NEERS Spring 2000 - Abstracts

Adams*,J.R., F.T.Short, B.S. Kopp, Jackson Estuarine Laboratory, University of New Hampshire, Durham, NH, 03824.

GIS MODELING OF WAVE EXPOSURE AND HABITAT SUITABILITY FOR EELGRASS RESTORATION IN NEW BEDFORD HARBOR, MASSACHUSETTS.

Exposure to wave energy has a dramatic effect on bottom sediments and organisms that reside there. In an area such as New Bedford Harbor, MA, the impact of wave energy on the nearshore habitat is very difficult to measure due to the irregular shoreline shape. The U.S. Army Corps of Engineers developed a method to rate wave exposure based on fetch measurements from any given point. Using a variation of that method developed by Murphey and Fonseca (1995) as input to a Geographic Information System (GIS), exposure was calculated for the entire New Bedford Harbor area. Local wind data was collected and summarized to determine average velocity and percent occurrence for the eight major compass headings. Effective fetch, the average of nine cosine weighted fetch measurements, was then calculated for each of these compass headings. The wind data was used to weight the effective fetch measurements and determine exposure, providing a rating of wind stress on eelgrass beds. The exposure information was then combined with existing eelgrass distribution data to identify the optimal habitat conditions where eelgrass currently grows. This information was then used to rate potential sites for transplant suitability.

Asselin*, N. P. M. and R. S. Warren. Connecticut College, New London, CT 06320.

IMPACTS OF PHRAGMITES AUSTRALIS INVASION AND CONTROL IN BRACKISH TIDAL WETLANDS: PATTERNS AND COMPOSTION OF SEDIMENT DEPOSITION

This study addresses the impact of Phragmites australis expansion within brackish tidal marshes on sediment trapping and deposition from flooding tidal water. Sediments were collected on ashless filter paper during the summer of 1999. Sampling was at nine sites along a ca. 1 km reach of the Lieutenant River, a sub-estuary of the Connecticut River, three each in areas domi- nated by Phragmites , un-invaded Typha and Spartina patens meadow, and in experimental Phragmites control sites now restored to brackish meadow vegetation. At each location sediment traps were deployed six times from June to September at creekside (0 m), on the levee (10m) and central high marsh (30, 35 or 60m); sampling periods varied from 4 to 6 days and 8 to 12 flooding events. Elevation, flooding frequency and flooding duration were determined for each trap site. Collected and calculated data included total deposition, % organic matter, and sedimentation rates expressed as mg hr flooded-1 and flooding event-1. For all sites and for low and high marsh locations considered separately, flooding duration was a better predictor of total sedimentation than flooding frequency. Sedimentation rates were significantly greater in low marsh (0 m) than high marsh sites; there were no rate differences between low marsh Phragmites and Spartina alterniflora; deposition in Phragmites was similar to other vegetation types, while in areas of Typha, deposition was greater than in S. patens. Organic content was less in low marsh than high and within the low marsh, greater in Phragmites than S. alterniflora; organic content of high marsh Phragmites and Typha sediments were similar and less than from S. patens and restored meadow sites.

Bowden*, A.A., D.M. Burdick, and F.T. Short. Jackson Estuarine Laboratory, University of New Hampshire, 85 Adams Point Road, Durham, NH 03824

