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Mondal M, Zhang T. Bloom dynamics under the effects of periodic driving forces. Math Biosci 2024; 372:109202. [PMID: 38692481 DOI: 10.1016/j.mbs.2024.109202] [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: 12/07/2023] [Revised: 03/26/2024] [Accepted: 04/17/2024] [Indexed: 05/03/2024]
Abstract
Phytoplankton bloom received considerable attention for many decades. Different approaches have been used to explain the bloom phenomena. In this paper, we study a Nutrient-Phytoplankton-Zooplankton (NPZ) model consisting of a periodic driving force in the growth rate of phytoplankton due to solar radiation and analyse the dynamics of the corresponding autonomous and non-autonomous systems in different parametric regions. Then we introduce a novel aspect to extend the model by incorporating another periodic driving force into the growth term of the phytoplankton due to sea surface temperature (SST), a key point of innovation. Temperature dependency of the maximum growth rate (μmax) of the phytoplankton is modelled by the well-known Q10 formulation: [Formula: see text] , where μ0 is maximum growth at 0oC. Stability conditions for all three equilibrium points are expressed in terms of the new parameter ρ2, which appears due to the incorporation of periodic driving forces. System dynamics is explored through a detailed bifurcation analysis, both mathematically and numerically, with respect to the light and temperature dependent phytoplankton growth response. Bloom phenomenon is explained by the saddle point bloom mechanism even when the co-existing equilibrium point does not exist for some values of ρ2. Solar radiation and SST are modelled using sinusoidal functions constructed from satellite data. Our results of the proposed model describe the initiation of the phytoplankton bloom better than an existing model for the region 25-35° W, 40-45° N of the North Atlantic Ocean. An improvement of 14 days (approximately) is observed in the bloom initiation time. The rate of change method (ROC) is applied to predict the bloom initiation.
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Affiliation(s)
- Milton Mondal
- Department of Mathematics, Swinburne University of Technology, John Street, Hawthorn, 3122, VIC, Australia; Department of Mathematics, Indian Institute Of Technology, Madras, Chennai, 600036, Tamil Nadu, India.
| | - Tonghua Zhang
- Department of Mathematics, Swinburne University of Technology, John Street, Hawthorn, 3122, VIC, Australia.
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2
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Eckmann CA, Bachy C, Wittmers F, Strauss J, Blanco-Bercial L, Vergin KL, Parsons RJ, Kudela RM, Johnson R, Bolaños LM, Giovannoni SJ, Carlson CA, Worden AZ. Recurring seasonality exposes dominant species and niche partitioning strategies of open ocean picoeukaryotic algae. COMMUNICATIONS EARTH & ENVIRONMENT 2024; 5:266. [PMID: 38779128 PMCID: PMC11106004 DOI: 10.1038/s43247-024-01395-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 04/16/2024] [Indexed: 05/25/2024]
Abstract
Ocean spring phytoplankton blooms are dynamic periods important to global primary production. We document vertical patterns of a diverse suite of eukaryotic algae, the prasinophytes, in the North Atlantic Subtropical Gyre with monthly sampling over four years at the Bermuda Atlantic Time-series Study site. Water column structure was used to delineate seasonal stability periods more ecologically relevant than seasons defined by calendar dates. During winter mixing, tiny prasinophytes dominated by Class II comprise 46 ± 24% of eukaryotic algal (plastid-derived) 16S rRNA V1-V2 amplicons, specifically Ostreococcus Clade OII, Micromonas commoda, and Bathycoccus calidus. In contrast, Class VII are rare and Classes I and VI peak during warm stratified periods when surface eukaryotic phytoplankton abundances are low. Seasonality underpins a reservoir of genetic diversity from multiple prasinophyte classes during warm periods that harbor ephemeral taxa. Persistent Class II sub-species dominating the winter/spring bloom period retreat to the deep chlorophyll maximum in summer, poised to seed the mixed layer upon winter convection, exposing a mechanism for initiating high abundances at bloom onset. Comparisons to tropical oceans reveal broad distributions of the dominant sub-species herein. This unparalleled window into temporal and spatial niche partitioning of picoeukaryotic primary producers demonstrates how key prasinophytes prevail in warm oceans.
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Affiliation(s)
- Charlotte A. Eckmann
- Marine Biological Laboratory, Woods Hole, MA 02543 USA
- Ocean Sciences Department, University of California, Santa Cruz, CA 95064 USA
| | - Charles Bachy
- Ocean EcoSystems Biology Research Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24148 Germany
- Station Biologique de Roscoff, Sorbonne Université, CNRS, FR2424, Roscoff, 29680 France
| | - Fabian Wittmers
- Marine Biological Laboratory, Woods Hole, MA 02543 USA
- Ocean EcoSystems Biology Research Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24148 Germany
| | - Jan Strauss
- Ocean EcoSystems Biology Research Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24148 Germany
| | | | | | - Rachel J. Parsons
- Bermuda Institute of Ocean Sciences—Arizona State University, St. George’s, GE 01 Bermuda
| | - Raphael M. Kudela
- Ocean Sciences Department, University of California, Santa Cruz, CA 95064 USA
| | - Rod Johnson
- Bermuda Institute of Ocean Sciences—Arizona State University, St. George’s, GE 01 Bermuda
| | - Luis M. Bolaños
- Department of Microbiology, Oregon State University, Corvallis, OR 97331 USA
| | | | - Craig A. Carlson
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106 USA
| | - Alexandra Z. Worden
- Marine Biological Laboratory, Woods Hole, MA 02543 USA
- Ocean Sciences Department, University of California, Santa Cruz, CA 95064 USA
- Ocean EcoSystems Biology Research Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24148 Germany
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Yang GG, Wang Q, Feng J, He L, Li R, Lu W, Liao E, Lai Z. Can three-dimensional nitrate structure be reconstructed from surface information with artificial intelligence? - A proof-of-concept study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171365. [PMID: 38458452 DOI: 10.1016/j.scitotenv.2024.171365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/09/2024] [Accepted: 02/27/2024] [Indexed: 03/10/2024]
Abstract
Nitrate is one of the essential variables in the ocean that is a primary control of the upper ocean pelagic ecosystem. Its three-dimensional (3D) structure is vital for understanding the dynamic and ecosystem. Although several gridded nitrate products exist, the possibility of reconstructing the 3D structure of nitrate from surface data has never been exploited. In this study, we employed two advanced artificial intelligence (AI) networks, U-net and Earthformer, to reconstruct nitrate concentration in the Indian Ocean from surface data. Simulation from an ecosystem model was utilized as the labeling data to train and test the AI networks, with wind vectors, wind stress, sea surface temperature, sea surface chlorophyll-a, solar radiation, and precipitation as the input. We compared the performance of two networks and different pre-processing methods. With the input features decomposed into climatology and anomaly components, the Earthformer achieved optimal reconstruction results with a lower normalized mean square error (NRMSE = 0.1591), spatially and temporally, outperforming U-net (NRMSE = 0.2007) and the climatology prediction (NRMSE = 0.2089). Furthermore, Earthformer was more capable of identifying interannual nitrate anomalies. With a network interpretation technique, we quantified the spatio-temporal importance of every input feature in the best case (Earthformer with decomposed inputs). The influence of different input features on nitrate concentration in the adjacent Java Sea exhibited seasonal variation, stronger than the interannual one. The feature importance highlighted the role of dynamic factors, particularly the wind, matching our understanding of the dynamic controls of the ecosystem. Our reconstruction and network interpretation technique can be extended to other ecosystem variables, providing new possibilities in studies of marine environment and ecology from an AI perspective.
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Affiliation(s)
- Guangyu Gary Yang
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - Qishuo Wang
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - Jiacheng Feng
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - Lechi He
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - Rongzu Li
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - Wenfang Lu
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China.
| | - Enhui Liao
- School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Zhigang Lai
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
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Zhang Y, Zhuang Y, Ji Z, Chen J, Bai Y, Wang B, Jin H. Impacts of Atlantic water intrusion on interannual variability of the phytoplankton community structure in the summer season of Kongsfjorden, Svalbard under rapid Arctic change. MARINE ENVIRONMENTAL RESEARCH 2023; 192:106195. [PMID: 37769556 DOI: 10.1016/j.marenvres.2023.106195] [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: 05/06/2023] [Revised: 09/13/2023] [Accepted: 09/20/2023] [Indexed: 10/03/2023]
Abstract
Atlantification, known as impacts of high-latitude Atlantic water inflows on the Arctic Ocean has strengthened owing to climate change, corresponding to the rapid ice retreat in the Arctic. The relationship between phytoplankton and environmental changes in the Arctic on the interannual scale is unclear because of the lack of long-time series data. In this study, we discuss the ecological response to Atlantic water intrusion in the Kongsfjorden,Svalbard. We measured chlorophyll a and photosynthesis pigments for the water column samples from a fixed section along the Kongsfjorden to study the response of phytoplankton biomass and communities to Atlantic water intrusion in the summer season from 2007 to 2018. The results showed that dinoflagellates, prasinophytes, cryptophytes, and chlorophytes consistently accounted for over 50% of the total biomass, with the distinct annual variation of chlorophyll a. Bioavailable nitrogen was the main limiting factor on phytoplankton growth in the study area, as inferred by its concentration and nutrients ratios. The relationship between phytoplankton and water mass analysis suggested that the intrusion of Atlantic water in Kongsfjorden may cause interannual variability of the phytoplankton biomass and community structure by influencing the nutrient supply and water stratification in the fjord region. Our study provides insights into the ongoing impact of Atlantification on the phytoplankton community in the Arctic fjord.
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Affiliation(s)
- Yang Zhang
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China; Ocean College, Zhejiang University, Zhoushan, 316000, China
| | - Yanpei Zhuang
- Polar and Marine Research Institute, Jimei University, Xiamen, 361000, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China
| | - Zhongqiang Ji
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China.
| | - Jianfang Chen
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China
| | - Youcheng Bai
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China
| | - Bin Wang
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China
| | - Haiyan Jin
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China; Ocean College, Zhejiang University, Zhoushan, 316000, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China.
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Sun X, Jiang D, Shao Y, Zhang S. A dataset of micro biodiversity in benthic sediment at a global scale. Sci Data 2023; 10:383. [PMID: 37322057 PMCID: PMC10272205 DOI: 10.1038/s41597-023-02292-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/06/2023] [Indexed: 06/17/2023] Open
Abstract
Microorganisms, occupying the largest biomass in deep sea, play essential roles in deep-sea ecosystem. It is believed that the microbes in deep-sea sediments are more representative of deep-sea microbial communities, the microbial composition of which is seldom affected by ocean currents. However, the community of benthic microbes on a global scale has not been adequately explored. Herein, we build a comprehensive global dataset determined by 16S rRNA gene sequencing to characterize the biodiversity of microorganisms in benthic sediment. The dataset comprised 212 records from 106 sites, included sequencing of bacteria and archaea for each site and yielded 4,766,502 and 1,562,989 reads, respectively. Through annotation, a total of 110,073 and 15,795 OTUs of bacteria and archaea were obtained, and 61 bacterial phyla and 15 archaeal phyla were identified, of which the dominant phyla were Proteobacteria and Thaumarchaeota in deep-sea sediment. Therefore, our findings provided a biodiversity data of microbial communities in deep-sea sediment at global-scale and laid a foundation to further reveal the structures of microorganism communities in deep sea.
