1
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Joosten ED, Hamelin J, Milferstedt K. Initial type and abundance of cyanobacteria determine morphotype development of phototrophic ecosystems. FEMS Microbiol Ecol 2023; 99:fiad099. [PMID: 37653452 DOI: 10.1093/femsec/fiad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/24/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023] Open
Abstract
Phototrophic aggregates containing filamentous cyanobacteria occur naturally, for example, as cryoconite on glaciers and microbialites in fresh or marine waters, but their formation is not fully understood. Laboratory models are now available to reproduce aggregation, that is, the formation of different morphotypes like hemispheroids, microbial mats or sphere-like aggregates we call photogranules. In the model, activated sludge as starting matrix is transformed into aggregates enclosed by a phototrophic layer of growing cyanobacteria. These cyanobacteria were either enriched from the matrix or we added them intentionally. We hypothesize that the resulting morphotype depends on the type and concentration of the added cyanobacteria. When cyanobacteria from mature photogranules were added to activated sludge, photogranulation was not observed, but microbial mats were formed. Photogranulation of sludge could be promoted when adding sufficient quantities of cyanobacterial strains that form clumps when grown as isolates. The cyanobacteria putatively responsible for photogranulation were undetectable or only present in low abundance in the final communities of photogranules, which were always dominated by mat-forming cyanobacteria. We suggest that, in a temporal succession, the ecosystem engineer initiating photogranulation eventually disappears, leaving behind its structural legacy. We conclude that understanding phototrophic aggregate formation requires considering the initial succession stages of the ecosystem development.
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Affiliation(s)
| | - Jérôme Hamelin
- INRAE, Univ Montpellier, LBE, 102 Avenue des Etangs, 11100, Narbonne, France
| | - Kim Milferstedt
- INRAE, Univ Montpellier, LBE, 102 Avenue des Etangs, 11100, Narbonne, France
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Interspecific Interactions Drive Nonribosomal Peptide Production in Nodularia spumigena. Appl Environ Microbiol 2022; 88:e0096622. [PMID: 35862669 PMCID: PMC9361812 DOI: 10.1128/aem.00966-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nodularia spumigena is a bloom-forming cyanobacterium that produces several classes of nonribosomal peptides (NRPs) that are biologically active; however, the ecological roles of specific NRPs remain largely unknown. Here, we explored the involvement of NRPs produced by N. spumigena in interspecific interactions by coculturing the cyanobacterium and its algal competitors, the diatom Phaeodactylum tricornutum and the cryptomonad Rhodomonas salina, and measuring NRP levels and growth responses in all three species. Contrary to the expected growth suppression in the algae, it was N. spumigena that was adversely affected by the diatom, while the cryptomonad had no effect. Reciprocal effects of N. spumigena on the algae were manifested as the prolonged lag phase in R. salina and growth stimulation in P. tricornutum; however, these responses were largely attributed to elevated pH and not to specific NRPs. Nevertheless, the NRP levels in the cocultures were significantly higher than in the monocultures, with an up to 5-fold upregulation of cell-bound nodularins and exudation of nodularin and anabaenopeptin. Thus, chemically mediated interspecific interactions can promote NRP production and release by cyanobacteria, resulting in increased input of these compounds into the water. IMPORTANCE NRPs were involved in growth responses of both cyanobacteria and algae; however, the primary driver of the growth trajectories was high pH induced by N. spumigena. Thus, the pH-mediated inhibition of eukaryotic phytoplankton may be involved in the bloom formation of N. spumigena. We also report, for the first time, the reciprocal growth inhibition of N. spumigena by diatoms resistant to alkaline conditions. As all species in this study can co-occur in the Baltic Sea during summer, these findings are highly relevant for understanding ecological interactions in planktonic communities in this and other systems experiencing regular cyanobacteria blooms.
