James S. Latimer

Dinoflagellate cyst records and human disturbance in two neighboring estuaries, New Bedford Harbor and Apponagansett Bay, Massachusetts (USA)

The dinoflagellate cyst records in sediments from New Bedford Harbor and Apponagansett Bay demonstrate sensitivity to environmental change caused by human activity in the watersheds over the last 500 years. Changes in the species richness, as well as absolute and relative abundance of dinoflagellate cyst taxa reflect recent periods of development around the estuaries. Cyst taxa sensitive to these changes include Dubridinium spp., Polykrikos schwartzii, Lingulodinium machaerophorum, Operculodinium israelianum and Selenopemphix quanta. The greatest changes in the dinoflagellate cyst record occur during the 20th century, when New Bedford Harbor was exposed to both toxic pollution and heavy nutrient loading from point and non-point sources. Apponagansett Bay was not subject to industrial pollution and nutrient enrichment has been lower (from non-point sources). In Apponagansett Bay there is an increase in the dinoflagellate cyst species richness while species richness first increased, then declined in New Bedford Harbor. During the same period, the total dinoflagellate cyst concentration in New Bedford Harbor fluctuated over a wide range. The decline of species richness and the large fluctuations in the total cyst abundances signal the intensified anthropogenic disturbance in the watershed, notably a high degree of eutrophication and toxic pollution.

POLLUTION MONITORING IN TWO NORTH AMERICAN ESTUARIES: HISTORICAL RECONSTRUCTIONS USING BENTHIC FORAMINIFERA

Both surface and core studies from two highly impacted estuaries (New Bedford Harbor, Massachusetts, USA and Halifax Harbour, Nova Scotia, Canada) were carried out to determine if benthic foraminifera could be used to detect changes through time in these areas. New Bedford Harbor is in a highly industrialized area that has undergone severe environmental stresses from a variety of sources for almost 400 years, and has been declared an U.S. Environmental Protection Agency (EPA) Superfund site (i.e., a site so impacted that a special EPA fund is set up to clean it up in designated time frame). Halifax Harbour has been subjected mostly to domestic pollution (i.e., organic carbon produced by human wastes), rather than industrial (chemical) pollution since the founding of the city in 1749. Although many geochemical studies have been done in both estuaries, there are few baseline data on the biota. In this paper we use benthic foraminiferal assemblages retrieved from sediment cores to reconstruct biotic changes of the recent past. It is then possible to correlate faunal changes with already known geochemical parameters. The character of the pollution has changed in New Bedford Harbor as remediation efforts have taken hold. This change was detected with the foraminifera. One outcome is that deformities among one species, Haynesina orbiculare, appear to occur simultaneously with high polychlorinated biphenyls (PCB’s) in the sediments. In Halifax Harbour, where the largest impact is due to high organic input from domestic sources, species tolerant of low-oxygen conditions are most prominent at present. Core studies show that prior to the rapid growth of Halifax (in the 1960s) the organic input was much lower than at present. The higher input of organic carbon (OC) at present is indicated by foraminiferal species tolerant of high OC in cores since 1960, generally those with agglutinated as opposed to calcareous tests. We define industrial vs. OC pollution in sediments using foraminifera as proxies, and further, the environmental history is accurately depicted without original baseline data. Data from these two estuaries can be compared to other sites where degradation may be in different stages, which can be assessed by looking at foraminiferal faunas in those areas.

The chemistry and toxicity of sediment affected by oil from the North Cape spilled into Rhode Island Sound

Abstract On 19 January 1996, the barge North Cape spilled more than three million liters of No. 2 fuel oil into Rhode Island Sound near Matunuck, Rhode Island. The toxicity and chemistry of this oil in two subtidal sediments were followed for more than 9 months. Maximum concentrations of polycyclic aromatic hydrocarbons (PAHs) in the sediments reached 730 μg / g dry weight (DW). Water samples taken immediately after the spill were phototoxic to embryos of the bivalve Mulinia lateralis. Total PAHs and toxicity to the amphipod Ampelisca abdita were high immediately after the spill, decreasing to background values ( 10 μg / g DW and

Environmental stress and recovery: the geochemical record of human disturbance in New Bedford Harbor and Apponagansett Bay, Massachusetts (USA)

Sediments record the history of contamination to estuaries. Analysis of the concentrations of toxic organic compounds, contaminant and crustal metals, organic carbon content and isotopic composition in sediment cores from two estuarine systems in Buzzards Bay allowed reconstruction of human impacts over 350 years. Vertical distributions of the contaminants correlate with changes in the nature of watershed/estuarine activities. All contaminants were highly enriched (tens to hundreds times background) in modern New Bedford Harbor sediments. Enrichment began around the turn of the 20th century for all but PCBs, which were first synthesized in the 1930s. An increase in organic carbon content and a shift of carbon isotopes toward a more terrestrial signature illustrates increasing anthropogenic impact in New Bedford as population grew along with the industrial base. Institution of environmental protection measures in the late 20th century was reflected in decreased, although still substantially elevated, concentrations of contaminants. A lack of industrial development in Apponagansett Bay resulted in much lower concentrations of the same indicators, although specific contaminants related to the early whaling industry increased significantly above background as early as the late 18th century. The similarity of indicators in older portions of cores from NBH and unimpacted Apponagansett Bay demonstrates that cores can be used to establish reference conditions as successfully as using separate sites judged a priori to represent the reference state. The historical reconstruction approach provides the basis for establishing relationships between environmental stressors and factors that drive the stressors, as well as a framework for the assessment of ecological response(s) to environmental stressors over a range of time and/or exposure scales.

