Grantee Research Project Results
Final Report: Dynamics, Variability and Patterns of Harmful and Red Tide Bloom-Species in Narragansett Bay: Ecological Analysis of a 38-Year Time Series
EPA Grant Number: R829368Title: Dynamics, Variability and Patterns of Harmful and Red Tide Bloom-Species in Narragansett Bay: Ecological Analysis of a 38-Year Time Series
Investigators: Smayda, Theodore J. , Borkman, David G.
Institution: University of Rhode Island
EPA Project Officer: Packard, Benjamin H
Project Period: September 28, 2001 through January 27, 2006 (Extended to September 30, 2006)
Project Amount: $348,912
RFA: Ecology and Oceanography of Harmful Algal Blooms (2001) RFA Text | Recipients Lists
Research Category: Water Quality , Water , Aquatic Ecosystems
Objective:
This project developed in response to the global increase and regional expansion of harmful algal blooms (HABs) and red tides occurring in global coastal waters. The global increase in HABs is having devastating impacts on public health, seafood safety, natural resources, ecosystems, aquaculture, marine-related local and regional economies, and tourism. It has been accompanied by human illness and mortality, ecosystem disruption, anoxia, and HAB-induced dieofs of fish, invertebrate, and marine mamals, including whales, manatees and dolphins. New toxic species and harmful impacts continue to be discovered; regions previously considered free from toxic blooms now suffer such blooms; species previously to be benign have become toxic; the geographic range of some toxic species appears to be spreading, and in many regions the frequency and intensity of HAB and red-tide outbreaks have been increasing. Enormous HAB-induced financial losses have resulted to commercial fisheries, fish farms and shellfish aquaculture, the losses sometimes exceeding $100 million per bloom outbreak. This project developed in response to the global HAB phenomenon, since the causes and regulation of HABs, both on local and global scales, are poorly understood. Public health is affected because of ingestion of edible shellfish that become toxic when feeding on the toxic micro-algae that produce HABs, and lead to illness such as Paralytic Shellfish Poisoning, Diarrhetic Shellfish Poisoning, among others.
The overall objective of this research project is to fill fundamental knowledge gaps in the ecology of harmful and nuisance algal blooms and red tides. The specific objectives are to: (1). describe the long-term trends, patterns and variablity in HABs in a representative estuary; (2). elucidate the ecological conditions and mechanisms underlying the selection and bloom cycles of 18 indigenous and representative HAB and benign red tide species in Narragansett Bay; (3). quantify the effects and interactions of meteorological, climatic, physical, chemical and biological parameters in this variability; and (4). apply and evaluate the "open niche" hypothesis as a general HAB paradigm. While this research is centered in Narragansett Bay, a representative estuary, the indigenous HAB and red tide species evaluated are cosmopolitan and well known for their blooms globally. The time series is based on weekly quantitative sampling of the physical and chemical conditions of Narragansett Bay and accompanying plankton populations, making it the longest time series of this type available globally. This provides an unusual opportunity both to evaluate human and climate influences on harmful blooms, and to apply the results from Narragansett Bay to coastal waters generally.
Approach:
Thirty-eight-year quantitative, process-oriented, time series based on weekly measurements of plankton - habitat variables in combination with autecological and field population approaches will be analyzed. Four different climatic indices will quantify the importance of climate in regulating HABs and benign red tides relative to habitat variability in physical, chemical and biological parameters. The hypothesis that the selection, succession and blooms of HAB and red tide taxa are under both multifactorial and species-specific control, and involve at least four different regulatory mechanisms, will be evaluated. The data management system and website to be developed will be based on an Excel and multiplatform relational database software allowing electronic/website access.Summary/Accomplishments (Outputs/Outcomes):
- Major shifts in the long-term bloom behavior of the diatom Skeletonema costatum, numerically the most important phytoplankton species in Narragansett Bay (NBay) impacted the niche and habitat properties, and affected harmful algal bloom (HAB) and red tide species dynamics. Over the 38-year time series (1959 - 1996), the mean annual abundance of Skeletonema declined two-fold, accompanied by a seasonal shift in the annual bloom maximum from winter-spring (1960s decade) to summer during the 1970s decade, which continued, at lower abundance, through the 1980s. During the 1990s decade (1990 - 1996), a series of annual blooms (n = 5) of nearly equal magnitude replaced the summer maximum of 1970s and 1980s and the annual bimodal bloom cycle consisting of a major and a minor bloom.
