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Alonso-Rodríguez R, Pichardo-Velarde JG. Effects of temperature and nutrients on growth and toxicity of Alexandrium affine from southeastern Gulf of California. MARINE POLLUTION BULLETIN 2024; 203:116464. [PMID: 38759464 DOI: 10.1016/j.marpolbul.2024.116464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 04/28/2024] [Accepted: 05/03/2024] [Indexed: 05/19/2024]
Abstract
An Alexandrium affine strain (AAJQ-1) from San José Island, Gulf of California was characterized for growth and toxicology. Fivefold of f/2 + Se cultures were incubated for 34 days in a temperature gradient (21-29 °C). Aliquots were collected every third day for cell counting, toxin determination, and nutrient analyses. In this study ELISA method was used to evaluate the PSP toxin production due to the lower detection limit than the HPLC method. The highest cell density (6724 cells mL-1) and growth rate (0.22 day-1) were obtained at 27 °C and they were related to temperature in all treatments. Cell density showed negative correlation with nitrate at temperatures ≥23 °C, and with orthophosphate 27 °C, furthermore, these correlations promote the toxin production (0.05-0.45 fmol STX cell-1); beyond that nitrite at high temperature seems to promote toxin production, which has not been sufficiently documented.
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Affiliation(s)
- Rosalba Alonso-Rodríguez
- Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Av. Joel Montes Camarena s/n, Mazatlán, Sinaloa 82040, Mexico.
| | - Jorge Gerardo Pichardo-Velarde
- Facultad de Ciencias del Mar (FACIMAR), Universidad Autónoma de Sinaloa (UAS), Paseo Claussen S/N, Centro, Mazatlán, Sinaloa 82000, Mexico
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2
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Cornett JC, Cates RJ, Ledger KJ, Pinger CW, Hart CE, Laboda KR, Larson WA, Hollarsmith JA. Assessing methods for detecting Alexandrium catenella (Dinophyceae) and paralytic shellfish toxins in Southeast Alaska. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2024. [PMID: 38712820 DOI: 10.1002/ieam.4944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 05/08/2024]
Abstract
Blooms of Alexandrium catenella threaten to disrupt subsistence, recreational, and commercial shellfish harvest in Alaska, as the paralytic shellfish toxins (PSTs) produced pose a serious public health risk and can lead to costly shutdowns for shellfish farmers. Current methods of PST detection in the region range from monitoring programs utilizing net tows to detect A. catenella to direct shellfish tissue testing via mouse bioassay (MBA) for commercial aquaculture harvest, as well as various optional testing methods for subsistence and recreational harvesters. The efficacy and feasibility of these methods vary, and they have not been directly compared in Southeast Alaska. In this study, we sought to assess and compare A. catenella and PST early detection methods to determine which can provide the most effective and accurate warning of A. catenella blooms or PST events. We found microscope counts to be variable and prone to missing lower numbers of A. catenella, which may be indicative of bloom formation. However, quantitative polymerase chain reaction (qPCR) significantly correlated with microscope counts and was able to effectively detect even low numbers of A. catenella on all sampling days. Paralytic shellfish toxin concentrations measured by enzyme-linked immunosorbent assay and MBA significantly correlated with each other, qPCR, and some microscope counts. These results show that qPCR is an effective tool for both monitoring A. catenella and serving as a proxy for PSTs. Further work is needed to refine qPCR protocols in this system to provide bloom warnings on an actionable timescale for the aquaculture industry and other shellfish harvesters. Integr Environ Assess Manag 2024;00:1-14. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Juliana C Cornett
- NOAA Fisheries Alaska Fisheries Science Center, Juneau, Alaska, USA
- Alaska Sea Grant, Fairbanks, Alaska, USA
| | - Rebecca J Cates
- NOAA Fisheries Alaska Fisheries Science Center, Juneau, Alaska, USA
- Cooperative Institute for Climate, Ocean, & Ecosystem Studies (CICOES), University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Kimberly J Ledger
- NOAA Fisheries Alaska Fisheries Science Center, Juneau, Alaska, USA
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, USA
| | - Cody W Pinger
- NOAA Fisheries Alaska Fisheries Science Center, Juneau, Alaska, USA
| | - Courtney E Hart
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, USA
| | | | - Wesley A Larson
- NOAA Fisheries Alaska Fisheries Science Center, Juneau, Alaska, USA
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3
