period of time than is otherwise

          possible. Such information is useful in evaluating the response of

          the ecosystem to environmental changes occurring at present and

          predicting its reponse to changes in the future.












          Addenda to the   Final Report'- The Effects of Anthropogenic Activi-
          ties and Natural Events on a Freshwater Tidal Marsh".


          The seed record of core JUG1, taken from the high marsh, shows an
          increase in SAV below 115 cm. There are very few SAV seeds above
          this interval. This suggests a higher water level at this site prior
          to European settlement.'The submerged aquatics represented by seeds
          in this core include Elodea canadensis, Najas guadalupensisL
          Potamogeton diversifolius and Zanichellia palustris. These plants
          typically grow along the channel edges where, at Jug Bay, water
          depth at low tide is 40-50 cm. They are also found further into the
          channel at water depths of upto 2 meters, if the turbidity is not
          too high (Odum et al, 1984). In contrast, high marsh species such as
          Bidens laevis, Gramineae and Polygonum arifolium, which are more
          abundant from 115 cm to the top of the core, do not survive in
          continously flooded conditions (Simpson et al, 1983a). They grow
          best where maximum water depth is 20-30 cm, but frequently falls
          close to zero, such as during low tide. Thus the presence of greater
          number of SAV at this site below 115 cm, as shown by the seed
          record, indicates that water here would have been at least 20 cm
          deeper than today with almost permanent inundation, representing
          stream edge conditions. However, since SAV can grow in water depths
          of upto 2 meters, water level at this site may well have been 50-100
          cm higher around 300 years ago, but this cannot be verified from the
          seed record. It can be concluded, however, that within three centu-
          ries this site has evolved from a continously submerged habitat,
          with water levels at least 20-30 cm higher than today, to a high
          marsh environment where alternate flooding and draining of the
          surface takes place.





                                          -28-



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                                                   0
           and saline estuarine sediments. J. Environ. Qual. 12: 514-518.

           Snedecor, G.W. and Cochran, W.G. 1967. Statistical methods. The Iowa
           State University Press, Ames, Iowa.----

           Sommers, L.E. ana Nelson, D.W. 1972. Determination of total
           phosphorus in soils: a rapid perchloric acid digestion procedure.
           Soil Sci. Soc. Am. Proc. 26: 902-904.

           Tilton, D.L. and Kadlec, R.H. 1979. The utilization of a freshwater
           wetland for nutrient removal from secondarily treated wastewater
           effluent. J. Environ. Qual. 8: 328-334.

           Tiner, R.W. Jr. 1985. Wetlands of Delaware. US Fish Wildl. Serv. and
           Delaware Dept. Nat. Res. Cooperative Publication. 77 pp.

           Watts, W.A. and Winter, T.C. 1966. Plant macrofossils from Kirchner
           Marsh, Minnesota - a paleoecological study. Bull. Geol. Soc. Am..
           77: 1339-1359.

           Whigham, D.F. and Simpson, R.L. 1976. The potential use of
           freshwater tidal marshes in the management of water quality in the
           Delaware River. In Biological Control of Water Pollution (Eds. J.
           Tourbier and R.W. Pierson). Univ. Penn. Press, Philadelphia.

           Whigham, D.F. and Simpson, R.L.-1980. The effect of sewage effluent
           on the structure and function of a freshwater tidal marsh ecosystem
           Tech. Compl. Rep., US Dept. Int., Office of I-later Re.s. Tech. Proj.
           B-60-NJ. 159 pp.

           Wolman, M.G. 1967. A cycle of sedimentation and. erosion in urban
           river channels. Geogr. Annal. 49A: 385-395.

           Zoltek, J., Bayley, S.E., Hermann, A.J., Tortora, L.R. and Dolan,
           T.J. 1979. Removal of nutrients from treated municipal wastewater
           by freshwater marshes.. Final report to City of Clermont, Florida.
           Center for Wetlands, University of Florida, Gainesville.







                                   7.