EFFECTS OF URBAN RUNOFF ON THE INVERTEBRATE COMMUNITIES OF NATURAL AND CREATED SALT MARSHES IN PORTSMOUTH, NEW HAMPSHIRE

Salt marshes created as mitigation are often adjacent to impacts from development, in urban areas subject to freshwater inputs carrying pollutantsfrom streets, combined sewer overflows, and industry. Faunal use of created salt marshes is not well documented, and little has been published about the effects of urban runoff on the fauna of created marshes. To compare the effects of runoff on invertebrate communities, epibenthic macroinvertebrates were sampled in 10 marshes in Portsmouth, New Hampshire. Four created and 6 natural marshes were studied. Half of the marshes of each origin (2 created, 3 natural) are subject to runoff from storm drains, and half are distant from outfalls. Litterbags composed of 5-mm mesh were filled with 50 g each of Spartina alterniflora, Zostera marina, and macroalgae, and placed in the marshes for two one-month periods in summer 1998. A total of 200 litterbags trapped 11,829 individuals of 24 highly stressed urban setting.were found to be similar. More invertebrates were trapped in both natural and created marshes influenced by stormwater runoff, with the greatest abundance closest to outfalls. Near outfalls deposit feeders dominated assemblages, while samples distant from sources of runoff were dominated by shredders and grazers. Changes in the pathways available for energy flow in the community appear to influence faunal assemblages in marshes near outfalls. Such changes may influence trophic transfer of energy from salt marshes to coastal ecosystems. These findings indicate that proximity to outfalls should be considered when selecting mitigation sites and assessing their fauna.

Buchsbaum, R.N., A. Ridlon*. Massachusetts Audubon Society, Wenham, MA 01984, J. Catena, E. Hutchins, National Marine Fisheries Service, Gloucester, MA 01930.

SALT MARSH VEGETATION RESPONSE TO INCREASED TIDAL FLUSHING IN IPSWICH, MA: ONE YEAR POST RESTORATION

Argilla Road Salt Marsh in Ipswich, MA has been degraded by a culvert sized too small to allow adequate seawater to flood the marsh at high tide. As a result of lowered salinities and less extensive flooding, the invasive grass, Phragmites australis, replaced natural salt and brackish marshes in many sections of this marsh. In late fall 1998, we replace the old 36 inch diameter culvert with an eight x five foot box culvert, thus increasing the amount of water flushing the marsh by about six fold. After one year, average Phragmites heights were reduced, groundwater salinities were higher, and the spatial cover of Phragmites has been reduced. At this point, however, we cannot attribute these changes solely to the increased tidal flushing resulting from our restoration, since Phragmites growing nearby at a marsh where no changes in tidal regime occurred, were also shorter on average in 1999. We attribute the general decline in Phragmites heights in 1999 compared to 1998 to the extremely dry spring and summer, which led to higher salinities and poorer growing conditions for Phragmites regardless of any alterations. Similarity indices were used to compare differences over time between the altered and control marshes. Despite the striking visual appearance of decline, it will likely take several years before we can detect a difference statistically in Phragmites as a result of our restoration.

Canfield*, Susannah K.E.; Ambrose, William; Ongley, Lois; Retelle, Michael; Wenzel, Tom; Bates College, Lewiston, ME, 04240

CHEMICAL ANALYSIS OF ANTHROPOGENIC HEAVY METAL CONTAMINATION AND ITS RELATION TO LAND USE IN TWO MAINE SALT MARSHES

Vibracores 2m in length were taken from two salt marshes in Wells and Phippsburg, ME, in order to examine the differences in modern anthropogenic pollution trends between a developed site and a relatively pristine one, and to relate such trends to the land use histories of each area. Sediments were dried to a constant weight, ashed, and digested in aqua regia, and concentrations of Cu, Fe, Mn, Pb, and Zn were determined using Inductively Coupled Plasma Emission Spectroscopy (ICP). 210Pb dating was used to examine the recent temporal patterns in the metal concentrations. A second preparation technique was also used for 6 samples selected from throughout the Wells core to compare the results between the methods. Samples prepared by drying to a constant weight, passing through a 250 um sieve, and digesting with a solution of aqua regia and H₂O₂ had metal concentrations 55 % lower on average than the first preparation technique. In the Wells core, concentrations of all metals more than doubled in the top 20cm of sediment. When standardized against Fe as a proxy indicator of sedimentation rate and sediment composition, however, Pb was the only metal that exhibited enrichment in the top 20cm of the sediment column. Results suggest that wastewater and industrial effluents have not had a major impact on the marsh. The Pb concentration profile, however, exhibits a pattern of surficial enrichment that closely correlates with modern anthropogenic inputs to the marsh, including runoff from major roads in the watershed and automobile emissions.