Assessing the Effects of Natural and Anthropogenic Stressors in the Potomac Estuary: Implications for Long-Term Monitoring

Ecological conditions in the Potomac Estuary are affected by a variety of natural and anthropogenic stressors. Natural climatic factors combined with anthropogenic activities affect fluxes of material through Potomac River watersheds and cause changes in ecological conditions in the Potomac Estuary. A basic premise of this ongoing study is that effects of anthropogenic and natural stressors can be distinguished. The investigation involves: 1) analysis of existing data using time series methods, 2) retrospective modeling to link the response of estuarine water quality to changes in stressors, and 3) new measurements on sediment cores from the Potomac Estuary. Estuarine effects being considered include changes in the distribution and abundance of chlorophyll a, diatoms, dinoflagellates, ostracods, submerged aquatic vegetation, benthic fauna, dissolved oxygen, and foraminifera. Since current conditions may be due to the accumulation of effects over many years, our research considers variability and changes during the past century in the context of long-term changes during the past 500 years. The availability of large data sets from the past century, long-term information on variability in precipitation from tree ring data from the past 300 years, and paleoecological studies by other investigators in the Potomac Estuary and main stem of Chesapeake Bay make the Potomac Estuary an ideal place to develop methods to distinguish between effects of natural and anthropogenic stressors in estuaries, in the context of a varying, and perhaps changing, climate.

State of the Estuaries in the Mid-Atlantic Region of the United States

The U.S. EPA has prepared a State of the Region Report for Mid-Atlantic Estuaries to increase knowledge of environmental condition for improved environmental management. Sources of information included the National Estuary Programs, the Chesapeake Bay Program, the state monitoring programs in Delaware, Maryland, and Virginia, Federal programs such as National Status & Trends, National Shellfish Register, National Wetlands Inventory, the Environmental Monitoring and Assessment Program, and other primary literature sources. The state of the estuarine environment was summarized using indicators for water and sediment quality, habitat change, condition of living resources, and aesthetic quality. Each indicator was briefly discussed relative to its importance in understanding estuarine condition. Wherever possible, data from multiple programs were used to depict condition. Finally, an overall evaluation of estuarine condition in the region was determined. The usefulness of monitoring programs that collect consistent information with a well-defined sampling design cannot be overemphasized.

Condition of the Mid-Atlantic Estuaries: Production of a State of the Environment Report

The U.S. Environmental Protection Agency has released a report entitled Condition of the Mid-Atlantic Estuaries. That report summarizes the findings of several studies conducted by federal and state agencies and academic institutions in Chesapeake Bay, Delaware Estuary, and the coastal bays of Delaware, Maryland, and Virginia, and simultaneously addresses two distinct audiences: environmental managers and the general public. This paper documents the process of preparing the Estuaries Report, emphasizing the lessons learned in merging information from a wide-variety of sources and in reporting the results to multiple audiences. The major difficulties in preparing the report included: 1) choosing a format and topics that adequately addressed both environmental managers and the public, 2) resolving spatial and temporal disparities in the assembled data sets, and 3) establishing threshold values that distinguished between acceptable and unacceptable conditions in indicators. Our solutions to these challenges and alternatives are discussed. We conclude that a small team of knowledgeable scientists can effectively merge the information of diverse sources into a document that is useful to both environmental managers and the interested public. However, considerable interaction between the team and other scientists was necessary to resolve ambiguities and assure relevancy and accuracy. These findings support the proposition that the vast sources of existing environmental information can be easily and effectively used to assess the ecological condition across large regions.

Biogeography of dinoflagellate cysts in northwest Atlantic estuaries.

Abstract Few biogeographic studies of dinoflagellate cysts include the near‐shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic‐walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present‐day species distribution, the factors controlling them, and to better predict how they may change in the future.

Synthesis for Management

Among the first and most densely settled of estuaries in the United States, Long Island Sound presents a trajectory of change common to many estuarine and coastal ecosystems. The challenges to managing this ecosystem for the future also are mirrored in other coastal systems. Improving management of Long Island Sound requires synthesis and integration of the underlying science. The implications of such insights to the ecosystem, including changes that may be driven by broader climate patterns, must be incorporated into regulatory and management approaches. To demonstrate the utility of this analysis, key advancements in the science of the Long Island Sound ecosystem are summarized. To support integration with management, we present essential elements of the Clean Water Act, providing specific examples of current program policies in synchrony or in conflict with the principles of ecosystem-based management. We then recommend a general framework and specific actions to support ongoing management of Long Island Sound.

Effect of nutrient pollution on dinoflagellate cyst assemblages across estuaries of the NW Atlantic

We analyzed surface sediments from 23 northeast USA estuaries, from Maine to Delaware, and nine estuaries from Prince Edward Island (PEI, Canada), to determine how dinoflagellate cyst assemblages varied with nutrient loading. Overall the abundance of cysts of heterotrophic dinoflagellates correlates with modeled nitrogen loading, but there were also regional signals. On PEI cysts of Gymnodinium microreticulatum characterized estuaries with high nitrogen loading while the sediments of eutrophic Boston Harbor were characterized by high abundances of Spiniferites spp. In Delaware Bay and the Delaware Inland Bays Polysphaeridium zoharyi correlated with higher temperatures and nutrient loading. This is the first study to document the dinoflagellate cyst eutrophication signal at such a large geographic scale in estuaries, thus confirming their value as indicators of water quality change and anthropogenic impact.