                                                                                 4




                                                                    SENIORS
                                                                     TRAIL






                                                                                        01


                                                                                              7@:


                                           Dr     IL

                                                                                 4t,
                           OA   RR            -7 14 L"._ .1








                                                                                                      JUG BAY
                                                        "OB
                                                                                               WETLANDS SANCTUARY
                                                                                                    TRAIL  GUIDE

                                                            W OR   TED
                                                                SWAMP
                                                                                                       WOODLANDS
                                                                TRAIL
                                                                                                                        .7z
                                                                                                       WETLANDS


                                                                                                       MEADOW


                                                                                                       PARKING

                                                                                A
                                                                                                       NATURECENTER





                                                                         7, @l








                                                       'ru& 7

                                                                                                     MAP SCALE IS I "=780'

                     MAP OF JUG BAY SHOWING LOCATION OF CORES





                                                 -32-






                Table 1. Pollen & Seed Taxa identified in JUG 1.




                Pollen                                           Seeds



                Arboreal:                                        Arboreal & nonarboreal
                                                                 emergents:
                Acer (maple), Alnus (alder)
                Betula (birch), Carya (hickory)                  Acnida cannabina
                Castenea (chestnut), Cornus                      (water hemp)
                (dogwood), Corylus (hazel)                       Alnus (alder)
                Fraxinus (ash), Ilex (holly)                     Bidens laevis (burmarigold)
                Juglans (walnut)                                 Betula nigra (river birch)
                Liquidambar (sweet gum)                          Carex spp. (sedges)
                Nyssa (black gum)                                Carya (hickory)
                Pinus (pine), Prunus (cherry)                    Gramineae (grasses)
                Quercus (oak), Salix (willow)                    Polygonum arifolium
                Tilia (linden)                                   (tearthumb)
                                                                 Polygonum punctatum
                                                                 (water smartweed)
                                                                 Pontederia cordata
                Non-arboreal:                                    (pickerelweed)
                                                                 Rubus (bramble)
                Ambrosia (ragweed)                               Sagittaria latifolia
                Artemisia (mugwort)                              (arrowhead)
                Bidens (burmarigold)                             Zizania aquatica (wild
                Chenopodium (pigweed)                                                rice)
                Cyperaceae spp. (sedges)
                Dryopteris (wood fern)
                Gramineae spp. (grasses)                         SAV:
                Impatiens (jewelweed)                            Elodea canadensis
                Lycopodium (club moss)                           (common elodea)
                Nuphar (spatterdock)                             Najas guadalupensis
                Nymphea (water lily)                             (naiad)
                Osmunda (fern)                                   Potamogeton diversifolius
                Plantago (plantain)                              (pondweed)
                Polypodium (polypody)                            Zanichellia palustris
                Rosa (marsh rose)                                (horned pondweed)
                Solidago (goldenrod)
                Typha (cattail)
                Umbelliferae (parsley family)
                Viburnum (arrowwood)





                                                -33-






                Table 2. Pollen and Seed taxa identified in JUG 3.




                Pollen                                             Seeds



                Arboreal:                                          Arboreal & Non-arboreal
                                                                   emergents:

                Acer (maple), Alnus (alder)                        Acnida cannabina
                Betula (birch),                                    (water hemp)
                Carya (hickory)                                    Alnus (alder)
                Castanea (chestnut)                                Bidens laevis----------
                Cornus (dogwood)                                   (burmarigold)
                Fraxinus (ash),                                    Carex spp. (sedges)
                Ilex (holly)                                       Gramineae (grasses)
                Juglans (walnut)                                   Polygonum arifolium
                Liquidambar (sweet gum)                            (tearthumb)
                Nyssa (black gum)                                  Polygonum punctatum
                Pinus (pine)                                       Pontederia cordata
                Platanus (sycamore)                                (pickerelweed)
                Prunus (cherry)                                    Sagittaria latifolia
                Quercus (oak)                                      (arrowhead)
                Salix (willow)                                     Zizania aquatica (wild
                                                                                       rice)

                Non-arboreal:                                      SAV:

                Ambrosia (ragweed)                                 Elodea canadensis
                Artemisia (mugwort)                                (common elodea)
                Bidens (burmarigold)                               Najas guadalupensis
                Chenopodium (pigweed)                              (naiad)
                Cyperaceae (sedges)                                Potamogeton diversifolius
                Dryopteris (wood fern)                             (pondweed)
                Gramineae (grasses)                                Zanichellia palustris
                Impatiens (jewelweed)                              (horned pondweed)
                Lycopodium (club moss)
                Nuphar (spatterdock)
                Nymphea (water lily)
                Plantago (plantain)
                Pteridium (bracken fern)
                Rosa (marsh rose)
                Solidago (goldenrod)
                Stellaria (chickweed)
                Typha (cattail)
                Umbelliferae (parsley family)
                Viburnum (arrowwood)





                                                 -34-





                Table 3. Pollen and Seed taxa identified in JUG 5.




