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Li J, Xie N, Liu X, Bai M, Hunt DE, Wang G. Oxygen levels differentially attenuate the structure and diversity of microbial communities in the oceanic oxygen minimal zones. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:174934. [PMID: 39047843 DOI: 10.1016/j.scitotenv.2024.174934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/18/2024] [Accepted: 07/19/2024] [Indexed: 07/27/2024]
Abstract
Global change mediated shifts in ocean temperature and circulation patterns, compounded by human activities, are leading to the expansion of marine oxygen minimum zones (OMZs) with concomitant alterations in nutrient and climate-active trace gas cycling. While many studies have reported distinct bacterial communities within OMZs, much of this research compares across depths rather with oxygen status and does not include eukayrotic microbes. Here, we investigated the Bay of Bengal (BoB) OMZ, where low oxygen conditions are persistent, but trace levels of oxygen remain (< 20 μM from 200 to 500 m). As other environmental variables are similar between OMZ and non-OMZ (NOZ) stations, we compared the abundance, diversity, and community composition of several microbial groups (bacterioplankton, Labyrinthulomycetes, and fungi) across oxygen levels. While prokaryote abundance decreased with depth, no significant differences existed across oxygen groups. In contrast, Labyrinthulomycetes abundance was significantly higher in non-OMZ stations but did not change significantly with depth, while fungal abundance was patchy without clear depth or oxygen-related trends. Bacterial and fungal diversity was lower in OMZ stations at 500 m, while Labyrinthulomycetes diversity only showed a depth-related profile, decreasing below the euphotic zone. Surprisingly, previously reported OMZ-associated bacterial taxa were not significantly more abundant at OMZ stations. Furthermore, compared to the bacterioplankton, fewer Labyrinthulomycetes and fungi taxa showed responses to oxygen status. Thus, this research identifies stronger oxygen-level linkages within the bacterioplankton than in the examined microeukaryotes.
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Affiliation(s)
- Jiaqian Li
- School of Environmental Science & Engineering, Center for Marine Environmental Ecology, Tianjin University, China; Duke University Marine Lab, Beaufort, NC, USA
| | - Ningdong Xie
- School of Environmental Science & Engineering, Center for Marine Environmental Ecology, Tianjin University, China
| | - Xiuping Liu
- School of Environmental Science & Engineering, Center for Marine Environmental Ecology, Tianjin University, China
| | - Mohan Bai
- School of Environmental Science & Engineering, Center for Marine Environmental Ecology, Tianjin University, China
| | - Dana E Hunt
- Duke University Marine Lab, Beaufort, NC, USA.
| | - Guangyi Wang
- School of Environmental Science & Engineering, Center for Marine Environmental Ecology, Tianjin University, China.
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Perkins AK, Rose AL, Grossart HP, Schulz KG, Neubauer D, Tonge MP, Rosentreter JA, Eyre BD, Rojas-Jimenez K, Deschaseaux E, Oakes JM. Fungi increases kelp (Ecklonia radiata) remineralisation and dissolved organic carbon, alkalinity, and dimethylsulfoniopropionate (DMSP) production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166957. [PMID: 37704140 DOI: 10.1016/j.scitotenv.2023.166957] [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: 06/15/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023]
Abstract
Fungi are key players in terrestrial organic matter (OM) degradation, but little is known about their role in marine environments. Here we compared the degradation of kelp (Ecklonia radiata) in mesocosms with and without fungicides over 45 days. The aim was to improve our understanding of the vital role of fungal OM degradation and remineralisation and its relevance to marine biogeochemical cycles (e.g., carbon, nitrogen, sulfur, or volatile sulfur). In the presence of fungi, 68 % of the kelp detritus degraded over 45 days, resulting in the production of 0.6 mol of dissolved organic carbon (DOC), 0.16 mol of dissolved inorganic carbon (DIC), 0.23 mol of total alkalinity (TA), and 0.076 mol of CO2, which was subsequently emitted to the atmosphere. Conversely, when fungi were inhibited, the bacterial community diversity was reduced, and only 25 % of the kelp detritus degraded over 45 days. The application of fungicides resulted in the generation of an excess amount of 1.5 mol of DOC, but we observed only 0.02 mol of DIC, and 0.04 mol of TA per one mole of kelp detritus, accompanied by a CO2 emission of 0.081 mol. In contrast, without fungi, remineralisation of kelp detritus to DIC, TA, dimethyl sulfide (DMS), dimethylsulfoniopropionate (DMSP) and methanethiol (MeSH) was significantly reduced. Fungal kelp remineralisation led to a remarkable 100,000 % increase in DMSP production. The observed substantial changes in sediment chemistry when fungi are inhibited highlight the important biogeochemical role of fungal remineralisation, which likely plays a crucial role in defining coastal biogeochemical cycling, blue carbon sequestration, and thus climate regulation.
