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Wang Z, Wang F, Wang C, Xie C, Tang T, Chen J, Ji S, Zhang S, Zhang Y, Jiang T. Annual variation in domoic acid in phytoplankton and shellfish samples from Daya Bay of the South China Sea. HARMFUL ALGAE 2023; 127:102438. [PMID: 37544665 DOI: 10.1016/j.hal.2023.102438] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/23/2023] [Accepted: 04/28/2023] [Indexed: 08/08/2023]
Abstract
Domoic acid (DA) is a well-known phycotoxin that causes amnesic shellfish poisoning (ASP) and is mainly produced by diatom species belonging to the genus Pseudo-nitzschia. An annual survey was conducted monthly over the period of September 2020 to August 2021 in Daya Bay of the South China Sea to investigate the dynamics of particulate and shellfish DA and their relationships with the abundance of Pseudo-nitzschia spp. and environmental parameters. Pseudo-nitzschia spp. was one of the most dominant phytoplankton taxa, and a Pseudo-nitzschia bloom occurred during the survey with the highest abundance of 1.91 × 106 cells L-1. DA was detected in almost all plankton samples with the highest value of 120.7 ng L-1, and high DA concentrations coincided with the abundant presence of Pseudo-nitzschia. DA is prevalent in Daya Bay throughout the year, with detection rates of 98.3%, 82.6%, and 82.6% in plankton samples, in-situ and purchased shellfish, respectively. Higher DA concentrations were detected in the scallop (Chamys nobilis), with the highest concentration of 5.34 µg g-1. High water temperature and low DSi:DIN ratio promoted the growth of Pseudo-nitzschia and DA production. The results suggest that the increasing nitrogen loading and silicate limitation during Pseudo-nitzschia blooms together with the increase in water temperature may increase the risk of DA contamination in Daya Bay.
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Affiliation(s)
- Zhaohui Wang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
| | - Fan Wang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Chaofan Wang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Changliang Xie
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Tao Tang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Jiazhuo Chen
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Shuanghui Ji
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Shuai Zhang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Yuning Zhang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Tianjian Jiang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
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Alexander P, Evgeniy G, Sergey V, Zhanna M, Tatiana O. The study of fluorescence features of microalgae from the genus Pseudo-nitzschia and the possibility of their detection in water. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dong HC, Lundholm N, Teng ST, Li A, Wang C, Hu Y, Li Y. Occurrence of Pseudo-nitzschia species and associated domoic acid production along the Guangdong coast, South China Sea. HARMFUL ALGAE 2020; 98:101899. [PMID: 33129456 DOI: 10.1016/j.hal.2020.101899] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 06/11/2023]
Abstract
The diatom genus Pseudo-nitzschia, which has been associated with amnesic shellfish poisoning events globally, is also one of the key harmful microalga groups in Guangdong coastal waters, off the north coast of the South China Sea. In order to explore the diversity and toxigenic characteristics, Pseudo-nitzschia isolates were established. Based on a combination of morphological and molecular features, in total 26 different Pseudo-nitzschia taxa were identified, including two new species, P. uniseriata H.C. Dong & Yang Li and P. yuensis H.C. Dong & Yang Li. Morphologically, P. uniseriata is unique by having striae mainly comprising one row of poroids, which are simple without divided hymen internally, and each poroid containing one, seldom two sectors. Pseudo-nitzschia yuensis is characterized by having striae comprising one to two rows of poroids. In biseriate striae, the poroids are polygonal and irregularly distributed, and a discontinuous row of poroids may be present in the middle. In uniseriate striae, the poroids usually contain 1-5 sectors. Both taxa are well differentiated from other Pseudo-nitzschia species in phylogenetic analyses inferred from ITS2 sequence-structure information. Pseudo-nitzschia uniseriata is sister to P. lineola, whereas P. yuensis forms a group together with P. micropora and P. delicatissima. When comparing ITS2 secondary structure, two hemi-compensatory base change (HCBCs) are found between P. uniseriata and P. lineola. One compensatory base change (CBC) and four HCBCs are found between P. yuensis and P. delicatissima, and there is one CBC and five HCBCs between P. yuensis and P. micropora. The ability of cultured strains to produce particulate DA (pDA) revealed production of pDA in twenty-nine strains belonging to seven species: P. bipertita, P. caciantha, P. cuspidata, P. fraudulenta, P. fukuyoi, P. lundholmiae and P. multiseries. This is the first report of P. bipertita being toxic, with pDA content of 15.6 ± 2.1 fg cell-1. The presence of brine shrimps significantly increased pDA content in P. cuspidata, P. fukuyoi, P. lundholmiae and P. multiseries 1.4 to 7 times, and induced pDA production in P. fraudulenta from below detection limit to 17.5 ± 1.6 fg cell-1. The highest pDA concentration, 4830.5 ± 120.3 fg cell-1, was detected in P. multiseries, a level much lower than previous reports on P. multiseries from North America and Europe. Overall, the cellular toxin levels in Pseudo-nitzschia spp. were low in Guangdong coastal isolates.