Chambers*,R.M., D.T. Osgood, N. Kalapasev. Biology Dept., Fairfield University, Fairfield, CT, 06430; and Dept. of Biology and Environmental Science, University of New Haven, 300 Orange St., West Haven, CT, 06516.

HYDROLOGIC AND CHEMICAL CONTROL OF PHRAGMITES GROWTH IN TIDAL MARSHES

The roles of hydrology and sediment chemistry on relative positions of Phragmites and Spartina alterniflora stands were investigated in three marshes along the estuarine salinity gradient of the lower Housatonic River in western CT. Continuous water table measurements and monthly analyses of porewater ammonium, phosphate, sulfide and salinity were completed along triplicate transects grading from pure Phragmites stands, through Phragmites/ Spartina mixed stands, and into pure Spartina stands. Although slack low tide water table depth was not different between the Phragmites and Spartina stands, the total water table change and flooding duration were higher at the Spartina and mixed stands relative to the Phragmites stands. Flooding depth in Phragmites stands at the lowest salinity site was greater than flooding in other Phragmites stands down the salinity gradient, suggesting that Phragmites is more tolerant of flooding at low salinity. Porewater hydrogen sulfide and ammonium were consistently highest in the mixed vegetation stands which coincided with the shallowest water table depth. Although Phragmites shoots were shorter in the mixed stands, no other measures of plant vigor (stem density, leaf carbon and nitrogen content) were different from pure Phragmites stands. Because of its extended tolerance to flooding in less saline water, opportunities for controlling Phragmites growth via manipulation of wetland hydrology decrease with distance up the estuarine salinity gradient.

Clancy*, M. Biological Sciences, Univ. Rhode Island

DEVELOPMENT AND USE OF A PASSIVE COLLECTOR TO SAMPLE MOBILE INVERTEBRATES IN RHODE ISLAND SALT MARSHES

Understanding how invertebrate communities respond to habitat changes requires background data. As part of a larger study of six Rhode Island salt marshes, I designed and tested a passive sampler, a pit trap, to collect mobile benthic invertebrates. Pit traps were 7.5 cm diameter by 60 cm long, constructed of rigid PVC pipe, contained approx. 10% formaldehyde and were allowed to sample for one week. I placed pit traps in subtidal soft sediment habitats and sampled each salt marsh with equal effort (8 traps per marsh). Samples were collected during late spring and late summer. A diverse fauna was present in the traps with seven phyla collected in spring and six collected in summer. Crustaceans, especially decapods, were found in all marshes and were abundant during both periods. Mean size of the green crab, Carcinus maenus, decreased during sampling which may suggest movement to, or from, the marshes. Invertebrate community diversity (Shannon-Weaver) differed significantly during each period with one marsh, Coggeshall marsh, having consistently high diversity. Bray–Curtis similarities were used to determine the organisms which contribute most to within marsh similarity. In many of the marshes the presence of crustaceans, especially shrimps, crabs and harpacticoid copepods, were determined to enhance within marsh similarity. Although pit traps are effective invertebrate samplers, they should be used with caution because they failed to collect at least one prominent member of the invertebrate marsh community: fiddler crabs from the genus Uca.

Colin*, Sean P. and Patricia Kremer, Marine Sciences, University of Connecticut.

THE SETTLEMENT AND POPULATION MAINTENANCE OF CYANEA SP. SCYPHISTOMA IN RELATION TO THE DISTRIBUTION OF MEDUSAE IN THE NIANTIC RIVER, CT, USA

Scyphozoan jellyfish are seasonally conspicuous in coastal waters, but relatively little is known about the factors that control their distribution and population dynamics. Cyanea sp. is a cosmopolitan species that is seasonally present in great abundance in the Niantic River, CT, USA. In order to get a better understanding of the factors controlling medusan abundance and distribution we examined the temporal and spatial distribution of settled scyphistoma in relation to that of the medusae. Both temporally and spatially scyphistoma settlement patterns were closely related to the presence of mature female medusae. In addition, the scyphistoma exhibited a strong vertical distribution pattern, primarily settling near the bottom. After settlement, planula cysts or polyps were out competed by large barnacle and ascidian sets resulting in a sharp decline in polyp population abundance. These findings should give insight into likely locations of medusan seed populations.

