Opportunities for Environmental Applications of Marine Biotechnology Proceedings of the October 5-6, 1999, Workshop (2000) / Chapter Skim
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Critical Needs in Harmful Algal Bloom Research
Critical Needs in Harmful Algal Bloom Research
Pages 126-149
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From page 126... ...
"Harmful algae" refers to algae that are undesirable to humans because (1) they produce toxins that impair the health of humans and desirable fish and wildlife; (2)
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From page 127... ...
This discussion first addresses remote sensing techniques for detecting harmful algae, as requested, and then focuses mostly on critical research needs regarding toxic algal species, as opposed to other types of harmful species that cause oxygen deprivation or other undesirable conditions but do not produce toxins. ADVANCED TECHNIQUES FOR DETECTING HARMFUL ALGAL BLOOMS Various remote sensing techniques are available for detecting certain harmful algal blooms, but their value is limited.
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From page 128... ...
Remote sensing techniques, then, are of use primarily to track environmental conditions that may be associated with harmful algae. CRITICAL RESEARCH NEEDS The four most critical research needs are research-quality cultures, life cycles, toxin identification and detection, and detection of toxic strains.
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From page 129... ...
, ostensibly to gain insights about toxic strains of harmful algae, is illustrated by the following example. The toxic dinoflagellate Pfiesteria piscicida is a complex animal-like organism, as mentioned (Burkholder and Glasgow 1997~.
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, and they respond to indirect stimulation by nutrient enrichment (mediated through algal prey) more strongly than toxic strains under certain conditions data with important ramifications if used as planned by state and federal agencies as a basis for setting levels of nutrient reductions to discourage Pfiesteria growth (e.g., State of Maryland 1998~.
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From page 131... ...
Although this stipulation of quality control/quality assurance may seem obvious, it unfortunately is not being required by many federal grant programs in harmful algal bloom research (e.g., indicated in correspondence from ECOHAB-funded scientists expressing concern about the culture quality issue, to the NOAA Coastal Ocean Program, July 1999~. Toward the goal of advancing knowledge about toxic strains of algal species the strains that are germane from the perspective of public concern assured availability of research-quality cultures is of critical importance and it needs to be more rigorously addressed by the consortium of federal agencies involved.
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. Toxic outbreaks followed change in nutrient supply ratios from cumulative increased nutrient loading (Europe; fish kills, toxic)
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; consistent seasonal blooms in the Mississippi and Atchafalyu River plume areas, associated with hypereutrophic conditions and in Prince Edward Island, Canada, following anthropogenic nutrient loading and drought) ." Prymnesium parvum Toxic Pseudo-nitzschia complex species tNote that many of the known harmful estuarine and marine microalgae and heterotrophic or animal-like dinoflagellates also have been shown to be stimulated by N and/or P enrichment in culture, which is expected since they are photosynthetic.
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Thus, in restricting the nutritional mode of these organisms, various stages in their life cycles may not have manifested (Popovsky and Pfiester 1990~. Characterization of the life cycles of many harmful algal species is a critical research need.
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136 U .= > U no.
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Before scientists can understand the chronic impacts of these toxins on aquatic organisms and human health, there is a critical need to identify more of these toxins chemically and to develop improved methods for their detection (Hallegraeff and others 1995~. Toxin identification and the development of rapid, field-amenable, reliable detection procedures are extremely critical needs in the field of harmful algal bloom research.
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From page 138... ...
are more problematic, in part because many are known, including both lipid-soluble and water-soluble substances (Bagnis 1993~. Purified toxin standards are available for very few of these toxins; and few assays are available similarly for rapid, reliable detection of certain Ciguatoxins in field water samples and animal tissues (Bagnis 1993; Lewis 1995~.
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From page 139... ...
In addition to the critical need to fully characterize more of the toxins from harmful algae, assays are also greatly needed to enable rapid, routine, reliable detection of these toxins in potable water supplies, natural waters, seafood, and aquaculture facilities. A probe for domoic acid, for example, together with species-specific molecular probes to verify the presence of the toxic algae that produce it, was valuable in relating the recent sea lion disease and die-off in California to diatoms in the toxic Pseudo-nitzschia complex (Scholin and others 2000~.
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PRESENT STATUS OF CONTROL AND PREDICTION Basic research on strategies to control harmful algal blooms has been limited, but such research remains in primitive status (Boesch and others 1997~. Many harmful algae are detected in a reactive rather than proactive response mode, in part because of the sporadic occurrence of these species, and scientists are currently faced with the problem of attempting to develop control strategies for species that they basically know very little about at least, for many harmful algae.
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From page 141... ...
In certain poorly flushed estuaries and marine coastal embayments, some harmful algal species have been linked to stimulation by nutrient pollution (Table 2~. As a result, long-term strategies targeting nutrient reductions are under consideration or, in the case of the Chesapeake Bay and Pfiesteria, are being imposed (State of Maryland 1998~.
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Some harmful algal species such as cyanobacteria are susceptible to reduction by clay additions, whereas others are not. Noxious freshwater species of Anabaena (including toxic Anabaena circinalis and A
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made the following statement in a publication that was cosponsored by NOAA and the National Fish and Wildlife Foundation: "It is premature to conclude whether control strategies are feasible, applicable or advisable because there is insufficient information to judge effectiveness and weigh benefits against costs." Thus, control is in primitive status within the realm of harmful algal blooms. Prediction obviously is in similar status, given scientists' fundamental lack of knowledge about many harmful algal species and the current limited technologies for recognizing and tracking toxic strains.
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From page 144... ...
as well as toxic strains that are physiologically and behaviorally distinct. Until scientists know much more about the life cycles and toxins of these organisms, harmful algae will remain in the realm of the enigmatic, difficult for the public to understand.
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In: Anderson DM, Cembella AD, Hallegraeff GM, eds. Physiological Ecology of Harmful Algal Blooms.
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In: Anderson DM, Cembella AD, Hallegraeff GM, eds. Physiological Ecology of Harmful Algal Blooms.
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2000 Heteroduplex Mobility Assay guided sequence discovery: Elucidation of the small subunit (18S) rDNA sequence of Pfiesteria piscicida from complex algal culture and environmental sample DNA pools.
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eds. Harmful and Toxic Algal Blooms.
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nov.) , a new toxic dinoflagellate genus and species with a complex life cycle and behavior.
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