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Affiliation(s)
- Huan Chang Dong
- Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou 510631, PR China.
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Øster Farimagsgade 5, 1307 Copenhagen K, Denmark.
| | - Sing Tung Teng
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, Kota Samarahan 94300, Sarawak, Malaysia.
| | - Aifeng Li
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China.
| | - Chao Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China.
| | - Yang Hu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China.
| | - Yang Li
- Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou 510631, PR China.
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Olesen AJ, Harðardóttir S, Daugbjerg N, Andersen P, Lyngsgaard M, Krock B, Lundholm N. The impact of urea on toxic diatoms - Potential effects of fertilizer silo breakdown on a Pseudo-nitzschia bloom. HARMFUL ALGAE 2020; 95:101817. [PMID: 32439060 DOI: 10.1016/j.hal.2020.101817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
In spring 2016, two silos containing liquid nitrogen-containing fertilizer collapsed on a harbor in Fredericia, Denmark. More than 2,750 tons of fertilizer spilled into inner Danish waters. A bloom of Pseudo-nitzschia occurred approximately one month after the incident. The bloom caused a 5-week quarantine of numerous mussel-harvesting areas along the eastern coast of Jutland. The levels of domoic acid measured up to 49 mg kg-1 in mussel meat after the bloom. In the months following the event, the species diversity of phytoplankton was low, while the abundance was high comprising few dominant species including Pseudo-nitzschia. The main part of the liquid nitrogen-containing compound was urea, chemically produced for agricultural use. To investigate the potential impact of urea on Pseudo-nitzschia, four strains, including one strain of P. delicatissima, two of P. seriata and one of P. obtusa, were exposed each to three concentrations of urea in a batch culture experiment: 10 μM, 20 μM and 100 μM N urea, and for comparison one concentration of nitrate (10 μM). Nitrate, ammonium, and urea were metabolized at different rates. Pseudo-nitzschia obtusa produced domoic acid and grew best at low urea concentrations. Both P. seriata strains had a positive correlation between urea concentration and growth rate, and the highest growth rate in the nitrate treatment. One strain of P. seriata produced domoic acid peaking at low N loads (10 µM N urea and 10 µM N nitrate). In conclusion, the ability to adapt to the available nitrogen source and retain a high growth rate was exceedingly varying and not only species-specific but also strain specific.
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Affiliation(s)
- Anna J Olesen
- Natural History Museum of Denmark, Department of Biology, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark.