Ebner*, Karen, Tammy Tuminelli, and Pamela A. Morgan, Department of Life Sciences, University of New England, Biddeford, ME 04005.

A COMPARATIVE STUDY OF TWO TIDALLY RESTRICTED MARSHES TO A NATURAL UNDISTURBED SALT MARSH IN OLD ORCHARD BEACH, ME.

Following a 1996 flood, two flapper gates were installed at the request of Ocean Park, ME residents. Citizens concerned with the health of the impacted salt marshes asked us to monitor the effect of the tide gates on the marshes. Our objective was to compare certain structural and functional attributes of marsh ecology at two restricted marshes and one natural site found outside the tide gate. We compared marsh characteristics such as soil salinity, above ground biomass, percent soil organic matter, and elevation using eight random quadrats in each site. We also compared creek salinity and plant diversity between the three sites. From our study we found that there was a significant difference in mean soil and creek salinity between the restricted site furthest from the tide gate and the natural site. Above ground dead biomass was significantly greater in the two disturbed marshes than in the natural site, however, no we found no significant difference in the live above ground biomass in the three sites. We found no significant difference in the average percent soil organic matter at each site. The elevation on the furthest restricted site was notably higher than the other two sites. The two disturbed sites had greater species richness as well as a greater percentage of upland species while the natural site had fewer total species but a greater percentage of obligate wetland species. From our results and study we have found that the tide gates have had a significant impact on the restricted Ocean Park marshes. These results support what has been observed in other tidally restricted marshes throughout New England.

Frank*, Dane¹, Lisa Ewert², Sandra Shumway², J. Evan Ward¹; 1Department of Marine Sciences, University of Connecticut, Groton, CT 06340; 2Southampton College, Long Island University, Southampton, NY 11968.

EFFECT OF CLAY SUSPENSIONS ON CLEARANCE RATE IN THREE SPECIES OF BENTHIC INVERTEBRATES.

Recent attempts are being made, especially in Asia, to displace harmful algal blooms by spraying fine particulate mineral suspensions ( e.g."china clay") over the surface of affected coastal waters. In practice, the particles adsorb onto the surface of the algal cells, promoting coagulation and displacement to the bottom. Very little is known, however, about the impact of this technique on benthic communities and processes. To examine the effects of differing concentrations of china clay on clearance rate, short-term laboratory experiments were performed on three benthic species: the bay scallop (Argopecten irradians), the eastern oyster (Crassostrea virginica), and a hydroid (Obelia sp.). Colleagues in Korea furnished us with the china clay used in their field trials. Depletion rate assays were performed using solutions of 10, 100, 1000, or 10,000 mg/l of china clay suspended with Rhodomonas lens (2.5 x 104 cells/ml) in 0.4 Fm filtered seawater. Particle concentrations and size distributions were determined using a Coulter Multisizer. Results showed a decrease in weight specific clearance rates with increasing concentrations of clay. Both the oyster and the scallop showed a slight increase in particle clearance at 100 mg/l. These results strongly suggest that further studies are required to determine the full effects of this clay-coagulation practice on the benthos.

Franz*, David R. and Ileana Friedman, Biology Department, Brooklyn College CUNY.

