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Li X, Li L, Huang Y, Wu H, Sheng S, Jiang X, Chen X, Ostrovsky I. Upstream nitrogen availability determines the Microcystis salt tolerance and influences microcystins release in brackish water. WATER RESEARCH 2024; 252:121213. [PMID: 38306752 DOI: 10.1016/j.watres.2024.121213] [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: 11/22/2023] [Revised: 01/20/2024] [Accepted: 01/26/2024] [Indexed: 02/04/2024]
Abstract
The occurrence of large Microcystis biomass in brackish waters is primarily caused by its downward transportation from the upstream freshwater lakes and reservoirs through rivers rather than due to in situ bloom formation. Factors that determine the survival of freshwater cyanobacteria in brackish waters have not been well investigated. Here, we studied the spatiotemporal variability of inorganic nitrogen in an upstream lake and conducted laboratory and in-situ experiments to assess the role of nitrogen availability on the salt tolerance of Microcystis and the release of microcystins. A series of field experiments were carried out during bloom seasons to evaluate the salt tolerance of natural Microcystis colonies. The salt tolerance threshold varied from 7 to 17 and showed a positive relationship with intracellular carbohydrate content and a negative relationship with nitrogen availability in water. In August when upstream nitrogen availability was lower, the Microcystis colonies could maintain their biomass even after a sudden increase in salinity from 4 to 10. Laboratory-cultivated Microcystis that accumulated higher carbohydrate content at lower nitrogen availability showed better cell survival at higher salinity. The sharp release of microcystins into the surrounding water occurred when salinity exceeded the salt tolerance threshold of the Microcystis. Thus, Microcystis with higher salt tolerance can accumulate more toxins in cells. The obtained results suggest that the cell survival and toxin concentration in brackish waters depend on the physiological properties of Microcystis formed in the upstream waters. Thus, the life history of Microcystis in upstream waters could have a significant impact on its salt tolerance in downstream brackish waters, where the ecological risk of the salt-tolerant Microcystis requires special and careful management in summer at low nitrogen availability.
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Affiliation(s)
- Xinlu Li
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Lei Li
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Yingying Huang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
| | - Haipeng Wu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Shiwen Sheng
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xinran Jiang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xuechu Chen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, 200241, China.
| | - Ilia Ostrovsky
- Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal 1495001, Israel
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Moreira MH, They NH, Rodrigues LR, Alvarenga-Lucius L, Pita-Barbosa A. Salty freshwater macrophytes: the effects of salinization in freshwaters upon non-halophyte aquatic plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159608. [PMID: 36280080 DOI: 10.1016/j.scitotenv.2022.159608] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/17/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Salinization is a threat that affects aquatic ecosystems worldwide. As primary producers, freshwater macrophytes are of paramount importance in these ecosystems, however, information regarding the potential impacts of salinization upon these organisms is still scarce. In this review we provide a comprehensive and updated discussion of how freshwater macrophytes deal with salinity increase in freshwaters. We reviewed the salinity tolerance of widespread non-halophyte macrophytes through an overview of salinity tolerance mechanisms, their tolerance classification, and salinity effects at different levels of organization: from individuals to ecosystems. Thus, we demonstrated that widespread macrophytes that inhabit freshwaters display efficient salinity tolerance to salinity levels between 5 and 10 g L-1, and only a few species display tolerance to salinities higher than 10 g L-1. Widespread macrophytes demonstrated salinity tolerance of approximately 5 g L-1. Widespread macrophytes demonstrated salinity tolerance of approximately 5 g L-1. Emergent, floating and submerged species showed no significant difference in salinity tolerance. Salinity stress symptoms in freshwater macrophytes are somewhat similar to those of terrestrial plants and can show up even at slight salinity increases. Salinities higher than 1 g L-1 can negatively affect both physiology and diversity of non-halophyte macrophytes and cause long-term - and not well understood - changes in freshwater ecosystems. Salinization of freshwater ecosystems, among others threats, in combination with climate change, raise concerns about the future ecological status of freshwater ecosystems and the services they can provide.