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Shin HH, Son MH, Park BS, Han KH, Youn JY, Kwak KY, Lee JH, Shin AY, Byun E, Yoo YD, Seo MH, Shin K, Li Z. Bloom development of toxic dinoflagellate Alexandrium catenella (Group I) in Jinhae-Masan Bay, Korea: Germination strategy of resting cysts in relation to temperature and salinity. MARINE POLLUTION BULLETIN 2023; 191:114995. [PMID: 37146546 DOI: 10.1016/j.marpolbul.2023.114995] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/23/2023] [Accepted: 04/24/2023] [Indexed: 05/07/2023]
Abstract
To better understand the role of resting cysts in the outbreak of paralytic shellfish poisoning and bloom dynamics in Jinhae-Masan Bay, Korea, this study investigated the germination features of ellipsoidal Alexandrium cysts isolated from sediments collected in winter and summer under different combinations of temperature and salinity. Morphology and phylogeny of germling cells revealed that the ellipsoidal Alexandrium cysts belong to Alexandrium catenella (Group I). The cysts could germinate across a wide range of temperature (5-25 °C) with germination success within 5 days, indicating that continuous seeding for the maintenance of vegetative cells in the water column may occur through the year without an endogenous clock to regulate germination timing. In addition, the cyst germination of A. catenella (Group I) was not controlled by seasonal salinity changes. Based on the results, this study provides a schematic scenario of the bloom development of A. catenella (Group I) in Jinhae-Masan Bay, Korea.
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Affiliation(s)
- Hyeon Ho Shin
- Library of Marine Samples, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea.
| | - Moon Ho Son
- National Institute of Fisheries Science, Busan 619-705, Republic of Korea
| | - Bum Soo Park
- Department of Life Science, Hanyang University, 222 Wangsipriro, Seongdonggu, Seoul 04763, Republic of Korea
| | - Kyung Ha Han
- Library of Marine Samples, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea; Department of Life Science, Hanyang University, 222 Wangsipriro, Seongdonggu, Seoul 04763, Republic of Korea
| | - Joo Yeon Youn
- Library of Marine Samples, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea
| | - Kyeong Yoon Kwak
- Library of Marine Samples, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea
| | - Ji Hoon Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan 49111, Republic of Korea
| | - A-Young Shin
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan 49111, Republic of Korea
| | - Eunjung Byun
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan 49111, Republic of Korea
| | - Yeong Du Yoo
- Faculty of Marine Applied Biosciences, Kunsan National University, Gunsan 54150, Republic of Korea
| | - Min Ho Seo
- Marine Ecology Research Center, Yeosu 59697, Republic of Korea
| | - Kyungsoon Shin
- Ballast Water Research Center, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea
| | - Zhun Li
- Biological Resource Center/Korean Collection for Type Cultures (KCTC), Korea Research Institute of Bioscience and Biotechnology, Jeongeup 56212, Republic of Korea.
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4
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Einarsson SV, Lowry KE, Lin P, Pickart RS, Ashjian CJ, Chappell PD. Alexandrium on the Alaskan Beaufort Sea shelf: Impact of upwelling in a warming Arctic. HARMFUL ALGAE 2022; 120:102346. [PMID: 36470603 DOI: 10.1016/j.hal.2022.102346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
The harmful algal genus Alexandrium has characteristically been found in temperate and subtropical regions; however recent evidence suggests global warming may be expanding its range into high latitude waters. Alexandrium cysts have previously been documented in the Chukchi Sea and we hypothesize that Alexandrium may be expanding further into the Arctic due to distribution by the Beaufort shelfbreak jet. Here we document the presence of Alexandrium catenella along the Alaskan Beaufort Sea shelf, marking an expansion of its known range. The observations of A. catenella were made using three different methods: FlowCAM imaging, 18S eukaryotic sequencing, and real-time quantitative PCR. Four occupations of a shelf/slope transect spanned the evolution of a strong wind-driven upwelling event over a 5-day period. A nearby mooring provided the physical context for the event, revealing that enhanced easterly winds reversed the Beaufort shelfbreak jet to the west and induced upwelling of colder, denser water onto the outer shelf. A. catenella sequences dominated the surface phytoplankton community at the onset of the upwelling event. This signal vanished during and after the event, likely due to a combination of alongstream advection, cross-stream advection, and wind mixing. These results suggest contrasting physical processes that are both subject to global warming amplification, delivery of warm waters via the Beaufort shelfbreak jet and upwelling, may control the proliferation of this potential harmful alga into the Arctic.