                Pollen                                              Seeds


                Arboreal:                                           Arboreal & nonarboreal.
                                                                    emergents:

                Acer (maple)                                        Acnida cannabina
                Alnus (alder)                                       (waterhemp)
                Carya (hickory)*                                    Alnus (alder)
                Castanea (chestnut)                                 Bidens laevis
                Fraxinus (ash)                                      (burmarigold)---
                Juglans (walnut)                                    Carex spp. (sedges)
                Liquidambar (sweet gum)                             Cyperaceae (sedges)
                Nyssa (black gum)                                   Gramineae (grasses)
                Pinus (pine)                                        Polygonum punctatum
                Platanus (sycamore)                                 (smartweed)
                Quercus (oak)                                       Pontederia cordata
                Salix (willow)                                      (pickerelweed)
                Tilia (linden)                                      Zizania aquatica
                                                                    (wild rice)


                Non-arboreal:                                       SAV:

                Ambrosia-(ragweed)                                  Elodea canadensis
                Artemisia (mugwort)                                 (common elodea)
                Biden!4 (burmarigold)                               Najas guadalupensis
                Chenopodium (pigweed)                               (naiad)
                Cyperaceae (sedges)                                 Potamogeton diversifolius
                Dryopteris (wood fern)                              (pondweed)
                Gramineae (grasses)                                 Zanichellia palustris
                Lycopodium (club moss)                              (horned pondweed)
                Nuphar (spatterdock)
                Nymphea (water lily)
                Plantago (plantain)
                Rosa (marsh rose)
                Solidago (goldenrod)
                Stellaria (chickweed)
                Typha (cattail)
                Umbelliferae (parsley  famiiy).






                                                -35-






                Table 4. Pollen and Seed taxa identified in JUG 7.




                Pollen                                            Seeds



                Arboreal:                                         Arboreal & nonarboreal
                                                                  emergents:

                Acer (maple)                                      Acnida cannabina
                Alnus (alder)                                     (waterhemp)
                Betula (birch)                                    Alnus (alder)
                Carya (hickory)                                   Bidens laevis
                Castanea (chestnut)                               (burmarig6ld)
                Cornus (dogwood)                                  Carex spp. (sedges)
                Fraxinus (ash)                                    Cyperaceae (sedges)
                Juglans (walnut)                                  Gramineae (grasses)
                Liquidambar (sweetgum)                            Polygonum punctatum
                Nyssa (blackgum)                                  (smartweed)
                Pinus (pine)                                      Pontederia cordata
                Platanus (sycamore)                               (pickerelweed)
                Prunus (cherry)                                   Zizania aquatica (wild
                Quercus (oak)                                                      rice)
                Salix (willow)
                Tilia (linden)



                Non-arboreal:                                     SAV:


                Ambrosia (ragweed)                                Elodea canadensis
                Artemisia (mugwort)                               (common elodea)
                Bidens (burmarigold)                              Najas guadalupensis
                Cephalanthus (buttonbush)                         (naiad)
                Chenopodium (pigweed)                             Potamogeton diversifolius
                Cyperaceae (sedges)                               (pondweed)
                Dryopteris (wood fern)                            Zanichellia palustris
                Gramineae (grasses)                               (horned pondweed)
                Lycopodium (club moss)
                Nuphar (spatterdock)
                Nymphea (water lily)
                Plantago (plantain)
                Pteridium (bracken fern)
                Rosa (marsh rose)
                Solidago (goldenrod)
                Typha (cattail)
                Umbelliferae (parsley family)





                                                        -36-



                   Tab@ie 5. Nutrient data for JUG 1.


