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TRANSPORT OF TOXIC ALEXANDRIUM POPULATIONS INTO MASSACHUSETTS BAY
Donald M. Anderson and Bruce A. Keafer
Biology Department, Woods Hole Oceanographic Institution, Woods Hole MA

Toxic or harmful algal blooms (commonly called "red tides") are a serious economic and public health problem throughout the US and the world. In the New England region, the most serious problem is that of paralytic shellfish poisoning (PSP), a potentially fatal neurological disorder caused by human ingestion of shellfish that accumulate toxins as they feed on dinoflagellates of the genus Alexandrium. Past research on these phenomena has led to the hypothesis that toxic Alexandrium cells are introduced to the Massachusetts and Cape Cod Bays via a coastal current formed from the outflow of rivers in southern Maine. When this coastal current enters Massachusetts Bay, it sometimes passes over or close to the new MWRA outfall site. This leads to concern that nutrient inputs from the outfall might stimulate the growth of red tide algae, worsening the PSP problem. This issue is especially relevant to South Shore and Cape Cod communities "downstream" from the outfall, given the typical north-to-south mesoscale circulation of the Bays. Recent public controversy over these possible effects have highlighted the limited understanding of the PSP phenomenon within the Bay itself or about the manner in which the PSP toxins move through the food chain to zooplankton, fish, and marine mammals. The objective of this poster is to summarize our understanding of the dynamics of Alexandrium within Massachusetts Bay by focusing on field data during one year (1993) when cells were abundant within the Bay and one year (1994) when they were not. A general conceptual model of how blooms and toxicity develop within the bay will be presented and discussed in the context of the Massachusetts Bay outfall.

See Alexandrium Poster (PDF 3,932 KB)

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SEDIMENT CONTAMINANT MONITORING IN MASSACHUSETTS
AND CAPE COD BAYS

Deirdre Dahlen, Lisa Lefkovitz and Carlton Hunt
Battelle, Duxbury, MA


Monitoring of toxic contaminants in sediments is one of three main concerns addressed by the Benthic (Sea-Floor) Monitoring component of the MWRA Harbor and Outfall Monitoring (HOM) program. Benthic monitoring collects data on the benthic macrofauna and flora, and the physical properties and levels of organic matter, nutrients, sewage indicators, and contaminants in the sediments in which the macrofauna reside. Measurements are made over a wide geographic area influenced by many natural and anthropogenic factors including effluents from MWRA wastewater outfall. Outfall monitoring includes nearfield and farfield sampling but is focused most intensely on the nearfield area (<8 km from outfall) where changes in water and sediment quality following initiation of the discharge is most likely to be detected, if they occur. Farfield locations (>8 km from the outfall) serve primarily as reference areas for the nearfield or as monitoring stations if the discharge affects sites distant from the diffuser. In addition, a Special Contaminant Study is performed three times a year at stations NF08, NF22, NF24, and FF10 to address possible short-term transport and impact.

The objectives of sediment contaminant monitoring component of the HOM program are to:

Concentrations of organic and metal contaminants are generally low and highly variable. Variability is related to grain size and TOC, which are variable also. Nearfield average concentrations of organic and metal contaminants are well below levels of ecological concern and are similar over time.

See Sediment Poster (PDF 1,959 KB)

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LONG-TERM TRENDS IN PRODUCTIVITY
Aimee Keller, Candace Oviatt, Tarquin Dorrington, Gywnne Holcombe, and Laura Reed
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI

Primary productivity represents the autotrophic fixation of carbon dioxide by phytoplankton during photosynthesis. Because phytoplankton form the base of the marine food web, primary production is the key process that brings food into a marine system. Changes in the rate of primary production are essential to measure since they affect not only the concentration of plant biomass but also the organisms that eat them.

Phytoplankton productivity is also important since it is closely tied to the cycling of nutrients and the concentration of oxygen. The major goal during the baseline monitoring of productivity was to establish the range and variability in annual productivity at two sites: near the site of the Massachusetts Bay outfall (Stations N04, N16 or N18) and near the entrance of Boston Harbor (Station F23).