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Affiliation(s)
- Anita K Perkins
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia; Southern Cross Geoscience, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia.
| | - Andrew L Rose
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia; Southern Cross Geoscience, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Hans-Peter Grossart
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Experimental Limnology, 16775 Neuglobsow, Germany; University of Potsdam, Institute of Biochemistry and Biology, Maulbeerallee 2, 14469 Potsdam, Germany
| | - Kai G Schulz
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Darshan Neubauer
- Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Experimental Limnology, 16775 Neuglobsow, Germany; University of Potsdam, Institute of Biochemistry and Biology, Maulbeerallee 2, 14469 Potsdam, Germany
| | - Matthew P Tonge
- Southern Cross Geoscience, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Judith A Rosentreter
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Bradley D Eyre
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | | | - Elisabeth Deschaseaux
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
| | - Joanne M Oakes
- Centre for Coastal Biogeochemistry, Faculty of Science and Engineering, Southern Cross University, Lismore, 2480, NSW, Australia
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Lane DM, Valentine DL, Peng X. Genomic analysis of the marine yeast Rhodotorula sphaerocarpa ETNP2018 reveals adaptation to the open ocean. BMC Genomics 2023; 24:695. [PMID: 37986036 PMCID: PMC10662464 DOI: 10.1186/s12864-023-09791-7] [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: 06/29/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023] Open
Abstract
BACKGROUND Despite a rising interest in the diversity and ecology of fungi in marine environments, there are few published genomes of fungi isolated from the ocean. The basidiomycetous yeast (unicellular fungus) genus Rhodotorula are prevalent and abundant in the open ocean, and they have been isolated from a wide range of other environments. Many of these environments are nutrient poor, such as the Antarctica and the Atacama deserts, raising the question as to how Rhodotorula yeasts may have adapted their metabolic strategies to optimize survival under low nutrient conditions. In order to understand their adaptive strategies in the ocean, the genome of R. sphaerocarpa ETNP2018 was compared to that of fourteen representative Rhodotorula yeasts, isolated from a variety of environments. RESULTS Rhodotorula sphaerocarpa ETNP2018, a strain isolated from the oligotrophic part of the eastern tropical North Pacific (ETNP) oxygen minimum zone (OMZ), hosts the smallest of the fifteen genomes and yet the number of protein-coding genes it possesses is on par with the other strains. Its genome exhibits a distinct reduction in genes dedicated to Major Facilitator Superfamily transporters as well as biosynthetic enzymes. However, its core metabolic pathways are fully conserved. Our research indicates that the selective pressures of the ETNP OMZ favor a streamlined genome with reduced overall biosynthetic potential balanced by a stable set of core metabolisms and an expansion of mechanisms for nutrient acquisition. CONCLUSIONS In summary, this study offers insights into the adaptation of fungi to the oligotrophic ocean and provides valuable information for understanding the ecological roles of fungi in the ocean.
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Affiliation(s)
- Dylan M Lane
- School of Earth, Ocean, and Environment, University of South Carolina, Columbia, SC, USA
| | - David L Valentine
- Marine Science Institute, University of California, Santa Barbara, CA, USA
- Department of Earth Science, University of California, Santa Barbara, CA, USA
| | - Xuefeng Peng
- School of Earth, Ocean, and Environment, University of South Carolina, Columbia, SC, USA.
- Marine Science Institute, University of California, Santa Barbara, CA, USA.
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Breyer E, Baltar F. The largely neglected ecological role of oceanic pelagic fungi. Trends Ecol Evol 2023; 38:870-888. [PMID: 37246083 DOI: 10.1016/j.tree.2023.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/25/2023] [Accepted: 05/02/2023] [Indexed: 05/30/2023]
Abstract
Most investigations into ocean ecology and biogeochemistry have tended to focus on marine bacteria, archaea, and protists, while pelagic fungi (mycoplankton) have traditionally been neglected and considered to reside only in association with benthic solid substrates. Nevertheless, recent studies have revealed that pelagic fungi are distributed ubiquitously throughout the water column in every ocean basin and play an active role in the degradation of organic matter and the cycling of nutrients. We review the current status of knowledge on the ecology of mycoplankton and highlight knowledge gaps and challenges. These findings underscore the need to recognize this neglected kingdom as significant contributors to the organic matter cycling and ecology of the oceans.