                   Depth (cm)               TOC                 Total N                   Total P


                       0                       17.33                  0.80                      0.16
                       5                       16.21                  0.81                      0.29
                     10                        14.79                  0.68                      0.15
                     20                        15.56                  0.77                      0.19
                     30                        13.71                  0.74                      0.20
                     40                        11.83                  0.64                      0.17
                     50                        --9.88-                0.61                      0.072
                     60                        6.51                   0.56                      0.077
                     70                        8.87                   0.53                      0.069
                     80                        7.09                 -0.49                       0. 07 1
                     90                        11.47                  0.78                      0.123
                     100                       8.53                   0.44                      0.049






                  Table 6. Nutrient data for JUG 3



                  Depth (cm)               TOC                  Total N                   Total P M


                       0                       9.89                   0.51                      0.16
                       5                       10.71'                 0.55                      0.14
                     l'O                       8.42                   0.49                      0.18
                     20                        8.79                   0.55                      0.19
                     30                        7.62                   0.32                      0.11
                     40                        7.88                   0.41                      0.10
                     50                        8.12                   0.43                      0.09
                     60                        10.'08                 0.48                      0.13
                     70                        11.21                  0.51                      0.15
                     80                        8.99                   0.50                      0.09
                     90                        10.45                  0.46                      0.11
                    100                        9.67                   0.43                      0.07





                  Note: % C, N and P are calculated as grams C, N and P per gram dry
                          weight sediment respectively.






                                                  -37-




                Table 7. Nutrient data for JUG 5.



                Depth (cm)            TOC                Total N                 Total P

                   0                      2.93                 0.25                    0.059
                   5                      3.33                 0.27                    0.063
                  10                      4.48                 0.22                    0.071
                  20                      3.09                 0.16                    0.051
                  30                      4.17                 0.18                    0.061
                  40                      4.26                 0.25                    0.082
                  50                      2.81                 0.20                    0.054
                  60                      3.56                 0.33                    0.048
                  70                      2.16                 0.22                    0.017
                  80                      2.25                 0.23                    0.004
                  90                      2.34                 0.18                    0.001
                  100                     2.09                 0.24                    0.006





                Table 8. Nutrient data for JUG 7.



                Depth (cm)           TOC                 Total N                 Total P

                   0                      4.01                 0.31                    0.041
                   5                      2.23                 0.30                    0.020
                  10                      3.01                 0.28                    0.025
                  20                      2.37                 0.18                    0.019
                  30                      4.11                 0.29                    0.060
                  40                      4.33                 0.27                    0.052
                  50                      3.06                 0.24                    0.028
                  60                      2.87                 0.21                    0.021
                  70                      2.45                 0.13                    0.005
                  80                      1.98                 0.17                    0.002
                  90                      2.05                 0.18                    0.003
                  100                     2.18                 0.11                    0.003




                Note: % C, N and P are calculated as grams C, N and P per gram dry
                       weight sediment respectively.






                                    38






                             Oak/Ragweed
                      0           10           20
                    0




                   20-



                 cD 40-

                 =r


                 0
                13, 60-


                   80-




                  100-




                 120


            Fig.l. Oak/Ragweed Pollen Ratio for JUG 1









                0.0       0.1      o.2      0.3                      0.0      0.1      0.2      .0.3
               0-                               1990                0                                1990


             20-                                                  20-

             40-                                1890              40-                               -1890

             60-                                                  60-
         0                                     1840                                                  1840
             So-                               1812               80                               -1812
                                               1776                                              -1776


            100-                                                  100


            120                                                   120
                    JUGI (high marsh)                                    JUG3 (low marsh)


                           1890    construction of railroad bed across the marsh
                           1840    40-50% land cleared for agriculture
                           1812    The War of 1812
                           1776    The Revolutionary War


                0.0       0.1      o.2     0.3                         0.0     0.1       0.2      o.3
              0- -                               1990                0                                1990


             20-                                                    20-

             40-                                1890                40-
                                                                                                     1890
             60-                                1840                60-
         01                                     1812
         a                                                                                          -1840
             80                                 1776                80-                         ---1812
                                                                                                    -1776

         CD
            100                                                    100-


                                                                   120
            120-
                  JUG5 (estuary upstream of    marsh)                  JUG7 (estuary downstream of
                                                                                            marsh)
                  Fig.l. % Total.P for cores   analyzed with timelines showing historic dates






            o.o o.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9               0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
                                              1990               0                                1990


          2o-                                                   20-

          40                                 1890               40-                             1890

                                                                60-
          60
                                             18W
                                             1812                                            --1812
          80-                       --1776                      80-                        -  -1776

                                                               100-
          100-
          1201                                                 120

                 JUG1 (high marsh)                                       JUG3 (low marsh)





               0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9             0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
            0                                  1990               0-                               1990