- The changes in Skeletonema's annual abundance and seasonal bloom pattern were a significant ecosystem change, and paralleled by changes in oceanic/atmospheric circulation patterns proxied by the North Atlantic Oscillation Index (NAOI) and the position of the Gulf Stream north-wall located 200 to 400 km offshore of NBay. Linear regression analysis of this association indicated the long-term changes in Skeletonema's bloom pattern were climatologically driven. Winter-spring bloom years tended to be bright, windy and cold, with reduced winter zooplankton (Acartia hudsonica) abundance. Summer bloom years were dark, warm, had calm winds, and winter A. hudsonica abundance was elevated. In years when the NAOI was low, winter water temperature was colder and the winter-spring bloom dominated the annual cycle (1960s). In years when the NAOI was elevated (1970s, 1980s), winters were warmer and summer blooms prevailed.
- Within this pattern, a NAOI threshold was identified. When the NAOI was < - 0.7 (i.e., cold winters) a winter-spring bloom developed; when the annual NAOI was > - 0.7 summer bloom maxima occurred. Consistent with this temperature - NAOI linkage, a threshold winter water temperature of + 2oC was identified. In years when the winter temperature was < + 2oC, a winter-spring maximum occurred; when it exceeded + 2oC, a summer maximum developed.
- The strong influence of atmospheric (climatological) and far field hydrological factors on diatom bloom cycles indicates NBay is an "open system" subject to external regulation (drivers); i.e., plankton dynamics and, by extension, HABs and red tides are under dual regulation – internal and external. This indicates regional climatological and hydrographic measurements must be incorporated into HAB field and modelling studies aimed at quantifying HAB regulation. Diatom dynamics – usually negected in HAB field investigations – also must be incorporated into HAB ecological studies at bloom sites where diatoms have a major ecosystem impact and, thereby, are a controlling variable affecting HAB and red tide dynamics. In NBay, Skeletonema is a major competitor for nutrients, which influences nutrient cycles, concentrations and nutrient ratios which in turn regulate HAB behavior. Skeletonema also is an important prey species for zooplankton, which influences grazer abundance and their predation on HAB and red tide species; climatological factors, such as proxied by the NAOI, influences Skeletonema's dynamics which has both direct and indirect affects on HAB dynamics.
- The linkage between HAB and red tide dynamics and the long-term bloom behavior of Skeletonema in NBay could not be more fully quantified from the data at hand – modelling studies beyond the scope of the present project are required. Nonetheless, the ecological assessment of Skeletonema's behavior has provided keen insights into the potential regulation of the patterns, trends, variability in the long-term behavior of HABs and red tides in NBay by diatoms, and point to the hitherto overlooked and neglected importance of the potential role of diatom competition as a factor influencing HAB dynamics in other regions.
- 1985 was an important transition year in the subsequent annual bloom behavior of Skeletonema costatum, HABs and red tides. Aureococcus anophagefferens, a previously unknown genus and species, initiated a novel brown tide bloom in May, 1985 that persisted for 5-months - the longest sustained bloom recorded in NBay. This high density, low biomass bloom (HDLB) also was the most harmful bloom recorded – it caused extensive mortality (99%) of the edible mussel (Mytilus edulis) population, impaired fish spawning, reduced zooplankton abundance, and caused seaweed mortality because the bloom reduced water transparency which inhibited photosynthesis.
- Principal Components Analysis revealed 1985 was a unique year within the 38-year time series. It clustered with drought years 1965 and 1966 in being among the 3 years in which annual irradiance was the highest and river flow the lowest. However, there is no quantitative evidence that reduced flushing accounted for the 1985 brown tide outbreak, or that it was related to nutrient anomalies. The brown tide was a bay-wide event, with extremely high abundance (up to 1 billion cells L-1) occurring at both high and low macro-nutrient (N, P) concentrations.
