Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean
Biogeochemical cycling of carbon (C) and nitrogen (N) in the ocean depends on both the composition and activity of underlying biological communities and on abiotic factors. The Southern Ocean is encircled by a series of strong currents and fronts, providing a barrier to microbial dispersion into adj...
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ftdoajarticles:oai:doaj.org/article:8445dd0241c34e67ac464aeba87207d2 2023-05-15T18:24:42+02:00 Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean C. Hörstmann E. J. Raes P. L. Buttigieg C. Lo Monaco U. John A. M. Waite 2021-06-01T00:00:00Z https://doi.org/10.5194/bg-18-3733-2021 https://doaj.org/article/8445dd0241c34e67ac464aeba87207d2 EN eng Copernicus Publications https://bg.copernicus.org/articles/18/3733/2021/bg-18-3733-2021.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-18-3733-2021 1726-4170 1726-4189 https://doaj.org/article/8445dd0241c34e67ac464aeba87207d2 Biogeosciences, Vol 18, Pp 3733-3749 (2021) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/bg-18-3733-2021 2022-12-31T07:30:25Z Biogeochemical cycling of carbon (C) and nitrogen (N) in the ocean depends on both the composition and activity of underlying biological communities and on abiotic factors. The Southern Ocean is encircled by a series of strong currents and fronts, providing a barrier to microbial dispersion into adjacent oligotrophic gyres. Our study region straddles the boundary between the nutrient-rich Southern Ocean and the adjacent oligotrophic gyre of the southern Indian Ocean, providing an ideal region to study changes in microbial productivity. Here, we measured the impact of C and N uptake on microbial community diversity, contextualized by hydrographic factors and local physico-chemical conditions across the Southern Ocean and southern Indian Ocean. We observed that contrasting physico-chemical characteristics led to unique microbial diversity patterns, with significant correlations between microbial alpha diversity and primary productivity (PP). However, we detected no link between specific PP (PP normalized by chlorophyll- a concentration) and microbial alpha and beta diversity. Prokaryotic alpha and beta diversity were correlated with biological N 2 fixation, which is itself a prokaryotic process, and we detected measurable N 2 fixation to 60 ∘ S. While regional water masses have distinct microbial genetic fingerprints in both the eukaryotic and prokaryotic fractions, PP and N 2 fixation vary more gradually and regionally. This suggests that microbial phylogenetic diversity is more strongly bounded by physical oceanographic features, while microbial activity responds more to chemical factors. We conclude that concomitant assessments of microbial diversity and activity are central to understanding the dynamics and complex responses of microorganisms to a changing ocean environment. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Indian Southern Ocean Biogeosciences 18 12 3733 3749 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 C. Hörstmann E. J. Raes P. L. Buttigieg C. Lo Monaco U. John A. M. Waite Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Biogeochemical cycling of carbon (C) and nitrogen (N) in the ocean depends on both the composition and activity of underlying biological communities and on abiotic factors. The Southern Ocean is encircled by a series of strong currents and fronts, providing a barrier to microbial dispersion into adjacent oligotrophic gyres. Our study region straddles the boundary between the nutrient-rich Southern Ocean and the adjacent oligotrophic gyre of the southern Indian Ocean, providing an ideal region to study changes in microbial productivity. Here, we measured the impact of C and N uptake on microbial community diversity, contextualized by hydrographic factors and local physico-chemical conditions across the Southern Ocean and southern Indian Ocean. We observed that contrasting physico-chemical characteristics led to unique microbial diversity patterns, with significant correlations between microbial alpha diversity and primary productivity (PP). However, we detected no link between specific PP (PP normalized by chlorophyll- a concentration) and microbial alpha and beta diversity. Prokaryotic alpha and beta diversity were correlated with biological N 2 fixation, which is itself a prokaryotic process, and we detected measurable N 2 fixation to 60 ∘ S. While regional water masses have distinct microbial genetic fingerprints in both the eukaryotic and prokaryotic fractions, PP and N 2 fixation vary more gradually and regionally. This suggests that microbial phylogenetic diversity is more strongly bounded by physical oceanographic features, while microbial activity responds more to chemical factors. We conclude that concomitant assessments of microbial diversity and activity are central to understanding the dynamics and complex responses of microorganisms to a changing ocean environment. |
format |
Article in Journal/Newspaper |
author |
C. Hörstmann E. J. Raes P. L. Buttigieg C. Lo Monaco U. John A. M. Waite |
author_facet |
C. Hörstmann E. J. Raes P. L. Buttigieg C. Lo Monaco U. John A. M. Waite |
author_sort |
C. Hörstmann |
title |
Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean |
title_short |
Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean |
title_full |
Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean |
title_fullStr |
Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean |
title_full_unstemmed |
Hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern Indian Ocean and the Southern Ocean |
title_sort |
hydrographic fronts shape productivity, nitrogen fixation, and microbial community composition in the southern indian ocean and the southern ocean |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/bg-18-3733-2021 https://doaj.org/article/8445dd0241c34e67ac464aeba87207d2 |
geographic |
Indian Southern Ocean |
geographic_facet |
Indian Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences, Vol 18, Pp 3733-3749 (2021) |
op_relation |
https://bg.copernicus.org/articles/18/3733/2021/bg-18-3733-2021.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-18-3733-2021 1726-4170 1726-4189 https://doaj.org/article/8445dd0241c34e67ac464aeba87207d2 |
op_doi |
https://doi.org/10.5194/bg-18-3733-2021 |
container_title |
Biogeosciences |
container_volume |
18 |
container_issue |
12 |
container_start_page |
3733 |
op_container_end_page |
3749 |
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1766205513171730432 |