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Wang X, Li J, Zheng J, Zhao L, Ruan C, Zhang D, Pan X. Polysaccharide preferred minority-dominant community assembly and exoenzyme enrichment in transparent exopolymer particles: Implication for global carbon cycle in water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169976. [PMID: 38199380 DOI: 10.1016/j.scitotenv.2024.169976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/12/2024]
Abstract
The ubiquitous transparent exopolymer particles (TEPs) are an important organic carbon pool and an ideal microhabitat for bacteria in aquatic environments. They play a crucial role in the global carbon cycle. Organic matter transformation and carbon turnover in TEPs strongly depend on the assembly of their associated bacterial communities and enzyme activity. However, the mechanisms of bacterial community assembly and their potential effects on the organic carbon cycle in TEPs are still unclear. In this study, we comparatively explored the community assembly of TEP-associated bacteria and bacterioplankton from surface freshwater using metagenomics. It was found that the bacterial community assembly in TEPs followed a minority-dominant rule and was governed by homogeneous selection. Pseudomonadota and Actinomycetota, which are responsible for polysaccharide degradation, serve as taxon-specific biomarkers among the abundant and diverse bacteria in TEPs. The network of TEP-associated bacteria displayed stronger robustness than that of bacterioplankton. Bin 76 (majorly Acinetobacter) was the overwhelmingly dominant taxa in TEPs, whereas there was no clearly dominant taxa in TEP-free water. Exoenzyme analysis showed that 64 out of 71 identified polysaccharide hydrolases were markedly linked with the dominant bin 76 in TEPs, while no such linkage was observed for bacterioplankton. Generally, Acinetobacter, which is capable of utilizing polysaccharides, is preferred to be assembled in TEPs together with high polysaccharide hydrolase activity. This may significantly accelerate the turnover of organic carbon in the giant global TEP pool. These findings are important for a deep understanding of the carbon cycle in water.
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Affiliation(s)
- Xiaonan Wang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Hangzhou 310015, China; School of Environment Science and Spatial Information, China University of Mining and Technology, Xuzhou 221116, China; Shaoxing Research Institute of Zhejiang University of Technology, Shaoxing 312000, China
| | - Jiahao Li
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jieyan Zheng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Lanxin Zhao
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Chenghao Ruan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Daoyong Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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Kim J, La HS, Kim JH, Jo N, Lee J, Kim BK, Son W, Kim K, Jang HK, Park S, Yoo H, Kim J, Park J, Ahn SH, Lee SH. Spatio-temporal variations in organic carbon composition driven by two different major phytoplankton communities in the Ross Sea, Antarctica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 891:164666. [PMID: 37286011 DOI: 10.1016/j.scitotenv.2023.164666] [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: 02/06/2023] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 06/09/2023]
Abstract
The compositions of organic carbon could be important in determining biological carbon pump efficiency. However, little information on them in relation to each algal assemblage is currently available in the Ross Sea. Here, we investigated the seasonal variations in organic carbon composition and the relative abundance of each organic carbon, including particulate organic carbon (POC), dissolved organic carbon (DOC), and transparent exopolymer particles (TEPs), characterized by different algal groups in the Ross Sea. The average POC and DOC contributions to the total organic carbon (TOC = POC + DOC) were 13.8 ± 3.7 % and 86.2 ± 3.7 % in mid-January 2019 and 20.9 ± 4.1 % and 79.1 ± 4.1 % in February-March 2018, respectively. The carbon content of TEP (TEP-C) contributed 19.6 ± 11.7 % and 4.6 ± 7.0 % of POC and TOC in mid-January and 36.2 ± 14.8 % and 9.0 ± 6.7 % in February-March, respectively. We found that the organic carbon compositions were affected by seasonal variations in the phytoplankton bloom phase, physical characteristics, and phytoplankton community structure. DOC concentrations and contributions to the TOC increased as phytoplankton cells became senescent in mid-January and decreased in February-March when phytoplankton were relatively active. From February-March, the deepened mixed layer depth encouraged TEP formation, subsequently increasing the TEP contributions. Regardless of the sampling season, all organic carbon concentrations per unit Chl-a were significantly higher in P. antarctica-abundant groups. The DOC contributions to the TOC were correspondingly higher at the P. antarctica-abundant stations in mid-January, which indicates that P. antarctica could be also important in the DOC contributions in the Ross Sea. The rapid alteration in environmental characteristics and phytoplankton community structures in the Ross Sea due to climate change could affect the organic carbon pool at the euphotic layer which consequently could determine the efficiency of the biological pump.