- There was a statistically significant correlation (r = + 0.55) between the North Atlantic Oscillation Index (NAOI) and the Groundwater Index (GWI), similar to that reported for Long Island brown tide bloom sites, where it was hypothesized that the relative supply and ratio of dissolved inorganic (DIN) and organic nitrogen (DON) associated with the NAOI influenced ground water discharge which regulated the brown tide. Although a highly significant inverse correlation (r2 = 0.41) occurred between mean Aureococcus abundance and the GW Index during the 1985 bloom in NBay, calculations of riverine and ground water influxes of dissolved organic nitrogen (DON), its ratio with dissolved inorganic nitrogen (DIN), N uptake rates by Aureococcus, and its population abundance do not support the view that a reduction in the ground water influx of NO3 elevated the ratio of DON to DIN and accounted for the bloom, unlike at Long Island brown tide bloom sites.
- A progressive cascade in the failure of grazing processes at several trophic levels favored Aureococcus bloom emergence and population increase. During the initial bloom stages, a reduction in microzooplankton abundance (ciliates, protoperidinians) facilitated the bloom; the progression to higher abundance levels then impaired zooplankton (copepod, cladoceran) grazing, fecundity and abundance. As the brown tide population continued to grow, the increasing abundance increasingly impaired benthic filter feeding, particularly that of mussels (Mytilus edulis), which suffered 99% mortalty, and prolonged the bloom. Experimental evidence (by others) supports the field evidence that cascading grazer impairment was an important factor in the Aureococcus bloom event. Electron micrographs of the population at the termination of the bloom in October, 1985 revealed heavy viral infestation, suggesting this was the cause of bloom termination. The results indicate the need to incorporate grazing processes into field studies of HAB ecology, processes that are usually neglected.
- The exact condtitions stimulating the local (NBay) and regional brown tide in 1985 are obscure, but regional climatology appears to be a factor. Evidence for this "external driver" includes the regional synchroneity in brown tide occurrence, the results of principal component analysis, and correlation of the ground water and NAO indices The NAOI is a proxy for atmospheric/weather parameters that influence plankton dynamics, such as wind direction, strength, rainfall, cloudiness, temperature and groundwater level. Conceptually, the novel 1985 brown tide, which has not recurred in NBay, was the result of a two-step process. Initially, a regional scale atmosphere/oceanic interaction set the ecological stage for the Aureococcus bloom which, once initiated, came under the control of internal ecosystem factors such as flushing, nutrients, grazing, etc.
- Blooms of HAB and red tide species in NBay, including bloom-species selection, bloom duration and magnitude, and ecosystem impact are highly variable and unpredictable, in contrast to recurrent seasonal and annual diatom blooms. The causes of the unpredictable, episodic bloom behavior of HAB and red tide species within NBay, and generally, remain obscure. This behavior has been characterized as a result of the bloom-species "being in the right place at the right time."
- Cyclical and rhythmic long-term patterns and trends in bloom behavior were embedded within the stochastic behavior and unpredictability that characterizes HABs and red tides. HAB and red tide species greatly increased in abundance beginning in the 1980s, which persisted for a decade accompanied by a pronounced change in annual diatom bloom behavior. Prior and subsequent to this efflorescense, diatoms dominated phytoplankton dynamics. The "HAB and red tide decade" was followed by equally remarkable declines in both major and minor bloom-species. Ichthyotoxic Heterosigma akashiwo, the primary HAB species through the mid-1980s, and the 4th most abundant species overall until then, progressively declined and is now unimportant. Prorocentrum minimum, a major bloom species during 1972 - 1987, was the 24th most abundant species overall through 1980, and has since fallen to 39th in abundance rank, its decline beginning wth the 1985 Aureococcus anophagefferens brown tide.
- The analyses do not provide a general explanation for the collective downward trends and diminished blooms of harmful and red tide species; the causes appear to be species-specific based on the evidence for Prorocentrum minimum and Heterosigma akashiwo. For P. minimum, in situ nutrient concentrations (especially NO3 and PO4), riverine organic N delivery – mediated by wet versus dry conditions – and zooplankton abundance were key factors regulating its blooms. In the case of H. akashiwo, its abundance was not statistically correlated with temperature, irradiance, nor nutrients. Grazer regulation was also eliminated – H. akashiwo is strongly allelopathic against grazers, ranging from microzooplankton to copepods to planktivorous fish. The nearly perfect long-term, inverse cycle found in the mean annual abundances of ichthyotoxic H. akashiwo and the diatom Skeletonema is consistent with the allelochemic competition between these two species demonstrated in laboratory experiments by others, and in which H. akashiwo outcompetes Skeletonema when grown together. This compettive outcome may help to explain the interannual variations found in H. akashiwo's bloom occurrence, but not its long-term decrease and eventual virtual disappearance from NBay.