EFFECTS OF SEA LETTUCE ON INTERTIDAL SAND FLAT COPEPODS IN JAMAICA BAY

The effects of Ulva biomass on interstitial copepods in a Jamaica Bay sand flat adjacent to a fringing salt marsh were studied from midjuly through October, 1999: Three treatments were established: Ulva present (UP), Ulva removed (UR), and Unvegetated (UV.) 18 species were identified from core samples. Mean sample species richness (SR) increased from 1.6 spp at the UP site to 3.29 spp at the UV site. Copepod densities increased from 9.7 (UP) to 28 per 20 cm-2 at the UV site. The overall effects of Ulva accumulation were a 52% and 65% reduction respectively in SR and abundance. SR and density were lowest in late summer, especially at the UP and UR sites. This is correlated with diurnal patterns in DO; periods of anoxia lasting up to 16 hrs per night and morning were recorded within the Ulva mat. Traps were deployed to sample the emergence of copepods on flood tides. Lowest rates occurred at the UV site. This study suggests that sea lettuce-related degradation of the shore environment could affect resident fish species (e.g. Fundulus majaii which, as post-larvae (<20 mm,) are obligate consumers of copepods.

Gaeckle*, J.L. and F.T. Short, Jackson Estuarine Laboratory, University of New Hampshire, Durham, NH, 03824.

THE EFFECTS OF MICROTOPOGRAPHY ON EELGRASS (ZOSTERA MARINA L.) PRODUCTION AND MORPHOLOGICAL CHARACTERISTICS

We monitored plant characteristics and production of eelgrass, Zostera marina L., at the intertidal Fishing Island eelgrass meadow in Kittery, Maine, between March 1999 and April 2000. Groups of eelgrass shoots were pinned within the leaf sheath every month at two sites 50 m apart: Fishing Island East (FIE) and Fishing Island West (FIW). Sites were similar except for small differences in water depth (< 0.25 m), which resulted in greater intertidal exposure at FIW during extreme low tide periods. As a result of this microtopography, there were important differences in several eelgrass morphological characteristics, including average leaf length and width, sheath length, shoot production, and plastochron between the two sites. Eelgrass leaf and sheath length at FIE, the less exposed site, were larger throughout the study and reached their maximum dimension two months earlier than FIW. In addition, maximum shoot growth at FIE occurred in June, two months earlier than the more exposed FIW. Larger shoots at FIE allowed greater daily growth per shoot through the spring and summer, but growth at both sites was similar throughout the fall and winter. The leaf plastochron followed a similar pattern between sites throughout the year, but during the spring and summer new leaves were produced faster at FIW. Surprisingly, this small difference in intertidal mircotopography affected plant morphology and overall site production between FIE and FIW and elucidate an important factor controlling eelgrass production throughout the intertidal Fishing Island eelgrass meadow.

Ray P. Gerber, Department of Biology, Saint Joseph's College, 278 Whites Bridge Rd., Standish, ME 04084.

AN IDENTIFICATION MANUAL TO THE COASTAL AND ESTUARINE ZOOPLANKTON OF THE GULF OF MAINE REGION

This new manual uses tabular style keys, large illustrations and text descriptions, to identify adult holoplanktonic zooplankton to species. All copepoda (calanoids, cyclopoids and harpacticoids), cladocera, ostracoda, chaetognatha and larvacea found in the region can be identified. Identifications are made without the removal of appendages. Instead, identifications are based on external features observed with compound and stereo- dissecting microscopes. Also, the common types of meroplanktonic organisms (e.g., larval stages of invertebrates and fish) are identified using illustrations and text descriptions. The manual consists of two separate parts. Part I contains the text that includes the instructions, identification keys, species descriptions, distributions, methods, glossary and references. Part 11 contains over 200 large illustrations that show dorsal and/or lateral views of the entire specimen as well as details of various body parts. Both male and female are shown for each species. The intended useful range of the manual is from Passamaquoddy Bay to Long Island Sound, though the maximum useful range encompasses the entire coastal Canadian Maritimes southward to about Delaware Bay.

Green, Mark, Saint Joseph's College of Maine.

SEASONAL PATTERNS OF CARBONATE DIAGENESIS IN NEARSHORE TERRIGENOUS MUDS: RELATION TO SPRING PHYOPLANKTON BLOOM AND TEMPERATURE.