| | - Sara Harðardóttir
- Natural History Museum of Denmark, Department of Biology, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark; Geological Survey of Denmark and Greenland, Department of Glaciology and Climate, Øster Voldgade 10, 1350 Copenhagen K, Denmark; Université Laval, Département de Biologie, Pavillon C-É Marchand, G1V 0A6 Québec City, Quebec, Canada
| | - Niels Daugbjerg
- Marine Biological Section, Dept of Biology, University of Copenhagen, Universitetsparken 4, 1st floor, 2100 Copenhagen, Denmark
| | | | - Maren Lyngsgaard
- Orbicon, Department for Nature and Environment, Jens Juuls vej 16, 8260 Viby, Denmark
| | - Bernd Krock
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Chemische Ökologie, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Nina Lundholm
- Natural History Museum of Denmark, Department of Biology, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark
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Fretwell PT, Jackson JA, Ulloa Encina MJ, Häussermann V, Perez Alvarez MJ, Olavarría C, Gutstein CS. Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. PLoS One 2019; 14:e0222498. [PMID: 31622348 PMCID: PMC6797088 DOI: 10.1371/journal.pone.0222498] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 08/31/2019] [Indexed: 12/20/2022] Open
Abstract
We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortality of baleen whales, with at least 343 whales, mainly sei whales (Balaenoptera borealis), documented as stranding. However, even with such a large number of whales, due to the remote location of the gulf the strandings went unrecorded for several weeks. Aerial and boat surveys of the area were conducted two to four months after the mortality event. In this study we use 50cm resolution WorldView2 imagery to identify and count strandings from two archival images acquired just after the stranding event and two months before the aerial and ground surveys, and to test manual and automated methods of detecting stranded whales. Our findings show that whales are easily detected manually in the images but due to the heterogeneous colouration of decomposing whales, spectral indices are unsuitable for automatic detection. Our satellite counts suggest that, at the time the satellite images were taken, more whales were stranded than recorded in the aerial survey, possibly due to the non-comprehensive coverage of the aerial survey or movement of the carcases between survey acquisition. With even higher resolution imagery now available, satellite imagery may be a cost effective alternative to aerial surveys for future assessment of the extent of mass whale stranding events, especially in remote and inaccessible areas.
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Affiliation(s)
- Peter T. Fretwell
- British Antarctic Survey, Madingley Road, Cambridge, England, United Kingdom
- * E-mail:
| | - Jennifer A. Jackson
- British Antarctic Survey, Madingley Road, Cambridge, England, United Kingdom
| | - Mauricio J. Ulloa Encina
- Aquatic Animal Rescue and Conservation Unit, National Fisheries and Aquaculture Service of Chile, Valparaiso, Chile
| | - Vreni Häussermann
- Pontificia Universidad Católica de Valparaíso, Facultad de Recursos Naturales, Escuela de Ciencias del Mar, Avda. Brazil, Valparaíso, Chile
- Huinay Scientific Field Station, Valparaíso, Chile
| | - Maria J. Perez Alvarez
- Escuela de Medicina Veterinaria, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Instituto de Ecología y Biodiversidad, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Centro de Investigación Eutropia, Santiago, Chile
| | - Carlos Olavarría
- Centro de Estudios Avanzados en Zonas Aridas (CEAZA), La Serena, Chile
| | - Carolina S. Gutstein
- Lab. Ontogenia y Filogenia, Depto. Biologiía, Fac. Ciencias, Universidad de Chile, Santiago, Chile
- Consultora Paleosuchus Ltda, oficina C, Providencia, Santiago, Chile
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Huang CX, Dong HC, Lundholm N, Teng ST, Zheng GC, Tan ZJ, Lim PT, Li Y. Species composition and toxicity of the genus Pseudo-nitzschia in Taiwan Strait, including P. chiniana sp. nov. and P. qiana sp. nov. HARMFUL ALGAE 2019; 84:195-209. [PMID: 31128805 DOI: 10.1016/j.hal.2019.04.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