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Affiliation(s)
- Xumei Sun
- School of Marine Sciences, Ningbo University, Ningbo, 315211, People's Republic of China
| | - Danni Jiang
- School of Marine Sciences, Ningbo University, Ningbo, 315211, People's Republic of China
| | - Yina Shao
- School of Marine Sciences, Ningbo University, Ningbo, 315211, People's Republic of China
| | - Siyuan Zhang
- School of Marine Sciences, Ningbo University, Ningbo, 315211, People's Republic of China.
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Control of Antarctic phytoplankton community composition and standing stock by light availability. Polar Biol 2022. [DOI: 10.1007/s00300-022-03094-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractSouthern Ocean phytoplankton are especially subjected to pronounced seasonal and interannual changes in light availability. Although previous studies have examined the role of light in these environments, very few combined pigment-based taxonomy with flow cytometry to better discriminate the light response of various phytoplankton groups. In particular the different populations within the diverse and important taxonomic group of diatoms require further investigation. Six incubation experiments (9–10 days) were performed during the main productive period with natural seawater collected at the Western Antarctic Peninsula. Standing stock of Phaeocystis spp. cells displayed relatively fast accumulation under all levels of light (low, medium, high; 4–7, 30–50 and 150–200 µmol quanta m−2 s−1), whilst the small- and larger-sized diatom populations (4.5 and 20 µm diameter) exhibited faster accumulation in medium and high light. In contrast, intermediate-sized diatoms (11.5 µm diameter) displayed fastest net growth under low light, subsequently dominating the phytoplankton community. Low light was a key factor limiting accumulation and peak phytoplankton biomass, except one incubation displaying relatively high accumulation rates under low light. The 3-week low-light period prior to experimentation likely allowed adaptation to maximize achievable growth and seems a strong determinant of whether the different natural Antarctic phytoplankton populations sustain, thrive or decline. Our study provides improved insight into how light intensity modulates the net response of key Antarctic phytoplankton, both between and within taxonomic groups.
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Fourquez M, Strzepek RF, Ellwood MJ, Hassler C, Cabanes D, Eggins S, Pearce I, Deppeler S, Trull TW, Boyd PW, Bressac M. Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy. Microorganisms 2022; 10:microorganisms10081655. [PMID: 36014073 PMCID: PMC9413495 DOI: 10.3390/microorganisms10081655] [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] [Received: 07/06/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
In the Subantarctic sector of the Southern Ocean, vertical entrainment of iron (Fe) triggers the seasonal productivity cycle but diminishing physical supply during the spring to summer transition forces microbial assemblages to rapidly acclimate. Here, we tested how phytoplankton and bacteria within an isolated eddy respond to different dissolved Fe (DFe)/ligand inputs. We used three treatments: one that mimicked the entrainment of new DFe (Fe-NEW), another in which DFe was supplied from bacterial regeneration of particles (Fe-REG), and a control with no addition of DFe (Fe-NO). After 6 days, 3.5 (Fe-NO, Fe-NEW) to 5-fold (Fe-REG) increases in Chlorophyll a were observed. These responses of the phytoplankton community were best explained by the differences between the treatments in the amount of DFe recycled during the incubation (Fe-REG, 15% recycled c.f. 40% Fe-NEW, 60% Fe-NO). This additional recycling was more likely mediated by bacteria. By day 6, bacterial production was comparable between Fe-NO and Fe-NEW but was approximately two-fold higher in Fe-REG. A preferential response of phytoplankton (haptophyte-dominated) relative to high nucleic acid (HNA) bacteria was also found in the Fe-REG treatment while the relative proportion of diatoms increased faster in the Fe-NEW and Fe-NO treatments. Comparisons between light and dark incubations further confirmed the competition between picophytoplankton and HNA for DFe. Overall, our results demonstrate great versatility by microorganisms to use different Fe sources that results in highly efficient Fe recycling within surface waters. This study also encourages future research to further investigate the interactions between functional groups of microbes (e.g. HNA and cyanobacteria) to better constraint modeling in Fe and carbon biogeochemical cycles.
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Affiliation(s)
- Marion Fourquez
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UMR 110, 13288 Marseille, France
- Correspondence:
| | - Robert F. Strzepek
- Australian Antarctic Program Partnership (AAPP), Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
| | - Michael J. Ellwood
- Research School of Earth Sciences, Australian National University, Canberra 2601, Australia
| | - Christel Hassler
- Marine and Lake Biogeochemistry, Department F.-A. Forel, University of Geneva, 1205 Geneva, Switzerland
- Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland
| | - Damien Cabanes
- Marine and Lake Biogeochemistry, Department F.-A. Forel, University of Geneva, 1205 Geneva, Switzerland
| | - Sam Eggins
- Research School of Earth Sciences, Australian National University, Canberra 2601, Australia
| | - Imojen Pearce
- Australian Antarctic Division (AAD), Kingston 7050, Australia
| | - Stacy Deppeler
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- National Institute of Water and Atmospheric Research, Wellington 6021, New Zealand
| | - Thomas W. Trull
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
- Climate Science Centre, Oceans and Atmosphere, Commonwealth Scientific and Industrial Research Organisation, Hobart 7004, Australia
| | - Philip W. Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobart 7004, Australia
| | - Matthieu Bressac
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7004, Australia
- Laboratoire d’Océanographie de Villefranche, Sorbonne Université, CNRS, 06230 Villefranche-sur-Mer, France
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Yang Z, Wei C, Liu D, Lin Q, Huang Y, Wang C, Ji D, Ma J, Yang H. The influence of hydraulic characteristics on algal bloom in three gorges reservoir, China: A combination of cultural experiments and field monitoring. WATER RESEARCH 2022; 211:118030. [PMID: 35065341 DOI: 10.1016/j.watres.2021.118030] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/09/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
It is essential to understand the mechanism of algal bloom and develop effect measures to control the hazard in aquatic environment, such as large reservoirs. In this study, a series of experiments, along with field observation from 2007 to 2016, were carried out to identify the hydrodynamic parameters that drive the algal bloom in the Three Gorges Reservoir (TGR), China, and their threshold values were determined. The results show that algae concentration was markedly diluted with a short retention time, and the threshold value of the retention time to avoid algal bloom was approximately less than 3 days. With strong stratification, the algae concentration was able to approach to the level of algal bloom in 10 days, even when the water temperature is lower than 12 °C. The ratio of mixing depth to euphotic depth (Zm/Ze) had significant negative correlations with both algae concentration and algae specific growth rate (SGR). The field monitoring data indicated that Zm/Ze is an important hydrodynamic parameter which sensitively affects algae growth and concentration. This study made the first attempt to determine Zm/Ze >2.8 to restrain algal bloom in the TGR. Our findings shed light on the influence of critical depth on the algal bloom in the TGR, and the results can serve to control algal bloom in reservoirs through discharge operation.
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Affiliation(s)
- Zhengjian Yang
- Hubei Observation and Research Station of Three Gorges Reservoir Ecosystem, China Three Gorges University, Yichang, 443002, China.
| | - Chenyu Wei
- Hubei Observation and Research Station of Three Gorges Reservoir Ecosystem, China Three Gorges University, Yichang, 443002, China
| | - Defu Liu
- Hubei Observation and Research Station of Three Gorges Reservoir Ecosystem, China Three Gorges University, Yichang, 443002, China; Hubei Key Laboratory of Ecological Restoration of River-lakes and Algal Utilization, Hubei University of Technology, Wuhan, 430068, China.
| | - Qicai Lin
- Shaanxi Provincial Academy of Environmental Sciences, Xi'an, 710061, China
| | - Yuling Huang
- Department of water environment, China Institute of Water Resources and Hydropower Research, Beijing, 10038, China
| | - Congfeng Wang
- Hubei Observation and Research Station of Three Gorges Reservoir Ecosystem, China Three Gorges University, Yichang, 443002, China
| | - Daobin Ji
- Hubei Observation and Research Station of Three Gorges Reservoir Ecosystem, China Three Gorges University, Yichang, 443002, China
| | - Jun Ma
- Hubei Key Laboratory of Ecological Restoration of River-lakes and Algal Utilization, Hubei University of Technology, Wuhan, 430068, China
| | - Hong Yang
- Department of Geography and Environmental Science, University of Reading, Whiteknights, Reading, RG6 5TX, UK.
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Ferreira A, Dias J, Brotas V, Brito AC. A perfect storm: An anomalous offshore phytoplankton bloom event in the NE Atlantic (March 2009). THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151253. [PMID: 34710413 DOI: 10.1016/j.scitotenv.2021.151253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
While primary productivity is more stable in oceanic regions, it may vary to a great extent with the proximity to coasts, where mesoscale processes may intertwine and shape phytoplankton community composition and biomass. Sometimes, this may lead to the development of anomalous phytoplankton blooms (i.e., episodic blooms that exceed several times the average phytoplankton biomass). A massive bloom observed off the Western Iberian Coast (SW Europe) during March 2009 prompted a full investigation on its spatial and temporal extent, its causes, and its potential impact on the ecosystem. Results revealed that the March 2009 bloom was both novel in terms of biomass in a regional context and one of the largest anomalous blooms until now described in terms of relative magnitude. Its causes were due to a concurrence of long-term (deep winter MLD) and short-term factors (coastal upwelling, sudden changes in the water column, consistent offshore water transport). Its impact on the regional ecosystem is difficult to gauge, although the high concentrations of particulate organic carbon at surface during the bloom period suggests that it may have had a significant local impact. Since climate change is expected to increase the frequency and intensity of extreme weather events, it is possible that anomalous blooms will also become more frequent, expanding their role in shaping carbon export and food webs. These results are crucial for the monitoring of the Western Iberian Coast and are applicable to other complex coastal upwelling regions where phytoplankton biomass and variability have a crucial link to fisheries.
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Affiliation(s)
- Afonso Ferreira
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
| | - Joaquim Dias
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Departamento de Engenharia Geográfica, Geofísica e Energia (DEGGE), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Vanda Brotas
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Ana C Brito
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
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10
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Andersson B, Godhe A, Filipsson HL, Zetterholm L, Edler L, Berglund O, Rengefors K. Intraspecific variation in metal tolerance modulate competition between two marine diatoms. THE ISME JOURNAL 2022; 16:511-520. [PMID: 34446855 PMCID: PMC8776739 DOI: 10.1038/s41396-021-01092-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 11/09/2022]
Abstract
Despite widespread metal pollution of coastal ecosystems, little is known of its effect on marine phytoplankton. We designed a co-cultivation experiment to test if toxic dose-response relationships can be used to predict the competitive outcome of two species under metal stress. Specifically, we took into account intraspecific strain variation and selection. We used 72 h dose-response relationships to model how silver (Ag), cadmium (Cd), and copper (Cu) affect both intraspecific strain selection and competition between taxa in two marine diatoms (Skeletonema marinoi and Thalassiosira baltica). The models were validated against 10-day co-culture experiments, using four strains per species. In the control treatment, we could predict the outcome using strain-specific growth rates, suggesting low levels of competitive interactions between the species. Our models correctly predicted which species would gain a competitive advantage under toxic stress. However, the absolute inhibition levels were confounded by the development of chronic toxic stress, resulting in a higher long-term inhibition by Cd and Cu. We failed to detect species differences in average Cu tolerance, but the model accounting for strain selection accurately predicted a competitive advantage for T. baltica. Our findings demonstrate the importance of incorporating multiple strains when determining traits and when performing microbial competition experiments.
