Bowers
Holly A.
Bowers
Holly A.
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PreprintIntra- and interspecies differences in growth and toxicity of Pseudo-nitzschia while using different nitrogen sources( 2009-01) Thessen, Anne E. ; Bowers, Holly A. ; Stoecker, Diane K.Clonal cultures of plankton are widely used in laboratory experiments and have contributed greatly to knowledge of microbial systems. However, many physiological characteristics vary drastically between strains of the same species, calling into question our ability to make ecologically relevant inferences about populations based on studying one or a few strains. This study included nineteen non-axenic strains of three species of the diatom Pseudo-nitzschia isolated primarily from the mid-Atlantic coastal region of the United States. Toxin (domoic acid) production and growth rates were measured in cultures using different nitrogen sources (NH4+, NO3- and urea) and growth irradiances. The strains exhibited broad differences in growth rate and toxin content even between strains isolated from the same water sample. The influence of bacteria on toxin production was not investigated. Both P. multiseries clones produced toxin, yet preferentially used different nitrogen sources. Only two out of nine P. calliantha and two out of five P. fraudulenta isolates were toxic and domoic acid content varied by orders of magnitude. All three species had variable intraspecies growth rates on each nitrogen source, but P. fraudulenta strains had the broadest range. Light-limited growth rate and maximum growth rate in P. fraudulenta and P. multiseries varied with species. These findings show the importance of defining intra- and interspecies variability in ecophysiology and toxicity. Ecologically relevant functional diversity in the form of ecotypes or cryptic species appears to be present in the genus Pseudo-nitzschia.
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PreprintDiversity and toxicity of Pseudo-nitzschia species in Monterey Bay : perspectives from targeted and adaptive sampling( 2018-08) Bowers, Holly A. ; Ryan, John P. ; Hayashi, Kendra ; Woods, April ; Marin, Roman ; Smith, G. Jason ; Hubbard, Katherine A. ; Doucette, Gregory J. ; Mikulski, Christina M. ; Gellene, Alyssa G. ; Zhang, Yanwu ; Kudela, Raphael M. ; Caron, David A. ; Birch, James M. ; Scholin, Christopher A.Monterey Bay, California experiences near-annual blooms of Pseudo-nitzschia that can affect marine animal health and the economy, including impacts to tourism and commercial/recreational fisheries. One species in particular, P. australis, has been implicated in the most toxic of events, however other species within the genus can contribute to widespread variability in community structure and associated toxicity across years. Current monitoring methods are limited in their spatial coverage as well as their ability to capture the full suite of species present, thereby hindering understanding of HAB events and limiting predictive accuracy. An integrated deployment of multiple in situ platforms, some with autonomous adaptive sampling capabilities, occurred during two divergent bloom years in the bay, and uncovered detailed aspects of population and toxicity dynamics. A bloom in 2013 was characterized by spatial differences in Pseudo39 nitzschia populations, with the low-toxin producer P. fraudulenta dominating the inshore community and toxic P. australis dominating the offshore community. An exceptionally toxic bloom in 2015 developed as a diverse Pseudo-nitzschia community abruptly transitioned into a bloom of highly toxic P. australis within the time frame of a week. Increases in cell density and proliferation coincided with strong upwelling of nutrients. High toxicity was driven by silicate limitation of the dense bloom. This temporal shift in species composition mirrored the shift observed further north in the California Current System off Oregon and Washington. The broad scope of sampling and unique platform capabilities employed during these studies revealed important patterns in bloom formation and persistence for Pseudo-nitzschia. Results underscore the benefit of expanded biological observing capabilities and targeted sampling methods to capture more comprehensive spatial and temporal scales for studying and predicting future events.
