Abstract
Abstract. 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 CO2 partial pressure,
pCO2) 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 pCO2 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.
Subject
Earth-Surface Processes,Ecology, Evolution, Behavior and Systematics
Reference102 articles.
1. Admiraal, W.: The ecology of estuarine sediment-inhabiting diatoms, in:
Progress in phycological Research, edited by: Round, F. E., and Chapman, D.
J., Biopress, Bristol, 269–322, 1984.
2. Allen, A., Gillooly, J., and Brown, J.: Linking the global carbon cycle to
individual metabolism, Funct. Ecol., 19, 202–213, https://doi.org/10.1111/j.1365-2435.2005.00952.x, 2005.
3. Allen, H. L.: Low molecular weight dissolved organic matter in five
soft-water ecosystems: a preliminary study and ecological implications: With
3 figures and 2 tables in the text and on 1 folder, