University of New Hampshire University of New Hampshire Scholars' Repository Institute for the Study of Earth, Oceans, and Space PREP Publications (EOS)
10-10-1992 The ecology of the Great Bay Estuary, New Hampshire and Maine: An Estuarine Profile and Bibliography Frederick T. Short The Jackson Laboratory, [email protected]
Follow this and additional works at: https://scholars.unh.edu/prep
Recommended Citation Short, Frederick T., "The ecology of the Great Bay Estuary, New Hampshire and Maine: An Estuarine Profile and Bibliography" (1992). PREP Publications. 376. https://scholars.unh.edu/prep/376
This Report is brought to you for free and open access by the Institute for the Study of Earth, Oceans, and Space (EOS) at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in PREP Publications by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. ,I,11 Chapter 7: Estuarine Primary Producers by F.T. Short and A.C. Mathieson I I The major contributors to estuarine depressum (NAI 1979a). Phytoplankton primary production are the hundreds of cell densities generally ranged from 20 to plant species that grow in and around the 5000 cells per liter. Great Bay Esttiary. All of these primary producers use sunlight to produce oxygen Some of the phytoplankton in Great and organic matter through the pro~ess of Bay are pennate diatoms (e.g. Navicula photosynthesis. The rate of primary spp. and Fragilaria spp.) that have been production for each plant species is suspended in the water column by the determined by the characteristics of that currents that also resuspend benthic species, local environmental conditions sediments (Donovan 1974). Denotula and the amount of available light reaching confervacea was a major component of the the plant. Primary production is the winter-spring Bay phytoplankton and major source of organic matter to the dominated over Thalassiosira spp. in areas estuary. Produced material accumulates of lower salinity (Donovan 1974). D. as living biomass and upon death enters confervacea was infrequent at the coastal the detrital cycle within the system or is stations in the Estuary (Donovan 1974). ·devoured directly by numerous species of estuarine consumers (see Chapter 8). Phytoplankton primary production in the Estuary is generally greatest during Phytoplankton April to July, declining through August and September with a slight increase in Phytoplankton are a major component October (NAI 1978a, b). The average of primary production within estuaries. annual phytoplankton production for the Little data is available concerning Estuary during 1977-78 was greater in phytoplankton species composition, Great Bay (14 mg C/m3 /h on ebb tide) abundances, or production within the than at more coastal stations. Chlorophyll Great Bay Estuary. The best data a values were similarly distributed, with 6 available for the Estuary was collected mg/m3 occurring in the surface ebb tide during 1970 to 1978 as part of a baseline sample for Great Bay (NAI 1978a, b). study for the Newington Electric Power Within the middle and upper estuary Generating Station; measurements of during 1973-1981, chlorophyll a concentra 3 phytoplankton populations (Table 7.1) tions varied from 1 to 14 mg/m , with an were made in Great Bay and on the average of 5 mg/m3 (Loder et al. 1983a). Piscataqua River (NAI 1971-19~80). The phytoplankton community was dominated Comparison of 1976-78 chlorophyll a by diatoms, primarily Chaetoceros spp. and and phaeophyton data (Loder et al. 1983a) Skeletonema costatum, with seasonal with recent values (Langan et al. 1990) occurrence of Rhizosolenia spp. and shows an absence of a "typical" April Asterionella glacialis, and the dinoflagellates May phytoplankton bloom (Fig. 7.1). Ceratium Iongipes, C. tripos and Peridinium Historic reports state that this spring
91 Table 7.1. Phytoplankton species collected during 1977 by net and whole water sampling within the Great Bay Estuary (modified from NAI 1978).
