Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean
Relative to their surface area, estuaries make a disproportionately large contribution of dissolved organic carbon (DOC) to the global carbon cycle, but it is unknown how this will change under a future climate. As such, the response of DOC fluxes from microbially dominated unvegetated sediments to...
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ftcopernicus:oai:publications.copernicus.org:bg89573 2023-05-15T17:50:32+02:00 Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean Simone, Michelle N. Schulz, Kai G. Oakes, Joanne M. Eyre, Bradley D. 2021-03-16 application/pdf https://doi.org/10.5194/bg-18-1823-2021 https://bg.copernicus.org/articles/18/1823/2021/ eng eng doi:10.5194/bg-18-1823-2021 https://bg.copernicus.org/articles/18/1823/2021/ eISSN: 1726-4189 Text 2021 ftcopernicus https://doi.org/10.5194/bg-18-1823-2021 2021-03-22T17:22:15Z Relative to their surface area, estuaries make a disproportionately large contribution of dissolved organic carbon (DOC) to the global carbon cycle, but it is unknown how this will change under a future climate. As such, the response of DOC fluxes from microbially dominated unvegetated sediments to individual and combined future climate stressors of temperature change (from Δ− 3 to Δ+ 5 ∘ C compared to ambient mean temperatures) and ocean acidification (OA, ∼ 2 × current CO 2 partial pressure, p CO 2 ) was investigated ex situ. Warming alone increased sediment heterotrophy, resulting in a proportional increase in sediment DOC uptake; sediments became net sinks of DOC (3.5 to 8.8 mmol C m −2 d −1 ) at warmer temperatures ( Δ+ 3 and Δ+ 5 ∘ C, respectively). This temperature response changed under OA conditions, with sediments becoming more autotrophic and a greater sink of DOC (up to 4 × greater than under current p CO 2 conditions). This response was attributed to the stimulation of heterotrophic bacteria with the autochthonous production of labile organic matter by microphytobenthos. Extrapolating these results to the global area of unvegetated subtidal estuarine sediments, we find that the future climate of warming ( Δ+ 3 ∘ C) and OA may decrease estuarine export of DOC by ∼ 80 % ( ∼ 150 Tg C yr −1 ) and have a disproportionately large impact on the global DOC budget. Text Ocean acidification Copernicus Publications: E-Journals Biogeosciences 18 5 1823 1838 |
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Copernicus Publications: E-Journals |
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English |
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Relative to their surface area, estuaries make a disproportionately large contribution of dissolved organic carbon (DOC) to the global carbon cycle, but it is unknown how this will change under a future climate. As such, the response of DOC fluxes from microbially dominated unvegetated sediments to individual and combined future climate stressors of temperature change (from Δ− 3 to Δ+ 5 ∘ C compared to ambient mean temperatures) and ocean acidification (OA, ∼ 2 × current CO 2 partial pressure, p CO 2 ) was investigated ex situ. Warming alone increased sediment heterotrophy, resulting in a proportional increase in sediment DOC uptake; sediments became net sinks of DOC (3.5 to 8.8 mmol C m −2 d −1 ) at warmer temperatures ( Δ+ 3 and Δ+ 5 ∘ C, respectively). This temperature response changed under OA conditions, with sediments becoming more autotrophic and a greater sink of DOC (up to 4 × greater than under current p CO 2 conditions). This response was attributed to the stimulation of heterotrophic bacteria with the autochthonous production of labile organic matter by microphytobenthos. Extrapolating these results to the global area of unvegetated subtidal estuarine sediments, we find that the future climate of warming ( Δ+ 3 ∘ C) and OA may decrease estuarine export of DOC by ∼ 80 % ( ∼ 150 Tg C yr −1 ) and have a disproportionately large impact on the global DOC budget. |
format |
Text |
author |
Simone, Michelle N. Schulz, Kai G. Oakes, Joanne M. Eyre, Bradley D. |
spellingShingle |
Simone, Michelle N. Schulz, Kai G. Oakes, Joanne M. Eyre, Bradley D. Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
author_facet |
Simone, Michelle N. Schulz, Kai G. Oakes, Joanne M. Eyre, Bradley D. |
author_sort |
Simone, Michelle N. |
title |
Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
title_short |
Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
title_full |
Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
title_fullStr |
Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
title_full_unstemmed |
Warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
title_sort |
warming and ocean acidification may decrease estuarine dissolved organic carbon export to the ocean |
publishDate |
2021 |
url |
https://doi.org/10.5194/bg-18-1823-2021 https://bg.copernicus.org/articles/18/1823/2021/ |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-18-1823-2021 https://bg.copernicus.org/articles/18/1823/2021/ |
op_doi |
https://doi.org/10.5194/bg-18-1823-2021 |
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Biogeosciences |
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18 |
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5 |
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1823 |
op_container_end_page |
1838 |
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1766157334100312064 |