Grantee Research Project Results
2003 Progress 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 Period Covered by this Report: September 28, 2002 through January 27, 2003
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:
The overall goal of this research project is to fill fundamental knowledge gaps in the ecology of harmful algal blooms (HABs) and red tides. The biological data of the 18 species to be evaluated and the accompanying physical and chemical data in the 38-year Narragansett Bay Time Series (NBTS) to be used in this research project will be made Web site accessible. The specific objectives of this research project are to: (1) elucidate the mechanisms underlying the selection and bloom cycles of 18 indigenous, cosmopolitan, and representative HAB and benign red tide taxa in Narragansett Bay; (2) describe the long-term patterns, trends, and variability in their blooms; (3) quantify the effects and interactions of meteorological, climatic, physical, chemical, and biological parameters in this variability; (4) apply and evaluate the “open niche” hypothesis as a general HAB paradigm; and (5) develop a Web site and a dedicated server, making the time-series data electronically available to the scientific community as well as local and state agencies.
Progress Summary:
The time-series analyses that revealed a great increase in the abundance of harmful species began in the 1980s and persisted for a decade, accompanied by a pronounced change in annual diatom bloom dynamics—the phytoplankton group indicative of healthy coastal ecosystems. HAB species usually are flagellated (motile), with an ecophysiology differing considerably from diatoms. Flagellates and their blooms often are considered indicative of habitat stress or “less healthy” ecosystems. Our analyses, among the first to show that diatom dynamics impact HABs, revealed a decreased ratio of diatoms to flagellates during the 1980s in Narragansett Bay, suggesting a deteriorated ecosystem. We related the significant shift in annual diatom blooms to an effect of global warming, enhanced secondarily by an increase in herbivorous grazer (zooplankton) abundance. Mean winter temperatures have increased by 3 ° C, causing a significant reduction in winter diatom abundance and a virtual disappearance of some species, altered behavior that has impacted summer habitat conditions and seasonal HAB behavior.
Traditionally, HAB scientists have searched for a single, common factor to explain the characteristically unpredictable blooms of HAB species and their global expansion in coastal waters. Two major hypotheses have been proposed: a habitat change hypothesis and an anthropogenically assisted global spreading (in ballast water + shellfish transplantations) hypothesis. Our results reveal that this search for a single, common mechanism is inappropriate. We are finding that temperature, nutrients, natural recycling of nitrogen and phosphorus, their ratio, dissolved organic nutrients introduced in river runoff, grazers, and other combinations of physical, chemical, and biological factors select for and regulate HABs. This requires revision of traditional conceptual and practical approaches to HAB dynamics (i.e., to multiple-factor regulation rather than single-factor regulation and recognition that the combination of factors involved varies in relative importance among species, from region-to-region, and from year-to-year at a given site and is not constant even for a given HAB species). Modest experimental and more detailed field analyses of the relationship between HAB species and copepod grazers (zooplankton) showed that the zooplankton community can either be inhibited by or graze down an HAB species. In either case, the nature of the predator-prey relationship varies among species and the predator-prey species’ pairings. This observation also points to the unlikelihood that a single cause explains the HAB epidemic ongoing in global coastal waters.
An ultimate objective of harmful algal research is to forecast, regulate, and mitigate against HABs. We continued analyses to refine our “open niche” hypothesis for use as a general paradigm of HAB species selection. The evidence from the NBTS points to the occurrence of a hierarchical bloom species selection process during the “open niche” period, from functional group (i.e., diatom vs. flagellate type) to generic to species-specific selection (in that sequence if a harmful or tide bloom is to take place).
Future Activities:
We will focus on the influence of climatological and anthropogenic factors on the long-term bloom patterns of the 18 bloom species. Analyses will seek to identify the mechanisms underlying the selection and bloom cycles of the bloom species and to evaluate the causes of harmful bloom intensification observed during the 1980s. Our focus on nutrient impacts on harmful bloom behavior will be intensified because of major fish and shellfish kills that occurred in Narragansett Bay in the summer of 2003 during algal blooms that the Rhode Island Department of Environmental Management attributed to nutrient enrichment and/or hypoxia. This conclusion, and our evidence that Prorocentrum blooms are sensitive to inorganic and organic nutrient levels (Borkman and Smayda, submitted, 2004a), stimulate this interest in nutrient effects. We will continue work on the development of the “open niche” hypothesis and on the data bank Web site development. Publications on the results of this overall effort also will be prepared. The results that are being obtained will enhance HAB bloom research and objectives of the Ecology of Harmful Algal Blooms (ECOHAB) Program, aid in the development of bloom control strategies, and contribute toward a better understanding of climate change effects on harmful blooms. The electronic and Web site availability of the NBTS data bank on the 18 bloom species that is being developed along with the accompanying environmental conditions will allow others in the scientific community and federal agencies to interrogate the time series, pose new questions, and apply new techniques in the future.
Journal Articles:
No journal articles submitted with this report: View all 35 publications for this projectSupplemental Keywords:
coastal ecosystems, harmful algal blooms, HABs, HAB ecology, red tide blooms, aquatic ecosystems and estuarine research, Narragansett Bay, east coast, Rhode Island, RI, Ecology of Harmful Algal Blooms, ECOHAB, Narragansett Bay Time Series, NBTS, ecosystem protection, ecosystem exposure/risk, ecosystem/assessment/indicators, oceanography, phytoplankton, multidecadal time series,, 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 BayProgress 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.