Class: BACILLARIOPHYCEAE Order: PENNALES Order: PERIDINIALES Amphora spp. Ceratium furca Order: CENTRALES Asterionella formosa Ceratium fusus Actinoptychus undulatus Asterionella glacialis Ceratium horridum Biddulphia alternans Bacillaria paxill ifer Ceratium longipes Biddulphia aurita Campylodiscus echeneis Ceratium minutum Ceratulina bergoni Climacosphenia moniligera Ceratium spp. Chaetoceros affinis Cocconeis scutellum Ceratium tripos Chaetoceros atlanticus Cylindrotheca closterium Peridinium conicum Chaetoceros brevis Fragilaria oceanica Peridinium depressum Chaetoceros compressus Fragilaria spp. Peridinium trochoideum Chaetoceros concavicornis Grammatophora marina Peridinium spp. Chaetoceros danicus Gyrosigma balticum Chaetoceros debilis Gyrosigma fasdola Order: DINOPHYSIALES Chaetoceros dedpiens Gyrosigma/ Pleurosigma spp. Dinophysis norvegica Chaetoceros diadema lsthmia nervosa Chaetoceros furcellatus Licomophora abbreviata Class: HAPTOPHYCEAE Chaetoceros laciniosus Licomophora flabellata Chaetoceros lauderi Navicula crucigera Order: PRYMNESIALES Chaetoceros lorenzianus Navicula spp. Phaeocystis pouchetti Chaetoceros lorenzianus Nitzschia delicatissima f. forceps Nitzschia longissima Class: CRYPTOPHYT A Chaetoceros similis Nitzschia paradoxa Chaetoceros socialis Nitzschia seriata Order: CRYPTOMONADALES Chaetoceros teres Rhabdonema arcuatum Chroomonas spp. Chaetoceros spp. Rhabdonema adriaticum Coretliron hysterix Surirella spp. Class: CHLOROPHYCEAE Coscinodiscus spp. Thalassionema nitzschioides Ditylum brightwellii unspecified Pennales Order: zycNEMAT ALES Detonula confervacea Staurastrum paradoxa Detonula sp. Class: CHRYSOPHYCEAE Eucampia zoodiacus Class: CY ANOPHYCEAE Guinardia flacdda Order: OCHROMONADALES Leptocylindrus danicus Dinobryon spp. Order: CHROOCOCCALES Lithodesmium undulatum Olisthodiscus luteus Agmenellum sp. Melosira moniliformis Melosira nummuloides Order: DICTYOCHALES Order: OSCILLATORIALES Paralia sulcata Dictyocha fibula Arthrospira subsalsa Porosira glacialis Distephanus speculum Rhizosolenia alata Ebria tripartita Class: EUGLENOPHYCEAE Rhizosolenia delicatula Skeletonema costatum Class: DINOPHYCEAE Order: EUGLENALES Thalassiosira nordenskioldii Eutreptia spp. Thalassiosira rotula Order: GYMNODINIALES Eutreptiella spp. Thalassiosira spp. Amphidinium crassum Gymnodinium spp.
Order: PROROCENTRALES Prorocentrum micans Prorocentrum triestinum
92 -...J -C> 1976-78 :::1. 8 ••.. -a-... 1988-90 Iii - I '•I I I 1' I cu ' ...I 6 ~ ...J JUL > J: a. 0 4 a: JAN 0 ...J 2 J: (..)
o-+-,.....,.....,....,.....,...... ,...... ,__ ...,...... , __..,..... __ ...... __ ...... __ ...... ,...... ,....;;;:-.-...,....,,.....,...... ,....,,.....,...""T'"""r--.-...... -r-1 0 2 4 6 8 1012141618202224262830323436
14 ~ I I ...J I - 12 1976-78 I I C> ..•. ·a- ... I - I :::1. 1988-90 - 10 z 8 0 I- > J:• 6 a. 0 4 w < J: 2 a.
0-+-,.....,.....,...... ,....,.....,...... ,.....,.....,...... ,...... _,...... ,...._...... ,... __ .....,.....,....., __ ...,...... ,_,...... ,...... ,_,...... ,.....,...... ,...... ,.~ 0 2 4 6 8 1012141618202224262830323436 MONTHS Fig. 7 .1 Comparison of chlorophyll and phaeophyton concentrations for 1976-78 and 1988-90 during low tide off Adams Point at the mouth of Great Bay, New Hampshire (Data from Loder et al. 1983b and Langan et al. 1990; see also Table 5.1).
93 "'--
bloom is frequent, but a large degree of a factor in and an indicator of the overall variability is apparent in the data. The health of bays and estuaries. peak chlorophyll a values observed in data from recent years occurred· much The three-dimensional structure of an later, in June or July. Currently, a project eelgrass bed provides breeding and is underway at JEL that will examine the nursery areas for young finfish and timing and magnitude of the spring shellfish, such as flounder, scallops, and bloom in greater detail. crabs (Thayer et al. 1984). The dense underwater meadows provide a vertical Eelgrass substratum, or place of attachment, in the water column as well as a haven from Eelgrass, Zostera marina,_ is a predators. In addition, birds such as submerged marine flowering plant that is Canada geese, brant geese, and ducks rooted within the sediments of coastal and consume the leaves and seeds of eelgrass estuarine waters, contributing significantly. as a principal food source. to the health and productivity of these areas. Eelgrass is known and appreciated In the normal life cycle of eelgrass, by shellfish enthusiasts, fishermen, and many of the leaves break away from the duck hunters because of its important role base of the shoots, especially in the fall. in the life cycle of scallops, crabs, finfish, Some float away, carried by the currents; geese, and ducks. Eelgrass and the others fall to the bottom where they ecosystem it fosters are an important decompose (Phillips 1984). Detritivores component of the Great Bay Estuary, begin to break down the leaves into covering 10 l 94 In most areas along the North 1988, Short et al. 1988), reduced water Atlantic coast including the Great Bay quality from coastal eutrophication (Orth Estuary, eelgrass recovered from the and Moore 1983 and 1988, Kemp et al. wasting disease by the 1960s, although in 1983, Twilley et al. 1985), and intensive some locations the eelgrass never grew phytoplankton blooms (Dennison et al. back (Thayer et al. 1984). Now a new . 