Annual productivity ranged from a low of 141 g C m-2 y-1 at station N04 to a high of 787 g C m-2 y-1 at Station F23 from 1992 -1998. Mean annual productivity was higher (mean 494 g C m-2 y-1) and more variable near the Harbor entrance (Station F23) than at the nearfield sites (Stations N04, N16 and N18). At station F23 productivity varied greater than 5-fold over the 7-year sampling period. Average annual productivity and variability around the means were considerably lower at Stations N04 (mean 285 g C m-2 y-1) and Station N16-18 (mean 396 g C m-2 y-1). Annual productivity in 1998 was unusually low at all three sites (<160 g C m-2 y-1) due to the failure of the winter-spring phytoplankton bloom. The absence of the 1998 bloom was linked to warmer winter temperature and increased grazing by zooplankton during the bloom period.

The seasonal cycle of areal primary productivity (mg C m-2 d-1) at the nearfield stations (N04, N16, N18) was generally characterized by a well-developed winter-spring bloom of several weeks duration, high production during the summer and a less prominent fall bloom. The majority of production (mg C m-3 d-1) typically occurred in the upper 20 m of the water column at the nearfield sites. At the Boston Harbor station (F23), a gradual pattern of increasing areal production from winter through summer was more typical with the majority of production occurring in the upper 5-10 m of the water column.

If nutrient concentrations increase in the euphotic zone as a result of the relocated outfall, primary production may increase perhaps leading to greater phytoplankton biomass or increased secondary productivity.


See Productivity Poster (PDF 113 KB)

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JUVENILE LOBSTERS AT THE NEW OUTFALL SITE: COMPARISONS WITH INSHORE AND POPULATION AND DISCUSSION OF POTENTIAL OUTFALL IMPACTS ON LOBSTER POPULATIONS
Kari L. Lavalli, Southwest Texas State University, San Marcos, TX
Roy K. Kropp, Battelle, Duxbury, MA
Kenneth E. Keay, MWRA, Boston, MA

In late May 1998, the MWRA was directed by the Outfall Monitoring Task Force to design and execute a study in the cobble-boulder habitats of the new outfall nearfield region to sample early benthic phase lobsters ("EBPs", 5 to 40 mm carapace length (CL)), particularly that of new recruits ("young-of-the-year", <12 mm CL) and yearling lobsters (shelter-restricted, <20 mm CL). Both of these life history phases are thought to be relatively nonmobile, obligate shelter-dwellers. MWRA was also required to determine if the numbers of these life history stages were comparable to those of nearby inshore habitats. This mandate resulted from serious concerns about the effects that the new outfall might have on juvenile lobsters and, thus, the future of the economically important lobster fishery.

MWRA responded to this mandate by proposing a survey plan that was developed from examination of videotapes from a remotely-operated vehicle survey conducted in September, 1994, and previous data on lobster density from hard bottom surveys to determine suitable locations for sampling. A mathematical calculation was used to determine an appropriate minimum sample size for the collection of species occurring only rarely in a region. These tactics were designed to maximize the chances of locating young-of-the-year and shelter-restricted lobsters at the outfall vicinity. In early September 1998, EBP-density sampling was undertaken by the foremost experts in airlifting for lobsters underwater at both the vicinity of the outfall and two nearby inshore stations. The data collected showed significantly lower densities of young-of-the-year, yearling lobsters, and larger EBP lobsters at the outfall compared to the inshore sites. Measures of the proportion of non-zero observations (which is another measure of frequency) for each size class also showed significantly fewer non-zero observations at the outfall. Taken together, these data demonstrate that while the cobble habitat at the vicinity of the outfall is suitable for settlement, it does not represent a major settlement site and thus there is no indication that the outfall will have any appreciable impact on these life stages of the American lobster.

