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Vanharanta M, Santoro M, Villena-Alemany C, Piiparinen J, Piwosz K, Grossart HP, Labrenz M, Spilling K. Microbial remineralization processes during postspring-bloom with excess phosphate available in the northern Baltic Sea. FEMS Microbiol Ecol 2024; 100:fiae103. [PMID: 39039015 DOI: 10.1093/femsec/fiae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/10/2024] [Accepted: 07/19/2024] [Indexed: 07/24/2024] Open
Abstract
The phosphorus (P) concentration is increasing in parts of the Baltic Sea following the spring bloom. The fate of this excess P-pool is an open question, and here we investigate the role of microbial degradation processes in the excess P assimilation phase. During a 17-day-long mesocosm experiment in the southwest Finnish archipelago, we examined nitrogen, phosphorus, and carbon acquiring extracellular enzyme activities in three size fractions (<0.2, 0.2-3, and >3 µm), bacterial abundance, production, community composition, and its predicted metabolic functions. The mesocosms received carbon (C) and nitrogen (N) amendments individually and in combination (NC) to distinguish between heterotrophic and autotrophic processes. Alkaline phosphatase activity occurred mainly in the dissolved form and likely contributed to the excess phosphate conditions together with grazing. At the beginning of the experiment, peptidolytic and glycolytic enzymes were mostly produced by free-living bacteria. However, by the end of the experiment, the NC-treatment induced a shift in peptidolytic and glycolytic activities and degradation of phosphomonoesters toward the particle-associated fraction, likely as a consequence of higher substrate availability. This would potentially promote retention of nutrients in the surface as opposed to sedimentation, but direct sedimentation measurements are needed to verify this hypothesis.
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Affiliation(s)
- Mari Vanharanta
- Tvärminne Zoological Station, University of Helsinki, J. A. Palménin tie 260, 10900 Hanko, Finland
- Marine and Freshwater Solutions, Finnish Environment Institute, Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Mariano Santoro
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde - IOW, Seestrasse 15, 18119 Rostock, Germany
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Cristian Villena-Alemany
- Laboratory of Anoxygenic Phototrophs, Institute of Microbiology, Czech Academy of Sciences, Novohradská 237 - Opatovický mlýn, 379 01 Třeboň, Czech Republic
| | - Jonna Piiparinen
- Marine and Freshwater Solutions, Finnish Environment Institute, Latokartanonkaari 11, 00790 Helsinki, Finland
| | - Kasia Piwosz
- Department of Fisheries Oceanography and Marine Ecology, National Marine Fisheries Research Institute, ul. Kołłątaja 1, 81-332 Gdynia, Poland
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute for Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, OT Neuglobsow, 16775 Stechlin, Germany
- Institute of Biology and Biochemistry, Potsdam University, Maulbeerallee 2, 14469 Potsdam, Germany
| | - Matthias Labrenz
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde - IOW, Seestrasse 15, 18119 Rostock, Germany
| | - Kristian Spilling
- Marine and Freshwater Solutions, Finnish Environment Institute, Latokartanonkaari 11, 00790 Helsinki, Finland
- Centre for Coastal Research, University of Agder, Universitetsveien 25, 4604 Kristiansand, Norway
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Dang YR, Cha QQ, Liu SS, Wang SY, Li PY, Li CY, Wang P, Chen XL, Tian JW, Xin Y, Chen Y, Zhang YZ, Qin QL. Phytoplankton-derived polysaccharides and microbial peptidoglycans are key nutrients for deep-sea microbes in the Mariana Trench. MICROBIOME 2024; 12:77. [PMID: 38664737 PMCID: PMC11044484 DOI: 10.1186/s40168-024-01789-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/04/2024] [Indexed: 04/28/2024]
Abstract
BACKGROUND The deep sea represents the largest marine ecosystem, driving global-scale biogeochemical cycles. Microorganisms are the most abundant biological entities and play a vital role in the cycling of organic matter in such ecosystems. The primary food source for abyssal biota is the sedimentation of particulate organic polymers. However, our knowledge of the specific biopolymers available to deep-sea microbes remains largely incomplete. One crucial rate-limiting step in organic matter cycling is the depolymerization of particulate organic polymers facilitated by extracellular enzymes (EEs). Therefore, the investigation of active EEs and the microbes responsible for their production is a top priority to better understand the key nutrient sources for deep-sea microbes. RESULTS In this study, we conducted analyses of extracellular enzymatic activities (EEAs), metagenomics, and metatranscriptomics from seawater samples of 50-9305 m from the Mariana Trench. While a diverse array of microbial groups was identified throughout the water column, only a few exhibited high levels of transcriptional activities. Notably, microbial populations actively transcribing EE genes involved in biopolymer processing in the abyssopelagic (4700 m) and hadopelagic zones (9305 m) were primarily associated with the class Actinobacteria. These microbes actively transcribed genes coding for enzymes such as cutinase, laccase, and xyloglucanase which are capable of degrading phytoplankton polysaccharides as well as GH23 peptidoglycan lyases and M23 peptidases which have the capacity to break down peptidoglycan. Consequently, corresponding enzyme activities including glycosidases, esterase, and peptidases can be detected in the deep ocean. Furthermore, cell-specific EEAs increased at 9305 m compared to 4700 m, indicating extracellular enzymes play a more significant role in nutrient cycling in the deeper regions of the Mariana Trench. CONCLUSIONS Transcriptomic analyses have shed light on the predominant microbial population actively participating in organic matter cycling in the deep-sea environment of the Mariana Trench. The categories of active EEs suggest that the complex phytoplankton polysaccharides (e.g., cutin, lignin, and hemicellulose) and microbial peptidoglycans serve as the primary nutrient sources available to deep-sea microbes. The high cell-specific EEA observed in the hadal zone underscores the robust polymer-degrading capacities of hadal microbes even in the face of the challenging conditions they encounter in this extreme environment. These findings provide valuable new insights into the sources of nutrition, the key microbes, and the EEs crucial for biopolymer degradation in the deep seawater of the Mariana Trench. Video Abstract.