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Affiliation(s)
- Björn Andersson
- Department of Marine Sciences, University of Gothenburg, Göteborg, Sweden.
| | - Anna Godhe
- Department of Marine Sciences, University of Gothenburg, Göteborg, Sweden
| | | | - Linda Zetterholm
- Department of Marine Sciences, University of Gothenburg, Göteborg, Sweden
| | - Lars Edler
- Doktorsg. 9d, Weaq Lab, Ängelholm, Sweden
| | - Olof Berglund
- Department of Biology, Lund University, Lund, Sweden
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11
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Tergolina VB, Calzavarini E, Mompean G, Berti S. Effects of large-scale advection and small-scale turbulent diffusion on vertical phytoplankton dynamics. Phys Rev E 2021; 104:065106. [PMID: 35030936 DOI: 10.1103/physreve.104.065106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Turbulence has been recognized as a factor of paramount importance for the survival or extinction of sinking phytoplankton species. However, dealing with its multiscale nature in models of coupled fluid and biological dynamics is a formidable challenge. Advection by coherent structures, such as those related to winter convection and Langmuir circulation, is also recognized to play a role in the survival and localization of phytoplankton. In this work we revisit a theoretically appealing model for phytoplankton vertical dynamics, and numerically investigate how large-scale fluid motions affect the survival conditions and the spatial distribution of the biological population. For this purpose, and to work with realistic parameter values, we adopt a kinematic flow field to account for the different spatial and temporal scales of turbulent motions. The dynamics of the population density are described by an advection-reaction-diffusion model with a spatially heterogeneous growth term proportional to sunlight availability. We explore the role of fluid transport by progressively increasing the complexity of the flow in terms of spatial and temporal scales. We find that, due to the large-scale circulation, phytoplankton accumulates in downwelling regions and its growth is reduced, confirming previous indications in slightly different conditions. We then explain the observed phenomenology in terms of a plankton filament model. Moreover, by contrasting the results in our different flow cases, we show that the large-scale coherent structures have an overwhelming importance. Indeed, we find that smaller-scale motions only quite weakly affect the dynamics, without altering the general mechanism identified. Such results are relevant for parametrizations in numerical models of phytoplankton life cycles in realistic oceanic flow conditions.
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Affiliation(s)
| | - Enrico Calzavarini
- Université Lille, ULR 7512 - Unité de Mécanique de Lille Joseph Boussinesq (UML), F-59000 Lille, France
| | - Gilmar Mompean
- Université Lille, ULR 7512 - Unité de Mécanique de Lille Joseph Boussinesq (UML), F-59000 Lille, France
| | - Stefano Berti
- Université Lille, ULR 7512 - Unité de Mécanique de Lille Joseph Boussinesq (UML), F-59000 Lille, France
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12
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Seasonal mixed layer depth shapes phytoplankton physiology, viral production, and accumulation in the North Atlantic. Nat Commun 2021; 12:6634. [PMID: 34789722 PMCID: PMC8599477 DOI: 10.1038/s41467-021-26836-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 10/20/2021] [Indexed: 12/03/2022] Open
Abstract
Seasonal shifts in phytoplankton accumulation and loss largely follow changes in mixed layer depth, but the impact of mixed layer depth on cell physiology remains unexplored. Here, we investigate the physiological state of phytoplankton populations associated with distinct bloom phases and mixing regimes in the North Atlantic. Stratification and deep mixing alter community physiology and viral production, effectively shaping accumulation rates. Communities in relatively deep, early-spring mixed layers are characterized by low levels of stress and high accumulation rates, while those in the recently shallowed mixed layers in late-spring have high levels of oxidative stress. Prolonged stratification into early autumn manifests in negative accumulation rates, along with pronounced signatures of compromised membranes, death-related protease activity, virus production, nutrient drawdown, and lipid markers indicative of nutrient stress. Positive accumulation renews during mixed layer deepening with transition into winter, concomitant with enhanced nutrient supply and lessened viral pressure. Phytoplankton are important primary producers. Here the authors investigate phytoplankton physiological changes associated with bloom phases and mixing regimes in the North Atlantic, finding that stratification and deep mixing shape accumulation rates by altering physiology and viral production.
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13
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Mojica KDA, Behrenfeld MJ, Clay M, Brussaard CPD. Spring Accumulation Rates in North Atlantic Phytoplankton Communities Linked to Alterations in the Balance Between Division and Loss. Front Microbiol 2021; 12:706137. [PMID: 34504477 PMCID: PMC8422905 DOI: 10.3389/fmicb.2021.706137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/19/2021] [Indexed: 12/02/2022] Open
Abstract
For nearly a century, phytoplankton spring blooms have largely been explained in the context of abiotic factors regulating cellular division rates (e.g., mixed-layer light levels). However, the accumulation of new phytoplankton biomass represents a mismatch between phytoplankton division and mortality rates. The balance between division and loss, therefore, has important implications for marine food webs and biogeochemical cycles. A large fraction of phytoplankton mortality is due to the combination of microzooplankton grazing and viral lysis, however, broad scale simultaneous measurements of these mortality processes are scarce. We applied the modified dilution assay along a West-to-East diagonal transect in the North Atlantic during spring. Our results demonstrate positive accumulation rates with losses dominated by microzooplankton grazing. Considering the dynamic light environment phytoplankton experience in the mixed surface layer, particularly in the spring, we tested the potential for incubation light conditions to affect observed rates. Incubations acted as short-term 'light' perturbations experiments, in which deeply mixed communities are exposed to elevated light levels. These "light perturbations" increased phytoplankton division rates and resulted in proportional changes in phytoplankton biomass while having no significant effect on mortality rates. These results provide experimental evidence for the Disturbance-Recovery Hypothesis, supporting the tenet that biomass accumulation rates co-vary with the specific rate of change in division.
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Affiliation(s)
- Kristina D. A. Mojica
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Michael J. Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Megan Clay
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Den Burg, Netherlands
- Australian Centre for Ecogenomics, University of Queensland, Brisbane, QLD, Australia
| | - Corina P. D. Brussaard
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Den Burg, Netherlands
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14
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Lakshmi RS, Prakash S, Lotliker AA, Baliarsingh SK, Samanta A, Mathew T, Chatterjee A, Sahu BK, Nair TMB. Physicochemical controls on the initiation of phytoplankton bloom during the winter monsoon in the Arabian Sea. Sci Rep 2021; 11:13448. [PMID: 34188247 PMCID: PMC8242075 DOI: 10.1038/s41598-021-92897-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 06/10/2021] [Indexed: 11/23/2022] Open
Abstract
Occurrence of phytoplankton bloom in the northern Arabian Sea (NAS) during the winter monsoon is perplexing. The convective mixing leads to a deeper and well-oxygenated (> 95% saturation) mixed layer. We encountered low chlorophyll conditions though the nutrient conditions were favorable for a bloom. The mean ratio of silicate (Si) to DIN (Dissolved Inorganic Nitrogen: nitrate + nitrite + ammonium) in the euphotic zone was 0.52 indicating a “silicate-stressed” condition for the proliferation of diatoms. Also, the euphotic depth was much shallower (~ 49 m) than the mixed layer (~ 110 m) suggesting the Sverdrup critical depth limitation in the NAS. We show that the bloom in this region initiates only when the mixed layer shoals towards the euphotic zone. Our observations further suggest that two primary factors, the stoichiometric ratio of nutrients, especially the Si/DIN ratio, in the mixed layer and re-stratification of the upper water column, govern the phytoplankton blooming in NAS during the later winter monsoon. The important finding of the present study is that the Sverdrup’s critical depth limitation gives rise to the observed low chl-a concentration in the NAS, despite having enough nutrients.
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Affiliation(s)
- R S Lakshmi
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India.,Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, 682506, India
| | - Satya Prakash
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India.
| | - Aneesh A Lotliker
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India
| | - Sanjiba K Baliarsingh
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India
| | - Alakes Samanta
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India
| | - Teesha Mathew
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India.,Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, 682506, India
| | - Abhisek Chatterjee
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India
| | - Biraja K Sahu
- Atal Centre for Ocean Science and Technology for Islands, National Institute of Ocean Technology, Ministry of Earth Sciences, Government of India, Port Blair, Andaman and Nicobar Islands, 744103, India
| | - T M Balakrishnan Nair
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Government of India, Hyderbad, 500090, India
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15
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Baetge N, Behrenfeld MJ, Fox J, Halsey KH, Mojica KDA, Novoa A, Stephens BM, Carlson CA. The Seasonal Flux and Fate of Dissolved Organic Carbon Through Bacterioplankton in the Western North Atlantic. Front Microbiol 2021; 12:669883. [PMID: 34220753 PMCID: PMC8249739 DOI: 10.3389/fmicb.2021.669883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
The oceans teem with heterotrophic bacterioplankton that play an appreciable role in the uptake of dissolved organic carbon (DOC) derived from phytoplankton net primary production (NPP). As such, bacterioplankton carbon demand (BCD), or gross heterotrophic production, represents a major carbon pathway that influences the seasonal accumulation of DOC in the surface ocean and, subsequently, the potential vertical or horizontal export of seasonally accumulated DOC. Here, we examine the contributions of bacterioplankton and DOM to ecological and biogeochemical carbon flow pathways, including those of the microbial loop and the biological carbon pump, in the Western North Atlantic Ocean (∼39-54°N along ∼40°W) over a composite annual phytoplankton bloom cycle. Combining field observations with data collected from corresponding DOC remineralization experiments, we estimate the efficiency at which bacterioplankton utilize DOC, demonstrate seasonality in the fraction of NPP that supports BCD, and provide evidence for shifts in the bioavailability and persistence of the seasonally accumulated DOC. Our results indicate that while the portion of DOC flux through bacterioplankton relative to NPP increased as seasons transitioned from high to low productivity, there was a fraction of the DOM production that accumulated and persisted. This persistent DOM is potentially an important pool of organic carbon available for export to the deep ocean via convective mixing, thus representing an important export term of the biological carbon pump.
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Affiliation(s)
- Nicholas Baetge
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Michael J. Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - James Fox
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Kimberly H. Halsey
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Kristina D. A. Mojica
- Division of Marine Science, School of Ocean Science and Engineering, The University of Southern Mississippi, John C. Stennis Space Center, Hattiesburg, MS, United States
| | - Anai Novoa
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Brandon M. Stephens
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Craig A. Carlson
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
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16
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Different Roles of Top-Down and Bottom-Up Processes in the Distribution of Size-Fractionated Phytoplankton in Gwangyang Bay. WATER 2021. [DOI: 10.3390/w13121682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The interactive roles of zooplankton grazing (top-down) and nutrient (bottom-up) processes on phytoplankton distribution in a temperate estuary were investigated via dilution and nutrient addition experiments. The responses of size-fractionated phytoplankton and major phytoplankton groups, as determined by flow cytometry, were examined in association with zooplankton grazing and nutrient availability. The summer bloom was attributed to nanoplankton, and microplankton was largely responsible for the winter bloom, whereas the picoplankton biomass was relatively consistent throughout the sampling periods, except for the fall. The nutrient addition experiments illustrated that nanoplankton responded more quickly to phosphate than the other groups in the summer, whereas microplankton had a faster response to most nutrients in the winter. The dilution experiments ascribed that the grazing mortality rates of eukaryotes were low compared to those of the other groups, whereas autotrophic cyanobacteria were more palatable to zooplankton than cryptophytes and eukaryotes. Our experimental results indicate that efficient escape from zooplankton grazing and fast response to nutrient availability synergistically caused the microplankton to bloom in the winter, whereas the bottom-up process (i.e., the phosphate effect) largely governed the nanoplankton bloom in the summer.