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3
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Zhang M, Zhang Y, Deng J, Liu M, Zhou Y, Zhang Y, Shi K, Jiang C. High-resolution temporal detection of cyanobacterial blooms in a deep and oligotrophic lake by high-frequency buoy data. ENVIRONMENTAL RESEARCH 2022; 203:111848. [PMID: 34390714 DOI: 10.1016/j.envres.2021.111848] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacterial blooms are increasing in magnitude, frequency, and duration worldwide. However, our knowledge of cyanobacterial blooms dynamics and driving mechanisms is still limited due to their high spatiotemporal variability. To determine the potential driving mechanisms of cyanobacterial blooms in oligotrophic lakes, we collected a high-frequency depth profile of chlorophyll fluorescence (ChlF) and synchronous water quality, hydrometeorological data in early spring 2016 in oligotrophic Lake Qiandaohu. The vertical distribution of ChlF exhibited two patterns, "aggregated" and "discrete", using Morisita's index, and the aggregated ChlF presented subsurface chlorophyll maxima during the thermal stratification period. The ChlF concentration was positively correlated with water temperature and negatively correlated with turbidity. Significantly linear relationships were observed between ChlF vertical structure parameters (e.g., Morisita's index, subsurface chlorophyll maxima depth and thickness) and thermal stratification parameters (e.g., mixing layer depth and relative water column stability). After rainstorm floods, the ChlF pattern suddenly change from "aggregated" to "discrete" and a ChlF concentration <1 μg/L was observed for 7-11 days with a significant increase in the mixing depth layer and turbidity. The results suggest that cyanobacterial blooms are robustly associated with thermal stratification and rainstorm floods in the deep and oligotrophic lake. Thermal stratification boosts surface phytoplankton accumulation by increasing water temperature, enhancing light availability and restricting phytoplankton vertical distribution. Rainstorm floods interrupt the accumulation by disrupting thermal stratification and decreasing the available light. Furthermore, wind speed and air temperature both regulate the phytoplankton dynamics by affecting thermal stratification. Our research quantifies the cyanobacterial bloom dynamics and their relationship between environmental factors, improving our knowledge of the driving mechanisms of cyanobacterial bloom for the protection of drinking water safety and aquatic organism health in lakes.
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Affiliation(s)
- Manxue Zhang
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; College of Water Resources and Hydrology, Hohai University, Nanjing, 210098, China
| | - Yunlin Zhang
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Jianming Deng
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Miao Liu
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongqiang Zhou
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yibo Zhang
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kun Shi
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Cuiling Jiang
- College of Water Resources and Hydrology, Hohai University, Nanjing, 210098, China
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4
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Karasiewicz S, Chapelle A, Bacher C, Soudant D. Harmful algae niche responses to environmental and community variation along the French coast. HARMFUL ALGAE 2020; 93:101785. [PMID: 32307069 DOI: 10.1016/j.hal.2020.101785] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/14/2020] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
Distribution, frequency and intensity of harmful phytoplanktonic species are impacted by changes in environmental conditions. In the Bay of Brest, Alexandrium minutum has been responsible for several harmful algal blooms (HABs) associated with toxin production causing paralytic shellfish poisoning (PSP). Additionally, Lepidodinium chlorophorum causes green water and hypoxia locally in the Bay of Biscay. Previous studies revealed that L. chlorophorum's success was related to possible competitive exclusion. Therefore, the phytoplankton composition and the environmental conditions should be taken into account. This study aims to assess the combined effect of changes in habitat conditions and community structure with the occurrence of HAB species, on a spatial-temporal scale. For the investigation we first used the Hutchinson's niche concept by means of the Outlying Mean Index (OMI) analysis. The OMI analysis enable us to observe the environmental variables defining the ecological niche of the harmful species among the community. Secondly, we used the subniche theory to highlight the environmental variables defining the subniches in cases of high and low abundance of HABs with an estimation of the biological constraint restricting the species' subniche. This was undertaken using the Within Outlying Mean indexes (WitOMI) calculated under environmental conditions promoting high (H) and low (L) abundance bloom. Thirdly, we used the Indicator Species Concept from the Indicator Species Analysis (ISA) to link the biological restriction with potential competing or indicator species. We combined a data set from the French National Phytoplankton and Phycotoxin Monitoring Network (REPHY), the Velyger network (oyster monitoring program) and satellite imagery. A total of 44 stations, over the period of 1998-2017 using 50 taxonomic units. 36 taxa had significant niche and were mostly distributed along nutrient and salinity gradients. The two species of interest L. chlorophorum and A. minutum seemed to have similar affinity for summer-like environmental conditions and both used a marginal habitat compared to the rest of the community. A. minutum had a larger niche due to a greater affinity to the estuarine-like conditions. The subniche of the two species had a similar response to the environmental variation; their respective abundance was partly caused by greater environmental restrains. Their success in abundance appeared to be linked to local hydrodynamics which increases or reduces resources. On the other hand, the biotic pressure exerted upon A. minutum and L. chlorophorum were antagonistic. A possible competitor assemblage was exposed but the analysis was inconclusive. The methodological limitations were discussed as well as a perspective for future similar studies.