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Affiliation(s)
- Yan-Ru Dang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Qian-Qian Cha
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Sha-Sha Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Shu-Yan Wang
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Ping-Yi Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology, Qingdao, China
| | - Chun-Yang Li
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology, Qingdao, China
| | - Peng Wang
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology, Qingdao, China
| | - Ji-Wei Tian
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yu Xin
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yin Chen
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
| | - Yu-Zhong Zhang
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology, Qingdao, China.
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
| | - Qi-Long Qin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology, Qingdao, China.
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Salazar-Alekseyeva K, Herndl GJ, Baltar F. Release of cell-free enzymes by marine pelagic fungal strains. FRONTIERS IN FUNGAL BIOLOGY 2023; 4:1209265. [PMID: 38025900 PMCID: PMC10658710 DOI: 10.3389/ffunb.2023.1209265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/22/2023] [Indexed: 12/01/2023]
Abstract
Fungi are ubiquitous organisms that secrete different enzymes to cleave large molecules into smaller ones so that can then be assimilated. Recent studies suggest that fungi are also present in the oceanic water column harboring the enzymatic repertoire necessary to cleave carbohydrates and proteins. In marine prokaryotes, the cell-free fraction is an important contributor to the oceanic extracellular enzymatic activities (EEAs), but the release of cell-free enzymes by marine fungi remains unknown. Here, to study the cell-free enzymatic activities of marine fungi and the potential influence of salinity on them, five strains of marine fungi that belong to the most abundant pelagic phyla (Ascomycota and Basidiomycota), were grown under non-saline and saline conditions (0 g/L and 35 g/L, respectively). The biomass was separated from the medium by filtration (0.2 μm), and the filtrate was used to perform fluorogenic enzymatic assays with substrate analogues of carbohydrates, lipids, organic phosphorus, sulfur moieties, and proteins. Kinetic parameters such as maximum velocity (Vmax) and half-saturation constant (Km) were obtained. The species studied were able to release cell-free enzymes, and this represented up to 85.1% of the respective total EEA. However, this differed between species and enzymes, with some of the highest contributions being found in those with low total EEA, with some exceptions. This suggests that some of these contributions to the enzymatic pool might be minimal compared to those with higher total EEA. Generally, in the saline medium, the release of cell-free enzymes degrading carbohydrates was reduced compared to the non-saline medium, but those degrading lipids and sulfur moieties were increased. For the remaining substrates, there was not a clear influence of the salinity. Taken together, our results suggest that marine fungi are potential contributors to the oceanic dissolved (i.e., cell-free) enzymatic pool. Our results also suggest that, under salinity changes, a potential effect of global warming, the hydrolysis of organic matter by marine fungal cell-free enzymes might be affected and hence, their potential contribution to the oceanic biogeochemical cycles.