In a field survey in the Taiwan Strait during April 2016, the species composition and the domoic acid production of the diatom genus Pseudo-nitzschia were investigated. A total of 80 strains of Pseudo-nitzschia were established, and species identification was determined based on a combination of morphological and molecular data. Fourteen taxa were recognized, i.e., P. americana, P. brasiliana, P. calliantha, P. cuspidata, P. galaxiae, P. lundholmiae, P. multiseries, P. multistriata, P. pseudodelicatissima, P. pungens var. aveirensis, P. pungenus var. pungens and P. sabit, as well as two novel species P. chiniana C.X. Huang & Yang Li and P. qiana C.X. Huang & Yang Li. Morphologically, P. chiniana is characterized by striae comprising one or two rows of poroids, and valve ends that are normally dominated by two rows of poroids within each stria. Whereas P. qiana is unique by having a narrow valve width (1.3-1.5 μm) and sharply pointed valve ends. Both taxa constitute their own monophyletic lineage in the phylogenetic analyses inferred from LSU and ITS2 rDNA, and are well differentiated from other Pseudo-nitzschia species. Pseudo-nitzschia chiniana forms a group with P. abrensis and P. batesiana in LSU and ITS trees, whereas P. qiana is sister to P. lineola. When comparing ITS2 secondary structure, five CBCs and seven HCBCs are recognized between P. chiniana and P. abrensis, and four CBCs and ten HCBCs between P. chiniana and P. batesiana. Two CBCs and eight HCBCs are found between P. qiana with P. lineola. The ability of the strains to produce domoic acid was assessed, including a potential toxin induction by the presence of brine shrimps. Results revealed production of domoic acid in six strains belonging to three species. Without presence of brine shrimps, cellular DA (pDA) was detected in four P. multiseries strains (1.6 ± 0.3, 26.6 ± 2.7, 68.3 ± 4.2 and 56.9 ± 4.7 fg cell-1, separately), one strain of P. pseudodelicatissima (0.8 ± 0.2 fg cell-1) and one strain of P. lundholmiae (2.5 ± 0.4 fg cell-1). In the presence of brine shrimps, pDA contents increased significantly (p < 0.05) in P. lundholmiae (strain MC4218) and P. multiseries (strain MC4177), from 2.5 ± 0.4 to 8.9 ± 0.7 and 1.6 ± 0.3 to 37.2 ± 2.5 fg cell-1 respectively.
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Affiliation(s)
- Chun Xiu Huang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou, 510631, PR China.
| | - Huan Chang Dong
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou, 510631, PR China.
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Øster Farimagsgade 5, 1307, Copenhagen K, Denmark.
| | - Sing Tung Teng
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, Kota Samarahan, 94300, Sarawak, Malaysia.
| | - Guan Chao Zheng
- Key Laboratory of Testing and Evaluation for Aquatic Product Safety and Quality, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, PR China.
| | - Zhi Jun Tan
- Key Laboratory of Testing and Evaluation for Aquatic Product Safety and Quality, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, PR China.
| | - Po Teen Lim
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310, Bachok, Kelantan, Malaysia.
| | - Yang Li
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou, 510631, PR China.
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A Time Series of Water Column Distributions and Sinking Particle Flux of Pseudo-Nitzschia and Domoic Acid in the Santa Barbara Basin, California. Toxins (Basel) 2018; 10:toxins10110480. [PMID: 30453659 PMCID: PMC6265954 DOI: 10.3390/toxins10110480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/10/2018] [Accepted: 11/12/2018] [Indexed: 01/01/2023] Open
Abstract
Water column bulk Pseudo-nitzschia abundance and the dissolved and particulate domoic acid (DA) concentrations were measured in the Santa Barbara Basin (SBB), California from 2009–2013 and compared to bulk Pseudo-nitzschia cell abundance and DA concentrations and fluxes in sediment traps moored at 147 m and 509 m. Pseudo-nitzschia abundance throughout the study period was spatially and temporally heterogeneous (<200 cells L−1 to 3.8 × 106 cells L−1, avg. 2 × 105 ± 5 × 105 cells L−1) and did not correspond with upwelling conditions or the total DA (tDA) concentration, which was also spatially and temporally diverse (<1.3 ng L−1 to 2.2 × 105 ng L−1, avg. 7.8 × 103 ± 2.2 × 104 ng L−1). We hypothesize that the toxicity is likely driven in part by specific Pseudo-nitzschia species as well as bloom stage. Dissolved (dDA) and particulate (pDA) DA were significantly and positively correlated (p < 0.01) and both comprised major components of the total DA pool (pDA = 57 ± 35%, and dDA = 42 ± 35%) with substantial water column concentrations (>1000 cells L−1 and tDA = 200 ng L−1) measured as deep as 150 m. Our results highlight that dDA should not be ignored when examining bloom toxicity. Although water column abundance and pDA concentrations were poorly correlated with sediment trap Pseudo-nitzschia abundance and fluxes, DA toxicity is likely associated with senescent blooms that rapidly sink to the seafloor, adding another potential source of DA to benthic organisms.