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Affiliation(s)
- Sveinn V Einarsson
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, USA
| | - Kate E Lowry
- Science Philanthropy Alliance, Palo Alto, CA, USA; Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Peigen Lin
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | | | - P Dreux Chappell
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, USA.
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5
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Anderson DM, Fachon E, Pickart RS, Lin P, Fischer AD, Richlen ML, Uva V, Brosnahan ML, McRaven L, Bahr F, Lefebvre K, Grebmeier JM, Danielson SL, Lyu Y, Fukai Y. Evidence for massive and recurrent toxic blooms of Alexandrium catenella in the Alaskan Arctic. Proc Natl Acad Sci U S A 2021; 118:e2107387118. [PMID: 34607950 PMCID: PMC8521661 DOI: 10.1073/pnas.2107387118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 11/28/2022] Open
Abstract
Among the organisms that spread into and flourish in Arctic waters with rising temperatures and sea ice loss are toxic algae, a group of harmful algal bloom species that produce potent biotoxins. Alexandrium catenella, a cyst-forming dinoflagellate that causes paralytic shellfish poisoning worldwide, has been a significant threat to human health in southeastern Alaska for centuries. It is known to be transported into Arctic regions in waters transiting northward through the Bering Strait, yet there is little recognition of this organism as a human health concern north of the Strait. Here, we describe an exceptionally large A. catenella benthic cyst bed and hydrographic conditions across the Chukchi Sea that support germination and development of recurrent, locally originating and self-seeding blooms. Two prominent cyst accumulation zones result from deposition promoted by weak circulation. Cyst concentrations are among the highest reported globally for this species, and the cyst bed is at least 6× larger in area than any other. These extraordinary accumulations are attributed to repeated inputs from advected southern blooms and to localized cyst formation and deposition. Over the past two decades, warming has likely increased the magnitude of the germination flux twofold and advanced the timing of cell inoculation into the euphotic zone by 20 d. Conditions are also now favorable for bloom development in surface waters. The region is poised to support annually recurrent A. catenella blooms that are massive in scale, posing a significant and worrisome threat to public and ecosystem health in Alaskan Arctic communities where economies are subsistence based.