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Affiliation(s)
- Stéphane Karasiewicz
- IFREMER-Centre de Bretagne, ODE/DYNECO, Plouzané, France; IFREMER-Centre de Bretagne, ODE/DYNECO, Plouzané, France.
| | - Annie Chapelle
- IFREMER-Centre de Bretagne, ODE/DYNECO, Plouzané, France
| | - Cédric Bacher
- IFREMER-Centre de Bretagne, ODE/DYNECO, Plouzané, France
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Burford MA, Carey CC, Hamilton DP, Huisman J, Paerl HW, Wood SA, Wulff A. Perspective: Advancing the research agenda for improving understanding of cyanobacteria in a future of global change. HARMFUL ALGAE 2020; 91:101601. [PMID: 32057347 DOI: 10.1016/j.hal.2019.04.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 05/19/2023]
Abstract
Harmful cyanobacterial blooms (=cyanoHABs) are an increasing feature of many waterbodies throughout the world. Many bloom-forming species produce toxins, making them of particular concern for drinking water supplies, recreation and fisheries in waterbodies along the freshwater to marine continuum. Global changes resulting from human impacts, such as climate change, over-enrichment and hydrological alterations of waterways, are major drivers of cyanoHAB proliferation and persistence. This review advocates that to better predict and manage cyanoHABs in a changing world, researchers need to leverage studies undertaken to date, but adopt a more complex and definitive suite of experiments, observations, and models which can effectively capture the temporal scales of processes driven by eutrophication and a changing climate. Better integration of laboratory culture and field experiments, as well as whole system and multiple-system studies are needed to improve confidence in models predicting impacts of climate change and anthropogenic over-enrichment and hydrological modifications. Recent studies examining adaptation of species and strains to long-term perturbations, e.g. temperature and carbon dioxide (CO2) levels, as well as incorporating multi-species and multi-stressor approaches emphasize the limitations of approaches focused on single stressors and individual species. There are also emerging species of concern, such as toxic benthic cyanobacteria, for which the effects of global change are less well understood, and require more detailed study. This review provides approaches and examples of studies tackling the challenging issue of understanding how global changes will affect cyanoHABs, and identifies critical information needs for effective prediction and management.
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Affiliation(s)
- M A Burford
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Queensland, 4111, Australia.
