Description: This paper is not subject to U.S. copyright. The definitive version was published in Harmful Algae 14 (2012): 271-300, doi:10.1016/j.hal.2011.10.025.

Description: Over the last decade, our understanding of the environmental controls on Pseudo-nitzschia blooms and domoic acid (DA) production has matured. Pseudo-nitzschia have been found along most of the world's coastlines, while the impacts of its toxin, DA, are most persistent and detrimental in upwelling systems. However, Pseudo-nitzschia and DA have recently been detected in the open ocean's high-nitrate, low-chlorophyll regions, in addition to fjords, gulfs and bays, showing their presence in diverse environments. The toxin has been measured in zooplankton, shellfish, crustaceans, echinoderms, worms, marine mammals and birds, as well as in sediments, demonstrating its stable transfer through the marine food web and abiotically to the benthos. The linkage of DA production to nitrogenous nutrient physiology, trace metal acquisition, and even salinity, suggests that the control of toxin production is complex and likely influenced by a suite of environmental factors that may be unique to a particular region. Advances in our knowledge of Pseudo-nitzschia sexual reproduction, also in field populations, illustrate its importance in bloom dynamics and toxicity. The combination of careful taxonomy and powerful new molecular methods now allow for the complete characterization of Pseudo-nitzschia populations and how they respond to environmental changes. Here we summarize research that represents our increased knowledge over the last decade of Pseudo-nitzschia and its production of DA, including changes in worldwide range, phylogeny, physiology, ecology, monitoring and public health impacts.

Description: © 2008 Author et al. This is an open access article distributed under the terms of the Creative Commons Attribution License The definitive version was published in Environmental Health 7 (2008): S2, doi:10.1186/1476-069X-7-S2-S2.

Description: Harmful algal blooms (HABs) are one focus of the national research initiatives on Oceans and Human Health (OHH) at NIEHS, NOAA and NSF. All of the OHH Centers, from the east coast to Hawaii, include one or more research projects devoted to studying HAB problems and their relationship to human health. The research shares common goals for understanding, monitoring and predicting HAB events to protect and improve human health: understanding the basic biology of the organisms; identifying how chemistry, hydrography and genetic diversity influence blooms; developing analytical methods and sensors for cells and toxins; understanding health effects of toxin exposure; and developing conceptual, empirical and numerical models of bloom dynamics. In the past several years, there has been significant progress toward all of the common goals. Several studies have elucidated the effects of environmental conditions and genetic heterogeneity on bloom dynamics. New methods have been developed or implemented for the detection of HAB cells and toxins, including genetic assays for Pseudo-nitzschia and Microcystis, and a biosensor for domoic acid. There have been advances in predictive models of blooms, most notably for the toxic dinoflagellates Alexandrium and Karenia. Other work is focused on the future, studying the ways in which climate change may affect HAB incidence, and assessing the threat from emerging HABs and toxins, such as the cyanobacterial neurotoxin β-N-methylamino-L-alanine. Along the way, many challenges have been encountered that are common to the OHH Centers and also echo those of the wider HAB community. Long-term field data and basic biological information are needed to develop accurate models. Sensor development is hindered by the lack of simple and rapid assays for algal cells and especially toxins. It is also critical to adequately understand the human health effects of HAB toxins. Currently, we understand best the effects of acute toxicity, but almost nothing is known about the effects of chronic, subacute toxin exposure. The OHH initiatives have brought scientists together to work collectively on HAB issues, within and across regions. The successes that have been achieved highlight the value of collaboration and cooperation across disciplines, if we are to continue to advance our understanding of HABs and their relationship to human health.

Description: This work was funded through grants from the NSF/NIEHS Centers for Oceans and Human Health, NIEHS P50 ES012742 and NSF OCE-043072 (DLE and DMA), NSF OCE04-32479 and NIEHS P50 ES012740 (PB and RRB), NSF OCE-0432368 and NIEHS P50 ES12736 (LEB), NIEHS P50 ES012762 and NSF OCE-0434087 (RCS, KAL, MSP, MLW, and KAH). Additional support was provided by the ECOHAB Grant program NSF Grant OCE-9808173 and NOAA Grant NA96OP0099 (DMA), NOAA OHHI NA04OAR4600206 (RRB) and Washington State Sea Grant NA16RG1044 (RCS). KAL and VLT were supported in part by the West Coast Center for Oceans and Human Health (WCCOHH) as part of the NOAA Oceans and Human Health Initiative.