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Affiliation(s)
- Donald M Anderson
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543;
| | - Evangeline Fachon
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Robert S Pickart
- Physical Oceanography Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Peigen Lin
- Physical Oceanography Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Alexis D Fischer
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Mindy L Richlen
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Victoria Uva
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Michael L Brosnahan
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Leah McRaven
- Physical Oceanography Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Frank Bahr
- Physical Oceanography Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Kathi Lefebvre
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, NOAA to National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Seattle, WA 98112
| | - Jacqueline M Grebmeier
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Sciences, Solomons, MD 20688
| | - Seth L Danielson
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775
| | - Yihua Lyu
- South China Sea Environmental Monitoring Center, State Oceanic Administration, Guangzhou 510300, People's Republic of China
| | - Yuri Fukai
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
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6
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Kim YO, Choi J, Baek SH, Lee M, Oh HM. Tracking Alexandrium catenella from seed-bed to bloom on the southern coast of Korea. HARMFUL ALGAE 2020; 99:101922. [PMID: 33218446 DOI: 10.1016/j.hal.2020.101922] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 10/10/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Alexandrium catenella was tracked from seed-bed to bloom at a hot spot of cyst deposition on the southern coast of Korea from June 2016 to Feb. 2020. Changes in cyst abundance and germinability from sediment, as well as the vegetative cell abundance and encystment in the water column were intensively monitored. Cyst germination of ca. 73% occurred synchronously in November of 2016 to 2019, when bottom water temperature was around 15 °C. After mass germination, vegetative cells formed a seed populations at low density (<10 cells L-1) during winter. Overwintering populations initiated growth in March and then proliferated into high density (ca. 4 × 104 cells L-1) spring blooms in mid-April 2017 when moderate temperature (15 °C) was recorded. There was no bloom in spring of 2018 and 2019, but small vegetative populations developed. Decline of the spring bloom was followed by massive encystment and an increase in Noctiluca abundance. An average spring encystment ratio of 0.002 was estimated for the study years. Newly formed cysts lay dormant during the warm season lasting about six months and then seeded the next population of vegetative cells. An average contribution ratio of cells recruited from the sediment was ca. 0.09 for seeding winter populations. The range in shift ratios for spring production of a daughter cyst population to prior cyst abundance of the mother population in fall was 0.1 to 0.6 for consecutive years, depending on annual variation of local environments. Tracking mass transformation of A. catenella cysts will contribute to more effective science based management of paralytic shellfish poisoning on the southern Korean coast.
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Affiliation(s)
- Young Ok Kim
- Marine Ecosystem Research Center, Korea Institute of Ocean Science & Technology, Busan, 49111, Republic of Korea.
| | - Jungmin Choi
- Marine Ecosystem Research Center, Korea Institute of Ocean Science & Technology, Busan, 49111, Republic of Korea
| | - Seung Ho Baek
- Risk Assessment Research Center, Korea Institute of Ocean Science & Technology, Geoje, 53201, Republic of Korea
| | - Minji Lee
- Risk Assessment Research Center, Korea Institute of Ocean Science & Technology, Geoje, 53201, Republic of Korea
| | - Hee-Mock Oh
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
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7
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Brosnahan ML, Fischer AD, Lopez CB, Moore SK, Anderson DM. Cyst-forming dinoflagellates in a warming climate. HARMFUL ALGAE 2020; 91:101728. [PMID: 32057345 PMCID: PMC7189352 DOI: 10.1016/j.hal.2019.101728] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 05/12/2023]
Abstract
Many phytoplankton species, including many harmful algal bloom (HAB) species, survive long periods between blooms through formation of benthic resting stages. Because they are crucial to the persistence of these species and the initiation of new blooms, the physiology of benthic stages must be considered to accurately predict responses to climate warming and associated environmental changes. The benthic stages of dinoflagellates, called resting cysts, germinate in response to the combination of favorable temperature, oxygen-availability, and release from dormancy. The latter is a mechanism that prevents germination even when oxygen and temperature conditions are favorable. Here, evidence of temperature-mediated control of dormancy duration from the dinoflagellates Alexandrium catenella and Pyrodinium bahamense-two HAB species that cause paralytic shellfish poisoning (PSP)-is reviewed and presented alongside new evidence of complementary, temperature-based control of cyst quiescence (the state in which cysts germinate on exposure to favorable conditions). Interaction of the two temperature-based mechanisms with climate is explored through a simple model parameterized using results from recent experiments with A. catenella. Simulations demonstrate the importance of seasonal temperature cycles for the synchronization of cysts' release from dormancy and are consistent with biogeography-based inferences that A. catenella is more tolerant of warming in habitats that experience a larger range of seasonal temperature variation (i.e., have higher temperature seasonality). Temperature seasonality is much greater in shallow, long-residence time habitats than in deep, open-water ones. As warming shifts species' ranges, cyst beds may persist longer in more seasonally variable, shallow inshore habitats than in deep offshore ones, promoting HABs that are more localized and commence earlier each year. Recent field investigations of A. catenella also point to the importance of new cyst formation as a factor triggering bloom termination through mass sexual induction. In areas where temperature seasonality restricts the flux of new swimming cells (germlings) to narrow temporal windows, warming is unlikely to promote longer and more intense HAB impacts-even when water column conditions would otherwise promote prolonged bloom development. Many species likely have a strong drive to sexually differentiate and produce new cysts once concentrations reach levels that are conducive to new cyst formation. This phenomenon can impose a limit to bloom intensification and suggests an important role for cyst bed quiescence in determining the duration of HAB risk periods.