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17
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Penta WB, Fox J, Halsey KH. Rapid photoacclimation during episodic deep mixing augments the biological carbon pump. LIMNOLOGY AND OCEANOGRAPHY 2021; 66:1850-1866. [PMID: 34248203 PMCID: PMC8252461 DOI: 10.1002/lno.11728] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/25/2020] [Accepted: 01/18/2021] [Indexed: 05/25/2023]
Abstract
Episodic deep mixing events are one component of the biological carbon pump that physically transports organic carbon into the mesopelagic. Episodic deep mixing also disrupts summertime thermal stratification thereby changing the light field and nutrient concentrations available for phytoplankton growth. Phytoplankton survival and growth below the mixed layer following restratification depends on how rapidly cells can employ a variety of photoacclimation processes in response to the environmental changes. To compare the relative timescales of summertime episodic deep mixing events with the timescales of phytoplankton photoacclimation processes, we first analyzed autonomous float data to survey the frequency and magnitude of deep mixing events in the western North Atlantic Ocean. Next, we simulated a sustained deep mixing event in the laboratory and measured rates of acclimation processes ranging from light harvesting to growth in a model diatom and green alga. In both algae increases in chlorophyll (Chl) were coupled to growth, but growth of the green alga lagged the diatom by about a day. In float profiles, significant increases in Chl and phytoplankton carbon (C phyto) were detected below the mixed layer following episodic deep mixing events. These events pose a previously unrecognized source of new production below the mixed layer that can significantly boost the amount of carbon available for export to the deep ocean.
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Affiliation(s)
- W Bryce Penta
- Department of Microbiology Oregon State University Corvallis Oregon USA
| | - James Fox
- Department of Microbiology Oregon State University Corvallis Oregon USA
| | - Kimberly H Halsey
- Department of Microbiology Oregon State University Corvallis Oregon USA
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18
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Physical mixing in coastal waters controls and decouples nitrification via biomass dilution. Proc Natl Acad Sci U S A 2021; 118:2004877118. [PMID: 33903227 PMCID: PMC8106330 DOI: 10.1073/pnas.2004877118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Changes in both quantity and speciation of nitrogen in coastal waters impact phytoplankton communities, contributing to eutrophication and harmful algal blooms. Multidisciplinary oceanographic time series of high resolution are rare but crucial for identifying complex mechanisms that underlie such anthropogenic impacts. Analysis and modeling of such a time series from a seasonally stratified fjord showed that dilution of nitrifier biomass by variable winter mixing altered the timing and rates of nitrification, which converts ammonia to nitrite and nitrate. This reveals a link among climate-sensitive physical dynamics, nitrifier abundance, and diversity, with controls on phytoplankton ecology. The findings imply that explicit measurement and modeling of microbial communities will be required to project impacts of climate change on coastal ecosystems. Nitrification is a central process of the aquatic nitrogen cycle that controls the supply of nitrate used in other key processes, such as phytoplankton growth and denitrification. Through time series observation and modeling of a seasonally stratified, eutrophic coastal basin, we demonstrate that physical dilution of nitrifying microorganisms by water column mixing can delay and decouple nitrification. The findings are based on a 4-y, weekly time series in the subsurface water of Bedford Basin, Nova Scotia, Canada, that included measurement of functional (amoA) and phylogenetic (16S rRNA) marker genes. In years with colder winters, more intense winter mixing resulted in strong dilution of resident nitrifiers in subsurface water, delaying nitrification for weeks to months despite availability of ammonium and oxygen. Delayed regrowth of nitrifiers also led to transient accumulation of nitrite (3 to 8 μmol · kgsw−1) due to decoupling of ammonia and nitrite oxidation. Nitrite accumulation was enhanced by ammonia-oxidizing bacteria (Nitrosomonadaceae) with fast enzyme kinetics, which temporarily outcompeted the ammonia-oxidizing archaea (Nitrosopumilus) that dominated under more stable conditions. The study reveals how physical mixing can drive seasonal and interannual variations in nitrification through control of microbial biomass and diversity. Variable, mixing-induced effects on functionally specialized microbial communities are likely relevant to biogeochemical transformation rates in other seasonally stratified water columns. The detailed study reveals a complex mechanism through which weather and climate variability impacts nitrogen speciation, with implications for coastal ecosystem productivity. It also emphasizes the value of high-frequency, multiparameter time series for identifying complex controls of biogeochemical processes in aquatic systems.
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19
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Franklin DJ. Examining the Evidence for Regulated and Programmed Cell Death in Cyanobacteria. How Significant Are Different Forms of Cell Death in Cyanobacteria Population Dynamics? Front Microbiol 2021; 12:633954. [PMID: 33828539 PMCID: PMC8019747 DOI: 10.3389/fmicb.2021.633954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/12/2021] [Indexed: 12/22/2022] Open
Abstract
Cyanobacteria are ancient and versatile members of almost all aquatic food webs. In freshwater ecosystems some cyanobacteria form “bloom” populations containing potent toxins and such blooms are therefore a key focus of study. Bloom populations can be ephemeral, with rapid population declines possible, though the factors causing such declines are generally poorly understood. Cell death could be a significant factor linked to population decline. Broadly, three forms of cell death are currently recognized – accidental, regulated and programmed – and efforts are underway to identify these and standardize the use of cell death terminology, guided by work on better-studied cells. For cyanobacteria, the study of such differing forms of cell death has received little attention, and classifying cell death across the group, and within complex natural populations, is therefore hard and experimentally difficult. The population dynamics of photosynthetic microbes have, in the past, been principally explained through reference to abiotic (“bottom-up”) factors. However, it has become clearer that in general, only a partial linkage exists between abiotic conditions and cyanobacteria population fluctuations in many situations. Instead, a range of biotic interactions both within and between cyanobacteria, and their competitors, pathogens and consumers, can be seen as the major drivers of the observed population fluctuations. Whilst some evolutionary processes may theoretically account for the existence of an intrinsic form of cell death in cyanobacteria, a range of biotic interactions are also likely to frequently cause the ecological incidence of cell death. New theoretical models and single-cell techniques are being developed to illuminate this area. The importance of such work is underlined by both (a) predictions of increasing cyanobacteria dominance due to anthropogenic factors and (b) the realization that influential ecosystem modeling work includes mortality terms with scant foundation, even though such terms can have a very large impact on model predictions. These ideas are explored and a prioritization of research needs is proposed.
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Affiliation(s)
- Daniel J Franklin
- Centre for Ecology, Environment and Sustainability, Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, United Kingdom
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20
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Mayersohn B, Smith KS, Mangolte I, Lévy M. Intrinsic timescales of variability in a marine plankton model. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2021.109446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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21
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Keerthi MG, Lévy M, Aumont O. Intermittency in phytoplankton bloom triggered by modulations in vertical stability. Sci Rep 2021; 11:1285. [PMID: 33446822 PMCID: PMC7809256 DOI: 10.1038/s41598-020-80331-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 12/17/2020] [Indexed: 01/29/2023] Open
Abstract
Seasonal surface chlorophyll (SChl) blooms are very chaotic in nature, but traditional bloom paradigms have climbed out of these subseasonal variations. Here we highlight the leading order role of wind bursts, by conjoining two decades of satellite SChl with atmospheric reanalysis in the Northwestern Mediterranean Sea. We demonstrate that weekly SChl fluctuations are in phase with weekly changes in wind stress and net heat flux during the intial state of the bloom in winter and early spring, thus expanding the convection shutdown hypothesis of bloom onset to subseasonal timescales. We postulate that the mechanism reflected by this link is intermittency in vertical stability due to short-term episodes of calm weather in winter or to stormy conditions in early spring, leading to short-term variations in light exposure or to events of vertical dilution. This strong intermittency in phytoplankton bloom may probably have important consequences on carbon export and trophic web structure and should not be overlooked.
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Affiliation(s)
| | - Marina Lévy
- grid.462844.80000 0001 2308 1657Sorbonne Université (CNRS/IRD/MNHN), LOCEAN-IPSL, Paris, France
| | - Olivier Aumont
- grid.462844.80000 0001 2308 1657Sorbonne Université (CNRS/IRD/MNHN), LOCEAN-IPSL, Paris, France
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22
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Remote Sensing and Argo Float Observations Reveal Physical Processes Initiating a Winter-Spring Phytoplankton Bloom South of the Kuroshio Current Near Shikoku. REMOTE SENSING 2020. [DOI: 10.3390/rs12244065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BIO-Argo float (chlorophyll a (Chl-a), temperature, and salinity profiles) and remote sensing data (Chl-a, photosynthetic available radiation (PAR), and wind) located south of the Kuroshio current near Shikoku from September 2018 to May 2019 were used to study phytoplankton bloom and their mechanisms of development in open oceans. Results show that higher (lower) Chl-a concentrations are correlated with a deeper (shallower) mixed layer (RPearson = 0.77, Rcrit = 0.12 (alpha = 0.05, n = 263)) compared to the average of Chl-a and mixed layer depth (0.13 mg/m3 and 105 m). The average net accumulation rates (r) of phytoplankton were close to 0.08 d−1. An increasing r corresponds to a gradually increasing surface Chl-a (S (Chl-a): 0–20 m average Chl-a) and integrated Chl-a inventory (I (Chl-a): integrated Chl-a from surface to euphotic depth). These phenomena indicate that the mechanism of winter-spring phytoplankton blooms is consistent with the dilution-recoupling hypotheses (DRH). During the bloom formation, winter deep mixing and eddy-wind Ekman pumping are enhanced by a strong winter monsoon. The enhancement may disturb predator–prey interactions and dilute zooplankton in deep mixed layers. Moreover, winter deep mixing and eddy-wind Ekman pumping can cause the nutrients to be transported into the euphotic layer, which can promote the growth of phytoplankton and increase grazing. During the bloom extinction, the stratification strengthens and the intensity of light increases; this increases grazing and nutrient consumption, and decreases the phytoplankton bloom significantly (S (Chl-a) and I (Chl-a) increase by 0.3 mg/m3 and 27 mg/m2, respectively). The output from a biogeochemistry model shows that nutrients are consistent with the temporal distribution of S (Chl-a) and I (Chl-a). Our results suggest that physical processes (deep winter mixing and eddy-wind Ekman pumping) under the DHR framework are critical factors for winter-spring blooms in open oceans with an anticyclone eddy.