- The variability in bloom regulation found has important ecological and practical implications. It reveals that the specific variables and their combinations controlling HAB dynamics and species selection are not fixed – they differ interannually and seasonally, and within a given year and season. This poses significant problems in developing bloom models and in seeking environmental thresholds for use as monitoring triggers to track potential bloom-species behavior (toxicity) whose occurrences are associated with those emergent environmental conditions. This monitoring strategy is used to provide an early warning system to protect human health and aquacultural enterprises (i.e., stock protection). The results also pose problems to ecosystem management strategies which seek to reduce the probability of HAB events at a given bloom site by bioengineering, such as reducing the quantity or impact of a controlling factor – for example, nutrients. The complicated regulation of P. minimum blooms in NBay, and by extrapolation HAB species generally, indicates attempts to mitigate HABs by manipulation of a single factor assumed to be the controlling factor are risky. Harmful species' selection and blooms are under multifactorial control.
- The ratio of the mean annual numerical abundance of diatoms to flagellates exhibited a pronounced multidecadal oscillation during the 38-yr time series – two distinct cycles were evident. From 1972 to 1996, the functional group ratio (diatom:flagellate) progressively decreased 5-fold, from ca. 5:1 to 1:1, and then progressively recovered to ca. 5:1, that is, a 25-year cycle. There is evidence a similar cycle was in progress between 1959 (when observations began) and 1972. The functional group oscillation was strongly and positively correlated with the ratios of Si:N (range ca. 4.5 to 0.45) and Si:P (range ca. 20 to < 10:1). This was the first field demonstration in support of the nutrient ratio hypothesis, i.e. that changes in the Si:N and Si:P ratios influenced HAB species-selection. Chemostat experiments conducted by us suggest, however, that the nutrient ratio theory is more applicable to functional group selection (i.e., dinoflagellate, raphidophyte, haptophyte, etc.) than to individual species selection, which remains unpredictable. Based on a combination of field, experimental and conceptual analysis, the nutrient ratio - HAB paradigm is revised as follows. Nutrient ratios are community structuring elements, not the cause of blooms; nutrient concentrations, not their proportions determine a species' abundance. Nutrient ratios primarily influence functional group selection, not bloom stimulation of individual species within that functional group. Long-term changes in nutrient ratios, probably over decadal timeframes, are needed to influence habitat receptivity to the different functional groups and the threat of HABs. The highly transitory day-to-day oscillations in nutrient ratios and their variable interannual fluctuations make it is less likely that they regulate short-term HAB occurrences and temporal variations, since the response to nutrients and their ratios is a whole-system process involving a suite of interactive physical, chemical and biotic factors.
- The effect of temperature in the long-term bloom behavior of HAB and red tide species was evaluated. Mean winter water temperature in NBay increased ca. 3oC, and summer temperatures ca. 1.5oC over the 38-year time series. While the field evidence suggests there is a thermal barrier to HABs, with the threshold at ca. 15oC, a statistical relationship between temperature and the bloom dynamics of the individual HAB and red tide species was not found. HAB and red tide events rarely occur below 15oC.
- The related issues of whether the long-term winter warming in NBay led to earlier HAB and red tide outbreaks, and whether the slight increase in summer temperature altered bloom patterns were examined. Experimental data on the temperature-cell division relationships for ca. 45 dinoflagellate and raphidophyte species representative of various toxicity modes and bloom patterns, combined with the time series data, suggest there is an ecophysiological temperature barrier – at approximately 15oC – to their blooms. Two distinct groups of species whose bloom occurrences exhibit a "bloom temperature" threshold are evident. Temperatures below, or near 15oC markedly suppress or are lethal to cellular growth of almost all toxic dinoflagellates and raphidophytes examined – their optimal growth temperature is usually ≥ 20oC. Dinoflagellate species capable of cell division below 15oC - "cold water tolerant" species, and which often bloom close to this temperature, are primarily non-toxic red tide species or, if toxic, usually ichthyotoxic. The experimental temperature-cell division relationships do not explain observed bloom behavior in NBay, which supplements the field evidence that the long-term patterns HAB and red tide bloom patterns are not attributable to the observed temperature changes, including earlier seasonal occurrences.