See Juvenile Lobster Poster text (PDF 63 KB)
See figure of larval life history stages (PDF 37 KB)
See map of Salem Harbor (PDF 330 KB)
See map with outfall location (PDF 377 KB)
See photo: Onboard sorting operations (PDF 358 KB)
See photo: Juvenile lobster collected at an inshore survey site in Salem Sound (PDF 371 KB)

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BENTHIC HABITATS OF BOSTON HARBOR AND NEARSHORE MASSACHUSETTS BAY AS CHARACTERIZED BY
SEDIMENT PROFILE IMAGING

Robert Diaz, R. J. Diaz and Daughters, Ware Neck, VA

Long-term trends and status of benthic habitats in Boston Harbor and Nearshore Massachusetts Bay was characterized using sediment profile imaging. In 1992, annual surveys started in Boston Harbor and in 1997 in the Nearfield area, initial SPI surveys in these areas were conducted in 1989 and 1992 respectively. Sediment profile imaging provided a means of assessing benthic habitat quality by collecting visual data on dominant physical and biological processes that structure benthic communities. Key indicators of habitat quality (amphipod tube mats, Redox Potential Discontinuity layer depth and Organism Sediment Index) in the Harbor declined in 1998 relative to previous years, however, major changes in habitat quality appeared to have occurred prior to 1992. Current habitat quality has developed in response to major disturbance events in 1991, a severe storm in October and sewage discharge abatement in December. Stations with poorest habitat quality in 1992 continued to have poor quality in 1998 (T04, R43). The decline in amphipod tube mats may represent a negative rebound of Ampelisca spp. populations that continually increased from 1992 to 1996. This amphiod is an important indicator that occurs in high abundance in areas trending from poor to good habitat quality. When habitat quality improves to a certain point, a decline in amphipod tube mats is to be expected. Trends in Nearfield habitat quality appeared to be related to the physically dynamics of the area. Bottom instability maintains a patchy mosaic of habitat quality. In 1998 and 1999, biological processes dominated surface sediments at almost all stations with an increase in the degree of bioturbation.

Predicted changes in benthic habitat quality with the operation of the Nearfield discharge are:

Boston Harbor:

  • Decline in Amphipod tube mats
  • Transition to a Stage III benthic community
  • Improved benthic habitat quality for inner harbor

    Nearfield:

  • Physical dynamics will control biological communities
  • Periodic appearance of Amphipod tube mats
  • Increase in epifauna

    Benthic Habitats Poster: Part 1 in Powerpoint (44,758 KB) Warning! May be slow to load
    Benthic Habitats Poster: Part 2 in Powerpoint (38,572 KB) Warning! May be slow to load
    Supplementary Information: Harbor Sediment Profile Imagery 1993-1998  (For the PC Only)

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    LOBSTER CONTAMINANT MONITORING IN
    MASSACHUSETTS AND CAPE COD BAYS

    Lisa Lefkovitz and Carlton Hunt
    Battelle Duxbury Operations, Duxbury, MA


    Lobsters have been collected from Deer Island, the Massachusetts Bay Outfall Site and Eastern Cape Cod Bay since 1992 to evaluate general health and contaminant levels. Edible meat and hepatopancreas tissues have been analyzed for selected organics and metals. Results from these analyses are used to evaluate the potential human-health exposure. Post -discharge results will be compared to the baseline period to determine if discharge from the outfall results in appreciable change from baseline values and to compare to the fish and shellfish monitoring thresholds. To date, chemical concentrations in edible meat for organics, such as PCBs and chlorinated pesticides, and mercury, have been highest in lobsters trapped near the present Deer Island outfall. The lowest concentrations are consistently found at the eastern Cape Cod Bay monitoring site. Hepatopancreas concentrations for organics show a similar trend. However, metals concentrations appear highest at the Outfall Site in Massachusetts Bay. Concentrations of most contaminants appear to have decreased since 1992 in both meat and hepatopancreas. The exceptions to this trend include silver in hepatopancreas tissue and PCBs and DDTs in both meat and hepatopancreas tissue at all locations. Metals concentrations have been much more variable than the organic contaminants among the sites over time. Concentrations measured throughout the baseline period were well below the monitoring threshold levels and human-health-consumption action limits.