| | - C C Carey
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, 24061, USA
| | - D P Hamilton
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Queensland, 4111, Australia
| | - J Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - H W Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, 28557, USA; College of Environment, Hohai University, Nanjing, 210098, China
| | - S A Wood
- Cawthron Institute, Nelson, 7010, New Zealand
| | - A Wulff
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 40530, Gothenburg, Sweden
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6
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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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7
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Greenstein KE, Wert EC. Using rapid quantification of adenosine triphosphate (ATP) as an indicator for early detection and treatment of cyanobacterial blooms. WATER RESEARCH 2019; 154:171-179. [PMID: 30797125 DOI: 10.1016/j.watres.2019.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/10/2019] [Accepted: 02/09/2019] [Indexed: 06/09/2023]
Abstract
Early detection of harmful cyanobacterial blooms allows identification of potential risk and appropriate selection of treatment techniques to prevent exposure in recreational water bodies and drinking water supplies. Here, luminescence-based adenosine triphosphate (ATP) analysis was applied to monitor and treat cultured and naturally occurring cyanobacteria cells. When evaluating lab-cultured Microcystis aeruginosa, ATP concentrations (≤252,000 pg/mL) had improved sensitivity and correlated well (R2 = 0.969) with optical density measurements at 730 nm (OD730; ≤0.297 cm-1). Following one year of monitoring of a surface water supply, ATP concentrations (≤2000 pg/mL) correlated (R2 = 0.791) with chlorophyll-a concentrations (≤50 μg/L). A preliminary early warning threshold of 175 pg ATP/mL corresponded with 5 μg/L chlorophyll-a to initiate increased monitoring (e.g., of cyanotoxins). Following oxidation processes (i.e., chlorine, chloramine, ozone, permanganate), ATP was demonstrated as an indicator of cell lysis and a threshold value of <100 pg/mL was recommended for complete release of intracellular cyanotoxins. ATP was also used to assess efficacy of copper (Cu(II)) treatment on cyanobacteria-laden surface water. While 24-h exposure to 2.5 mg Cu(II)/L did not impact chlorophyll-a, ATP decreased from 13,500 to 128 pg/mL indicating metabolic activity was minimized. Ultimately, ATP analysis holds promise for early detection and mitigation of potentially harmful algal blooms based on superior sensitivity, independence from cell morphology artifacts, rapid time for analysis (<10 min), and ease of deployment in the field compared to conventional methods.
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Affiliation(s)
- Katherine E Greenstein
- Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV, 89193-9954, United States
| | - Eric C Wert
- Southern Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, NV, 89193-9954, United States.
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Yue WZ, Sun CC, Shi P, Engel A, Wang YS, He WH. Effect of temperature on the accumulation of marine biogenic gels in the surface microlayer near the outlet of nuclear power plants and adjacent areas in the Daya Bay, China. PLoS One 2018; 13:e0198735. [PMID: 29889860 PMCID: PMC5995428 DOI: 10.1371/journal.pone.0198735] [Citation(s) in RCA: 7] [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: 01/05/2018] [Accepted: 05/24/2018] [Indexed: 11/19/2022] Open
Abstract
The surface microlayer (SML) in marine systems is often characterized by an enrichment of biogenic, gel-like particles, such as the polysaccharide-containing transparent exopolymer particles (TEP) and the protein-containing Coomassie stainable particles (CSP). This study investigated the distribution of TEP and CSP, in the SML and underlying water, as well as their bio-physical controlling factors in Daya Bay, an area impacted by warm discharge from two Nuclear power plants (Npp’s) and aquaculture during a research cruise in July 2014. The SML had higher proportions of cyanobacteria and of pico-size Chl a contrast to the underlayer water, particularly at the nearest outlet station characterized by higher temperature. Diatoms, dinoflagellates and chlorophyll a were depleted in the SML. Both CSP and TEP abundance and total area were enriched in the SML relative to the underlying water, with enrichment factors (EFs) of 1.5–3.4 for CSP numbers and 1.32–3.2 for TEP numbers. Although TEP and CSP showed highest concentration in the region where high productivity and high nutrient concertation were observed, EFs of gels and of dissolved organic carbon (DOC) and dissolved acidic polysaccharide (> 1 kDa), exhibited higher values near the outlet of the Npp’s than in the adjacent waters. The positive relation between EF’s of gels and temperature and the enrichment of cyanobacteria in the SML may be indicative of future conditions in a warmer ocean, suggesting potential effects on adjusting phytoplankton community, biogenic element cycling and air-sea exchange processes.