- The analyses confirmed, strengthened and further developed the "open niche" concept as a general paradigm. This concept was introduced by Smayda and Villareal, based on the 1985 brown tide event, to characterize the inability to predict which phylogenetic groups and species would be selected to bloom in the four-month period following the annual winter-spring diatom bloom in NBay. This unpredictable bloom behavior characterized the entire 38-year time series. The "open niche" period persistently developed in late May when water temperature warmed to 15oC – consistent with the ecophysiological evidence for this "temperature barrier" – and continued thereafter through September. During the "open niche" period, the phylogenetic and taxon lineages of the bloom-species could not be forecast; six different phylogenetic lineages of the bloom-species were recorded, including diatoms, dinoflagellates, raphidophytes, and pelagophytes. The genus from within the phylogeny selected to bloom, and the species within that genus selected to bloom were equally unpredictable and varied interannually.
- Comparative ecological analyses indicate the "open niche" is a general ecosystem feature, with the "open niche" period seasonally intermediate between winter-spring and autumn diatom blooms. Accordingly, the "open niche" concept is developed as a general paradigm. On a hierarchical scale, three major and unpredictable taxonomic selections occur during the "open niche" period: phylogenetic, generic and species selections. The bloom-species selected may be a diatom, dinoflagellate, raphidophyte, pelagophyte, or represent another phylogeny. Thus, three hierarchical and taxonomically distinct adaptive strategies are operational: phylogenetic, generic and species-specific – in that sequence and culminating in bloom-species selection. Of these, the critical stage is at the generic level. Efforts to model HAB events, such as Paralytic Shellfish Poison (PSP), Diarrhetic Shellfish Poison (DSP) and Amnesic Shellfish Poison (ASP) bloom outbreaks, might be more tractable and successful if based on generic ecophysiological criteria, rather than on individual bloom-species.
- The organization and assembly of HAB communities were considered. Seven rules of assembly and selection of HAB species were proposed, organized around an abiotic template of irradiance, nutrient supply and physical mixing, and their various permutations, and the three major adaptive strategies that are found among bloom-species.
- Statistical associations were found between the decadal NAO cycles and long-term trends in physical, chemical and biological factors that impact bloom dynamics and bloom-species selection. Two specific effects on bloom behavior are associated with NAO dynamics – its capacity as a taxonomic switch, and capacity to induce trophic restructuring. As a climatological taxonomic switch, the NAO induced changes in the abundance and composition of the bloom communities, an effect particularly evident in the long-term bloom behavior of the diatom Skeletonema costatum. As a climatological driver of trophic restructuring, the NAO modified processes that affected the abundance and composition of the bloom communities, with outcomes such as the long-term pattern observed in the diatom:flagellate abundance ratio, i.e., functional group ratio. This influence of the NAO is consistent with other evidence from the time series analyses that NBay is an "open ecosystem" responsive to regional hydrographic and climatologic drivers, not only to local (internal) conditions.
- The progressive, long-term trends and cyclical patterns found in physical, chemical and bloom behavior are marked by "hinge events", such as the 1985 novel brown tide bloom of Aureococcus anophagefferens, and change-point years, as illustrated for the diatom Skeletonema costatum. Hinge events and change-point years mark the initiation of persistent and important ecosystem changes. Numerous examples of altered habitat and bloom-species behavior following the statistically identifiable change-point years and the 1985 hinge event are evident in the time series. Such events have not previously been recognized in HAB ecological studies; their occurrence poses formidable problems to analyses of the environmental regulation of HABs. The conditions triggering hinge and change-point events, and the environmental thresholds that led to their emergence in NBay eluded analysis.
- A major hypothesis is suggested by the analyses – a long-term, ecosystem "regime shift" has occurred in NBay, which in its present phase is selecting against HABs and red tides. Studies to confirm this conclusion are needed because the long-term variability and trends in HAB dynamics in NBay have many elements in common with HAB and red tide behavior generally, excluding the progressive long-term decline that occurred in HAB occurrences and species-abundance. Confirmation that a signficant regional shift occurred would be relevant to the unresolved question of whether a global synchrony underlies the HAB phenomenon, and is reflective of "regime shifts" generally or, and the alternative question, whether the apparent global synchrony in HABs is a coincidence of regionally independent blooms that are being enhanced by local and variable anthropogenic factors, such as nutrient enrichment, climate change, resource harvesting that is modifying food webs, and ballast water dispersal of harmful species. HAB scientists currently tend to seek singular explanations for the global increase in HABs, focusing on ballast water vectoring, shellfish transplantation, eutrophication or climate change as the principle driver, an approach the NBay analyses suggest is misguided. Complex, broad-based ecosystem changes, which are locally or regionally unique, may be the root cause driving some HAB behavior, rather than specific triggering events associated with ecosystem change.