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Affiliation(s)
- Katherine Salazar-Alekseyeva
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
- Department of Agrotechnology and Food Sciences, Bioprocess Engineering Group, Wageningen University and Research, Wageningen, Netherlands
| | - Gerhard J. Herndl
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), University of Utrecht, Texel, Netherlands
| | - Federico Baltar
- Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Vienna, Austria
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Schmidt JM, Royalty TM, Lloyd KG, Steen AD. Potential Activities and Long Lifetimes of Organic Carbon-Degrading Extracellular Enzymes in Deep Subsurface Sediments of the Baltic Sea. Front Microbiol 2021; 12:702015. [PMID: 34603228 PMCID: PMC8485070 DOI: 10.3389/fmicb.2021.702015] [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: 04/28/2021] [Accepted: 08/12/2021] [Indexed: 11/17/2022] Open
Abstract
Heterotrophic microorganisms in marine sediments produce extracellular enzymes to hydrolyze organic macromolecules, so their products can be transported inside the cell and used for energy and growth. Therefore, extracellular enzymes may mediate the fate of organic carbon in sediments. The Baltic Sea Basin is a primarily depositional environment with high potential for organic matter preservation. The potential activities of multiple organic carbon-degrading enzymes were measured in samples obtained by the International Ocean Discovery Program Expedition 347 from the Little Belt Strait, Denmark, core M0059C. Potential maximum hydrolysis rates (Vmax) were measured at depths down to 77.9mbsf for the following enzymes: alkaline phosphatase, β-d-xylosidase, β-d-cellobiohydrolase, N-acetyl-β-d-glucosaminidase, β-glucosidase, α-glucosidase, leucyl aminopeptidase, arginyl aminopeptidase, prolyl aminopeptidase, gingipain, and clostripain. Extracellular peptidase activities were detectable at depths shallower than 54.95mbsf, and alkaline phosphatase activity was detectable throughout the core, albeit against a relatively high activity in autoclaved sediments. β-glucosidase activities were detected above 30mbsf; however, activities of other glycosyl hydrolases (β-xylosidase, β-cellobiohydrolase, N-acetyl-β-glucosaminidase, and α-glucosidase) were generally indistinguishable from zero at all depths. These extracellular enzymes appear to be extremely stable: Among all enzymes, a median of 51.3% of enzyme activity was retained after autoclaving for an hour. We show that enzyme turnover times scale with the inverse of community metabolic rates, such that enzyme lifetimes in subsurface sediments, in which metabolic rates are very slow, are likely to be extraordinarily long. A back-of-the-envelope calculation suggests enzyme lifetimes are, at minimum, on the order of 230days, and may be substantially longer. These results lend empirical support to the hypothesis that a population of subsurface microbes persist by using extracellular enzymes to slowly metabolize old, highly degraded organic carbon.
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Affiliation(s)
- Jenna M Schmidt
- Department of Earth and Planetary Sciences, College of Arts and Sciences, The University of Tennessee, Knoxville, TN, United States
| | - Taylor M Royalty
- Department of Microbiology, University of Tennessee - Knoxville, Knoxville, TN, United States
| | - Karen G Lloyd
- Department of Microbiology, University of Tennessee - Knoxville, Knoxville, TN, United States
| | - Andrew D Steen
- Department of Microbiology, University of Tennessee - Knoxville, Knoxville, TN, United States.,Department of Earth and Planetary Sciences, College of Arts and Sciences, The University of Tennessee, Knoxville, TN, United States
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Li Y, Sun LL, Sun YY, Cha QQ, Li CY, Zhao DL, Song XY, Wang M, McMinn A, Chen XL, Zhang YZ, Qin QL. Extracellular Enzyme Activity and Its Implications for Organic Matter Cycling in Northern Chinese Marginal Seas. Front Microbiol 2019; 10:2137. [PMID: 31608022 PMCID: PMC6755343 DOI: 10.3389/fmicb.2019.02137] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/30/2019] [Indexed: 01/23/2023] Open
Abstract
Extracellular enzymes, initiating the degradation of organic macromolecules, are important functional components of marine ecosystems. Measuring in situ seawater extracellular enzyme activity (EEA) can provide fundamental information for understanding the biogeochemical cycling of organic matter in the ocean. Here we investigate the patterns of EEA and the major factors affecting the seawater EEA of Chinese marginal seas. The geographic distribution of EEA along a latitudinal transect was examined and found to be associated with dissolved organic carbon. Compared with offshore waters, inshore waters had higher enzyme activity. All the tested substrates were hydrolyzed at different rates and phosphatase, β-glucosidase and protease contributed greatly to summed hydrolysis rates. For any particular enzyme activity, the contribution of dissolved to total EEA was strongly heterogenous between stations. Comparisons of hydrolysis rates of the polymers and their corresponding oligomers suggest that molecule size does not necessarily limit the turnover of marine organic matter. In addition, several typical enzyme-producing clades, such as Bacteroidetes, Planctomycetes, Chloroflexi, Roseobacter, Alteromonas, and Pseudoalteromonas, were detected in the in situ environments. These enzyme-producing clades may be responsible for the production of different enzymes. Overall, each enzyme was found to flexibly respond to environmental conditions and were linked to microbial community composition. It is likely that this activity will profoundly affect organic matter cycling in the Chinese marginal seas.
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Affiliation(s)
- Yi Li
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Lin-Lin Sun
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Yuan-Yuan Sun
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Qian-Qian Cha
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Chun-Yang Li
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Dian-Li Zhao
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiao-Yan Song
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Min Wang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Andrew McMinn
- College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China.,College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Qi-Long Qin
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
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