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Brunson JK, Thukral M, Ryan JP, Anderson CR, Kolody BC, James C, Chavez FP, Leaw CP, Rabines AJ, Venepally P, Zheng H, Kudela RM, Smith GJ, Moore BS, Allen AE. Molecular Forecasting of Domoic Acid during a Pervasive Toxic Diatom Bloom. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.02.565333. [PMID: 37961417 PMCID: PMC10635071 DOI: 10.1101/2023.11.02.565333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
In 2015, the largest recorded harmful algal bloom (HAB) occurred in the Northeast Pacific, causing nearly 100 million dollars in damages to fisheries and killing many protected marine mammals. Dominated by the toxic diatom Pseudo-nitzschia australis , this bloom produced high levels of the neurotoxin domoic acid (DA). Through molecular and transcriptional characterization of 52 near-weekly phytoplankton net-tow samples collected at a bloom hotspot in Monterey Bay, California, we identified active transcription of known DA biosynthesis ( dab ) genes from the three identified toxigenic species, including P. australis as the primary origin of toxicity. Elevated expression of silicon transporters ( sit1 ) during the bloom supports the previously hypothesized role of dissolved silica (Si) exhaustion in contributing to bloom physiology and toxicity. We find that co-expression of the dabA and sit1 genes serves as a robust predictor of DA one week in advance, potentially enabling the forecasting of DA-producing HABs. We additionally present evidence that low levels of iron could have co-limited the diatom population along with low Si. Iron limitation represents a previously unrecognized driver of both toxin production and ecological success of the low iron adapted Pseudo-nitzschia genus during the 2015 bloom, and increasing pervasiveness of iron limitation may fuel the escalating magnitude and frequency of toxic Pseudo-nitzschia blooms globally. Our results advance understanding of bloom physiology underlying toxin production, bloom prediction, and the impact of global change on toxic blooms. Significance Pseudo-nitzschia diatoms form oceanic harmful algal blooms that threaten human health through production of the neurotoxin domoic acid (DA). DA biosynthetic gene expression is hypothesized to control DA production in the environment, yet what regulates expression of these genes is yet to be discovered. In this study, we uncovered expression of DA biosynthesis genes by multiple toxigenic Pseudo-nitzschia species during an economically impactful bloom along the North American West Coast, and identified genes that predict DA in advance of its production. We discovered that iron and silica co-limitation restrained the bloom and likely promoted toxin production. This work suggests that increasing iron limitation due to global change may play a previously unrecognized role in driving bloom frequency and toxicity.
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Hioki N, Kuma K, Morita Y, Sasayama R, Ooki A, Kondo Y, Obata H, Nishioka J, Yamashita Y, Nishino S, Kikuchi T, Aoyama M. Laterally spreading iron, humic-like dissolved organic matter and nutrients in cold, dense subsurface water of the Arctic Ocean. Sci Rep 2014; 4:6775. [PMID: 25345398 PMCID: PMC5381382 DOI: 10.1038/srep06775] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/06/2014] [Indexed: 11/17/2022] Open
Abstract
The location and magnitude of oceanic iron sources remain uncertain owing to a scarcity of data, particularly in the Arctic Ocean. The formation of cold, dense water in the subsurface layer of the western Arctic Ocean is a key process in the lateral transport of iron, macronutrients, and other chemical constituents. Here, we present iron, humic-like fluorescent dissolved organic matter, and nutrient concentration data in waters above the continental slope and shelf and along two transects across the shelf–basin interface in the western Arctic Ocean. We detected high concentrations in shelf bottom waters and in a plume that extended in the subsurface cold dense water of the halocline layer in slope and basin regions. At σθ = 26.5, dissolved Fe, humic-like fluorescence intensity, and nutrient maxima coincided with N* minima (large negative values of N* indicate significant denitrification within shelf sediments). These results suggest that these constituents are supplied from the shelf sediments and then transported laterally to basin regions. Humic dissolved organic matter probably plays the most important role in the subsurface maxima and lateral transport of dissolved Fe in the halocline layer as natural Fe-binding organic ligand.
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Affiliation(s)
- Nanako Hioki
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Kenshi Kuma
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Yuichirou Morita
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Ryouhei Sasayama
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Atsushi Ooki
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Yoshiko Kondo
- National Institute of Polar Research, Tachikawa 190-8518, Japan
| | - Hajime Obata
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8564, Japan
| | - Jun Nishioka
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0189, Japan
| | - Youhei Yamashita
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Shigeto Nishino
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
| | - Takashi Kikuchi
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan
| | - Michio Aoyama
- 1] Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka 237-0061, Japan [2] Institute of Environmental Radioactivity, Fukushima University, Fukushima 960-1296, Japan
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Nishimura S, Kuma K, Ishikawa S, Omata A, Saitoh SI. Iron, nutrients, and humic-type fluorescent dissolved organic matter in the northern Bering Sea shelf, Bering Strait, and Chukchi Sea. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jc007355] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Nakayama Y, Fujita S, Kuma K, Shimada K. Iron and humic‐type fluorescent dissolved organic matter in the Chukchi Sea and Canada Basin of the western Arctic Ocean. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006779] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuta Nakayama
- Graduate School of Environmental Science Hokkaido University Sapporo, Hokkaido Japan
| | - Satoshi Fujita
- Graduate School of Environmental Science Hokkaido University Sapporo, Hokkaido Japan
| | - Kenshi Kuma
- Faculty of Fisheries Sciences Hokkaido University Hakodate Japan
| | - Koji Shimada
- Department of Ocean Sciences Tokyo University of Marine Science and Technology Tokyo Japan
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Nishioka J, Ono T, Saito H, Sakaoka K, Yoshimura T. Oceanic iron supply mechanisms which support the spring diatom bloom in the Oyashio region, western subarctic Pacific. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006321] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Fujita S, Kuma K, Ishikawa S, Nishimura S, Nakayama Y, Ushizaka S, Isoda Y, Otosaka S, Aramaki T. Iron distributions in the water column of the Japan Basin and Yamato Basin (Japan Sea). ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jc006123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Conaway CH, Black FJ, Gault-Ringold M, Pennington JT, Chavez FP, Flegal AR. Dimethylmercury in coastal upwelling waters, Monterey Bay, California. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:1305-1309. [PMID: 19350895 DOI: 10.1021/es802705t] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Depth profiles of dimethylmercury (DMHg) concentration were determined at nearshore to offshore sites in Monterey Bay, California. The onset of spring upwelling in the bay was accompanied by increases in DMHg concentrations. Profiles show DMHg increasing gradually with depth in fall and winter from <0.03 pM at the surface to 0.5 pM at 200 m. During the spring, DMHg concentrations increased between 30 and 100 m, first within Monterey Bay, then offshore. This change was accompanied by an increase in DMHg concentrations in the surface water DMHg between fall/winter (<0.03 pM) and spring (0.06-0.29 pM). Microbial activity associated with the remineralization of sinking organic matter produced by the high primary production in the bay may result in the relatively high DMHg in subsurface water in the bay, which when upwelled may facilitate the incorporation of organomercury into biota. As a result, productive coastal upwelling areas may represent an important source of methylated mercury to surface waters, and thus be an important source of mercury to marine ecosystems.
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Affiliation(s)
- Christopher H Conaway
- Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
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