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Affiliation(s)
- Jaehong Kim
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Hyoung Sul La
- Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Jeong-Hoon Kim
- Division of Life Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Naeun Jo
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Junbeom Lee
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Bo Kyung Kim
- Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Wuju Son
- Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea; Department of Polar Science, University of Science and Technology, Daejeon, South Korea
| | - Kwanwoo Kim
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Hyo-Keun Jang
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Sanghoon Park
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Hyeju Yoo
- Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Jaesoon Kim
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Jisoo Park
- Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - So Hyun Ahn
- Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, USA
| | - Sang Heon Lee
- Department of Oceanography, Pusan National University, Busan, South Korea.
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Cabrera-Brufau M, Marrasé C, Ortega-Retuerta E, Nunes S, Estrada M, Sala MM, Vaqué D, Pérez GL, Simó R, Cermeño P. Particulate and dissolved fluorescent organic matter fractionation and composition: Abiotic and ecological controls in the Southern Ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:156921. [PMID: 35760176 DOI: 10.1016/j.scitotenv.2022.156921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/03/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Phytoplankton-derived organic matter sustains heterotrophic marine life in regions away from terrestrial inputs such as the Southern Ocean. Fluorescence spectroscopy has long been used to characterize the fluorescent organic matter (FOM) pool. However, most studies focus only in the dissolved FOM fraction (FDOM) disregarding the contribution of particles. In order to assess the dynamics and drivers of the dissolved and particulate fractions of FOM, we used a Lagrangian approach to follow the time evolution of phytoplankton proliferations at four different sites in the Southern Ocean and compared the FOM in filtered and unfiltered seawater aliquots. We found that filtration had little effects on FOM visible spectrum fluorescence intensities, implying that most of this signal was due to dissolved fluorophores. On the other hand, protein-like fluorescence was strongly supressed by filtration, with fluorescence of particles accounting for up to 90 % of the total protein-like FOM. Photobleaching was identified as the main driver of visible FDOM composition, which was better described by indices of phytoplankton photoacclimation than by measurements of the incident solar radiation dose. In contrast, protein-like FOM intensity and fractionation were primarily related to abundance, composition and physiological state of phytoplankton proliferations. The chlorophyll a concentration from non-diatom phytoplankton explained 91 % of the particulate protein-like FOM variability. The proportion of protein-like fluorescence found in the dissolved phase was predicted by the combination of potential viral and grazing pressures, which accounted for 51 and 29 % of its variability, respectively. Our results show that comparing FOM measurements from filtered and unfiltered seawater provides relevant information on the taxonomic composition and cell integrity of phytoplankton communities. A better understanding of the commonly overlooked FOM fractionation process is essential for the implementation of in situ fluorescence sensors and will also help us better understand the processes that govern OM cycling in marine systems.
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Affiliation(s)
- Miguel Cabrera-Brufau
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain; Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain
| | - Cèlia Marrasé
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain.
| | - Eva Ortega-Retuerta
- CNRS/Sorbonne Université, UMR7621 Laboratoire d'Océanographie Microbienne, Banyuls sur Mer, France
| | - Sdena Nunes
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Marta Estrada
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain
| | - M Montserrat Sala
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain
| | - Dolors Vaqué
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain
| | - Gonzalo L Pérez
- GESAP, INBIOMA (UNComahue-CONICET), San Carlos de Bariloche, Argentina
| | - Rafel Simó
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain
| | - Pedro Cermeño
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (CSIC), Barcelona, Spain
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Guo S, Wu Y, Zhu M, Sun X. Concentrations of transparent exopolymer particles (TEPs) and their role in the carbon export in the South China Sea and western tropical North Pacific. MARINE ENVIRONMENTAL RESEARCH 2022; 179:105699. [PMID: 35839746 DOI: 10.1016/j.marenvres.2022.105699] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
The role of TEPs in the carbon cycle remains inadequately understood in oligotrophic tropical oceans. This study investigates TEP concentrations, distributions, sinking behavior and fluxes in the oligotrophic South China Sea (SCS) and western tropical North Pacific (WTNP). The results suggested that TEPs levels were relatively low [< 60 μg Xeq. L-1 (μg xanthan gum equivalent per liter)] in both regions, and they were higher in the epipelagic layer than in deeper layers. TEP concentrations correlated significantly positively with Chl a and picophytoplankton biomass, and TEP-associated carbon contributed significantly to particulate organic carbon (POC) pool in the SCS and WTNP. The sinking flux of TEPs constituted a mean of 61% of the total POC flux in the SCS and 46% in the WTNP, highlighting their important role in carbon export in these areas. Generally, this study should provide good insight into the role TEPs play in the carbon cycle in oligotrophic tropical oceans.