Description: Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 8 (2008): 39-53, doi:10.1016/j.hal.2008.08.017.

Description: Coastal waters of the United States (U.S.) are subject to many of the major harmful algal bloom (HAB) poisoning syndromes and impacts. These include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), ciguatera fish poisoning (CFP) and various other HAB phenomena such as fish kills, loss of submerged vegetation, shellfish mortalities, and widespread marine mammal mortalities. Here, the occurrences of selected HABs in a selected set of regions are described in terms of their relationship to eutrophication, illustrating a range of responses. Evidence suggestive of changes in the frequency, extent or magnitude of HABs in these areas is explored in the context of the nutrient sources underlying those blooms, both natural and anthropogenic. In some regions of the U.S., the linkages between HABs and eutrophication are clear and well documented, whereas in others, information is limited, thereby highlighting important areas for further research.

Description: Support was provided through the Woods Hole Center for Oceans and Human Health (to DMA), National Science Foundation (NSF) grants OCE-9808173 and OCE-0430724 (to DMA), OCE-0234587 (to WPC), OCE04-32479 (to MLP), OCE-0138544 (to RMK), OCE-9981617 (to PMG); National Institute of Environmental Health Sciences (NIEHS) grants P50ES012742-01 (to DMA) and P50ES012740 (to MLP); NOAA Grants NA96OP0099 (to DMA), NA16OP1450 (to VLT), NA96P00084 (to GAV and CAH), NA160C2936 and NA108H-C (to RMK), NA860P0493 and NA04NOS4780241 (to PMG), NA04NOS4780239-02 (to RMK), NA06NOS4780245 (to DWT). Support was also provided from the West Coast Center for Oceans and Human Health (to VLT and WPC), USEPA Grant CR826792-01-0 (to GAV and CAH), and the State of Florida Grant S7701617826 (to GAV and CAH).

Description: This paper is not subject to U.S. copyright. The definitive version was published in Journal of Phycology 52 (2016): 230–238, doi:10.1111/jpy.12386.

Description: Toxin-producing blooms of dinoflagellates in the genus Alexandrium have plagued the inhabitants of the Salish Sea for centuries. Yet the environmental conditions that promote accelerated growth of this organism, a producer of paralytic shellfish toxins, is lacking. This study quantitatively determined the growth response of two Alexandrium isolates to a range of temperatures and salinities, factors that will strongly respond to future climate change scenarios. An empirical equation, derived from observed growth rates describing the temperature and salinity dependence of growth, was used to hindcast bloom risk. Hindcasting was achieved by comparing predicted growth rates, calculated from in situ temperature and salinity data from Quartermaster Harbor, with corresponding Alexandrium cell counts and shellfish toxin data. The greatest bloom risk, defined at μ 〉0.25 d−1, generally occurred from April through November annually; however, growth rates rarely fell below 0.10 d−1. Except for a few occasions, Alexandrium cells were only observed during the periods of highest bloom risk and paralytic shellfish toxins above the regulatory limit always fell within the periods of predicted bloom occurrence. While acknowledging that Alexandrium growth rates are affected by other abiotic and biotic factors, such as grazing pressure and nutrient availability, the use of this empirical growth function to predict higher risk time frames for blooms and toxic shellfish within the Salish Sea provides the groundwork for a more comprehensive biological model of Alexandrium bloom dynamics in the region and will enhance our ability to forecast blooms in the Salish Sea under future climate change scenarios.

Description: NOAA Ecology and Oceanography of Harmful Algal Bloom (ECOHAB) Program; Woods Hole Center for Oceans and Human Health; National Science Foundation Grant Number: OCE-1314642; National Institute of Environmental Health Sciences Grant Number: 1-P01-ES021923-01

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Anderson, D. M., Fensin, E., Gobler, C. J., Hoeglund, A. E., Hubbard, K. A., Kulis, D. M., Landsberg, J. H., Lefebvre, K. A., Provoost, P., Richlen, M. L., Smith, J. L., Solow, A. R., & Trainer, V. L. Marine harmful algal blooms (HABs) in the united states: history, current status and future trends. Harmful Algae, 102, (2021): 101975, https://doi.org/10.1016/j.hal.2021.101975.