            20-                                                 20-


                                            -1890
           40                                                   40
                                                                                                  1890
         0  60-                                                 60-
                                              1840
                                             -1812                                                1840
                                          -- 1776
         (D  80-                                                80-                               1812
                                                                                                  1776

           100-                                                 100


          120                                                   120
               JUG5 (estuary upstream of marsh)                   JUG7 (estuary downstream of marsh)

                 Fig.2. % Total N for cores analyzed with timelines showing historic dates







            0 2 4 6 8 10 12 14 16 18                    0 2 4 6 8 10 12 14 16 18
          0--I   I  I I  I  I 1  1     1990            0-    1  g                  1990


         20-                                         20-


         40-                           1890          4o-                          1890

         60-                                         60-
        +1                           1840                                         1840
        P                            1812            80-                          1812
         80-                         1776                                       -1776
                       >                            100-
        100-
        120 L-                                      120
               JUG1 (high marsh)                            JUG3 Uaw marsh)




            0 2 4 6 8 10 12 14 16 18                    0 2 4 6 8 10 12 14 16 18
            0-                          1990           0-                         1990


          2o-                                        2o-

          4+0                          1890          40-
                                                                                  1890
          60                           1840          60-
                                     - 1812
                                                                                  1840
                                     - 1776
          80-                                        80-                          1812
                                                                                  1776

         100-                                       100-



         120                                        120
           ZUG5 (estuary upstream of marsh)            JUG7 (estuary downstream of marsh)
             Fig-3. % TOC for cores analyzed with timelines showing historic dates








                  0             10            20                    0            10            20
                0--                               1990             0-                             1990


               20-                                              20-


               40-                                1890          40-                               1890


               60-                                              .60-
                                                  18W                                            1840
                                                  1812
             0                                    1776          80-                               1812
               80                                                                                 1776


               100-                                             100-


              120                                               120

                       JUGI (high marsh)                                JUG3 (low marsh)




                                                                    0       10       20        30
                0        10       20       30                     0-                               1990
               0-                               1990


                                                                20-
             20-

                                               1890             40-
             40-
                                                                                                 1890
             60-                                                60-
                                                                                                 1840
                                               1812
                                               1776             80-                            -  1812
             80-                                                                               -  1776

                                                                100-
             100-


             120-                                               120

               JUG5 .(estuary upstream of marsh)                    JUG7 (estuary downstream of marsh)


                   Fig.4. Oak/Ragweed Pollen Ratio for cores analyzed with timelines showing
                           historic dates







                                                                                                   41







                                                                                               % Nuphar Pollen

                                                                         0                                  10                                 20
                                                                     0-




                                                                 20-




                                                                 40-
                                                           CD                                                                                         0-0- *0--0
                                                           _0                                                                                         z      z

                                                                 60-
                                                           0
                                                           3


                                                                                                                                                      C-     C-
                                                                                                                                                      c      C:
                                                                 80-                                                                                  G)     G)
                                                                                                                                                      Ln


                                                               100-




                                                              120


                                                             Fig.5. % Nuphar Pollen in JUG 1 and JUG 5






                                   42







                                    Oak/Ragweed


                           0       10       20       30
                          0-



                        20-




                        40-

                      0
                      CD

                        60-
                      0
                      3


                        80-




                       100-




                       120


                       Fig.6. Oak/ Ragweed -Po I I e-n-B-ati o-fo r-JU G-5,






                                                   43







                       20

                       3o

                       40

                       so

                       60

                       '70

                       so

                       90

                       too


              d                                2.5          roc
              m


                          0      T N



              C3                 -rp   o,,


                          Fig. 7. Nutrient Profile for JUG 5.
              cl






              n
              3--      01
                       to -


                       20

                       3o

                       4o

                       50

                       60

                       '70
                       to                                                   Fig. 9. Nutrient Profile
                       90                                                             for JUG-7-

                       100


                         0                     2.5         -roe

                         0     TN     0,!g


                         0 c/o T P   0-1






                                   44







                                    Oak/Ragweed

                           0        10      20       30
                          0-




                        20-




                        40-


                      CD

                        60-

                      0
                      3

                        80-



                       100-




                       120


                      Fig.8. Oak/Ragweed Pollen Ratio for JUG 7





                                                     -45-


                 Appendix 1. Sedimentation rates and chronologies.
                    I



                 JUG 1.