1989). outbreak of the disease, discovered first in the Great Bay Estuary and now found on Eelgrass abundance in the Great Bay both sides of the Atlantic, is threatening has been monitored seasonally in a eelgrass populations again (Short et al. number of studies through the 1970s and 1986). The symptoms of the current 1980s. Monthly samples of eelgrass disease are similar to those in the 1930s. abundance were monitored in 1972 by First, pinhead-sized black dots appear on Riggs and Fralick (1975), in 1980-81 by the leaves (Short et al. 1988). The dots Nelson (1981, 1982), and in 1986-90 by spread, forming large black stripes and Short, Jones and Burdick (1991). The patches. Eventually the whole leaf results of all these studies (Fig. 7.2) show blackens, dies, and sinks or breaks off and the same seasonal pattern of abundance floats away. The causal agent of the with low biomass occurring during the wasting disease has recently been winter and rapid biomass increase during identified as a marine slime mold, the spring and early summer. Maximum 2 Labyrinthula zosterae (see Chapter 10). The biomass, 250 g dry wt/m , occurs in late recurrence of the disease was first noticed July or August. Such a pattern of in 1984 in the Great Bay Estuary (Short et abundance appears typical for eelgrass at al. 1986) and has continued during recent this latitude (Short et al. 1989). Detailed years (Fig. 10.2). Now diseased plants analyses of seagrass populations in the have been found from Nova Scotia to Great Bay . Estuary are presented in a North Carolina, on the west coast of the recent summary report for the National United States, on the coast of Europe Estuarine Research Reserve Program (Short et al. 1988), and Japan (Short et al. (Short et al. 1992) and in an ongoing in press). investigation of the Portsmouth Naval Shipyard (Munns et al. 1992). Besides the wasting disease, another major factor that limits the production and Seaweed survival of eelgrass in coastal areas is pollution resulting in decreased water The Great Bay Estuary is typical of clarity. Decreased water clarity reduces northern New England estuaries in having the amount of light reaching eelgrass and a wide diversity of seaweed species. The therefore reduces eelgrass growth dominant species within the Estuary are (Dennison 1987). Of the two main factors the substantial intertidal populations of contributing to water clarity reduction, the fucoid macroalgae, Ascophyllum suspended sediments shade or smother nodosum and Fucus vesiculosus, covering an the plants directly while nutrient loading area of 0.011 krn2 (0.010 mi2 or 7 acres) shades the plants by promoting planktonic within Great Bay alone, growing on the and macroalgal growth. shingle cobble and granitic outcrops. The causes for the many recently A total of 219 seaweed species are reported declines of eelgrass along the known in New Hampshire marine and East Coast are varied and include: the estuarine waters, including the Isles of wasting disease (Short et al. 1987, Short Shoals (Mathieson and Hehre 1986, 95 300 1972 Josselyn & Mathieson '80 200 - 100 C'll E 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT t'DJ [EC -C) -en en 300 < :: 1980 Nelson '81 0 200 al en 100 en c:c a: 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT t'DJ CEC '-'...J w w 300 1990 Short et al. '91 200 100 0 JAN FEB MAR APR MAY JUN JUL PLG SEP ccr ~ CEC Fig. 7.2 Comparison of eelgrass biomass in Great Bay for 1972, 1980 and 1990. Data source for each year is indicated on the respective graph. 