- This study has produced multiple products of value to scientists, and stakeholders concerned with the public health effects of HABs, their mitigation and management, and ensuring sea food safety. For scientists, the analyses unequivocally show the need to vastly expand the traditional field ecological studies on HABs to include data on nutrients, physics, grazers, diatom behavior and climatological drivers, at an appropriate sampling frequency. The current, piecemeal and incomplete sampling of factors known to affect both short-term and long-term bloom behavior, species selections and their human and ecosystem consequences that characterize field studies on HABs is inadequate. The results also provide significant and new insights into the environmental regulation of HABs, both the direct observations made and the development of testable hypotheses based on these results. This will facilitate the development of models and more quantitative monitoring studies useful to scientists, ecosystem managers, publc health officials and state and federal agencies charged with seeking answers to the causes of, and the solutions to the global increase in harmful algal blooms.
Expected Results:
The published results will enhance HAB bloom research and objectives of the ECOHAB program, aide in the development of bloom control strategies, and contribute towards better understanding of climate change effects on harmful blooms. The electronic and website availability of the NBTS data bank on the 18 bloom species and accompanying environmental conditions will allow others in the scientific community and federal agencies to interrogate the time series posing new questions and applying new techniques in the future.Journal Articles on this Report : 4 Displayed | Download in RIS Format
Other project views: | All 35 publications | 8 publications in selected types | All 5 journal articles |
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Type | Citation | ||
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Smayda TJ. Turbulence, watermass stratification and harmful algal blooms:an alternative view and frontal zones as "pelagic seed banks." Harmful Algae 2002;1(1):95-112. |
R829368 (2002) R829368 (Final) |
Exit Exit |
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Smayda TJ, Reynolds CS. Strategies of marine dinoflagellate survival and some rules of assembly. Journal of Sea Research 2003;49(2):95-106. |
R829368 (2002) R829368 (Final) |
Exit |
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Smayda TJ. Reflections on the ballast water dispersal—harmful algae bloom paradigm. Harmful Algae 2007;6(4):601-622. |
R829368 (Final) |
Exit Exit |
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Tomas CR, Smayda TJ. Red tide blooms of Cochlodinium polykrikoides in a coastal cove. Harmful Algae 2008;7(3):308-317. |
R829368 (Final) |
Exit Exit |
Supplemental Keywords:
Coastal ecosystems, estuary, harmful algal blooms (HABs), HAB ecology, red tide blooms, ecological effects, aquatic ecosystems, estuarine research, Narragansett Bay, East Coast (RI), ECOHAB, time series, ecosystem protection, ecosystem exposure/risk, ecosystem/assessment/indicators, oceanography, RFA, Scientific Discipline, Air, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Aquatic Ecosystems & Estuarine Research, estuarine research, Ecosystem/Assessment/Indicators, Ecosystem Protection, Oceanography, climate change, Air Pollution Effects, Ecological Effects - Environmental Exposure & Risk, Aquatic Ecosystem, algal blooms, computing technology, Biology, Atmosphere, East Coast, ecological exposure, environmental monitoring, red tides, Narragansett Bay Time Series (NBTS), harmful algal blooms, marine biology, HAB ecology, coastal environments, data management, ECOHAB, World Wide Web, red tide bloom, Narragansett BayRelevant Websites:
Development of a Narragansett Bay Plankton Time Series Web page was initiated with the assistance of the University of Rhode Island Environmental Data Center (EDC) to reside within the existing Narragansett Bay Web Portal (http://www.narrbay.org). This portal is designed as the Internet entry point for the scientific community, State of RI and other Narragansett Bay stakeholders, and federal agencies looking for information about Narragansett Bay and coastal Rhode Island, including harmful algal blooms.
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.