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23
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Seasonal modulation of phytoplankton biomass in the Southern Ocean. Nat Commun 2020; 11:5364. [PMID: 33097697 PMCID: PMC7584623 DOI: 10.1038/s41467-020-19157-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 09/28/2020] [Indexed: 11/08/2022] Open
Abstract
Over the last ten years, satellite and geographically constrained in situ observations largely focused on the northern hemisphere have suggested that annual phytoplankton biomass cycles cannot be fully understood from environmental properties controlling phytoplankton division rates (e.g., nutrients and light), as they omit the role of ecological and environmental loss processes (e.g., grazing, viruses, sinking). Here, we use multi-year observations from a very large array of robotic drifting floats in the Southern Ocean to determine key factors governing phytoplankton biomass dynamics over the annual cycle. Our analysis reveals seasonal phytoplankton accumulation ('blooming') events occurring during periods of declining modeled division rates, an observation that highlights the importance of loss processes in dictating the evolution of the seasonal cycle in biomass. In the open Southern Ocean, the spring bloom magnitude is found to be greatest in areas with high dissolved iron concentrations, consistent with iron being a well-established primary limiting nutrient in this region. Under ice observations show that biomass starts increasing in early winter, well before sea ice begins to retreat. The average theoretical sensitivity of the Southern Ocean to potential changes in seasonal nutrient and light availability suggests that a 10% change in phytoplankton division rate may be associated with a 50% reduction in mean bloom magnitude and annual primary productivity, assuming simple changes in the seasonal magnitude of phytoplankton division rates. Overall, our results highlight the importance of quantifying and accounting for both division and loss processes when modeling future changes in phytoplankton biomass cycles.
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24
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Zhang F, Fan Y, Zhang D, Chen S, Bai X, Ma X, Xie Z, Xu H. Effect and mechanism of the algicidal bacterium Sulfitobacter porphyrae ZFX1 on the mitigation of harmful algal blooms caused by Prorocentrum donghaiense. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 263:114475. [PMID: 33618477 DOI: 10.1016/j.envpol.2020.114475] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/12/2020] [Accepted: 03/25/2020] [Indexed: 06/12/2023]
Abstract
Sulfitobacter porphyrae ZFX1, isolated from surface seawater of the East China Sea during a Prorocentrum donghaiense bloom recession, exhibits high algicidal activity against P. donghaiense. To evaluate the algicidal effect of ZFX1, the algicidal mode and stability were investigated. The results showed that ZFX1 indirectly attacked algae by secreting algicidal compounds, and the algicidal activity of the ZFX1 supernatant was insensitive to different temperatures, light intensities and pH values (pH 3-12). To explore the algicidal mechanism of the ZFX1 supernatant, its effects on the morphological and ultrastructural alterations, photosynthetic capacity, reactive oxygen species (ROS) and antioxidative system of P. donghaiense were investigated. Scanning and transmission electron microscopy revealed that the ZFX1 supernatant destroyed the algal cell membrane structure and caused intracellular leakage. The decrease in the chlorophyll a content and the marked declines in both the photosynthetic efficiency (Fv/Fm) and the electron transport rate (rETR) indicated that the ZFX1 supernatant could damage the photosynthetic system of P. donghaiense. The excessive production of ROS in algal cells demonstrated the oxidative damage triggered by the ZFX1 supernatant. Although the antioxidant defense system of P. donghaiense was activated to scavenge excessive ROS, lipid oxidation occurred. The fatty acid composition profile indicated that the ZFX1 supernatant markedly increased the contents of two saturated fatty acids and a monounsaturated fatty acid and decreased the proportion of two polyunsaturated fatty acids, which resulted in lipids with a lower degree of unsaturation (DU). The decline in the DU decreased the lipid fluidity and rigidified the membrane system, and these effects destroyed the function of the membrane system and ultimately resulted in algal cell death. Therefore, ZFX1 probably plays a key role in mitigating P. donghaiense bloom by inducing lipid oxidation, decreasing the DU of lipids and ultimately destroying the membrane systems of algal cells.
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Affiliation(s)
- Fuxing Zhang
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Yongxiang Fan
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Danyang Zhang
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Shuangshuang Chen
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Xue Bai
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Xiaohong Ma
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Zhong Xie
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China
| | - Hong Xu
- State Key Laboratory of Cellular Stress Biology, and School of Life Sciences, Xiamen University, Xiamen, Fujian, 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, Fujian, 361102, PR China.
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25
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Small phytoplankton dominate western North Atlantic biomass. ISME JOURNAL 2020; 14:1663-1674. [PMID: 32231247 PMCID: PMC7305139 DOI: 10.1038/s41396-020-0636-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 03/06/2020] [Accepted: 03/16/2020] [Indexed: 02/02/2023]
Abstract
The North Atlantic phytoplankton spring bloom is the pinnacle in an annual cycle that is driven by physical, chemical, and biological seasonality. Despite its important contributions to the global carbon cycle, transitions in plankton community composition between the winter and spring have been scarcely examined in the North Atlantic. Phytoplankton composition in early winter was compared with latitudinal transects that captured the subsequent spring bloom climax. Amplicon sequence variants (ASVs), imaging flow cytometry, and flow-cytometry provided a synoptic view of phytoplankton diversity. Phytoplankton communities were not uniform across the sites studied, but rather mapped with apparent fidelity onto subpolar- and subtropical-influenced water masses of the North Atlantic. At most stations, cells < 20-µm diameter were the main contributors to phytoplankton biomass. Winter phytoplankton communities were dominated by cyanobacteria and pico-phytoeukaryotes. These transitioned to more diverse and dynamic spring communities in which pico- and nano-phytoeukaryotes, including many prasinophyte algae, dominated. Diatoms, which are often assumed to be the dominant phytoplankton in blooms, were contributors but not the major component of biomass. We show that diverse, small phytoplankton taxa are unexpectedly common in the western North Atlantic and that regional influences play a large role in modulating community transitions during the seasonal progression of blooms.
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26
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Murillo FJ, Weigel B, Bouchard Marmen M, Kenchington E. Marine epibenthic functional diversity on Flemish Cap (north‐west Atlantic)—Identifying trait responses to the environment and mapping ecosystem functions. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
| | - Benjamin Weigel
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland
| | | | - Ellen Kenchington
- Bedford Institute of Oceanography, Fisheries and Oceans Canada Dartmouth NS Canada
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27
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28
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Abstract
Photosynthesis evolved in the ocean more than 2 billion years ago and is now performed by a wide range of evolutionarily distinct organisms, including both prokaryotes and eukaryotes. Our appreciation of their abundance, distributions, and contributions to primary production in the ocean has been increasing since they were first discovered in the seventeenth century and has now been enhanced by data emerging from the Tara Oceans project, which performed a comprehensive worldwide sampling of plankton in the upper layers of the ocean between 2009 and 2013. Largely using recent data from Tara Oceans, here we review the geographic distributions of phytoplankton in the global ocean and their diversity, abundance, and standing stock biomass. We also discuss how omics-based information can be incorporated into studies of photosynthesis in the ocean and show the likely importance of mixotrophs and photosymbionts.
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Affiliation(s)
- Juan José Pierella Karlusich
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université de Recherche Paris Sciences et Lettres (Université PSL), 75005 Paris, France;
| | - Federico M Ibarbalz
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université de Recherche Paris Sciences et Lettres (Université PSL), 75005 Paris, France;
| | - Chris Bowler
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université de Recherche Paris Sciences et Lettres (Université PSL), 75005 Paris, France;
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29
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Opdal AF, Lindemann C, Aksnes DL. Centennial decline in North Sea water clarity causes strong delay in phytoplankton bloom timing. GLOBAL CHANGE BIOLOGY 2019; 25:3946-3953. [PMID: 31442348 DOI: 10.1111/gcb.14810] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 05/20/2023]
Abstract
With climate warming, a widespread expectation is that events in spring, such as flowering, bird migrations, and insect bursts, will occur earlier because of increasing temperature. At high latitudes, increased ocean temperature is suggested to advance the spring phytoplankton bloom due to earlier stabilization of the water column. However, climate warming is also expected to cause browning in lakes and rivers due to increases in terrestrial greening, ultimately reducing water clarity in coastal areas where freshwater drain. In shallow areas, decreased retention of sediments on the seabed will add to this effect. Both browning and resuspension of sediments imply a reduction of the euphotic zone and Sverdrup's critical depth leading to a delay in the spring bloom, counteracting the effect of increasing temperature. Here, we provide evidence that such a transparency reduction has already taken place in both the deep and shallow areas of the North Sea during the 20th century. A sensitivity analysis using a water column model suggests that the reduced transparency might have caused up to 3 weeks delay in the spring bloom over the last century. This delay stands in contrast to the earlier bloom onset expected from global warming, thus highlighting the importance of including changing water transparency in analyses of phytoplankton phenology and primary production. This appears to be of particular relevance for coastal waters, where increased concentrations of absorbing and scattering substances (sediments, dissolved organic matter) have been suggested to lead to coastal darkening.
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Affiliation(s)
| | | | - Dag L Aksnes
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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30
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Asch RG, Stock CA, Sarmiento JL. Climate change impacts on mismatches between phytoplankton blooms and fish spawning phenology. GLOBAL CHANGE BIOLOGY 2019; 25:2544-2559. [PMID: 31152499 DOI: 10.1111/gcb.14650] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 03/01/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
Substantial interannual variability in marine fish recruitment (i.e., the number of young fish entering a fishery each year) has been hypothesized to be related to whether the timing of fish spawning matches that of seasonal plankton blooms. Environmental processes that control the phenology of blooms, such as stratification, may differ from those that influence fish spawning, such as temperature-linked reproductive maturation. These different controlling mechanisms could cause the timing of these events to diverge under climate change with negative consequences for fisheries. We use an earth system model to examine the impact of a high-emissions, climate-warming scenario (RCP8.5) on the future spawning time of two classes of temperate, epipelagic fishes: "geographic spawners" whose spawning grounds are defined by fixed geographic features (e.g., rivers, estuaries, reefs) and "environmental spawners" whose spawning grounds move responding to variations in environmental properties, such as temperature. By the century's end, our results indicate that projections of increased stratification cause spring and summer phytoplankton blooms to start 16 days earlier on average (±0.05 days SE) at latitudes >40°N. The temperature-linked phenology of geographic spawners changes at a rate twice as fast as phytoplankton, causing these fishes to spawn before the bloom starts across >85% of this region. "Extreme events," defined here as seasonal mismatches >30 days that could lead to fish recruitment failure, increase 10-fold for geographic spawners in many areas under the RCP8.5 scenario. Mismatches between environmental spawners and phytoplankton were smaller and less widespread, although sizable mismatches still emerged in some regions. This indicates that range shifts undertaken by environmental spawners may increase the resiliency of fishes to climate change impacts associated with phenological mismatches, potentially buffering against declines in larval fish survival, recruitment, and fisheries. Our model results are supported by empirical evidence from ecosystems with multidecadal observations of both fish and phytoplankton phenology.