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Affiliation(s)
- Shujin Guo
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, PR China
| | - Ying Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 201100, PR China
| | - Mingliang Zhu
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, PR China
| | - Xiaoxia Sun
- Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, PR China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
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Ge Z, Li QP, Yang W, Liu X, Wu Z. Transparent exopolymer particle dynamics along a shelf-to-sea gradient and impacts on the regional carbon cycle. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:152117. [PMID: 34863747 DOI: 10.1016/j.scitotenv.2021.152117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/28/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
Transparent exopolymer particles (TEPs) have drawn extensive attention in recent decades due to their crucial role in the biogeochemical and ecological processes of the ocean. However, TEP distribution and fluxes are relatively less addressed in the shelf-seas, where its variability can be affected by not only biology but also complex physical dynamics. Here, we present a comprehensive study of TEP from the coast to the basin (12 sampling sites) of the northern South China Sea (NSCS). We found a large TEP variability from 0.6 to 78.6 μg Xeq. L-1 with higher levels in the coastal waters than the offshore epipelagic waters and the deep waters. In addition, the spatial distribution of TEP was significantly correlated to the cross-shelf change of temperature, salinity, and chlorophyll-a, revealing the complex physical-biogeochemical controls on TEP variability. We found the TEP dynamics nearshore largely influenced by the sedimentation and transportation of TEP-rich aggregates from the river plume. The contribution of TEP to particulate organic carbon (POC) increased gradually when approaching the shore from the sea, suggesting an elevated role of TEP in the coastal carbon cycle. Finally, a good correlation of particle-attached bacteria (PAB) with TEP but not POC revealed a preferential utilization of TEP by PAB. Thus, TEP may play an essential role in the recycling of carbon and nitrogen in the shelf-sea. These findings are crucial for understanding of the TEP dynamics under a changing environment and the associated impacts on the oceanic carbon cycle.
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Affiliation(s)
- Zaiming Ge
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qian P Li
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
| | - Weifeng Yang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Xin Liu
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Zhengchao Wu
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
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Seasonal Variations in the Biochemical Compositions of Phytoplankton and Transparent Exopolymer Particles (TEPs) at Jang Bogo Station (Terra Nova Bay, Ross Sea), 2017–2018. WATER 2021. [DOI: 10.3390/w13162173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The biochemical composition of particulate organic matter (POM) mainly originates from phytoplankton. Transparent exopolymer particles (TEPs) depend on environmental conditions and play a role in the food web and biogeochemical cycle in marine ecosystems. However, little information on their characteristics in the Southern Ocean is available, particularly in winter. To investigate the seasonal characteristics of POM and TEPSs, seawater samples were collected once every two weeks from November 2017 to October 2018 at Jang Bogo Station (JBS) located on the coast of Terra Nova Bay in the Ross Sea. The total chlorophyll-a (Chl-a) concentrations increased from spring (0.08 ± 0.06 μg L−1) to summer (0.97 ± 0.95 μg L−1) with a highest Chl-a value of 2.15 μg L−1. After sea ice formation, Chl-a rapidly decreased in autumn (0.12 ± 0.10 μg L−1) and winter (0.01 ± 0.01 μg L−1). The low phytoplankton Chl-a measured in this study was related to a short ice-free period in summer. Strong seasonal variations were detected in the concentrations of proteins and lipids (one-way ANOVA test, p < 0.05), whereas no significant difference in carbohydrate concentrations was observed among different seasons (one-way ANOVA test, p > 0.05). The phytoplankton community was mostly composed of diatoms (88.8% ± 11.6%) with a large accumulation of lipids. During the summer, the POM primarily consisted of proteins. The composition being high in lipids and proteins and the high caloric content in summer indicated that the phytoplankton would make a good food source. In winter, the concentrations of proteins decreased sharply. In contrast, relatively stable concentrations of carbohydrates and lipids have been utilized for respiration and long-term energy storage in the survival of phytoplankton. The TEPS values were significantly correlated with variations in the biomass and species of the phytoplankton. Our study site was characterized by dominant diatoms and low Chl-a concentrations, which could have resulted in relatively low TEP concentrations compared to other areas. The average contributions of TEP-C to the total POC were relatively high in autumn (26.9% ± 6.1%), followed by those in summer (21.9% ± 7.1%), winter (13.0% ± 4.2%), and spring (9.8% ± 3.1%).