Pore water saturation states with respect to calcite and aragonite minerals in Long Island Sound sediments fluctuate ftom saturated and near-saturated conditions in late fall, to undersaturated during winter, before slowly changing to supersaturated conditions during late spring and summer. Undersaturation occurs during cold, winter periods when lower rates of ‡CO2 production (low rates of heterotrophic metabolism) and oxidation of reduced minerals such as FeS lower calcium carbonate saturation states. Higher ‡CO2 production rates during warmer periods cause the CO2- concentration to become supersaturated for both calcite and aragonite. Direct evidence that dissolution is occuring during periods of undersaturation comes from increases in pore water Ca2+, Sr2+, and F- in excess of overlying water concentrations. In addition, pore water undersauration coincides with periods of rapid foraminifera disappearance and suggests that benthic forams are a component in the yearly cycling of CaCO3 in estuarine sediments. Other organisms with carbonate tests, particularly juvenile bivalves, may also be affected by periods of undersaturated pore waters.

Hodum, D.G. University of Maine and Maine Department of Environmental Protection PO Box 404 Milford, ME 04461-0404

INTERTIDAL INVERTEBRATES IN CASCO BAY: BEFORE AND AFTER THE JULIE N OIL SPILL

In late September, 1996, the Julie N oil tanker struck the Million Dollar Bridge between Portland and South Portland, Maine and spilled oil into the Fore River region of Casco Bay. A fortnight before the spill occurred, biological and sediment samples were collected from the intertidal mudflats of the Fore River for master’s thesis work. Armed with limited pre-spill data, samples were collected one year after the spill and compared with previous data. The results revealed a community that responded in various ways, depending upon the biological level considered. Each species and feeding guild responded in varying ways, not revealing any definitive short-term effects. At the community level though, the results exhibited a potential shift in community structure from a more evenly distributed population to one in which two taxa accounted for over sixty percent of the total population.

James-Pirri*, M.-J., K.B. Raposa, J.G. Catena. NOAA/NMFS Restoration Center, Narragansett Laboratory, Narragansett, RI 02882; Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882; NOAA/NMFS Restoration Center, 1 Blackburn Dr., Gloucester, MA 01930

GUT CONTENTS OF MUMMICHOGS, FUNDULUS HETEROCLITUS (L.) FROM RESTORING AND UNRESTRICTED REGIONS OF SACHUEST PONT SALT MARSH, MIDDLETOWN, RI

Gut contents of mummichogs, Fundulus heteroclitus (L.), from three habitats (creeks, pools, and marsh surface) within restoring and unrestricted regions of Sachuest Point salt marsh was examined. Major diet components were detritus, copepods, diatoms, insects (larvae and adults), ostracods, and chironomids. The percentage of fish that had items in their guts and the percent gut fullness were similar between restoring and unrestricted regions of the marsh. Diet composition and percent abundance of diet items were also similar between the unrestricted and restoring marshes. However, differences in foraging patterns were observed among marsh habitats (creeks, pools, and marsh surface). Samples collected from creeks had the highest percentage of fish with items in their guts (96%), followed by fish sampled from pools (78%) and the marsh surface (69%). Fish from creeks also had the fullest guts, followed by fish from pools and marsh surface. Diet composition also differed among marsh habitats. Fish sampled from the creeks foraged primarily on detritus, diatoms and copepods, whereas fish from the pools foraged on mainly detritus, copepods and chironomids. Detritus, insects and diatoms were most a that restoring New England salt marshes can quickly reach functional equivalency with natural salt marshes in terms of feeding patterns of dominant marsh consumers.