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Affiliation(s)
- Rebecca G Asch
- Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey
- Department of Biology, East Carolina University, Greenville, North Carolina
| | - Charles A Stock
- Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, New Jersey
| | - Jorge L Sarmiento
- Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey
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Biogenic Aerosol in the Artic from Eight Years of MSA Data from Ny Ålesund (Svalbard Islands) and Thule (Greenland). ATMOSPHERE 2019. [DOI: 10.3390/atmos10070349] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In remote marine areas, biogenic productivity and atmospheric particulate are coupled through dimethylsulfide (DMS) emission by phytoplankton. Once in the atmosphere, the gaseous DMS is oxidized to produce H2SO4 and methanesulfonic acid (MSA); both species can affect the formation of cloud condensation nuclei. This study analyses eight years of biogenic aerosol evolution and variability at two Arctic sites: Thule (76.5° N, 68.8° W) and Ny Ålesund (78.9° N, 11.9° E). Sea ice plays a key role in determining the MSA concentration in polar regions. At the beginning of the melting season, in April, up to June, the biogenic aerosol concentration appears inversely correlated with sea ice extent and area, and positively correlated with the extent of the ice-free area in the marginal ice zone (IF-MIZ). The upper ocean stratification induced by sea ice melting might have a role in these correlations, since the springtime formation of this surface layer regulates the accumulation of phytoplankton and nutrients, allowing the DMS to escape from the sea to the atmosphere. The multiyear analysis reveals a progressive decrease in MSA concentration in May at Thule and an increase in July August at Ny Ålesund. Therefore, while the MSA seasonal evolution is mainly related with the sea ice retreat in April, May, and June, the IF-MIZ extent appears as the main factor affecting the longer-term behavior of MSA.
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32
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Abstract
The evolution of the near-surface phytoplankton bloom towards a Deep Chlorophyll Maximum (DCM) in mid-latitudes and subpolar regions of the global ocean is a well-known biological feature. However, our knowledge about the exact mechanism that determines the end of the bloom and its irreversible evolution towards a DCM is still limited. In this work, combining satellite and in-situ oceanographic data together with reanalysis data, we investigate why and when this transition between the near-surface phytoplankton bloom and the development of a DCM occurs. For this aim, we investigate the links between changes in air-sea heat exchanges, the near-surface signature of phytoplankton bloom, and the water column vertical structure by calculating the mixed layer depth (MLD) and depth of the DCM on hydrographic and chlorophyll profiles. We find that the occurrence of the last convective mixing event (heat loss by the ocean surface) at the end of the spring which is able to reach the base of the MLD and inject new nutrients into the mixed layer marks the end of the near-surface bloom and its transition towards a DCM. Identified in this way, the spring bloom duration and the start of the transition towards a DCM can be systematically and objectively determined, providing sensitive indexes of climate and ecosystem variability.
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Trombetta T, Vidussi F, Mas S, Parin D, Simier M, Mostajir B. Water temperature drives phytoplankton blooms in coastal waters. PLoS One 2019; 14:e0214933. [PMID: 30951553 PMCID: PMC6450617 DOI: 10.1371/journal.pone.0214933] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 03/24/2019] [Indexed: 11/30/2022] Open
Abstract
Phytoplankton blooms are an important, widespread phenomenon in open oceans, coastal waters and freshwaters, supporting food webs and essential ecosystem services. Blooms are even more important in exploited coastal waters for maintaining high resource production. However, the environmental factors driving blooms in shallow productive coastal waters are still unclear, making it difficult to assess how environmental fluctuations influence bloom phenology and productivity. To gain insights into bloom phenology, Chl a fluorescence and meteorological and hydrological parameters were monitored at high-frequency (15 min) and nutrient concentrations and phytoplankton abundance and diversity, were monitored weekly in a typical Mediterranean shallow coastal system (Thau Lagoon). This study was carried out from winter to late spring in two successive years with different climatic conditions: 2014/2015 was typical, but the winter of 2015/2016 was the warmest on record. Rising water temperature was the main driver of phytoplankton blooms. However, blooms were sometimes correlated with winds and sometimes correlated with salinity, suggesting nutrients were supplied by water transport via winds, saltier seawater intake, rain and water flow events. This finding indicates the joint role of these factors in determining the success of phytoplankton blooms. Furthermore, interannual variability showed that winter water temperature was higher in 2016 than in 2015, resulting in lower phytoplankton biomass accumulation in the following spring. Moreover, the phytoplankton abundances and diversity also changed: cyanobacteria (< 1 μm), picoeukaryotes (< 1 μm) and nanoeukaryotes (3–6 μm) increased to the detriment of larger phytoplankton such as diatoms. Water temperature is a key factor affecting phytoplankton bloom dynamics in shallow productive coastal waters and could become crucial with future global warming by modifying bloom phenology and changing phytoplankton community structure, in turn affecting the entire food web and ecosystem services.
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Affiliation(s)
- Thomas Trombetta
- MARBEC (Marine Biodiversity, Exploitation and Conservation), Centre National de la Recherche Scientifique, Université de Montpellier, Institut Français de Recherche pour l’Exploitation de la Mer, Institut de Recherche pour le Développement, Montpellier, France
- * E-mail:
| | - Francesca Vidussi
- MARBEC (Marine Biodiversity, Exploitation and Conservation), Centre National de la Recherche Scientifique, Université de Montpellier, Institut Français de Recherche pour l’Exploitation de la Mer, Institut de Recherche pour le Développement, Montpellier, France
| | - Sébastien Mas
- MEDIMEER (Mediterranean Platform for Marine Ecosystems Experimental Research), Observatoire de Recherche Méditerranéen de l’Environnement, Centre National de la Recherche Scientifique, Université de Montpellier, Institut de Recherche pour le Développement, Institut National de Recherche en Sciences et Technologies pour l’Environnement et l’Agriculture, Sète, France
| | - David Parin
- MEDIMEER (Mediterranean Platform for Marine Ecosystems Experimental Research), Observatoire de Recherche Méditerranéen de l’Environnement, Centre National de la Recherche Scientifique, Université de Montpellier, Institut de Recherche pour le Développement, Institut National de Recherche en Sciences et Technologies pour l’Environnement et l’Agriculture, Sète, France
| | - Monique Simier
- MARBEC (Marine Biodiversity, Exploitation and Conservation), Institut de Recherche pour le Développement, Centre National de la Recherche Scientifique, Université de Montpellier, Institut Français de Recherche pour l’Exploitation de la Mer, Sète, France
| | - Behzad Mostajir
- MARBEC (Marine Biodiversity, Exploitation and Conservation), Centre National de la Recherche Scientifique, Université de Montpellier, Institut Français de Recherche pour l’Exploitation de la Mer, Institut de Recherche pour le Développement, Montpellier, France
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34
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Kulk G, Buist A, van de Poll WH, Rozema PD, Buma AGJ. Size scaling of photophysiology and growth in four freshly isolated diatom species from Ryder Bay, western Antarctic peninsula. JOURNAL OF PHYCOLOGY 2019; 55:314-328. [PMID: 30449029 PMCID: PMC6590143 DOI: 10.1111/jpy.12813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/19/2018] [Indexed: 06/09/2023]
Abstract
Diatoms are one of the dominant groups in phytoplankton communities of the western Antarctic Peninsula (WAP). Although generally well-studied, little is known about size dependent photophysiological responses in diatom bloom formation and succession. To increase this understanding, four Antarctic diatom species covering two orders of magnitude in cell size were isolated in northern Marguerite Bay (WAP). Fragilariopsis sp., Pseudo-nitzschia cf. subcurvata, Thalassiosira cf. antarctica, and Proboscia cf. alata were acclimated to three different irradiances after which photophysiology, electron transport, carbon fixation, and growth were assessed. The small species Fragilariopsis sp., Pseudo-nitzschia cf. subcurvata, and large species Proboscia cf. alata showed similar photoacclimation to higher irradiances with a decrease in cellular chlorophyll a and an increase in chlorophyll a specific absorption and xanthophyll cycle pigments and activity. In contrast, pigment concentrations and absorption remained unaffected by higher irradiances in the large species Thalassiosira cf. antarctica. Overall, the small species showed significantly higher growth rates compared to the large species, which was related to relatively high light harvesting capacity and electron transport rates in the smaller species. However, photophysiological responses related to photoinhibition and photoprotection and carbon fixation showed no relationship with cell size. This study supports the dominance of small diatoms at low irradiances during winter and early spring, but does not provide photophysiological evidence for the dominance of large diatoms during the phytoplankton bloom in the WAP. This suggests that other factors such as grazing and nutrient availability are likely to play a major role in diatom bloom formation.
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Affiliation(s)
- Gemma Kulk
- Department of Ocean EcosystemsEnergy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
| | - Anton Buist
- Department of Ocean EcosystemsEnergy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
| | - Willem H. van de Poll
- Department of Ocean EcosystemsEnergy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
| | - Patrick D. Rozema
- Department of Ocean EcosystemsEnergy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
| | - Anita G. J. Buma
- Department of Ocean EcosystemsEnergy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenthe Netherlands
- Arctic CentreFaculty of ArtsUniversity of GroningenAweg 309718 CWGroningenthe Netherlands
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35
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Lambert S, Tragin M, Lozano JC, Ghiglione JF, Vaulot D, Bouget FY, Galand PE. Rhythmicity of coastal marine picoeukaryotes, bacteria and archaea despite irregular environmental perturbations. THE ISME JOURNAL 2019; 13:388-401. [PMID: 30254323 PMCID: PMC6331585 DOI: 10.1038/s41396-018-0281-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/20/2018] [Accepted: 08/26/2018] [Indexed: 01/15/2023]
Abstract
Seasonality in marine microorganisms has been classically observed in phytoplankton blooms, and more recently studied at the community level in prokaryotes, but rarely investigated at the scale of individual microbial taxa. Here we test if specific marine eukaryotic phytoplankton, bacterial and archaeal taxa display yearly rhythms at a coastal site impacted by irregular environmental perturbations. Our seven-year study in the Bay of Banyuls (North Western Mediterranean Sea) shows that despite some fluctuating environmental conditions, many microbial taxa displayed significant yearly rhythms. The robust rhythmicity was found in both autotrophs (picoeukaryotes and cyanobacteria) and heterotrophic prokaryotes. Sporadic meteorological events and irregular nutrient supplies did, however, trigger the appearance of less common non-rhythmic taxa. Among the environmental parameters that were measured, the main drivers of rhythmicity were temperature and day length. Seasonal autotrophs may thus be setting the pace for rhythmic heterotrophs. Similar environmental niches may be driving seasonality as well. The observed strong association between Micromonas and SAR11, which both need thiamine precursors for growth, could be a first indication that shared nutritional niches may explain some rhythmic patterns of co-occurrence.
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Affiliation(s)
- Stefan Lambert
- CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, Sorbonne Université, Banyuls sur Mer, Paris, France
| | - Margot Tragin
- CNRS, UMR7144, Station Biologique de Roscoff, Sorbonne Université, Roscoff, Paris, France
| | - Jean-Claude Lozano
- CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, Sorbonne Université, Banyuls sur Mer, Paris, France
| | - Jean-François Ghiglione
- CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, Sorbonne Université, Banyuls sur Mer, Paris, France
| | - Daniel Vaulot
- CNRS, UMR7144, Station Biologique de Roscoff, Sorbonne Université, Roscoff, Paris, France
| | - François-Yves Bouget
- CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, Sorbonne Université, Banyuls sur Mer, Paris, France.
| | - Pierre E Galand
- CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique de Banyuls, Sorbonne Université, Banyuls sur Mer, Paris, France.