Description: Harmful algal blooms (HABs) are diverse phenomena involving multiple. species and classes of algae that occupy a broad range of habitats from lakes to oceans and produce a multiplicity of toxins or bioactive compounds that impact many different resources. Here, a review of the status of this complex array of marine HAB problems in the U.S. is presented, providing historical information and trends as well as future perspectives. The study relies on thirty years (1990–2019) of data in HAEDAT - the IOC-ICES-PICES Harmful Algal Event database, but also includes many other reports. At a qualitative level, the U.S. national HAB problem is far more extensive than was the case decades ago, with more toxic species and toxins to monitor, as well as a larger range of impacted resources and areas affected. Quantitatively, no significant trend is seen for paralytic shellfish toxin (PST) events over the study interval, though there is clear evidence of the expansion of the problem into new regions and the emergence of a species that produces PSTs in Florida – Pyrodinium bahamense. Amnesic shellfish toxin (AST) events have significantly increased in the U.S., with an overall pattern of frequent outbreaks on the West Coast, emerging, recurring outbreaks on the East Coast, and sporadic incidents in the Gulf of Mexico. Despite the long historical record of neurotoxic shellfish toxin (NST) events, no significant trend is observed over the past 30 years. The recent emergence of diarrhetic shellfish toxins (DSTs) in the U.S. began along the Gulf Coast in 2008 and expanded to the West and East Coasts, though no significant trend through time is seen since then. Ciguatoxin (CTX) events caused by Gambierdiscus dinoflagellates have long impacted tropical and subtropical locations in the U.S., but due to a lack of monitoring programs as well as under-reporting of illnesses, data on these events are not available for time series analysis. Geographic expansion of Gambierdiscus into temperate and non-endemic areas (e.g., northern Gulf of Mexico) is apparent, and fostered by ocean warming. HAB-related marine wildlife morbidity and mortality events appear to be increasing, with statistically significant increasing trends observed in marine mammal poisonings caused by ASTs along the coast of California and NSTs in Florida. Since their first occurrence in 1985 in New York, brown tides resulting from high-density blooms of Aureococcus have spread south to Delaware, Maryland, and Virginia, while those caused by Aureoumbra have spread from the Gulf Coast to the east coast of Florida. Blooms of Margalefidinium polykrikoides occurred in four locations in the U.S. from 1921–2001 but have appeared in more than 15  U.S. estuaries since then, with ocean warming implicated as a causative factor. Numerous blooms of toxic cyanobacteria have been documented in all 50  U.S. states and the transport of cyanotoxins from freshwater systems into marine coastal waters is a recently identified and potentially significant threat to public and ecosystem health. Taken together, there is a significant increasing trend in all HAB events in HAEDAT over the 30-year study interval. Part of this observed HAB expansion simply reflects a better realization of the true or historic scale of the problem, long obscured by inadequate monitoring. Other contributing factors include the dispersion of species to new areas, the discovery of new HAB poisoning syndromes or impacts, and the stimulatory effects of human activities like nutrient pollution, aquaculture expansion, and ocean warming, among others. One result of this multifaceted expansion is that many regions of the U.S. now face a daunting diversity of species and toxins, representing a significant and growing challenge to resource managers and public health officials in terms of toxins, regions, and time intervals to monitor, and necessitating new approaches to monitoring and management. Mobilization of funding and resources for research, monitoring and management of HABs requires accurate information on the scale and nature of the national problem. HAEDAT and other databases can be of great value in this regard but efforts are needed to expand and sustain the collection of data regionally and nationally.