96 Mathieson and Penniman 1991). Of this A variety of seaweed species occur total, 169 taxa (77.2% of total) are within Great Bay that are absent on the recorded within the Great Bay Estuary, open Atlantic coast north of Cape Cod. including 45 Chlorophyceae, 46 These species, which have a disjunct Phaeophyceae and 78 Rhodophyceae distributional pattern, may represent relict (Table 7.2). A "typical" estuarine · populations that were more widely reduction pattern occurs from the distributed during a previous time when Piscataqua River (144 taxa, 85.2% total coastal water temperatures were warmer estuarine) to Little Bay (132 taxa, 89.1 % (Bousfield and Thomas 1975). total estuarine) and Great Bay proper (90 Alternatively, they may be introduced taxa, 53.3% total estuarine). Each of the from the south. These seaweeds (e.g. seven tidal rivers entering the Great Bay Graci/aria tikvahiae, Bryopsis plumosa, Dasya Estuary has a relatively reduced flora, baillouviana, Chondria tenuissima, Lomentaria ranging from only 4 taxa within the clavellosa, Lomentaria orcadensis and Winnicut River to 49 taxa in the Oyster Polysiphonia subtilissima) grow and repro River. duce during the warm summer and are able to tolerate colder winter temperatures Within the Great Bay Estuary, two (Fralick and Mathieson 1975, Mathieson basic distributional patterns have been and Hehre 1986). Several of these identified (Mathieson and Penniman seaweed taxa exhibiting this same pattern 1991): also occur in the Great Salt Bay at the head of the Damariscotta River in Maine, • Cosmopolitan - present in both an area somewhat similar to Great Bay. estuarine and open coastal environments The disjunct distributional pattern • Estuarine - restricted to estuarine described for the seaweeds is also found environments for several marine/ estuarine invertebrates (Bousfield and Thomas 1975, Turgeon Most species (i.e. 85% or 144 taxa) exhibit 1976). cosmopolitan distributional patterns of varying degrees - i.e. 66 Rhodophyceae, 41 Ascophyllum nodosum, rockweed, Phaeophyceae and 39 Chlorophyceae. reaches maximum development in Great Twenty-five taxa (15%) are restricted to Bay because it is intolerant of extreme estuarine habitats - i.e. 13 Rhodophyceae, wave exposure and prefers the sheltered 6 Phaeophyceae and 6 Chlorophyceae. Six shoreline. Throughout the Estuary, the of the latter only occur within riverine percent cover of Ascophyllum varies from habitats near the headwaters of tidal 0 to 97.8% within the mid-intertidal zone tributaries - i.e. Mougeotia, Oedogonium, (Nelson 1981a). The standing crop of Spirogyra and Stigeoclonium species, plus fucoids throughout the Estuary has a Audouinella violacea and Sacheria fucina. range of 0-5,474 g dry wt/m2 (average 2 2,073 g dry wt/m ) (Nelson 1982). Of the 169 total taxa within the Great Maximum seasonal growth of Ascophyllum Bay Estuary, 83 species are interpreted as occurs during spring and fall in the Great annuals (49.1 %), 2 (1.2%) as aseasonal Bay Estuary (Mathieson et al. 1976). annuals or pseudoperennials, and 84 Ascophyllum plants may be quite long (49.7%) as perennials (Table 7.2). Overall, lived in some areas, persisting for 15 years the green algae exhibit the highest number (Baardseth 1970). Within Great Bay of annuals (38 taxa, 84.4%), while the Ascophyllum can be heavily pruned browns are intermediate (23 taxa, 50%) annually by ice, losing up to one-half its and the reds the lowest (25 taxa, 32.1 %). standing crop (Mathieson et al. 1982). The 97 TABLE 7.2. Summary Of seaweed species composition from ten Great Bay Estuarine areas (modified from Mathieson and Penniman 1991). ci ci ~ Total Chlorophyta Taxa 35 37 25 14 12 11 20 11 14 4 * = Longevity designations (A = annual, AA = aseasonal annual, P = perennial, PP = pseudoperennial) ** = Only found in culture 98 Table 7.2 (continued) .!a «I ~ '>, ;:l >. >. ;f °' .... °' «I 8 ..... O" «I 0 ;:l co >. u ~ i:: °'u ·;;: «I co °'.... °'(1) .... (1) °' (1) "' (1) ..... s 0... 0 s ·2 ~ «I ..!!! ..c:: °'.... «I bO u tl (1) u s s ;:l i:: i:: "' .... 0 «I "' g 0 PHAEOPHYfA 0: ;.:J l? ~ u ...J 6 ~ ~ ...J Agarum cribrosum x p Ascophyllum nodosum x x x x x x x x x p Ascophyllum nodosum ecad scorpioides x x x x x p Chorda filum x x A Chorda tomentosa x x A Chordaria flagelliformis x x A Delamarea attenuata x A Desmarestia aculeata x p Desmarestia viridis x A Desmotrichum undulatum x A Didyosiphon foeniculaceus x A Edocarpus fasciculatus x A Edocarpus siliculosus x x x x x x A Elachista fucicola x x x p Fucus distichus ssp. distichus x p Fucus distichus ssp. edentatus x p Fucus distichus ssp. evanescens x x x x p Fucus spiralis x x x p Fucus vesiculosus x p Fucus vesiculosus var. spiralis x x x x x x x x x p Giffordia granulosa x x A Giffordia sandriana x x A Isthmoplea sphaerophora x x... A Laminaria digitata x x p Laminaria longicruris x x p Laminaria saccharina x x x p Myrionema corunnae x A Myrionema strangulans x x x A Petalonia fascia x x x x x A Petalonia zosterifolia x A Petroderma maculiforme x x x p Pilayella littoralis x x x x x x x A Pseudolithoderma extensum · x x x p Pundaria latifolia x x A Ralfsia bornetii x x x P(?) Ralfsia clavata x x x P(?) Ralfsia fungiformis x p Ralfsia verrucosa x x x p Scytosiphon lomentaria var. complanatus x A Scytosiphon lomentaria var. lomentaria x x x x A Sorocarpus micromorus x A Sphacelaria cirrosa x x x p Spongonema tomentosum x P(?) Stidyosiphon