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36
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Silkin VA, Pautova LA, Giordano M, Chasovnikov VK, Vostokov SV, Podymov OI, Pakhomova SV, Moskalenko LV. Drivers of phytoplankton blooms in the northeastern Black Sea. MARINE POLLUTION BULLETIN 2019; 138:274-284. [PMID: 30660274 DOI: 10.1016/j.marpolbul.2018.11.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
In order to understand of the processes controlling phytoplankton successions in the NE Black Sea, long-term data series are needed. We compiled 15 years (2002-2017) of measurements from which the existence emerges of a tight link between phytoplankton species dominance and nutrients concentrations. The latter is strongly influenced by wind direction. The link between algal dominance and nutrients is mediated by the growth strategy adopted by algal species. In spring, when nutrients are abundant, small diatoms such as Pseudo-nitzschia pseudodelicatissima, with a "rapid growth strategy", prevail. In late spring and early summer, when N is low and P and Si are high, coccolithophorids such as Emiliania huxhleyi dominate, thanks to an "affinity growth strategy". Large diatoms, especially Pseudosolenia calcar-avis, dominate in summer and autumn, when their "storage growth strategy" allows the exploitation of discontinuous upwelling of nutrients. These seasonal changes of dominant species influence the structure of the food web.
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Affiliation(s)
- V A Silkin
- The Southern Branch of the P.P. Shirshov Institute of Oceanology RAS, Gelendzhik, Krasnodar region, Russia
| | - L A Pautova
- P.P. Shirshov Institute of Oceanology RAS, Nakhimovski av., Moscow, Russia
| | - M Giordano
- Laboratorio di Fisiologia delle Alghe e delle Piante, Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy; STU-UNIVPM Joint Algal Research Center, Shantou, China; Institute of Microbiology, Academy of Sciences of the Czech Republic, Algatech, Trebon, Czech Republic; National Research Council, Institute of Marine Science ISMAR, Venezia, Italy.
| | - V K Chasovnikov
- The Southern Branch of the P.P. Shirshov Institute of Oceanology RAS, Gelendzhik, Krasnodar region, Russia
| | - S V Vostokov
- P.P. Shirshov Institute of Oceanology RAS, Nakhimovski av., Moscow, Russia
| | - O I Podymov
- The Southern Branch of the P.P. Shirshov Institute of Oceanology RAS, Gelendzhik, Krasnodar region, Russia
| | - S V Pakhomova
- P.P. Shirshov Institute of Oceanology RAS, Nakhimovski av., Moscow, Russia
| | - L V Moskalenko
- The Southern Branch of the P.P. Shirshov Institute of Oceanology RAS, Gelendzhik, Krasnodar region, Russia
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37
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Zhang D, Lavender S, Muller JP, Walton D, Zou X, Shi F. MERIS observations of phytoplankton phenology in the Baltic Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:447-462. [PMID: 29908504 DOI: 10.1016/j.scitotenv.2018.06.019] [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: 01/29/2018] [Revised: 06/01/2018] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
The historical data from the MEdium Resolution Imaging Spectrometer (MERIS) is an invaluable archive for studying global waters from inland lakes to open oceans. Although the MERIS sensor ceased to operate in April 2012, the data capacities are now re-established through the recently launched Sentinel-3 Ocean and Land Colour Instrument (OLCI). The development of a consistent time series for investigating phytoplankton phenology features is crucial if the potential of MERIS and OLCI data is to be fully exploited for inland water monitoring. This study presents a time series of phytoplankton abundance and bloom spatial extent for the highly eutrophic inland water of the Baltic Sea using the 10-year MERIS archive (2002-2011) and a chlorophyll-a based Summed Positive Peaks (SPP) algorithm. A gradient approach in conjunction with the histogram analysis was used to determine a global threshold from the entire collection of SPP images for identifying phytoplankton blooms. This allows spatio-temporal dynamics of daily bloom coverage, timing, phytoplankton abundance and spatial extent to be investigated for each Baltic basin. Furthermore, a number of meteorological and hydrological variables, including spring excess phosphate, summer sea surface temperature and photosynthetically active radiation, were explored using boosted regression trees and generalised additive models to understand the ecological response of phytoplankton assemblages to environmental perturbations and potential predictor variables of summer blooms. The results indicate that the surface layer excess phosphate available in February and March had paramount importance over all other variables considered in governing summer bloom abundance in the major Baltic basins. This finding allows new insights into the development of early warning systems for summer phytoplankton blooms in the Baltic Sea and elsewhere.
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Affiliation(s)
- Daoxi Zhang
- Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences, Wuhan 430079, PR China; Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK.
| | - Samantha Lavender
- Pixalytics Ltd., Plymouth Science Park, 1 Davy Road, Plymouth, Devon PL6 8BX, UK; School of Marine Science and Engineering, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK
| | - Jan-Peter Muller
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK
| | - David Walton
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK
| | - Xi Zou
- Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences, Wuhan 430079, PR China
| | - Fang Shi
- Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences, Wuhan 430079, PR China
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Lee Z, Shang S, Du K, Liu B, Lin G, Wei J, Li X. Enhance field water-color measurements with a Secchi disk and its implication for fusion of active and passive ocean-color remote sensing. APPLIED OPTICS 2018; 57:3463-3473. [PMID: 29726515 DOI: 10.1364/ao.57.003463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 03/25/2018] [Indexed: 06/08/2023]
Abstract
Inversion of the total absorption (a) and backscattering coefficients of bulk water through a fusion of remote sensing reflectance (Rrs) and Secchi disk depth (ZSD) is developed. An application of such a system to a synthesized wide-range dataset shows a reduction of ∼3 folds in the uncertainties of inverted a(λ) (in a range of ∼0.01-6.8 m-1) from Rrs(λ) for the 350-560 nm range. Such a fusion is further proposed to process concurrent active (ocean LiDAR) and passive (ocean-color) measurements, which can lead to nearly "exact" analytical inversion of an Rrs spectrum. With such a fusion, it is found that the uncertainty in the inverted total a in the 350-560 nm range could be reduced to ∼2% for the synthesized data, which can thus significantly improve the derivation of a coefficients of other varying components. Although the inclusion of ZSD places an extra constraint in the inversion of Rrs, no apparent improvement over the quasi-analytical algorithm (QAA) was found when the fusion of ZSD and Rrs was applied to a field dataset, which calls for more accurate determination of the absorption coefficients from water samples.
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Rahav E, Raveh O, Hazan O, Gordon N, Kress N, Silverman J, Herut B. Impact of nutrient enrichment on productivity of coastal water along the SE Mediterranean shore of Israel - A bioassay approach. MARINE POLLUTION BULLETIN 2018; 127:559-567. [PMID: 29475698 DOI: 10.1016/j.marpolbul.2017.12.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 12/07/2017] [Accepted: 12/19/2017] [Indexed: 06/08/2023]
Abstract
The coastal waters of the southeastern Mediterranean-Sea (SEMS) are routinely enriched with naturally-occurring and anthropogenic land-based nutrient loads. These external inputs may affect autotrophic and heterotrophic microbial biomass and activity. Here, we conducted 13 microcosm bioassays with different additions of inorganic NO3-(N), PO4-(P) and Si(OH)4-(Si) in different seasons along the Mediterranean coast of Israel. Our results indicate that cyanobacteria are mainly N-limited, whereas N or Si (or both) limit pico-eukaryotes. Furthermore, the degree to which N affects phytoplankton depends on the ambient seawater's inorganic N and N:P characteristics. Heterotrophic bacteria displayed no response in all treatments, except when all nutrients were added simultaneously, suggesting a possible co-limitation by nutrients. These results contrast the N+P co-limitation of phytoplankton and the P-limitation of bacteria in the open waters of the SEMS. These observations enable the application for a better science-based environmental monitoring and policy implementation along the SEMS coast of Israel.
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Affiliation(s)
- Eyal Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel.
| | - Ofrat Raveh
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Or Hazan
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Nurit Gordon
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Nurit Kress
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Jacob Silverman
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
| | - Barak Herut
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 31080, Israel
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40
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Balaguru K, Doney SC, Bianucci L, Rasch PJ, Leung LR, Yoon JH, Lima ID. Linking deep convection and phytoplankton blooms in the northern Labrador Sea in a changing climate. PLoS One 2018; 13:e0191509. [PMID: 29370224 PMCID: PMC5784959 DOI: 10.1371/journal.pone.0191509] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 01/05/2018] [Indexed: 12/03/2022] Open
Abstract
Wintertime convective mixing plays a pivotal role in the sub-polar North Atlantic spring phytoplankton blooms by favoring phytoplankton survival in the competition between light-dependent production and losses due to grazing and gravitational settling. We use satellite and ocean reanalyses to show that the area-averaged maximum winter mixed layer depth is positively correlated with April chlorophyll concentration in the northern Labrador Sea. A simple theoretical framework is developed to understand the relative roles of winter/spring convection and gravitational sedimentation in spring blooms in this region. Combining climate model simulations that project a weakening of wintertime Labrador Sea convection from Arctic sea ice melt with our framework suggests a potentially significant reduction in the initial fall phytoplankton population that survive the winter to seed the region’s spring bloom by the end of the 21st century.
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Affiliation(s)
- Karthik Balaguru
- Marine Sciences Laboratory, Pacific Northwest National Laboratory, Seattle, WA, United States of America - 98109
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States of America - 99354
- * E-mail:
| | - Scott C. Doney
- Now at Department of Environmental Sciences, University of Virginia, Charlottesville, VA, United States of America - 22904
- Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America - 02543
| | - Laura Bianucci
- Marine Sciences Laboratory, Pacific Northwest National Laboratory, Seattle, WA, United States of America - 98109
- Now at Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney BC, Canada - V8L 4B2
| | - Philip J. Rasch
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States of America - 99354
| | - L. Ruby Leung
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States of America - 99354
| | - Jin-Ho Yoon
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Ivan D. Lima
- Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America - 02543
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41
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Hazan O, Silverman J, Sisma-Ventura G, Ozer T, Gertman I, Shoham-Frider E, Kress N, Rahav E. Mesopelagic Prokaryotes Alter Surface Phytoplankton Production during Simulated Deep Mixing Experiments in Eastern Mediterranean Sea Waters. FRONTIERS IN MARINE SCIENCE 2018. [PMID: 0 DOI: 10.3389/fmars.2018.00001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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42
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Mignot A, Ferrari R, Claustre H. Floats with bio-optical sensors reveal what processes trigger the North Atlantic bloom. Nat Commun 2018; 9:190. [PMID: 29335403 PMCID: PMC5768750 DOI: 10.1038/s41467-017-02143-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 11/08/2017] [Indexed: 11/20/2022] Open
Abstract
The North Atlantic bloom corresponds to a strong seasonal increase in phytoplankton that produces organic carbon through photosynthesis. It is still debated what physical and biological conditions trigger the bloom, because comprehensive time series of the vertical distribution of phytoplankton biomass are lacking. Vertical profiles from nine floats that sampled the waters of the North Atlantic every few days for a couple of years reveal that phytoplankton populations start growing in early winter at very weak rates. A proper bloom with rapidly accelerating population growth rates instead starts only in spring when atmospheric cooling subsides and the mixed layer rapidly shoals. While the weak accumulation of phytoplankton in winter is crucial to maintaining a viable population, the spring bloom dominates the overall seasonal production of organic carbon. The drivers of North Atlantic phytoplankton bloom have been debated for decades, partially owing to incomplete sub-surface observations. Here, Mignot et al. use robotic sensors to provide detailed observations of developing blooms and to explore the drivers of different phases of plankton growth.