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Affiliation(s)
- Michael L Brosnahan
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA USA.
| | - Alexis D Fischer
- Ocean Sciences Department, University of California, Santa Cruz, CA USA
| | - Cary B Lopez
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Saint Petersburg, FL USA
| | - Stephanie K Moore
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA USA
| | - Donald M Anderson
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA USA
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Gao C, Lin S, Chen M, Hong J, Liu C. Prevalence of phycotoxin contamination in shellfish from the Northern Bering Sea and the Chukchi Sea. Toxicon 2019; 167:76-81. [DOI: 10.1016/j.toxicon.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 04/25/2019] [Accepted: 06/03/2019] [Indexed: 10/26/2022]
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9
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Fischer AD, Brosnahan ML, Anderson DM. Quantitative Response of Alexandrium catenella Cyst Dormancy to Cold Exposure. Protist 2018; 169:645-661. [DOI: 10.1016/j.protis.2018.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 06/05/2018] [Accepted: 06/07/2018] [Indexed: 11/28/2022]
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Natsuike M, Saito R, Fujiwara A, Matsuno K, Yamaguchi A, Shiga N, Hirawake T, Kikuchi T, Nishino S, Imai I. Evidence of increased toxic Alexandrium tamarense dinoflagellate blooms in the eastern Bering Sea in the summers of 2004 and 2005. PLoS One 2017; 12:e0188565. [PMID: 29182651 PMCID: PMC5705126 DOI: 10.1371/journal.pone.0188565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 11/09/2017] [Indexed: 11/19/2022] Open
Abstract
The eastern Bering Sea has a vast continental shelf, which contains various endangered marine mammals and large fishery resources. Recently, high numbers of toxic A. tamarense resting cysts were found in the bottom sediment surface of the eastern Bering Sea shelf, suggesting that the blooms have recently occurred. However, little is known about the presence of A. tamarense vegetative cells in the eastern Bering Sea. This study's goals were to detect the occurrence of A. tamarense vegetative cells on the eastern Bering Sea shelf and to find a relationship between environmental factors and their presence. Inter-annual field surveys were conducted to detect A. tamarense cells and environmental factors, such as nutrients, salinity, chlorophyll a, and water temperature, along a transect line on the eastern Bering Sea shelf during the summers of 2004, 2005, 2006, 2009, 2012, and 2013. A. tamarense vegetative cells were detected during every sampling year, and their quantities varied greatly from year to year. The maximum cell densities of A. tamarense observed during the summers of 2004 and 2005 were much higher than the Paralytic shellfish poisoning warning levels, which are greater than 100-1,000 cells L-1, in other subarctic areas. Lower quantities of the species occurred during the summers of 2009, 2012, and 2013. A significant positive correlation between A. tamarense quantity and water temperature and significant negative correlations between A. tamarense quantity and nutrient concentrations (of phosphate, silicate, and nitrite and nitrate) were detected in every sampling period. The surface- and bottom-water temperatures varied significantly from year to year, suggesting that water temperatures, which have been known to affect the cell growth and cyst germination of A. tamarense, might have affected the cells' quantities in the eastern Bering Sea each summer. Thus, an increase in the Bering Sea shelf's water temperature during the summer will increase the frequency and scale of toxic blooms and the toxin contamination of plankton feeders. This poses serious threats to humans and the marine ecosystem.
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Affiliation(s)
- Masafumi Natsuike
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
- * E-mail:
| | - Rui Saito
- Center for Marine Environmental Studies, Ehime University, Matsuyama, Ehime, Japan
| | - Amane Fujiwara
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Kohei Matsuno
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Atsushi Yamaguchi
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Naonobu Shiga
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Toru Hirawake
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
| | - Takashi Kikuchi
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Shigeto Nishino
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Ichiro Imai
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan
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