Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean

Dark carbon fixation (DCF) is a source of new and labile carbon in the deep ocean, while heterotrophic microbial production (HMP) promotes organic matter transfer through the microbial loop. Despite their ecological relevance, there is a scientific gap regarding the estimates of DCF and HMP in the...

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Main Authors: Julia Gasparini Passos, Luiza Ferreira Soares, Paulo Yukio Gomes Sumida, Amanda Gonçalves Bendia, Fernanda Mancini Nakamura, Vivian Helena Pellizari, Camila Negrão Signori
Format: Article
Language:English
Published: Instituto Oceanográfico da Universidade de São Paulo 2023-03-01
Series:Ocean and Coastal Research
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Online Access:https://www.journals.usp.br/ocr/article/view/210009
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author Julia Gasparini Passos
Luiza Ferreira Soares
Paulo Yukio Gomes Sumida
Amanda Gonçalves Bendia
Fernanda Mancini Nakamura
Vivian Helena Pellizari
Camila Negrão Signori
author_facet Julia Gasparini Passos
Luiza Ferreira Soares
Paulo Yukio Gomes Sumida
Amanda Gonçalves Bendia
Fernanda Mancini Nakamura
Vivian Helena Pellizari
Camila Negrão Signori
author_sort Julia Gasparini Passos
collection DOAJ
description Dark carbon fixation (DCF) is a source of new and labile carbon in the deep ocean, while heterotrophic microbial production (HMP) promotes organic matter transfer through the microbial loop. Despite their ecological relevance, there is a scientific gap regarding the estimates of DCF and HMP in the Southwestern Atlantic Ocean. Thus, the aim of this study was to investigate the spatial distribution of DCF and HMP; their relevance to the ocean carbon cycle; their relationship with environmental parameters and amongst themselves on the upper slope of Santos Basin. The samples were collected at three different water depths and sediment layers aboard the R/V Alpha Crucis in November 2019. DCF and HMP rates were measured by 14C-bicarbonate and 3H-leucine incorporation, respectively, and incubated in the dark. In the water column, DCF rates varied from 1.51 x 101 to 3.24 x 102 µg C m-3 h-1, which were one to two orders of magnitude lower than the HMP rates, from 1.26 x 102 to 1.48 x 104 µg C m-3 h-1. In the sediments, the DCF ranged from 1.15 x 104 to 1.83 x 105 µg C m-3 h-1, while HMP was one to four orders of magnitude lower, 3.22 x 101 to 1.56 x 103 µ gC m-3 h-1. DCF rates were significantly higher in the sediments, due to a higher availability of energy sources than in the oligotrophic water above. The HMP had higher rates in the water column as it is deeply dependent on organic matter derived from photosynthesis. This is the first study to investigate DCF and HMP considering the water column and sediments of the Southwestern Atlantic Ocean, thus contributing to a better understanding of the microbial role in the marine carbon cycle and ecosystem functioning.
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spelling doaj-art-19500b72dc0f427db800ea0b35ce25be2025-08-20T02:13:26ZengInstituto Oceanográfico da Universidade de São PauloOcean and Coastal Research2675-28242023-03-0170Suppl. 2Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic OceanJulia Gasparini PassosLuiza Ferreira SoaresPaulo Yukio Gomes SumidaAmanda Gonçalves BendiaFernanda Mancini NakamuraVivian Helena PellizariCamila Negrão Signori Dark carbon fixation (DCF) is a source of new and labile carbon in the deep ocean, while heterotrophic microbial production (HMP) promotes organic matter transfer through the microbial loop. Despite their ecological relevance, there is a scientific gap regarding the estimates of DCF and HMP in the Southwestern Atlantic Ocean. Thus, the aim of this study was to investigate the spatial distribution of DCF and HMP; their relevance to the ocean carbon cycle; their relationship with environmental parameters and amongst themselves on the upper slope of Santos Basin. The samples were collected at three different water depths and sediment layers aboard the R/V Alpha Crucis in November 2019. DCF and HMP rates were measured by 14C-bicarbonate and 3H-leucine incorporation, respectively, and incubated in the dark. In the water column, DCF rates varied from 1.51 x 101 to 3.24 x 102 µg C m-3 h-1, which were one to two orders of magnitude lower than the HMP rates, from 1.26 x 102 to 1.48 x 104 µg C m-3 h-1. In the sediments, the DCF ranged from 1.15 x 104 to 1.83 x 105 µg C m-3 h-1, while HMP was one to four orders of magnitude lower, 3.22 x 101 to 1.56 x 103 µ gC m-3 h-1. DCF rates were significantly higher in the sediments, due to a higher availability of energy sources than in the oligotrophic water above. The HMP had higher rates in the water column as it is deeply dependent on organic matter derived from photosynthesis. This is the first study to investigate DCF and HMP considering the water column and sediments of the Southwestern Atlantic Ocean, thus contributing to a better understanding of the microbial role in the marine carbon cycle and ecosystem functioning. https://www.journals.usp.br/ocr/article/view/210009Dark carbon fixationMicrobial loopMarine carbon cyclePelagic and benthic microbial processes
spellingShingle Julia Gasparini Passos
Luiza Ferreira Soares
Paulo Yukio Gomes Sumida
Amanda Gonçalves Bendia
Fernanda Mancini Nakamura
Vivian Helena Pellizari
Camila Negrão Signori
Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean
Ocean and Coastal Research
Dark carbon fixation
Microbial loop
Marine carbon cycle
Pelagic and benthic microbial processes
title Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean
title_full Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean
title_fullStr Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean
title_full_unstemmed Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean
title_short Contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the Southwestern Atlantic Ocean
title_sort contribution of chemoautotrophy and heterotrophy to the microbial carbon cycle in the southwestern atlantic ocean
topic Dark carbon fixation
Microbial loop
Marine carbon cycle
Pelagic and benthic microbial processes
url https://www.journals.usp.br/ocr/article/view/210009
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