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Affiliation(s)
- Mauricio Hoffmann Moreira
- Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil
| | - Ng Haig They
- Programa de Pós-Graduação em Biologia de Ambientes Aquáticos Continentais, Universidade Federal do Rio Grande (FURG), Rio Grande, RS, 96203-900, Brazil; Departamento Interdisciplinar, Centro de Estudos Limnológicos, Costeiros e Marinhos, Campus Litoral Norte, Universidade Federal do Rio Grande do Sul, Imbé, RS 95625-000, Brazil
| | - Lúcia Ribeiro Rodrigues
- Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande Do Sul, Porto Alegre, RS 91501-970, Brazil
| | - Luna Alvarenga-Lucius
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock D-18059, Germany
| | - Alice Pita-Barbosa
- Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil; Departamento Interdisciplinar, Centro de Estudos Limnológicos, Costeiros e Marinhos, Campus Litoral Norte, Universidade Federal do Rio Grande do Sul, Imbé, RS 95625-000, Brazil.
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Dreher TW, Foss AJ, Davis EW, Mueller RS. 7-epi-cylindrospermopsin and microcystin producers among diverse Anabaena/Dolichospermum/Aphanizomenon CyanoHABs in Oregon, USA. HARMFUL ALGAE 2022; 116:102241. [PMID: 35710201 DOI: 10.1016/j.hal.2022.102241] [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: 01/11/2022] [Revised: 03/18/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Several genomes of Nostocales ADA clade members from the US Pacific Northwest were recently sequenced. Biosynthetic genes for microcystin, cylindrospermopsin or anatoxin-a were present in 7 of the 15 Dolichospermum/Anabaena strains and none of the 5 Aphanizomenon flos-aquae (AFA) strains. Toxin analyses (ELISA and LC-MS/MS) were conducted to quantitate and identify microcystin (MC) and cylindrospermopsin (CYN) congeners/analogs in samples dominated by Dolichospermum spp. of known genome sequence. MC-LR was the main congener produced by Dolichospermum spp. from Junipers Reservoir, Lake Billy Chinook and Odell Lake, while a congener provisionally identified as [Dha7]MC-HtyR was produced by a Dolichospermum sp. in Detroit Reservoir. A second Dolichospermum sp. from Detroit Reservoir was found to produce 7-epi-CYN, with 7-deoxy-CYN also present, but no CYN. The monitoring history of each of these lakes indicates the capacity for high levels of cyanotoxins during periods when Dolichospermum spp. are the dominant cyanobacteria. The diversity of ADA strains found in the US Pacific NW emphasizes the importance of these cyanobacteria as potentially toxic HAB formers in this temperate climatic region. Our results linking congener and genetic identity add data points that will help guide development of improved tools for predicting congener specificity from cyanotoxin gene sequences.
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Affiliation(s)
- Theo W Dreher
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
| | - Amanda J Foss
- GreenWater Laboratories, 205 Zeagler Drive, Suite 302, Palatka, FL 32177, USA.
| | - Edward W Davis
- Center for Quantitative Life Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Ryan S Mueller
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
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Olofsson M, Hagan JG, Karlson B, Gamfeldt L. Large seasonal and spatial variation in nano- and microphytoplankton diversity along a Baltic Sea-North Sea salinity gradient. Sci Rep 2020; 10:17666. [PMID: 33077730 PMCID: PMC7572517 DOI: 10.1038/s41598-020-74428-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 09/30/2020] [Indexed: 11/09/2022] Open
Abstract
Aquatic phytoplankton experience large fluctuations in environmental conditions during seasonal succession and across salinity gradients, but the impact of this variation on their diversity is poorly understood. We examined spatio-temporal variation in nano- and microphytoplankton (> 2 µm) community structure using almost two decades of light-microscope based monitoring data. The dataset encompasses 19 stations that span a salinity gradient from 2.8 to 35 along the Swedish coastline. Spatially, both regional and local phytoplankton diversity increased with broad-scale salinity variation. Diatoms dominated at high salinity and the proportion of cyanobacteria increased with decreasing salinity. Temporally, cell abundance peaked in winter-spring at high salinity but in summer at low salinity. This was likely due to large filamentous cyanobacteria blooms that occur in summer in low salinity areas, but which are absent in higher salinities. In contrast, phytoplankton local diversity peaked in spring at low salinity but in fall and winter at high salinity. Whilst differences in seasonal variation in cell abundance were reasonably well-explained by variation in salinity and nutrient availability, variation in local-scale phytoplankton diversity was poorly predicted by environmental variables. Overall, we provide insights into the causes of spatio-temporal variation in coastal phytoplankton community structure while also identifying knowledge gaps.