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Bates SS, Hubbard KA, Lundholm N, Montresor M, Leaw CP. Pseudo-nitzschia, Nitzschia, and domoic acid: New research since 2011. HARMFUL ALGAE 2018; 79:3-43. [PMID: 30420013 DOI: 10.1016/j.hal.2018.06.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 05/11/2023]
Abstract
Some diatoms of the genera Pseudo-nitzschia and Nitzschia produce the neurotoxin domoic acid (DA), a compound that caused amnesic shellfish poisoning (ASP) in humans just over 30 years ago (December 1987) in eastern Canada. This review covers new information since two previous reviews in 2012. Nitzschia bizertensis was subsequently discovered to be toxigenic in Tunisian waters. The known distribution of N. navis-varingica has expanded from Vietnam to Malaysia, Indonesia, the Philippines and Australia. Furthermore, 15 new species (and one new variety) of Pseudo-nitzschia have been discovered, bringing the total to 52. Seven new species were found to produce DA, bringing the total of toxigenic species to 26. We list all Pseudo-nitzschia species, their ability to produce DA, and show their global distribution. A consequence of the extended distribution and increased number of toxigenic species worldwide is that DA is now found more pervasively in the food web, contaminating new marine organisms (especially marine mammals), affecting their physiology and disrupting ecosystems. Recent findings highlight how zooplankton grazers can induce DA production in Pseudo-nitzschia and how bacteria interact with Pseudo-nitzschia. Since 2012, new discoveries have been reported on physiological controls of Pseudo-nitzschia growth and DA production, its sexual reproduction, and infection by an oomycete parasitoid. Many advances are the result of applying molecular approaches to discovering new species, and to understanding the population genetic structure of Pseudo-nitzschia and mechanisms used to cope with iron limitation. The availability of genomes from three Pseudo-nitzschia species, coupled with a comparative transcriptomic approach, has allowed advances in our understanding of the sexual reproduction of Pseudo-nitzschia, its signaling pathways, its interactions with bacteria, and genes involved in iron and vitamin B12 and B7 metabolism. Although there have been no new confirmed cases of ASP since 1987 because of monitoring efforts, new blooms have occurred. A massive toxic Pseudo-nitzschia bloom affected the entire west coast of North America during 2015-2016, and was linked to a 'warm blob' of ocean water. Other smaller toxic blooms occurred in the Gulf of Mexico and east coast of North America. Knowledge gaps remain, including how and why DA and its isomers are produced, the world distribution of potentially toxigenic Nitzschia species, the prevalence of DA isomers, and molecular markers to discriminate between toxigenic and non-toxigenic species and to discover sexually reproducing populations in the field.
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Affiliation(s)
- Stephen S Bates
- Fisheries and Oceans Canada, Gulf Fisheries Centre, P.O. Box 5030, Moncton, New Brunswick, E1C 9B6, Canada.