Description: Support for DMA, MLR, and DMK was provided through the Woods Hole Center for Oceans and Human Health (National Science Foundation grant OCE-1840381 and National Institutes of Health grants NIEHS‐1P01-ES028938–01) and the U.S. National Office for Harmful Algal Blooms with funding from NOAA's National Centers for Coastal Ocean Science (NCCOS) through the Cooperative Institute for the North Atlantic Region (CINAR) (NA14OAR4320158, NA19OAR4320074). Funding for KAL and DMA was provided by the National Oceanic and Atmospheric Administration National Centers for Coastal Ocean Science Competitive Research Program under award NA20NOS4780195 to the Woods Hole Oceanographic Institution and NOAA's Northwest Fisheries Science Center. We also acknowledge support for A.H. from the National Oceanic and Atmospheric Administration [NOAA] Office of Ocean and Coastal Resource Management Award NA19NOS4780183, C.J.G from NOAA-MERHAB (NA19NOS4780186) and (NA16NOS4780189) for VLT Support was also received for JLS, CJG, and VLT from NOAA-NCCOS-ECOHAB under awards NA17NOS4780184 and NA19NOS4780182. This is ECOHAB publication number ECO972.

Description: Azaspiracids, produced by some species of the dinoflagellate genera Azadinium and Amphidoma, can cause a syndrome in humans called azaspiracid shellfish poisoning (AZP). In 1995, mussels from the Irish west coast contaminated with azaspiracids were, for the first time, linked to this human illness that has symptoms of nausea, vomiting, severe diarrhea, and stomach cramps. The only confirmed cases of AZP to date in the United States occurred in Washington State in 2008 from mussels imported from Ireland. Shortly after this case, several others involving similar gastrointestinal symptoms were reported by shellfish consumers from Washington State. However, no detectable diarrhetic shellfish toxins or Vibrio contamination were found. Cursory analysis of Solid Phase Adsorption Toxin Tracking (SPATT) samplers suggested the presence of azaspiracids in Washington State waters and motivated a study to evaluate the presence and distribution of Azadinium species in the region. During the spring and summer months of 2014–2015, quantitative polymerase chain reaction (qPCR) analyses detected the presence of the toxigenic species Azadinium poporum and A. spinosum on the outer coast and throughout the inland waters of Washington State. In 2016–2018, standard curves developed using A. poporum isolated from Puget Sound and A. spinosum isolated from the North Sea were used to quantify abundances of up to 10,525 cells L−1 of A. poporum and 156 cells L−1 of A. spinosum at shore-based sites. Abundances up to 1,206 cells L−1 of A. poporum and 30 cells L−1 of A. spinosum were measured in the coastal waters of the Pacific Northwest in 2017. Other harmful genera, including Alexandrium, Dinophysis, and Pseudo-nitzschia, were observed using light microscopy at coastal sites where A. poporum was also observed. In some samples where both A. poporum and A. spinosum were absent, an Amphidomataceae-specific qPCR assay indicated that other species of Azadinium or Amphidoma were present. The identification of Azadinium species in the PNW demonstrates the need to assess their toxicity and to incorporate their routine detection in monitoring programs to aid resource managers in mitigating risks to azaspiracid shellfish poisoning in this region.

Description: To date, the putative shellfish toxin azaspiracid 59 (AZA-59) produced by Azadinium poporum (Dinophyceae) has been the only AZA found in isolates from the Pacific Northwest coast of the USA (Northeast Pacific Ocean). Anecdotal reports of sporadic diarrhetic shellfish poisoning-like illness, with the absence of DSP toxin or Vibrio contamination, led to efforts to look for other potential toxins, such as AZAs, in water and shellfish from the region. A. poporum was found in Puget Sound and the outer coast of Washington State, USA, and a novel AZA (putative AZA-59) was detected in low quantities in SPATT resins and shellfish. Here, an A. poporum strain from Puget Sound was mass-cultured and AZA-59 was subsequently purified and structurally characterized. In vitro cytotoxicity of AZA-59 towards Jurkat T lymphocytes and acute intraperitoneal toxicity in mice in comparison to AZA-1 allowed the derivation of a provisional toxicity equivalency factor of 0.8 for AZA-59. Quantification of AZA-59 using ELISA and LC-MS/MS yielded reasonable quantitative results when AZA-1 was used as an external reference standard. This study assesses the toxic potency of AZA-59 and will inform guidelines for its potential monitoring in case of increasing toxin levels in edible shellfish.