Grantee Research Project Results
1999 Progress Report: ECOHAB: Control of Harmful Algal Blooms using Clay
EPA Grant Number: R827090Title: ECOHAB: Control of Harmful Algal Blooms using Clay
Investigators: Anderson, Donald M. , Greene, Richard M. , Bricelj, V. Monica , Lewis, Michael , Chapman, Peter , Pierce, Richard
Current Investigators: Anderson, Donald M. , Greene, Richard M. , Bricelj, V. Monica , Lewis, Michael , Pierce, Richard
Institution: Woods Hole Oceanographic Institution
EPA Project Officer: Packard, Benjamin H
Project Period: November 23, 1998 through November 22, 2001 (Extended to November 22, 2002)
Project Period Covered by this Report: November 23, 1998 through November 22, 1999
Project Amount: $332,938
RFA: Ecology and Oceanography of Harmful Algal Blooms (1998) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Harmful Algal Blooms , Water Quality , Water
Objective:
The general objectives of this project are to use laboratory cultures, aquaria, and mesocosms to: (1) determine the removal efficiencies of selected clays on three HAB species found in U.S. waters (the Florida red tide dinoflagellate Gymnodinium breve [G. breve], the New York brown tide chrysophyte Aureococcus anophagefferens, and fish-killing Pfiesteria-like dinoflagellates; (2) determine the variability in cell removal efficiencies due to such factors as species differences, growth stage, and cell density; (3) determine whether cell removal efficiencies can be improved by addition of alum or polymeric coagulants; (4) investigate changes in water chemistry following clay treatment, including the release or removal of nutrients such as phosphorus and nitrogen, release of radioactivity, trace metals, and other toxicants; (5) investigate toxin release and uptake by clays during the flocculation process; (6) investigate the use of clays to mitigate the impacts of aerosolized brevetoxins; (7) conduct larger scale aquarium and mesocosm studies to examine flocculation efficiencies on natural plankton assemblages and to assess the impacts of sedimented biomass and toxins on benthic organisms; (8) evaluate the engineering requirements, economic costs, and environmental clearances that must be addressed if this control strategy is to be applied to blooms in natural waters; and (9) design a pilot program for field application of this bloom mitigation strategy.Progress Summary:
The first year of this project has been one of considerable activity. The following progress has been made to date. Screening of Domestic Clays Against HABs. Thus far, 25 different clays from a variety of manufacturers, representing a number of mineral types and purity, have been tested against selected HAB species (including G. breve, Pfiesteria piscicida, and Aureococcus anophagefferens). These clays display a wide range of removal efficiencies against these species, indicating that the most suitable clay for a given species must be determined empirically. Determining the Variability in Cell Removal Efficiencies Due to Cell Density, Water Column Height, Surface Area, Mixing, and Salinity. Various factors that influence cell removal efficiency have been examined using laboratory cultures. In a series of laboratory experiments using settling columns of different heights and containers with varying surface areas, removal efficiencies were measured using phosphatic clay against G. breve. Use of Coagulants to Enhance Cell Removal Using Clays. Twelve organic polymers and inorganic coagulants have been studied to examine the possible enhancement of cell removal efficiency. These compounds can be added to seawater at very low concentrations (ppm) to form "bridges" between the clay and cell particles. In our studies, most organic coagulants have not enhanced cell removal efficiency, but some inorganic compounds show excellent promise in this regard. Nutrient Release or Uptake of Clays. Preliminary laboratory experiments have been conducted to examine the release of major plant nutrients such as nitrogen and phosphorous from clays upon addition to seawater. Thus far, results have been mixed. On the positive side, clay additions will remove ammonium, which is a very important source of nitrogen for algae in coastal waters; on the negative side, we have found that some clays release measurable amounts of phosphorous into the seawater. Methods to mediate this effect currently are being explored. Overall, significant progress has been made on this project and results continue to be encouraging.Future Activities:
A project meeting was held in Sarasota, FL, in August, where all the Principal Investigators (PIs) met and discussed future activities for investigating the impacts of clay flocculation on the environment. The plans for future work include investigating the fate of toxin in flocs, effects of clay on aerosolized toxin, effects of clay on suspension feeders, and studies of "chemical" exposure to zooplankton and the benthos. These activities will be expanded to measurement of brevetoxin in water and sediment, with consideration of bacterial activities and oxygen consumption. Experiments also have been designed to test whether clays or PAC-treated clays remove brevetoxin from seawater. Experiments to examine the effects of clay on suspension feeders will utilize several bivalve species, and their viability, growth rate, and feeding rate will be measured. Information obtained from these experiments will provide insight into the effect when flocs reach the sediment, and what interference clay treatment causes due to burial as well as resuspension of flocs.Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 34 publications | 14 publications in selected types | All 14 journal articles |
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Li A, Sengco MR, Anderson DM. Controlling harmful algal blooms through clay flocculation. JOURNAL OF EUKARYOTIC MICROBIOLOGY 2004;51(2):169-72 |
R827090 (1999) R827090 (2000) |
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Sengco MR, Li AS, Tugend K, Kulis D, Anderson DM. Removal of red- and brown-tide cells using clay flocculation. I. Laboratory culture experiments with Gymnodinium breve and Aureococcus anophagefferens. Marine Ecology-Progress Series 2001;210():41-53 |
R827090 (1999) R827090 (2000) R827090 (2001) R827090 (Final) |
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Supplemental Keywords:
ecological effects, cellular, biology, modeling., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Geographic Area, Water, algal blooms, Ecological Risk Assessment, State, Ecosystem Protection, Ecosystem/Assessment/Indicators, Environmental Microbiology, Ecological Effects - Environmental Exposure & Risk, Biochemistry, Hydrology, Ecology and Ecosystems, Environmental Engineering, FLA, biotoxin risk, ECOHAB, phytoplankton, sustainable fisheries, ecological effects, Florida, clay, G. breve red tides, water quality, control of algal blooms, oceanography, New York (NY), benthic algae, bloom dynamics, brevetoxins, nutrient kinetics, ecological exposure, dinoflagellates, fish kills, harmful algal bloomsProgress 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.