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Affiliation(s)
- Wei-zhong Yue
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Cui-ci Sun
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China
- * E-mail:
| | - Ping Shi
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Anja Engel
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - You-shao Wang
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China
| | - Wei-Hong He
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
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Wulff A, Karlberg M, Olofsson M, Torstensson A, Riemann L, Steinhoff FS, Mohlin M, Ekstrand N, Chierici M. Ocean acidification and desalination: climate-driven change in a Baltic Sea summer microplanktonic community. MARINE BIOLOGY 2018; 165:63. [PMID: 29563649 PMCID: PMC5843668 DOI: 10.1007/s00227-018-3321-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/01/2018] [Indexed: 05/19/2023]
Abstract
Helcom scenario modelling suggests that the Baltic Sea, one of the largest brackish-water bodies in the world, could expect increased precipitation (decreased salinity) and increased concentration of atmospheric CO2 over the next 100 years. These changes are expected to affect the microplanktonic food web, and thereby nutrient and carbon cycling, in a complex and possibly synergistic manner. In the Baltic Proper, the extensive summer blooms dominated by the filamentous cyanobacteria Aphanizomenon sp., Dolichospermum spp. and the toxic Nodularia spumigena contribute up to 30% of the yearly new nitrogen and carbon exported to the sediment. In a 12 days outdoor microcosm experiment, we tested the combined effects of decreased salinity (from 6 to 3) and elevated CO2 concentrations (380 and 960 µatm) on a natural summer microplanktonic community, focusing on diazotrophic filamentous cyanobacteria. Elevated pCO2 had no significant effects on the natural microplanktonic community except for higher biovolume of Dolichospermum spp. and lower biomass of heterotrophic bacteria. At the end of the experimental period, heterotrophic bacterial abundance was correlated to the biovolume of N. spumigena. Lower salinity significantly affected cyanobacteria together with biovolumes of dinoflagellates, diatoms, ciliates and heterotrophic bacteria, with higher biovolume of Dolichospermum spp. and lower biovolume of N. spumigena, dinoflagellates, diatoms, ciliates and heterotrophic bacteria in reduced salinity. Although the salinity effects on diatoms were apparent, they could not clearly be separated from the influence of inorganic nutrients. We found a clear diurnal cycle in photosynthetic activity and pH, but without significant treatment effects. The same diurnal pattern was also observed in situ (pCO2, pH). Thus, considering the Baltic Proper, we do not expect any dramatic effects of increased pCO2 in combination with decreased salinity on the microplanktonic food web. However, long-term effects of the experimental treatments need to be further studied, and indirect effects of the lower salinity treatments could not be ruled out. Our study adds one piece to the complicated puzzle to reveal the combined effects of increased pCO2 and reduced salinity levels on the Baltic microplanktonic community.
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Affiliation(s)
- Angela Wulff
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
| | - Maria Karlberg
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
| | - Malin Olofsson
- Department of Marine Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
| | - Anders Torstensson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
- Present Address: School of Oceanography, University of Washington, Box 357940, Seattle, WA 98195 USA
| | - Lasse Riemann
- Department of Biology, Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
| | - Franciska S. Steinhoff
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
| | - Malin Mohlin
- Swedish Meteorological and Hydrological Institute, Sven Källfelts gata 15, 426 71 Västra Frölunda, Sweden
| | - Nina Ekstrand
- Department of Marine Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
| | - Melissa Chierici
- Department of Marine Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden
- Present Address: Institute of Marine Research, Sykehusveien 23, Tromsø, Norway
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Rolff C, Elfwing T. Increasing nitrogen limitation in the Bothnian Sea, potentially caused by inflow of phosphate-rich water from the Baltic Proper. AMBIO 2015; 44:601-11. [PMID: 25990584 PMCID: PMC4591228 DOI: 10.1007/s13280-015-0675-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 02/24/2015] [Accepted: 04/29/2015] [Indexed: 05/18/2023]
Abstract
The study showed that the open water of the Bothnian Sea (BS) is likely to have shifted from altering nitrogen and phosphorous limitations of the spring bloom to more nitrogen-limited conditions during the last 20 years. This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water. The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water. The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms. There does not appear to be any immediate concern in the short-term perspective for the state of the BS, but a progression of the processes may lead to a more eutrophic state of the BS.