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Affiliation(s)
- Malin Olofsson
- Research and Development, Oceanography, Swedish Meteorological and Hydrological Institute, Sven Källfelts gata 15, 426 71, Västra Frölunda, Sweden.
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 750 07, Uppsala, Sweden.
| | - James G Hagan
- Department of Marine Sciences, University of Gothenburg, Box 100, 405 30 Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Box 461, 405 30, Gothenburg, Sweden
| | - Bengt Karlson
- Research and Development, Oceanography, Swedish Meteorological and Hydrological Institute, Sven Källfelts gata 15, 426 71, Västra Frölunda, Sweden
| | - Lars Gamfeldt
- Department of Marine Sciences, University of Gothenburg, Box 100, 405 30 Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Box 461, 405 30, Gothenburg, Sweden
- Centre for Sea and Society, Box 260, 405 30, Gothenburg, Sweden
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Li H, Barber M, Lu J, Goel R. Microbial community successions and their dynamic functions during harmful cyanobacterial blooms in a freshwater lake. WATER RESEARCH 2020; 185:116292. [PMID: 33086464 PMCID: PMC7737503 DOI: 10.1016/j.watres.2020.116292] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/08/2020] [Accepted: 08/10/2020] [Indexed: 05/06/2023]
Abstract
The current study reports the community succession of different toxin and non-toxin producing cyanobacteria at different stages of cyanobacterial harmful algal blooms (CyanoHABs) and their connectivity with nitrogen and phosphorus cycles in a freshwater lake using an ecogenomics framework. Comprehensive high throughput DNA sequencing, water quality parameter measurements, and functional gene expressions over temporal and spatial scales were employed. Among the cyanobacterial community, the lake was initially dominated by Cyanobium during the months of May, June, and early July, and later primarily by Aphanizomenon and Dolichospermum depicting functional redundancy. Finally, Planktothrix appeared in late August and then the dominance switched to Planktothrix in September. Microcystis aeruginosa and Microcystis panniformis; two species responsible for cyanotoxin production, were also present in August and September, but in significantly smaller relative abundance. MC-LR (0.06-1.32 µg/L) and MC-RR (0.01-0.26 µg/L) were two major types of cyanotoxins detected. The presence of MC-LR and MC-RR were significantly correlated with the Microcystis-related genes (16SMic/mcyA/mcyG) and their expressions (r = 0.33 to 0.8, p < 0.05). The metabolic analyses further linked the presence of different cyanobacterial groups with distinct functions. The nitrogen metabolisms detected a relatively higher abundance of nitrite/nitrate reductase in early summer, indicating significant denitrification activity and the activation of N-fixation in the blooms dominated by Aphanizomenon/Dolichospermum (community richness) during nutrient-limited conditions. The phosphorus and carbohydrate metabolisms detected a trend to initiate a nutrient starvation alert and store nutrients from early summer, while utilizing the stored polyphosphate and carbohydrate (PPX and F6PPK) during the extreme ortho-P scarcity period, mostly in August or September. Specifically, the abundance of Aphanizomenon and Dolichospermum was positively correlated with the nitrogen-fixing nif gene and (p < 0.001) and the PPX enzyme for the stored polyphosphate utilization (r = 0.77, p < 0.001). Interestingly, the lake experienced a longer N-fixing period (2-3 months) before non-fixing cyanobacteria (Planktothrix) dominated the entire lake in late summer. The Provo Bay site, which is known to be nutrient-rich historically, had early episodes of filamentous cyanobacteria blooms compared to the rest of the lake.
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Affiliation(s)
- Hanyan Li
- Civil & Environmental Engineering, University of Utah, 110 S. Central Campus Drive, 2000 MCE, Salt Lake City, UT 84121, USA
| | - Mike Barber
- Civil & Environmental Engineering, University of Utah, 110 S. Central Campus Drive, 2000 MCE, Salt Lake City, UT 84121, USA
| | - Jingrang Lu
- United States Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA
| | - Ramesh Goel
- Civil & Environmental Engineering, University of Utah, 110 S. Central Campus Drive, 2000 MCE, Salt Lake City, UT 84121, USA.