    See Lobster Contaminant Poster (PDF 663 KB)

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    PHYTOPLANKTON AND ZOOPLANKTON OF BOSTON HARBOR, MASSACHUSETTS AND CAPE COD BAYS, 1992-1999,
    WITHIN A REGIONAL CONTEXT
    Jefferson T. Turner, David G. Borkman, & Jean A. Lincoln
    Center For Marine Sciences and Technology and Biology Department, University Of Massachusetts Dartmouth, Dartmouth, MA

    Phytoplankton and zooplankton have been sampled in Massachusetts and Cape Cod Bays and Boston Harbor since 1992. Patterns of community composition, abundance and seasonality of phytoplankton and zooplankton in Massachusetts and Cape Cod Bays are variable in time, on scales from daily (within a survey), to monthly (between surveys), to interannually. Spatial patterns of community composition are generally similar within a given survey for areas outside Boston Harbor, but the Harbor is usually distinct from adjacent offshore areas. Plankton patterns both within Boston Harbor, and offshore in Massachusetts and Cape Cod Bays are generally similar to those in contiguous areas such as the upstream Gulf of Maine, and adjacent areas to the south such as Buzzards Bay, New Bedford Harbor, and Georges Bank.

    See Phytoplankton Poster (PDF 91 KB)

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    INITIAL EFFLUENT DILUTION VERIFICATION
    AND PLUME TRACKING PLAN

    Carl Albro, Elizabeth Bruce, and Carlton Hunt, Battelle, Duxbury, MA
    Rocky Geyer, Woods Hole Oceanographic Institution, Woods Hole, MA
    Michael Mickelson, Massachusetts Water Resources Authority

    This poster describes the proposed plume tracking surveys to determine that initial dilution characteristics of the outfall meet NPDES permit requirements, and track the longer-term location and mixing dynamics of the outfall plume to verify that the plume continues to disperse and does not travel intact to resource areas.

    See Plume Poster (PDF 3,149 KB)

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    ASSESSING TEMPORAL CHANGES IN HIGHLY VARIABLE FECAL COLIFORM AND ENTEROCOCCUS DATA IN BOSTON HARBOR AND ITS TRIBUTARIES BY RANDOMIZED BLOCK FACTORIAL ANOVA
    G. Gong and J. Lieberman, ENSR, Inc., Acton, MA
    D. McLaughlin, Massachusetts Institute of Technology, Cambridge, MA
    A. Rex, Massachusetts Water Resources Authority, Boston, MA

    The "Boston Harbor clean-up" is a multi-billion dollar public investment in major public works projects, including addressing wet weather pollution from combined sewer overflows (CSOs). Since 1989, MWRA has monitored fecal coliform and Enterococcus counts in Boston Harbor and its tributaries. Water quality is poorest during wet weather; CSOs and stormwater are the major sources of bacteria. If CSO controls are effective, then bacteria counts in wet weather will be lower than counts before CSO controls were implemented. Tracking environmental effects of pollution control projects is complicated by high variability in the data that make it difficult to interpret changes in bacteria counts over time. Rainfall, geographic location, season, salinity, temperature, and tide are all sources of variation. The purpose of this study was to develop and use a statistical method to answer the question, "Have fecal coliform and Enterococcus counts in these waters changed significantly over time?" Fecal coliform and Enterococcus counts from more than 8,000 water samples at 130 locations were included in the analysis. Preliminary regression analyses failed to detect statistically significant changes in the relationship between bacteria counts and rainfall over time. Factorial ANOVA with randomized blocking to partition the data and control for factors (location, tide, season) not contained in the ANOVA treatments (time and rain) detected significantly lower counts in the study area as a whole after some CSO controls were implemented. Decreases were significant for fecal coliform, but not Enterococcus.