griffithsianus x x A Ulonema rhizophorum x x A Total Phaeophyta Taxa 38 35 18 7 4 3 8 2 2 0 99 Table 7.2 (continued) ~ ~ ..!!l 100 Table 7.2 (continued) ~ ~ .!!l C<:I ~ ~ ~ ;:l >, >, ~ ~ .... '>.. C<:I ~ .... C<:I 0 ~ 8 Total Rhodophyta Taxa 71 60 47 17 10 15 21 3 14 0 Grand Total seaweed Taxa 144 132 90 38 26 29 49 16 30 4 101 distal tips of fronds freeze into ice cover 1987). In contrast to the detailed studies and are then torn free when ice-out occurs of intertidal macrophytes at Cedar Point, (Mathieson et al. 1982). Fragments of Little Bay (Chock and Mathieson 1983), no Ascophyllum torn loose by ice-pruning may quantitative studies have been conducted enter the detrital cycle or they may lodge to determine standing crops of subtidal amongst Spartina alterniflora culrns and seaweeds throughout Great Bay. grow, forming the unattached ecad scorpioides of Ascophyllum nodosum (Chock In recent years, other subtidal and Mathieson 1983). In certain areas of seaweeds have appeared to dominate Great Bay, the biomass of the ecad seaweed populations in part of the Great scorpioides within the upper intertidal can Bay Estuary. Ulva lactua and Enteromorpha reach 896 g dry wt/m2 (Chock and spp. are found in large abundance often Mathieson 1983). intermixed with or attached to eelgrass or overgrowing oyster beds. The Ascophyllum produces an abundance proliferation of these nuisance seaweeds is of reproductive cells over an annual cycle often an indicator of coastal (Baardseth 1970). Lateral shoots, termed eutrophication (Lewis 1964, Harlin and receptacles, bear the gametes that are Thome-Miller 1981, and Short et al. 1991). released during March-May within the Great Bay Estuary (Mathieson et al. 1976) Salt Marsh and may equal the standing biomass of vegetative plant material (Josselyn 1978, Salt marshes are an important Josselyn and Mathieson 1978, 1980). Inter component of the Great Bay Estuary, tidal seaweeds such as Ascophyllum and forming continuous meadows and Fucus, release large quantities of dissolved fringing areas around the shoreline. organic matter into the Estuary. Approximately 4.1 krn2 (1.6 mi2 or 1000 acres) of salt marsh surround Great Bay. On stable rocky substrata, within the Within Great Bay, extensive salt marshes low intertidal to upper subtidal zone, Irish are found along the Squamscott 1.6 krn2 moss, Chondrus crispus, forms significant (0.6 mi2 or 400 acres) and Winnicut Rivers, communities. Even so, the most abundant and Lubberland and Crommett Creeks. subtidal macroalga within Great Bay is Gracilaria tikvahiae (Penniman et al. 1986). Salt marshes in the Great Bay Estuary The primary occurrence of G. tikvahiae in are dominated by Spartina alterniflora (cord Great Bay (e.g. Footman Islands, Thomas grass) and Spartina patens (salt hay). Both Point, and Nannie Island) is limited by a species are perennial grasses, . annually lack of stable subtidal substrata in the producing large amounts of organic euphotic zone. G. tikvahiae, as well as matter that are exported from the marshes other subtidal seaweeds, grow attached to into the detrital food web or deposited oyster shells, small rocks, discarded within the marshes, contributing to the bottles and sunken logs. underlying marsh peat (Nixon 1982, Teal and Teal 1962). The "New England salt The growth of G. tikvahiae may reach marsh", typical of salt marshes in the 103/day during the summer; overall its Estuary, is dominated by monospecific growth is primarily limited by water stands of S. alterniflora in the low marsh temperature and light, while dissolved and monospecific stands of S. patens in the nutrients (i.e. nitrogen and phosphorus) high marsh. The ecology of these two do not appear to limit production species in the Great Bay Estuary has had (Penniman 1983, Penniman and Mathieson only limited study in the past. 102 The other primary high salt marsh The marshes surrounding the Great species in the Great Bay Estuary include Bay Estuary are subject to extreme Juncus gerardii, and Distichlis spicata. A environmental variation. The large tidal variety of other plant species also occur in amplitude in the region enhances the ex the Great Bay Estuary salt marshes (Table port of marsh grass from the marshes to 7.3) appearing as a mosaic of plant zones. the Estuary. Annual ice scouring of the Furthermore, several species found within intertidal marsh surface removes most the the Estuary salt marshes are classified as remaining marsh grass during the high rare or endangered by the state of New spring tides in late winter. Ice cover and Hampshire (e.g. Iva frutescens). freezing activity in intertidal salt marsh dislodge portions of the surface peat. In the mid '70s, the seasonality of leaf Whole sections of marsh with intact production in S. alterniflora was