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Working PaperHarmful Algal Research & Response: A National Environmental Science Strategy (HARRNESS), 2024-2034(Woods Hole Oceanographic Institution, 2024-08-01) Anderson, Donald M. ; Backer, Lorraine C. ; Bouma-Gregson, Keith ; Bowers, Holly A. ; Bricelj, V. Monica ; D’Anglada, Lesley ; Deeds, Jonathan ; Dortch, Quay ; Doucette, Gregory J. ; Graham, Jennifer ; Howard, Meredith ; Kirkpatrick, Barbara ; Kudela, Raphael M. ; Lefebvre, Kathi A. ; Moore, Stephanie K. ; Parsons, Michael L. ; Pokrzywinski, Kaytee ; Ramsdell, John S. ; Raymond, Heather ; Richlen, Mindy L. ; Roberts, Virginia A. ; Smith, Jayme ; Smith, Juliette L. ; Stauffer, Beth ; Suddleson, Marc ; Tester, Patricia A. ; Whitehead, ChristopherHarmful and toxic algal blooms (HABs) are a well-established and severe threat to human health, economies, and marine and freshwater ecosystems on all coasts of the United States and its inland waters. HABs can comprise microalgae, cyanobacteria, and macroalgae (seaweeds). Their impacts, intensity, and geographic range have increased over past decades due to both human-induced and natural changes. In this report, HABs refers to both marine algal and freshwater cyanobacterial events. This Harmful Algal Research and Response: A National Environmental Science Strategy (HARRNESS) 2024-2034 plan builds on major accomplishments from past efforts, provides a state of the science update since the previous decadal HARRNESS plan (2005-2015), identifies key information gaps, and presents forward-thinking solutions. Major achievements on many fronts since the last HARRNESS are detailed in this report. They include improved understanding of bloom dynamics of large-scale regional HABs such as those of Pseudo-nitzschia on the west coast, Alexandrium on the east coast, Karenia brevis on the west Florida shelf, and Microcystis in Lake Erie, and advances in HAB sensor technology, allowing deployment on fixed and mobile platforms for long-term, continuous, remote HAB cell and toxin observations. New HABs and impacts have emerged. Freshwater HABs now occur in many inland waterways and their public health impacts through drinking and recreational water contamination have been characterized and new monitoring efforts have been initiated. Freshwater HAB toxins are finding their way into marine environments and contaminating seafood with unknown consequences. Blooms of Dinophysis spp., which can cause diarrhetic shellfish poisoning, have appeared around the US coast, but the causes are not understood. Similarly, blooms of fish- and shellfish-killing HABs are occurring in many regions and are especially threatening to aquaculture. The science, management, and decision-making necessary to manage the threat of HABs continue to involve a multidisciplinary group of scientists, managers, and agencies at various levels. The initial HARRNESS framework and the resulting National HAB Committee (NHC) have proven effective means to coordinate the academic, management, and stakeholder communities interested in national HAB issues and provide these entities with a collective voice, in part through this updated HARRNESS report. Congress and the Executive Branch have supported most of the advances achieved under HARRNESS (2005-2015) and continue to make HABs a priority. Congress has reauthorized the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA) multiple times and continues to authorize the National Oceanic and Atmospheric Administration (NOAA) to fund and conduct HAB research and response, has given new roles to the US Environmental Protection Agency (EPA), and required an Interagency Working Group on HABHRCA (IWG HABHRCA). These efforts have been instrumental in coordinating HAB responses by federal and state agencies. Initial appropriations for NOAA HAB research and response decreased after 2005, but have increased substantially in the last few years, leading to many advances in HAB management in marine coastal and Great Lakes regions. With no specific funding for HABs, the US EPA has provided funding to states through existing laws, such as the Clean Water Act, Safe Drinking Water Act, and to members of the Great Lakes Interagency Task Force through the Great Lakes Restoration Initiative, to assist states and tribes in addressing issues related to HAB toxins and hypoxia. The US EPA has also worked towards fulfilling its mandate by providing tools and resources to states, territories, and local governments to help manage HABs and cyanotoxins, to effectively communicate the risks of cyanotoxins and to assist public water systems and water managers to manage HABs. These tools and resources include documents to assist with adopting recommended recreational criteria and/or swimming advisories, recommendations for public water systems to choose to apply health advisories for cyanotoxins, risk communication templates, videos and toolkits, monitoring guidance, and drinking water treatment optimization documents. Beginning in 2018, Congress has directed the U.S. Army Corps of Engineers (USACE) to develop a HAB research initiative to deliver scalable HAB prevention, detection, and management technologies intended to reduce the frequency and severity of HAB impacts to our Nation’s freshwater resources. Since the initial HARRNESS report, other federal agencies have become increasingly engaged in addressing HABs, a trend likely to continue given the evolution of regulations(e.g., US EPA drinking water health advisories and recreational water quality criteria for two cyanotoxins), and new understanding of risks associated with freshwater HABs. The NSF/NIEHS Oceans and Human Health Program has contributed substantially to our understanding of HABs. The US Geological Survey, Centers for Disease Control and Prevention, and the National Aeronautics Space Administration also contribute to HAB-related activities. In the preparation of this report, input was sought early on from a wide range of stakeholders, including participants from academia, industry, and government. The aim of this interdisciplinary effort is to provide summary information that will guide future research and management of HABs and inform policy development at the agency and congressional levels. As a result of this information gathering effort, four major HAB focus/programmatic areas were identified: 1) Observing systems, modeling, and forecasting; 2) Detection and ecological impacts, including genetics and bloom ecology; 3) HAB management including prevention, control, and mitigation, and 4) Human dimensions, including public health, socio-economics, outreach, and education. Focus groups were tasked with addressing a) our current understanding based on advances since HARRNESS 2005-2015, b) identification of critical information gaps and opportunities, and c) proposed recommendations for the future. The vision statement for HARRNESS 2024-2034 has been updated, as follows: “Over the next decade, in the context of global climate change projections, HARRNESS will define the magnitude, scope, and diversity of the HAB problem in US marine, brackish and freshwaters; strengthen coordination among agencies, stakeholders, and partners; advance the development of effective research and management solutions; and build resilience to address the broad range of US HAB problems impacting vulnerable communities and ecosystems.” This will guide federal, state, local and tribal agencies and nations, researchers, industry, and other organizations over the next decade to collectively work to address HAB problems in the United States.