| | - Katherine A Hubbard
- Fish and Wildlife Research Institute (FWRI), Florida Fish and Wildlife Conservation Commission (FWC), 100 Eighth Avenue SE, St. Petersburg, FL 33701 USA; Woods Hole Center for Oceans and Human Health, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA, 02543 USA
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, DK-1307 Copenhagen K, Denmark
| | - Marina Montresor
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Chui Pin Leaw
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310 Bachok, Kelantan, Malaysia
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Gai FF, Hedemand CK, Louw DC, Grobler K, Krock B, Moestrup Ø, Lundholm N. Morphological, molecular and toxigenic characteristics of Namibian Pseudo-nitzschia species - including Pseudo-nitzschia bucculenta sp. nov. HARMFUL ALGAE 2018; 76:80-95. [PMID: 29887207 DOI: 10.1016/j.hal.2018.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 05/14/2018] [Accepted: 05/14/2018] [Indexed: 06/08/2023]
Abstract
A field study was undertaken to investigate the occurrence and toxin production of species in the diatom genus Pseudo-nitzschia in Namibian waters, in the extremely productive Benguela upwelling system. From surveys conducted on the R/V Mirabilis and the R/V !Anichab, 52 strains were morphologically determined to species level, supported by nuclear ITS rDNA data. Seven species were identified; P. australis, P. decipiens, P. dolorosa, P. fraudulenta, P. plurisecta, P. pungens var. cingulata, and the new species P. bucculenta F. Gai, C. K. Hedemand, N. Lundholm & Ø. Moestrup sp. nov. Molecular and morphological diversity of the Namibian Pseudo-nitzschia species is discussed. Most importantly, P. bucculenta is both morphologically and phylogenetically most similar to P. dolorosa differing mainly in valve width and densities of striae, poroids and band striae as well as by four hemi-compensatory base changes in the ITS2. Morphological and molecular differences among the strains of P. decipiens suggest a temperate and a warm water subdivision. The geographical and toxigenic characteristics of the identified Pseudo-nitzschia species are described and compared to previous studies. Initial tests of toxin production in all seven species revealed production of domoic acid (DA) in two species: one strain of P. australis (0.074 pg DA cell-1) and two strains of P. plurisecta (0.338 pg DA cell-1 and 0.385 pg DA cell-1).
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Affiliation(s)
- Frederik Frøsig Gai
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307, Copenhagen K, Denmark
| | | | - Deon C Louw
- Ministry of Fisheries and Marine Resources, National Marine Information and Research Centre (NatMIRC), Swakopmund, P.O. Box 912, Namibia
| | - Kolette Grobler
- Ministry of Fisheries and Marine Resources, National Marine Information and Research Centre (NatMIRC), Lüderitz, PO Box 394, Shark Island, Namibia
| | - Bernd Krock
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
| | - Øjvind Moestrup
- Marine Biological Section, University of Copenhagen, Universitetsparken 4, 2100, Copenhagen Ø, Denmark
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307, Copenhagen K, Denmark.
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Louw DC, Doucette GJ, Lundholm N. Morphology and toxicity of Pseudo-nitzschia species in the northern Benguela Upwelling System. HARMFUL ALGAE 2018; 75:118-128. [PMID: 29778221 DOI: 10.1016/j.hal.2018.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/22/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
The Benguela upwelling system, considered the world's most productive marine ecosystem, has a long record of potentially toxic diatoms belonging to the genus Pseudo-nitzschia. Species of Pseudo-nitzschia were reported as early as 1936 from the northern Benguela upwelling system (nBUS). For the current study, long-term phytoplankton monitoring data (2004-2011) for the Namibian coast were analysed to examine inshore and offshore temporal distribution of Pseudo-nitzschia species, their diversity and ultrastructure. The potentially toxigenic P. pungens and P. australis were the dominant inshore species, whereas offshore Pseudo-nitzschia showed a higher diversity that also included potentially toxic species. During a warming event, a community shift from P. pungens and P. australis dominance to P. fraudulenta and P. multiseries was documented in the central nBUS. A case study of a toxic event (August 2004) revealed that P. australis and P. pungens were present at multiple inshore and offshore stations, coincident with fish (pilchard) and bird mortalities reported from the central part of Namibia. Toxin analyses (LC-MS/MS) of samples collected from June to August 2004 revealed the presence of particulate domoic acid (DA) in seawater at multiple stations (maximum ∼180 ng DA/L) in the >0.45 μm size-fraction, as well as detectable DA (0.12 μg DA/g) in the gut of one of two pilchard samples tested. These findings indicate that DA may have been associated with the fish and bird mortalities reported from this event in the nBUS. However, the co-occurrence of very high biomass phytoplankton blooms suggests that other explanations may be possible.
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Affiliation(s)
- Deon C Louw
- National Marine Information and Research Centre, PO Box 912, Swakopmund, Namibia.
| | - Gregory J Doucette
- National Centers for Coastal Ocean Science, NOAA/National Ocean Service, Charleston, SC, 29412, USA.
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, DK-1307 Copenhagen K, Denmark.
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