monitored intertidal communities are rafted into at Cedar Point in Little Bay (Chock 1975). lower intertidal or subtidal areas that are The data show the seasonal maximum often too deep for them to survive (Hard 2 biomass, 630 g dry wt/m , occurring in wick-Witman 1985). Ice-rafted marsh August (Fig. 7.3). Flower production of S. segments that are deposited within the alterniflora begins in July and continues intertidal zone are a potential means of into October, after which the main salt marsh propagation within the Great vegetative stalks begin to die, the entire Bay (Hardwick-Witman 1985, 1986). above ground plant biomass dies off, and enters the detrital cycle, either being Breeding et al. (1974) described the exported from the Bay or decomposing numerous soil types of coastal New within the estuarine system. Much Hampshire salt marshes. Marshes research has dealt with efforts to restore S. bordering streams. on the Squamscott alterniflora in areas where it has been River and Crommett and Lubberland destroyed or introduce it into new areas Creeks in Great Bay, as well as the other as part of mitigation efforts (see Chapter rivers in the Estuary, are generally 10). sulfihemist. Fringing marshes, which are common around the Estuary, also have The annual production of S. patens sulfihemist soils of varying thicknesses; was assessed during the mid 1980s. Stem · these overlay a variety of substrata (i.e. density and standing biomass was mud, sand or bedrock). The sulfihemist measured in the Squamscott River north soil type has slow internal drainage, a of Chapman's Landing at the time of very high water table, and contains large seasonal maximum standing crop (Fig. amounts of organic matter and sulfidic 7.4). The biomass measured at this site minerals. Studies of gas flux from the was extremely high compared to other Squamscott River marsh demonstrates that sites in northern Massachusetts, on the sulfur gas is a major emission from this New Hampshire coast, and at the Wells marsh system (Chapter 9). Estuarine Research Reserve in southern Maine (Short 1988). This biomass of 820 Clearly, the salt marshes of the Great g dry wt/m2 was almost 20% higher than Bay Estuary are a productive part of the any other sites measured. On the same estuarine environment. A project to map samples, the measurement of stem density the salt marsh of the Great Bay Estuary is was 6600 stems/m2 similar to other sites currently underway through funding from measured in New Hampshire and slightly NH Coastal Zone Management Program less than those measured in the Parker (Ward per. com.). Other studies within River Marsh in Massachusetts (Fig. 7.5). the Great Bay Estuary have shown the 103 Table 7.3. Major plant species occurring within New Hampshire salt marshes (modified from Breeding et al. 1974). Acnida cannabina Water hemp Aster subulatus Annual salt marsh aster Aster tenuifolius Perennial salt marsh aster Atriplex glabriuscula Orach Atriplex patula Orach Bassia hirsuta Hairy smothenveed Carex scoparia Sedge Carex ·hormathodes Marsh straw sedge Cladium mariscoides Twig rush Distichlis spicata Spike grass Eleocharis halophila Salt marsh spike-rush Eleocharis parvula Dwarf spike-rush Eleocharis smallii Small's spike-rush Elymus virginicus Virginia rye grass Euphorbia polygonifoli.a Seaside spurge Gerardia maritima Seaside gerardia Glaux maritima Sea milkwort Hordeum jubatum Squirrel-tail grass Iva frutes cens Marsh elder l uncus balticus Baltic rush Juncus canadensis Canadian rush funcu s gerardii Black grass Lathyrus japonicus Beach pea Limonium nashii Sea lavender Lythrum salicari.a Purple loosestrife Myrica pensylvanica Northern bayberry Panicum virgatum Switchgrass Phragmites australis Common reed Plantago maritima Seaside plantain Polygonum aviculare Knotweed Polygonum ramosissimum Bushy knotweed Potamogeton pectinatus Sago pondweed. Prunus maritima Beach plum Puccinelli.a. maritima Seashore alkali grass Puccinelli.a. paupercula Alkali grass Quercus alba White oak Quercus bicolor Swamp white oak Ranunculus cymbalaria Seaside crowfoot Rosa rugosa Rugosa rose Rosa virginiana Low rose Ruppia maritima Widgeon grass Sanguisorba canadensis Canadian burnet 104 Table 7.3 (continued) Salicornia bigelovii Dwarf glasswort Salicornia europaea Common glasswort Salicornia virginica Perennial glasswort Scirpus americanus Three-square bulrush Scirpus acutus Hard-stemmed bulrush Scirpus atrovirens Bulrush Scirpus cyperinus Wool grass Scirpus maritimus Salt marsh bulrush Scirpus paludosus Ba yo net-grass Scirpus robustus Salt marsh bulrush Scirpus validus Soft-stemmed bulrush Smilax rotundifolia Common greenbrier Solidago sempervirens Seaside goldenrod Spartina alterniflora Salt water cord grass Spartina patens Salt meadow grass Spartina pedinata Fresh water cord grass Spergularia canadensis Common sand spurrey Spergularia marina Salt marsh sand spurrey Suaeda linearis Sea blite Suaeda maritima Sea blite Suaeda richii Sea blite Toxicodendron radicans Poison ivy Triglochin maritima Seaside arrow grass Typha angustifolia Narrow-leaved cattail Typha latifolia Broad-leaved cattail Zannichellia palustris Homed pondweed Zostera marina Eelgrass 105 J 0 1972 I 1973 BIOMASS E:J,; REPRODUCTION 1.0 N E ...... 