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Affiliation(s)
- Carl Rolff
- Stockholm University Baltic Sea Centre, 106 91, Stockholm, Sweden.
| | - Tina Elfwing
- Stockholm University Baltic Sea Centre, 106 91, Stockholm, Sweden.
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11
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Wells ML, Trainer VL, Smayda TJ, Karlson BSO, Trick CG, Kudela RM, Ishikawa A, Bernard S, Wulff A, Anderson DM, Cochlan WP. Harmful algal blooms and climate change: Learning from the past and present to forecast the future. HARMFUL ALGAE 2015; 49:68-93. [PMID: 27011761 PMCID: PMC4800334 DOI: 10.1016/j.hal.2015.07.009] [Citation(s) in RCA: 316] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Climate change pressures will influence marine planktonic systems globally, and it is conceivable that harmful algal blooms may increase in frequency and severity. These pressures will be manifest as alterations in temperature, stratification, light, ocean acidification, precipitation-induced nutrient inputs, and grazing, but absence of fundamental knowledge of the mechanisms driving harmful algal blooms frustrates most hope of forecasting their future prevalence. Summarized here is the consensus of a recent workshop held to address what currently is known and not known about the environmental conditions that favor initiation and maintenance of harmful algal blooms. There is expectation that harmful algal bloom (HAB) geographical domains should expand in some cases, as will seasonal windows of opportunity for harmful algal blooms at higher latitudes. Nonetheless there is only basic information to speculate upon which regions or habitats HAB species may be the most resilient or susceptible. Moreover, current research strategies are not well suited to inform these fundamental linkages. There is a critical absence of tenable hypotheses for how climate pressures mechanistically affect HAB species, and the lack of uniform experimental protocols limits the quantitative cross-investigation comparisons essential to advancement. A HAB "best practices" manual would help foster more uniform research strategies and protocols, and selection of a small target list of model HAB species or isolates for study would greatly promote the accumulation of knowledge. Despite the need to focus on keystone species, more studies need to address strain variability within species, their responses under multifactorial conditions, and the retrospective analyses of long-term plankton and cyst core data; research topics that are departures from the norm. Examples of some fundamental unknowns include how larger and more frequent extreme weather events may break down natural biogeographic barriers, how stratification may enhance or diminish HAB events, how trace nutrients (metals, vitamins) influence cell toxicity, and how grazing pressures may leverage, or mitigate HAB development. There is an absence of high quality time-series data in most regions currently experiencing HAB outbreaks, and little if any data from regions expected to develop HAB events in the future. A subset of observer sites is recommended to help develop stronger linkages among global, national, and regional climate change and HAB observation programs, providing fundamental datasets for investigating global changes in the prevalence of harmful algal blooms. Forecasting changes in HAB patterns over the next few decades will depend critically upon considering harmful algal blooms within the competitive context of plankton communities, and linking these insights to ecosystem, oceanographic and climate models. From a broader perspective, the nexus of HAB science and the social sciences of harmful algal blooms is inadequate and prevents quantitative assessment of impacts of future HAB changes on human well-being. These and other fundamental changes in HAB research will be necessary if HAB science is to obtain compelling evidence that climate change has caused alterations in HAB distributions, prevalence or character, and to develop the theoretical, experimental, and empirical evidence explaining the mechanisms underpinning these ecological shifts.