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Österholm J, Popin RV, Fewer DP, Sivonen K. Phylogenomic Analysis of Secondary Metabolism in the Toxic Cyanobacterial Genera Anabaena, Dolichospermum and Aphanizomenon. Toxins (Basel) 2020; 12:E248. [PMID: 32290496 PMCID: PMC7232259 DOI: 10.3390/toxins12040248] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 01/20/2023] Open
Abstract
Cyanobacteria produce an array of toxins that pose serious health risks to humans and animals. The closely related diazotrophic genera, Anabaena, Dolichospermum, and Aphanizomenon, frequently form poisonous blooms in lakes and brackish waters around the world. These genera form a complex now termed the Anabaena, Dolichospermum, and Aphanizomenon (ADA) clade and produce a greater array of toxins than any other cyanobacteria group. However, taxonomic confusion masks the distribution of toxin biosynthetic pathways in cyanobacteria. Here we obtained 11 new draft genomes to improve the understanding of toxin production in these genera. Comparison of secondary metabolite pathways in all available 31 genomes for these three genera suggests that the ability to produce microcystin, anatoxin-a, and saxitoxin is associated with specific subgroups. Each toxin gene cluster was concentrated or even limited to a certain subgroup within the ADA clade. Our results indicate that members of the ADA clade encode a variety of secondary metabolites following the phylogenetic clustering of constituent species. The newly sequenced members of the ADA clade show that phylogenetic separation of planktonic Dolichospermum and benthic Anabaena is not complete. This underscores the importance of taxonomic revision of Anabaena, Dolichospermum, and Aphanizomenon genera to reflect current phylogenomic understanding.
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Affiliation(s)
| | | | | | - Kaarina Sivonen
- Department of Microbiology, University of Helsinki, Viikinkaari 9, FI-00014 Helsinki, Finland; (J.Ö.); (R.V.P.); (D.P.F.)
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Olofsson M, Suikkanen S, Kobos J, Wasmund N, Karlson B. Basin-specific changes in filamentous cyanobacteria community composition across four decades in the Baltic Sea. HARMFUL ALGAE 2020; 91:101685. [PMID: 32057344 DOI: 10.1016/j.hal.2019.101685] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/23/2019] [Accepted: 09/29/2019] [Indexed: 06/10/2023]
Abstract
Almost every summer, dense blooms of filamentous cyanobacteria are formed in the Baltic Sea. These blooms may cause problems for tourism and ecosystem services, where surface accumulations and beach fouling are commonly occurring. Future changes in environmental drivers, including climate change and other anthropogenic disturbances, may further enhance these problems. By compiling monitoring data from countries adjacent to the Baltic Sea, we present spatial and temporal genus-specific distribution of diazotrophic filamentous cyanobacteria (Nostocales) during four decades (1979-2017). While the summer surface salinity decreased with a half up to one unit, the surface temperature in July-August increased with 2-3 °C in most sub-basins of the Baltic Sea, during the time period. The biovolumes of the toxic Nodularia spumigena did not change in any of the sub-basins during the period. On the other hand, the biovolume of the non-toxic Aphanizomenon sp. and the potentially toxic Dolichospermum spp. increased in the northern parts of the Baltic Sea, along with the decreased salinity and elevated temperatures, but Aphanizomenon sp. decreased in the southern parts despite decreased salinity and increased temperatures. These contradictory changes in biovolume of Aphanizomenon sp. between the northern and southern parts of the Baltic Sea may be due to basin-specific effects of the changed environmental conditions, or can be related to local adaptation by sub-populations of the genera. Overall, this comprehensive dataset presents insights to genus-specific bloom dynamics by potentially harmful diazotrophic filamentous cyanobacteria in the Baltic Sea.
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Affiliation(s)
- Malin Olofsson
- Research and Development, Oceanography, Swedish Meteorological and Hydrological Institute, Sven Källfelts Gata 15, 426 71, Västra Frölunda, Sweden.
| | - Sanna Suikkanen
- Marine Research Centre, Finnish Environment Institute, Latokartanonkaari 11, 00790, Helsinki, Finland.
| | - Justyna Kobos
- University of Gdansk, Faculty of Oceanography and Geography, Institute of Oceanography, Division of Marine Biotechnology, al. Marszałka Józefa Piłsudskiego 46, 81-378, Gdynia, Poland.
| | - Norbert Wasmund
- Leibniz Institute for Baltic Sea Research, Warnemünde, Seestrasse 15, D-18119, Rostock, Germany.
| | - Bengt Karlson
- Research and Development, Oceanography, Swedish Meteorological and Hydrological Institute, Sven Källfelts Gata 15, 426 71, Västra Frölunda, Sweden.
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