                 Depth  (cm)                Sedimentation  rate (cm/yr)                  Years

                    0-1                              0.34    -                          1990-1987
                    1-2                              0.37                               1987-1984
                    2-3                              0.20                               1984-1979
                    3-4                              0.24                               1979-1975
                    4-5                              0.26                               1974-1970
                    5-6                              0.23                               197/0-1966
                    6-7                              0.25                               1966-1962
                    7-8                              0.23                               1962-1958
                    8-9                              0.33                               1958-1955
                   9-10                              1.30                               1955-1954
                 10-11                               1.00                               1954-1953
                 11-12                               0.50                               1953-1951
                 12-13                               0.62                               1951-1949
                 13-14                               0.56                               1949-1947
                 14-15                               0.49                               1947-1945
                 15-16                               0.44                               1945-1943
                 16-17                               0.51                               1943-1941
                 17-18                               0.34                               1941-1938
                 18-19                               0.33                               1938-1935
                 19-20                               0.26                               1935-1931
                 20-21                               0.37                               1931-1928
                 21-22                               0.21                               1928-1923
                 22-23                               0.57                               1923-1921
                 23-24                               0.54                               1921-1919
                 24-25                               0.63                               1919-1917
                 25-26                               0.40                               1917-1914
                 26-27                               0.45                               1914-1912
                 27-28                               0.47                               1912-1910
                 28-29                               0.48                               1910-1908
                 29-30                               0.37                               1908-1905
                 30-31                               0..33                              1905-1902
                 31-32                               0.41                               1902-1900
                 32-33                               0.52                               1900-1898
                 33-34                               b.31                               1898-1895
                 34-35                               0.29                               1895-1892
                 35-36                               0.30                               1892-1889
                 36-37                               0.42                               1881@-A$57
                 37-38                               0.46                               1887-1885
                 38-39                               0.21                               1885-1880
                 39-40                               0.33                               1880-1877
                 40-41                               0.48                               1877-1875
                 41-42                               0.53                               1875-1873
                 42-43                               0.55                               1873-1871
                 43-44                               0.49                               1871-1869
                 44-45                               0.6i-                              i869' 1867





                                                  -46-



                 JUG, 3
                 Depth (cm)               Sedimentation rate (cm/yr)                Years
                   0-1                            0.26                             1990-1986
                   1-2                            0.31                             1986-1983
                   2-3                            0.32                             1983-1980
                   3-4                            0.29                             1980-1977
                   4-5                            0.22                             1977-1972
                   5-6                            0.21                             1972-1967
                   6-7                            0.39                             1967-1964
                   7-8                            0.43                             1964-1962
                   8-9                            0 ' 48                           1962-1960
                   9-10                           0.50                             1960-1958
                  10-11                           0.51                             19508-1956
                  11-12                           0.61                             1956-1954
                  12-13                           0.55                             1954-1952
                  13-14                           0.58                             1952-1950
                  14-15                           0.52                             1950-1948
                  15-16                           0.60                             1948-1946
                  16-17                           0.55                             1946-1944
                  17-18                           0.46                             1944-1942
                  18-19                           0.51                             1942-1940
                  19-20                           0.35                             1940-1937

                 JUG 5

                   0-1                            0.22                             1990-1986
                   1-2                            0.32                             1986-1983
                   2-3                            0.25                             1983-1979
                   3-4                            0.23                             1979-1975
                   4-5                            0.27                             1975-1971
                   5-6                            0.-29                            1971-1968
                   6-7                            0.30                             1968-1965
                   7-8                            0.34                             1965-1962
                   8-9                            0.41                             1962-1960
                   9-10                           0.38                             1960-1957
                  39-40                           0.51
                  40-41                           0.55
                  41-42                           0..49
                  42-43                           0.57


                 JUG 7

                   0-1                            0.27                             1990-1986
                   1-2                                                             1 q-8 6c7l.9 a II - -
                   2-3                            0.22                             1981-1977
                   3-4                            0.19                             1977-1972
                   4-5                            0.28                             1972-1969
                   5-6                            0.30                             1969-1966
                   6-7                            0.29                             1966-1963
                   7-8                            0.34                             1963-1960
                   8-9                            0.36                             1960-1957
                   9-10                           0.41-
                  10-11                           0.44                             1955-1953
                  11-12                           0.44                             1953-1951




                                                                                 3 6668 14109 4856