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Moallemi A, Landwehr S, Robinson C, Simó R, Zamanillo M, Chen G, Baccarini A, Schnaiter M, Henning S, Modini RL, Gysel‐Beer M, Schmale J. Sources, Occurrence and Characteristics of Fluorescent Biological Aerosol Particles Measured Over the Pristine Southern Ocean. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2021; 126:e2021JD034811. [PMID: 34221783 PMCID: PMC8244095 DOI: 10.1029/2021jd034811] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 06/13/2023]
Abstract
In this study, we investigate the occurrence of primary biological aerosol particles (PBAP) over all sectors of the Southern Ocean (SO) based on a 90-day data set collected during the Antarctic Circumnavigation Expedition (ACE) in austral summer 2016-2017. Super-micrometer PBAP (1-16 µm diameter) were measured by a wide band integrated bioaerosol sensor (WIBS-4). Low (3σ) and high (9σ) fluorescence thresholds are used to obtain statistics on fluorescent and hyper-fluorescent PBAP, respectively. Our focus is on data obtained over the pristine ocean, that is, more than 200 km away from land. The results indicate that (hyper-)fluorescent PBAP are correlated to atmospheric variables associated with sea spray aerosol (SSA) particles (wind speed, total super-micrometer aerosol number concentration, chloride and sodium concentrations). This suggests that a main source of PBAP over the SO is SSA. The median percentage contribution of fluorescent and hyper-fluorescent PBAP to super-micrometer SSA was 1.6% and 0.13%, respectively. We demonstrate that the fraction of (hyper-)fluorescent PBAP to total super-micrometer particles positively correlates with concentrations of bacteria and several taxa of pythoplankton measured in seawater, indicating that marine biota concentrations modulate the PBAP source flux. We investigate the fluorescent properties of (hyper-)fluorescent PBAP for several events that occurred near land masses. We find that the fluorescence signal characteristics of particles near land is much more variable than over the pristine ocean. We conclude that the source and concentration of fluorescent PBAP over the open ocean is similar across all sampled sectors of the SO.
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Affiliation(s)
- Alireza Moallemi
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
| | - Sebastian Landwehr
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
- Extreme Environments Research LaboratoryÉcole Polytechnique Fédérale de Lausanne, School of Architecture, Civil and Environmental EngineeringLausanneSwitzerland
| | - Charlotte Robinson
- Remote Sensing and Satellite Research GroupCurtin UniversityBentleyWAAustralia
| | - Rafel Simó
- Institut de Ciències del Mar (CSIC)BarcelonaSpain
| | | | - Gang Chen
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
| | - Andrea Baccarini
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
- Extreme Environments Research LaboratoryÉcole Polytechnique Fédérale de Lausanne, School of Architecture, Civil and Environmental EngineeringLausanneSwitzerland
| | - Martin Schnaiter
- Institut für Meteorologie und KlimaforschungKarlsruher Institut für TechnologieKarlsruheGermany
- schnaiTEC GmbHBruchsalGermany
| | - Silvia Henning
- Leibniz Institute for Tropospheric Research, Experimental Aerosol and Cloud MicrophysicsLeipzigGermany
| | - Robin L. Modini
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
| | - Martin Gysel‐Beer
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
| | - Julia Schmale
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
- Extreme Environments Research LaboratoryÉcole Polytechnique Fédérale de Lausanne, School of Architecture, Civil and Environmental EngineeringLausanneSwitzerland
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Distribution and Drivers of Marine Isoprene Concentration across the Southern Ocean. ATMOSPHERE 2020. [DOI: 10.3390/atmos11060556] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Isoprene is a biogenic trace gas produced by terrestrial vegetation and marine phytoplankton. In the remote oceans, where secondary aerosols are mostly biogenic, marine isoprene emissions affect atmospheric chemistry and influence cloud formation and brightness. Here, we present the first compilation of new and published measurements of isoprene concentrations in the Southern Ocean and explore their distribution patterns. Surface ocean isoprene concentrations in November through April span 1 to 94 pM. A band of higher concentrations is observed around a latitude of ≈40 ∘ S and a surface sea temperature of 15 ∘ C. High isoprene also occurs in high productivity waters near islands and continental coasts. We use concurrent measurements of physical, chemical, and biological variables to explore the main potential drivers of isoprene concentration by means of paired regressions and multivariate analysis. Isoprene is best explained by phytoplankton-related variables like the concentrations of chlorophyll-a, photoprotective pigments and particulate organic matter, photosynthetic efficiency (influenced by iron availability), and the chlorophyll-a shares of most phytoplankton groups, and not by macronutrients or bacterial abundance. A simple statistical model based on chlorophyll-a concentration and a sea surface temperature discontinuity accounts for half of the variance of isoprene concentrations in surface waters of the Southern Ocean.
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