0.8 z > I.. 0 -c f Cl 0.6 ...:.: u ::::l l/) 0 l/) 0 -<1'. ~ a... ::: 0.4 0 50 ~ 40 ~ 0.2 30 20 10 O'--_...... --L.J Fig. 7.3. Seasonal comparison of Sparrina alterniflora biomass and percent reproduction in 1972-73 for Cedar Point, Great Bay Estuary, NH (Chock 1975). 106 ( ...... r \ ! 393 ±268 I Spartina pa tens BIOMASS g/m 2 X ±SD Fig~ 7.4. Seasonal maximum biomass (g dry wt/m2) for Spartina patens along the northern New England coast (Shon 1986). 107 \ \ \ ~~ ~ DENSITY Shoots/ m2 X ±SD .r Fig. 7 .5. Shoot density (shoots/m2) for Spartina patens along the northern New England coast (Short 1986). . . 108 importance · of salt marshes in diatom abundance and grain size or total biogeochemical processes .(see Chapter 9) organic carbon (Fig. 7.6). and in the uptake and cooperation of methylated tin compounds (see Chapter Upland 6). The importance of salt marsh habitats within the Great Bay Estuary, including The uplands surrounding the Great the value of these systems as fisheries Bay Estuary have both deciduous and habitat, is described in Chapter 2. coniferous forests. The most common tree species includes white pine, red oak, red Benthic Microalgae pine, hemlock, red maple, gray birch, and· quaking aspen. A more complete listing Another important microalgal of the common upland vascular plants component of the estuarine flora are found within Strafford County, N.H., is diatoms and other microscopic algae presented in Table 7.4. . occurring on mudflats. These micr-0algae may contribute a substantial portion of The plants comprising the upland total estuarine primary production. which surrounds the Great Bay Estuary Recently, two masters theses have form a valuable buffer that protects the included an assessment of the benthic estuarine ecology in several ways. microalgal biomass in their studies of Research on riverine systems has shown intertidal sediment stability (Sickley 1989 clearly that an intact buffer zone or and Webster 1991). These geologically riparian zone along a river system has a based studies provide the first significant role in maintaining the water quantitative evidence for benthic diatom quality, wildlife value, aesthetic beauty abundance in Great Bay. Seasonal and riverine health (Jones 1986). chlorophyll a data from Adams Cove Similarly, the buffer zone around an shows a bimodal annual pattern of diatom estuary provides the same functions. abundance (Fig. 7.6). A spring diatom bloom occurs in March-April (Webster In particular, for the Great Bay 1991) and a second bloom begins in late Estuary, these buffer zones are important July and lasts through October (Fig. 7.6). in trapping nutrients and sediments that The chlorophyll a content for the two would otherwise wash into the Estuary studies ranged from 8-24 mg/l (Sickley contributing to the reduction in water 1989 and Webster 1991). quality. These zones also provide shelter and habitat for animals and birds that The diatom layer on the sediment frequent the Estuary and utilize estuarine surface was found to be related to a resources. In addition to these values, the reduction in sediment resuspension (Fig. upland also provides large amounts of 7.6) with the benthic algal population organic matter to the Estuary, adding fuel binding the sediment surface together to the detrital food chain. These materials (Sickley 1989). Reduction in the binding include leaf fall and other dead plant of sediments was associated with the material. Overall, the upland buffer is grazing and disturbing activity of both critical to the continued maintenance of a mud snails and horseshoe crabs on the healthy Estuary and is an important mudflat (Sickley 1989). No clear consideration in regulating shoreline relationship was found between benthic development. 109 ...... "' .,.., ::i ..... '°00 Q..(1Q ,;93~ Control resuspension (II O'I concentration (mg/I) §~ Control chlorophyll a (uglcm "3) Total organic carbon (wt%) ..... cr.:ig ...... N -l \D ..... L>l V\ -l \D ..... ~.~ 0 § § ::s ::i' 0 0 0 0 0 0 0 0 N N N N N L>l L>l L>l ~.E. 0 iv '.i:.. Oo 0 iv '.i:.. N 0 6Apr 6Apr (II 0 °' .....3 6Apr ::i "O 17-Apr 17-Apr 17-Apr ~~- 00 Cl) 5-May 5-May 00 0 5-May ::i 15-May O' 0 15-May 15-May '"1 ...... () ::r ::r 3-JWl 3-Jun 3-Jwi (II ...... 