    See Poster (HTML 22 KB)

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    NEARFIELD HARD-BOTTOM COMMUNITIES
    NEAR THE MASSACHUSETTS BAY OUTFALL

    Barbara Hecker, Hecker Environmental Consulting, Falmouth MA

    Benthic communities inhabiting hard-bottom habitats (drumlins - rock covered topographic highs) near the Massachusetts Bay outfall have been surveyed annually since 1995. The surveys were conducted using a Benthos Mini Rover ROV to collect video images and color slides at selected sites (waypoints) near the outfall and at reference sites further away. The number of waypoints surveyed has expanded from 19 waypoints (17 near the outfall and 2 reference) in 1995 to 23 waypoints (16 near the outfall, 6 reference, and diffuser head #44) in 1997. Diffuser #44 will not discharge effluent, and was added to the survey because it affords a worst-case example in the extreme nearfield. The major emphasis of the hard-bottom survey was shifted from video images to color slides since 1996, because of the greater resolution afforded by still images. Approximately 20 minutes of video footage and 30 color slides were collected at each waypoint. The video images were used primarily to qualitatively evaluate sea floor characteristics (habitat relief, substratum size class, degree of sediment drape, and habitat heterogeneity) and the occurrence of sparse larger organisms. The still photographs were used to semi-quantitatively assess the relative proportion of benthic inhabitants at each waypoint.

    The sea floor on the drumlin tops consisted typically of a mix of boulders and cobbles. Habitat relief in these areas varied from high (predominantly boulders) to moderate (cobbles with occasional boulders). Sediment drape on the drumlin tops was usually light to moderate, but was occasionally heavy at locations that supported a high abundance of upright algae. The sea floor on the flanks of the drumlins usually consisted of a cobble pavement interrupted by occasional patches of gravel, sand or boulders. Habitat relief in these areas usually ranged from low to moderate, depending on the number of boulders present. Sediment drape in the drumlin flank areas usually ranged from moderate to heavy. While some areas were homogeneous with regard to sea floor characteristics, many areas were quite heterogeneous, such that slight lateral shifts in position resulted in markedly different habitats. This spatial heterogeneity was frequently most pronounced on the flanks of the drumlins.

    The benthic communities inhabiting the drumlins appeared to be controlled by a combination of location on the drumlin (concurrent with depth), substratum size class and associated habitat relief, and degree of sediment drape. Algae usually dominated the benthic communities inhabiting the tops of drumlins, while invertebrates (mostly encrusting or attached forms) frequently dominated the communities on the flanks. The encrusting coralline alga Lithothamnion spp. dominated in drumlin top areas that had little sediment drape. In contrast, upright algae (Asparagopsis hamifera, dulse and shot-gun kelp) dominated in areas of high relief. The holdfasts of the upright algae appeared to trap sediment, resulting in a reduction of Lithothamnion. Other taxa commonly encountered were the horse mussel Modiolus modiolus, the northern sea star Asterias spp., the sea pork tunnicate Aplidium spp., and the cunner Tautogolabrus adspersus. Sediment areas tended to be depauperate, while the diffuser heads typically supported dense aggregations of the frilly anemone Metridium senile and numerous Asterias spp.

    The benthic communities were temporally quite stable over the 1995 to 1998 time period. Within-site changes in the percent cover of Lithothamnion spp. and in-community composition between sampling periods frequently reflected slight lateral shifts in sampling location. This temporal stability enhances the likelihood of detecting large changes in the composition of the hard-bottom communities during discharge monitoring. Of all species encountered during this study, Lithothamnion spp. was the least variable and most predictable. As a result, Lithothamnion appears to hold the most promise as an "indicator" of habitat health during monitoring of the outfall discharge. It is abundant, widely distributed, predictable in terms of habitat requirements, and appears to be sensitive to particulate loading.

    See Hard-bottom Communities Poster (PDF 80 KB)

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