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Affiliation(s)
- Mark L Wells
- School of Marine Sciences, University of Maine, Orono, ME 04469, USA
| | - Vera L Trainer
- Marine Biotoxins Program, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. E., Seattle, WA 98112, USA
| | - Theodore J Smayda
- Graduate School of Oceanography, University of Rhode Island, Kingston, RI 02881, USA
| | - Bengt S O Karlson
- SMHI Research & Development, Oceanography, Sven Källfelts gata 15, 426 71 Västra Frölunda, Sweden
| | - Charles G Trick
- Department of Biology, Western University, London, ON, Canada N6A 5B7
| | - Raphael M Kudela
- Ocean Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Akira Ishikawa
- Laboratory of Biological Oceanography, Graduate School of Bioresources, Mie University, 1577 Kurima-machiya-cho, Tsu-shi, Mie-ken 514-8507, Japan
| | - Stewart Bernard
- Earth Systems Earth Observation, CSIR-NRE Centre for High Performance Computing, 15 Lower Hope Street, Rosebank, Cape Town 7700, South Africa
| | - Angela Wulff
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE405 30 Göteborg, Sweden
| | | | - William P Cochlan
- Romberg Tiburon Center for Environmental Studies, San Francisco State University, 3152 Paradise Drive, Tiburon, CA 94920-1205, USA
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Svedén JB, Adam B, Walve J, Nahar N, Musat N, Lavik G, Whitehouse MJ, Kuypers MMM, Ploug H. High cell-specific rates of nitrogen and carbon fixation by the cyanobacterium Aphanizomenon sp. at low temperatures in the Baltic Sea. FEMS Microbiol Ecol 2015; 91:fiv131. [PMID: 26511856 DOI: 10.1093/femsec/fiv131] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2015] [Indexed: 11/14/2022] Open
Abstract
Aphanizomenon is a widespread genus of nitrogen (N2)-fixing cyanobacteria in lakes and estuaries, accounting for a large fraction of the summer N2-fixation in the Baltic Sea. However, information about its cell-specific carbon (C)- and N2-fixation rates in the early growth season has not previously been reported. We combined various methods to study N2-fixation, photosynthesis and respiration in field-sampled Baltic Sea Aphanizomenon sp. during early summer at 10°C. Stable isotope incubations at in situ light intensities during 24 h combined with cell-specific secondary ion mass spectrometry showed an average net N2-fixation rate of 55 fmol N cell(-1) day(-1). Dark net N2-fixation rates over a course of 12 h were 20% of those measured in light. C-fixation, but not N2-fixation, was inhibited by high ambient light intensities during daytime. Consequently, the C:N fixation ratio varied substantially over the diel cycle. C- and N2-fixation rates were comparable to those reported for Aphanizomenon sp. in August at 19°C, using the same methods. High respiration rates (23% of gross photosynthesis) were measured with (14)C-incubations and O2-microsensors, and presumably reflect the energy needed for high N2-fixation rates. Hence, Aphanizomenon sp. is an important contributor to N2-fixation at low in situ temperatures in the early growth season.
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Affiliation(s)
- Jennie B Svedén
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden
| | - Birgit Adam
- Max Planck Institute for Marine Microbiology, Celsiusstr. 1, DE-28359 Bremen, Germany
| | - Jakob Walve
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden
| | - Nurun Nahar
- Department of Marine Sciences, University of Gothenburg, Box 460, SE-405 30 Gothenburg, Sweden
| | - Niculina Musat
- Max Planck Institute for Marine Microbiology, Celsiusstr. 1, DE-28359 Bremen, Germany Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, DE-04318 Leipzig, Germany
| | - Gaute Lavik
- Max Planck Institute for Marine Microbiology, Celsiusstr. 1, DE-28359 Bremen, Germany
| | | | - Marcel M M Kuypers
- Max Planck Institute for Marine Microbiology, Celsiusstr. 1, DE-28359 Bremen, Germany
| | - Helle Ploug
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden Department of Marine Sciences, University of Gothenburg, Box 460, SE-405 30 Gothenburg, Sweden
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13
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Steinhoff FS, Karlberg M, Graeve M, Wulff A. Cyanobacteria in Scandinavian coastal waters — A potential source for biofuels and fatty acids? ALGAL RES 2014. [DOI: 10.1016/j.algal.2014.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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