Kalapasev*, N., and D. Osgood, Department of Biology and Environmental Science, University of New Haven, West Haven, CT 06516 and R. Chambers, Department of Biology, Fairfield University, Fairfield, CT 06430

GROWTH STRATEGY AND DISTRIBUTION OF PHRAGMITES AUSTRALIS ALONG ESTUARINE GRADIENT

Recent expansion of common reed (Phragmites australis) into tidal marshes of the Northeast U.S. has resulted in significant changes to the plant community and possibly wetland function. Above- and below-ground growth and plant nutrient status of P. australis were measured to predict the potential for spread in three marshes along the estuarine gradient of the Housatonic River, CT. Differences in allocation of growth and plant nutrients were also related to environmental variables (salinity, flooding duration, and sulfide). In contrast to higher average flooding depth between P. australis stands at the lowest salinity and high salinity sites (24.6 cm; 8.7 cm, respectively), average flooding duration was not significantly different between P. australis stands at the lowest salinity site and P. australis stands in the high salinity site (21.9%; 17.6%, respectively). Sulfide concentrations were higher in high salinity marsh, where P. australis is limited to small, isolated stands, relative to low salinity marsh, where P. australis is a near monoculture. The allocation of below-ground resources was lower in expanding P. australis stands in the lower salinity marshes. Rhizome characteristics (node length, diameter, number of root and rhizome buds) however, increased as we moved in the direction of decreasing salinity, along the estuarine gradient, suggesting that P. australis is allocating energy and resources towards vegetative propagation and expansion. Because of higher porewater sulfide and perhaps higher salinity, we suggest that P. australis is merely maintaining existing stands in higher salinity marshes and expanding in lower salinity marshes.

Kasper*, J.M., Bates College, Lewiston, ME, 04240

PHENOTYPIC VARIATIONS IN THE DOG-WHELK, NUCELLA LAPILLUS , ACROSS A GRADIENT OF WAVE EXPOSURE IN MAINE, USA

Different phenotypes of Nucella lapillus, an intertidal gastropod that exhibits non-pelagic, direct development, were measured across a gradient of wave exposure, ranging from environments with high wave energy (exposed) to environments with low wave energy (protected). Whelks were collected from six sites: three exposed to wave action sites (Pemaquid Point, Long Cove Point, and Giant Stairs) and three protected from wave action sites (Simpson Point, Cobworks Bridge, and Pemaquid Beach). The morphologies of shell shape and banding patterns were measured for all individuals. A dynamometer was used to measure exposure and group sites into exposed shores and protected shores. Whelks from protected shores were significantly larger in overall length then whelks from exposed shores (51.96%). After controlling for the variations in overall shell lengths, aperture lengths and widths were found to vary significantly as a function of exposure. Whelks from exposed shores showed a 11.22% increase in aperture length and a 23.07% increase in aperture width. There was a significant increase in the number of banding patterns that occurred at the exposed shores over the protected shores. Twelve different banding patterns were observed on the whelks from exposed shores and six different banding patterns were observed on the whelks from protected shores. Additionally, banding patterns were found to vary among locations. The variations in shell shape morphologies are largely adaptive: larger apertures offer more resistance to dislodgment at the wave exposed sites; smaller apertures offer greater resistance to increased predation intensities at the protected sites. The mechanism for the variations in banding pattern is still unknown.

Keay*, Kenneth, Mass. Water Resources Authority, Boston MA. Eugene Gallagher, U/Mass Boston, Boston, MA. Roy Kropp, Battelle, Duxbury MA. James Blake, ENSR, Woods Hole MA.

SPECIES RICHNESS INCREASES IN MASSACHUSETTS COASTAL SEDIMENTS.

Soft-bottom benthic monitoring in coastal waters of the Massachusetts Bays system has been carried out annually by MWRA since August 1992. Sampling has been carried out at from 9-20 nearfield stations within 5 km of the future offshore outfall in western Massachusetts Bay and at an additional 11 farfield reference stations in the remainder of the system. Species richness at relatively shallow nearfield and farfield stations in western Mass. Bay decreased approximately 20% between 1992 and 1993, from an average log-series alpha of 12.7 (1992) to 10.4 (1993). A similar decrease is apparent in average species per grab, which declined from 63.3 to 47.6. Species richness at these sites i