0 13-Jwi 13-Jun 13-Jwi ai:: "Oa 0. ::r 2-Jul :;:!J'< 2-Jul 2-Jul "' ::::: 14-Jul ; ,P 14-Jul 14-Jul .... '"1 31-Jul >~ 31-Jul 1 I 31-Jul ~ o.i:: 12-Aug ~ ~ "'Cl) 0 3 "O 28-Aug 12-Aug 12-Aug Cl) g oO()~. 9-Sep 28-Aug 28-Aug < ::i (II () 29-Sep 9-Sep • 0 H 9-Sep o::i 11-0ct '"1 () 0 >-'! (II (II 29-Sep 29-Sep 26-0ct ~- ...."' ::iq 8 11-0cl 11-0cl tJj "' 11-Nov "'F:i" "' ::t. 0 '-<: 0 ::s 26-0ctl \t--q---1 I 26-0ct tTl. 23-Nov Cl) ...... 0 12-Dec i:: ..... 11-Nov ~ 11-Nov I.I\ -._] -._] 23-Nov ~~ {_,, 23-Nov • '"1 b"' u."' b u. :z: I ~a~. 12-Dec ,...... () en o Mean grain size (phi units) B:g-·~ (II ::s '-<: • j Table 7.4. Common upland overstory and understory vascular plant species in Strafford County, N.H. by habitat (modified from Hodgdon 1932 in Texas Instruments, Inc. 1974). A specific list for the upland area within the Reserve boundaries is not presently available. DRY UPLAND FOREST Primary overstory species Acer rubrum Red maple. Betula alleghaniensis Yellow birch Betula lenta Sweet birch _Betula papyrifera Paper birch Betula populifolia Gray birch Carya ovalis Sweet pignut Carya ovata Shagbark hickory Fagus grandifolia American beech Fraxinus americana White ash Picea glauca White spruce Picea rubens Red spruce Pinus resinosa Red pine Pinus strobus White pine Populus tremuloides Quaking aspen Pyrus malus Apple Quercus alba White oak Quercus rubra Red oak Quercus velutin Black oak Salix alba White willow Sassafras albidum White sassafras Tsuga canadensis Hemlock Primary understory species Aralia nudicaulis Wild sarparilla . Berberis vulgaris Common barberry Castanea dentata Chestnut Comptonia peregrina Sweet-fem Dennstaedtia punctilobula Hay-scented fern Gaultheria procumbens Teaberry Hamamelis virginiana Witch hazel f uniperus communis Common juniper Kalmia angustifolia . Sheep laurel Lycopodium complanatum Trailing evergreen Myrica pensylvanica Bayberry Prunus pensylvanica Pin cherry Prunus virginiana Choke cherry Pteridium aquilinum Bracken fem Quercus ilicifolia Scrub oak Rubus pubescens Dwarf raspberry Toxicodendron radicans Poison ivy Vaccinium angustifolium Lowbush blueberry Viburnum acerifolium Maple-leaved viburnum WET-LOWLAND FOREST Primary overstory species Acer rubrum Red maple Betula alleghaniensis Yellow birch Betula lenta Sweet birch 111 Betula papyrifera Paper birch Carpinus caroliniana American hornbeam Chamaecyparis thyoides Atlantic white cedar Nyssa sylvatica Blackgum Picea mariana Black spruce Salix alba White willow Salix nigra Black willow Tsuga canadensis Hemlock Ulmus americana American elm Primary understory species A/nus rugosa Speckled alder Cornus amomum Silky dogwood Cypripedium sp. Lady slipper Gaultheria procumbens Teaberry Ilex verticillata Swamp winterberry Kalmia angustifolia· Sheep laurel Lycopodium obscurum Ground pine Mitchella repens Partridge berry Osmunda cinnamomea Cinnamon fern Polytrichum commune Hairy cap moss Rosa sp. Rose Smilax rotundifolia Common greenbrier Vaccinium corymbosum Highbush blueberry Viburnum alnifolium Dockmackie Viburnum cassinoides Wild raisin Viburnum recognitum Arrow-wood Vitis sp. Grape OPEN AND OVERGROWN FIELDS Overstory species Betula populifolia Gray birch /uniperus communis Common juniper /uniperus virginiana Red cedar Prunus serotina Black cherry Prunus virginiana Choke cherry Viburnum sp. Viburnum Rhus typhina Staghorn sumac Ground cover species Achillea millefolium Common yarrow Amaranthus retroflexus Amaranth Ambrosia artemisiifolia Common ragweed Aster sp. Aster Dactylis glomerata Orchard grass Daucus carota Queen Anne's lace Festuca rubra Red fescue Oxalis corniculata Creeping lady's sorrel Phalaris arundinacea Reed canary grass Phleum pratense Common timothy Poa pratensis Kentucky bluegrass Solidago s p. Goldenrod Spiraea latifolia Meadow sweet Trifolium pratense Red clover 112 I: ~I: Aerial view of the Great Bay Estuary from offshore, showing Portsmouth Harbor and the Piscataqua River with Portsmouth Naval Shipyard (center), Kittery, Maine (right), and Portsmouth, New Hampshire (top, center). Aerial view of the l:iscataq_ua River showing i ndustria] development on the New Hampshire side (foreground) and residential development on the Maine side. Recreational boating on the Great Bay Estuary. Canada geese feeding on eelgrass in Great Bay. Juvenile lobster foraging within the protection of a shallow eelgrass meadow in Portsmouth Harbor. Aerial view of Great Bay Marina on Little Bay. Recent expansion of the marina is indicative of increased boating activity in the Estuary. Aerial view of Adams Point at the juncture of Great and Little Bays, showing the Adams Point Wildlife Management Arca and the Jackson Estuarine Laboratory. Aerial view of the Squamscott River near the Route 108 bridge in Stratham, NH. The extensive salt marshes along the river are part of the Great Bay National Estuarine Research Reserve.