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Affiliation(s)
- A Mignot
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,Laboratoire d'Océanographie de Villefranche (LOV), UPMC Univ. Paris 06, CNRS, UMR 7093, Sorbonne Universités, 181 Chemin du Lazaret, 06230, Villefranche-sur-mer, France.
| | - R Ferrari
- Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - H Claustre
- Laboratoire d'Océanographie de Villefranche (LOV), UPMC Univ. Paris 06, CNRS, UMR 7093, Sorbonne Universités, 181 Chemin du Lazaret, 06230, Villefranche-sur-mer, France
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Beaugrand G, Kirby RR. How Do Marine Pelagic Species Respond to Climate Change? Theories and Observations. ANNUAL REVIEW OF MARINE SCIENCE 2018; 10:169-197. [PMID: 29298137 DOI: 10.1146/annurev-marine-121916-063304] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this review, we show how climate affects species, communities, and ecosystems, and why many responses from the species to the biome level originate from the interaction between the species' ecological niche and changes in the environmental regime in both space and time. We describe a theory that allows us to understand and predict how marine species react to climate-induced changes in ecological conditions, how communities form and are reconfigured, and so how biodiversity is arranged and may respond to climate change. Our study shows that the responses of species to climate change are therefore intelligible-that is, they have a strong deterministic component and can be predicted.
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Affiliation(s)
- Grégory Beaugrand
- Laboratoire d'Océanologie et de Géosciences, CNRS UMR 8187 LOG, Université de Lille and Université du Littoral Côte d'Opale, F-62930 Wimereux, France;
- Sir Alister Hardy Foundation for Ocean Science, Plymouth PL1 2PB, United Kingdom
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Lehahn Y, d'Ovidio F, Koren I. A Satellite-Based Lagrangian View on Phytoplankton Dynamics. ANNUAL REVIEW OF MARINE SCIENCE 2018; 10:99-119. [PMID: 28961072 DOI: 10.1146/annurev-marine-121916-063204] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The well-lit upper layer of the open ocean is a dynamical environment that hosts approximately half of global primary production. In the remote parts of this environment, distant from the coast and from the seabed, there is no obvious spatially fixed reference frame for describing the dynamics of the microscopic drifting organisms responsible for this immense production of organic matter-the phytoplankton. Thus, a natural perspective for studying phytoplankton dynamics is to follow the trajectories of water parcels in which the organisms are embedded. With the advent of satellite oceanography, this Lagrangian perspective has provided valuable information on different aspects of phytoplankton dynamics, including bloom initiation and termination, spatial distribution patterns, biodiversity, export of carbon to the deep ocean, and, more recently, bottom-up mechanisms that affect the distribution and behavior of higher-trophic-level organisms. Upcoming submesoscale-resolving satellite observations and swarms of autonomous platforms open the way to the integration of vertical dynamics into the Lagrangian view of phytoplankton dynamics.
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Affiliation(s)
- Yoav Lehahn
- Department of Marine Geosciences, University of Haifa, Haifa 3498838, Israel;
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Francesco d'Ovidio
- Sorbonne Université (UPMC Paris 6/CNRS/IRD/MNHN), LOCEAN-IPSL, 75005 Paris, France;
| | - Ilan Koren
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel;
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Behrenfeld MJ, Boss ES. Student's tutorial on bloom hypotheses in the context of phytoplankton annual cycles. GLOBAL CHANGE BIOLOGY 2018; 24:55-77. [PMID: 28787760 PMCID: PMC5763361 DOI: 10.1111/gcb.13858] [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: 02/07/2017] [Accepted: 07/31/2017] [Indexed: 05/07/2023]
Abstract
Phytoplankton blooms are elements in repeating annual cycles of phytoplankton biomass and they have significant ecological and biogeochemical consequences. Temporal changes in phytoplankton biomass are governed by complex predator-prey interactions and physically driven variations in upper water column growth conditions (light, nutrient, and temperature). Understanding these dependencies is fundamental to assess future change in bloom frequency, duration, and magnitude and thus represents a quintessential challenge in global change biology. A variety of contrasting hypotheses have emerged in the literature to explain phytoplankton blooms, but over time the basic tenets of these hypotheses have become unclear. Here, we provide a "tutorial" on the development of these concepts and the fundamental elements distinguishing each hypothesis. The intent of this tutorial is to provide a useful background and set of tools for reading the bloom literature and to give some suggestions for future studies. Our tutorial is written for "students" at all stages of their career. We hope it is equally useful and interesting to those with only a cursory interest in blooms as those deeply immersed in the challenge of understanding the temporal dynamics of phytoplankton biomass and predicting its future change.
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46
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Bach LT, Alvarez-Fernandez S, Hornick T, Stuhr A, Riebesell U. Simulated ocean acidification reveals winners and losers in coastal phytoplankton. PLoS One 2017; 12:e0188198. [PMID: 29190760 PMCID: PMC5708705 DOI: 10.1371/journal.pone.0188198] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 11/02/2017] [Indexed: 11/29/2022] Open
Abstract
The oceans absorb ~25% of the annual anthropogenic CO2 emissions. This causes a shift in the marine carbonate chemistry termed ocean acidification (OA). OA is expected to influence metabolic processes in phytoplankton species but it is unclear how the combination of individual physiological changes alters the structure of entire phytoplankton communities. To investigate this, we deployed ten pelagic mesocosms (volume ~50 m3) for 113 days at the west coast of Sweden and simulated OA (pCO2 = 760 μatm) in five of them while the other five served as controls (380 μatm). We found: (1) Bulk chlorophyll a concentration and 10 out of 16 investigated phytoplankton groups were significantly and mostly positively affected by elevated CO2 concentrations. However, CO2 effects on abundance or biomass were generally subtle and present only during certain succession stages. (2) Some of the CO2-affected phytoplankton groups seemed to respond directly to altered carbonate chemistry (e.g. diatoms) while others (e.g. Synechococcus) were more likely to be indirectly affected through CO2 sensitive competitors or grazers. (3) Picoeukaryotic phytoplankton (0.2-2 μm) showed the clearest and relatively strong positive CO2 responses during several succession stages. We attribute this not only to a CO2 fertilization of their photosynthetic apparatus but also to an increased nutrient competitiveness under acidified (i.e. low pH) conditions. The stimulating influence of high CO2/low pH on picoeukaryote abundance observed in this experiment is strikingly consistent with results from previous studies, suggesting that picoeukaryotes are among the winners in a future ocean.
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Affiliation(s)
- Lennart T. Bach
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Santiago Alvarez-Fernandez
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Helgoland, Germany
| | - Thomas Hornick
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Experimental Limnology, Stechlin, Germany
| | - Annegret Stuhr
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Ulf Riebesell
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
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47
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Reply to Dees et al.: Ocean warming promotes species-specific increases in the cellular growth rates of harmful algal blooms. Proc Natl Acad Sci U S A 2017; 114:E9765-E9766. [PMID: 29087349 DOI: 10.1073/pnas.1715749114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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48
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Environmental structuring of marine plankton phenology. Nat Ecol Evol 2017; 1:1484-1494. [PMID: 29185511 DOI: 10.1038/s41559-017-0287-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/18/2017] [Indexed: 11/08/2022]
Abstract
Seasonal cycles of primary production (phenology) critically influence biogeochemical cycles, ecosystem structure and climate. In the oceans, primary production is dominated by microbial phytoplankton that drift with currents, and show rapid turnover and chaotic dynamics, factors that have hindered understanding of their phenology. We used all available observations of upper-ocean phytoplankton concentration (1995-2015) to describe global patterns of phytoplankton phenology, the environmental factors that structure them, and their relationships to terrestrial patterns. Phytoplankton phenologies varied strongly by latitude and productivity regime: those in high-production regimes were governed by insolation, whereas those in low-production regimes were constrained by vertical mixing. In eight of ten ocean regions, our findings contradict the hypothesis that phytoplankton phenologies are coherent at basin scales. Lastly, the spatial organization of phenological patterns in the oceans was broadly similar to those on land, suggesting an overarching effect of insolation on the phenology of primary producers globally.
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49
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Abstract
Antarctic krill (Euphausia superba) – one of the most abundant animal species on Earth – exhibits a 5-6 year population cycle, with oscillations in biomass exceeding one order of magnitude. Previous studies have postulated that the krill cycle is induced by periodic climatological factors, but these postulated drivers neither show consistent agreement, nor are they supported by quantitative models. Here, using data analysis complemented with modeling of krill ontogeny and population dynamics, we identify intraspecific competition for food as the main driver of the krill cycle, while external climatological factors possibly modulate its phase and synchronization over large scales. Our model indicates that the cycle amplitude increases with reduction of krill loss rates. Thus, a decline of apex predators is likely to increase the oscillation amplitude, potentially destabilizing the marine food web with drastic consequences for the entire Antarctic ecosystem.
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50
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Hoppe C, Klaas C, Ossebaar S, Soppa M, Cheah W, Laglera L, Santos-Echeandia J, Rost B, Wolf-Gladrow D, Bracher A, Hoppema M, Strass V, Trimborn S. Controls of primary production in two phytoplankton blooms in the Antarctic Circumpolar Current. DEEP-SEA RESEARCH. PART II, TOPICAL STUDIES IN OCEANOGRAPHY 2017; 138:63-73. [PMID: 28515575 PMCID: PMC5421167 DOI: 10.1016/j.dsr2.2015.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The Antarctic Circumpolar Current has a high potential for primary production and carbon sequestration through the biological pump. In the current study, two large-scale blooms observed in 2012 during a cruise with R.V. Polarstern were investigated with respect to phytoplankton standing stocks, primary productivity and nutrient budgets. While net primary productivity was similar in both blooms, chlorophyll a -specific photosynthesis was more efficient in the bloom closer to the island of South Georgia (39 °W, 50 °S) compared to the open ocean bloom further east (12 °W, 51 °S). We did not find evidence for light being the driver of bloom dynamics as chlorophyll standing stocks up to 165 mg m-2 developed despite mixed layers as deep as 90 m. Since the two bloom regions differ in their distance to shelf areas, potential sources of iron vary. Nutrient (nitrate, phosphate, silicate) deficits were similar in both areas despite different bloom ages, but their ratios indicated more pronounced iron limitation at 12 °W compared to 39 °W. While primarily the supply of iron and not the availability of light seemed to control onset and duration of the blooms, higher grazing pressure could have exerted a stronger control toward the declining phase of the blooms.
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Affiliation(s)
- C.J.M. Hoppe
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - C. Klaas
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - S. Ossebaar
- NIOZ-Royal Netherlands Institute for Sea Research, Landsdiep 4, 1797 SZ’t Horntje, Texel, The Netherlands
| | - M.A. Soppa
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - W. Cheah
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Research Center for Environmental Changes, Academia Sinica, 128 Academia Road, 11529 Taipei, Taiwan
| | - L.M. Laglera
- FITRACE, Departamento de Química, Universidad de las Islas Baleares, Cra. de Valldemossa, Palma, Balearic Islands, 07122, Spain
| | - J. Santos-Echeandia
- Marine Biogeochemistry, Instituto de Investigaciones marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain
| | - B. Rost
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - D.A. Wolf-Gladrow
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - A. Bracher
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Institute of Environmental Physics, University Bremen, Otto Hahn Allee 1, 28359 Bremen, Germany
| | - M. Hoppema
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - V. Strass
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - S. Trimborn
- Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Marine Botany, University Bremen, Leobener Straße NW2, 28359 Bremen, Germany
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