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Affiliation(s)
- Eva Breyer
- Fungal and Biogeochemical Oceanography Group, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
| | - Federico Baltar
- Fungal and Biogeochemical Oceanography Group, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria.
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Fuchsman CA, Cherubini L, Hays MD. An analysis of protists in Pacific oxygen deficient zones: implications for Prochlorococcus and N 2 -producing bacteria. Environ Microbiol 2022; 24:1790-1804. [PMID: 34995411 DOI: 10.1111/1462-2920.15893] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 12/27/2021] [Accepted: 12/29/2021] [Indexed: 11/26/2022]
Abstract
Ocean oxygen deficient zones (ODZs) host 30%-50% of marine N2 production. Cyanobacteria photosynthesizing in the ODZ create a secondary chlorophyll maximum and provide organic matter to N2 -producing bacteria. This chlorophyll maximum is thought to occur due to reduced grazing in anoxic waters. We first examine ODZ protists with long amplicon reads. We then use non-primer-based methods to examine the composition and relative abundance of protists in metagenomes from the Eastern Tropical North and South Pacific ODZs and compare these data to the oxic Hawaii Ocean Time-series (HOT) in the North Pacific. We identify and quantify protists in proportion to the total microbial community. From metagenomic data, we see a large drop in abundance of fungi and protists such as choanoflagellates, radiolarians, cercozoa and ciliates in the ODZs but not in the oxic mesopelagic at HOT. Diplonemid euglenozoa were the only protists that increased in the ODZ. Dinoflagellates and foraminifera reads were also present in the ODZ though less abundant compared to oxic waters. Denitrification has been found in foraminifera but not yet in dinoflagellates. DNA techniques cannot separate dinoflagellate cells and cysts. Metagenomic analysis found taxonomic groups missed by amplicon sequencing and identified trends in abundance.
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Affiliation(s)
- Clara A Fuchsman
- University of Maryland Center for Environmental Science Horn Point Laboratory, Cambridge, MD, 21613, USA
| | - Luca Cherubini
- Maryland Sea Grant College, College Park, MD, 20740, USA
| | - Matthew D Hays
- University of Maryland Center for Environmental Science Horn Point Laboratory, Cambridge, MD, 21613, USA
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Peng X, Gat D, Paytan A, Rudich Y. The Response of Airborne Mycobiome to Dust Storms in the Eastern Mediterranean. J Fungi (Basel) 2021; 7:802. [PMID: 34682226 PMCID: PMC8540267 DOI: 10.3390/jof7100802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/11/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022] Open
Abstract
Airborne microbial communities directly impact the health of humans, animals, plants, and receiving ecosystems. While airborne bacterial and fungal communities have been studied by both cultivation-based methods and metabarcoding surveys targeting specific molecular markers, fewer studies have used shotgun metagenomics to study the airborne mycobiome. We analyzed the diversity and relative abundance of fungi in nine airborne metagenomes collected on clear days ("background") and during dust storms in the Eastern Mediterranean. The negative correlation between the relative abundance of fungal reads and the concentrations of atmospheric particulate matter having an aerodynamic diameter smaller than 10 μm (PM10) indicate that dust storms lower the proportion of fungi in the airborne microbiome, possibly due to the lower relative abundance of fungi in the dust storm source regions and/or more effective transport of bacteria by the dust. Airborne fungal community composition was altered by the dust storms, particularly those originated from Syria, which was enriched with xerophilic fungi. We reconstructed a high-quality fungal metagenome-assembled genome (MAG) from the order Cladosporiales, which include fungi known to adapt to environmental extremes commonly faced by airborne microbes. The negative correlation between the relative abundance of Cladosporiales MAG and PM10 concentrations indicate that its origin is dominated by local sources and likely includes the indoor environments found in the city.
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Affiliation(s)
- Xuefeng Peng
- School of Earth, Ocean and Environment, University of South Carolina, Columbia, SC 29208, USA
| | - Daniela Gat
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel;
- Joint Mass Spectrometry Centre (JMSC) of Comprehensive Molecular Analytics (CMA), Helmholtz Zentrum München–German Research Center for Environmental Health GmbH, 81379 Munich, Germany
| | - Adina Paytan
- Institute of Marine Science, University of California, Santa Cruz, CA 95064, USA;
| | - Yinon Rudich
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel;
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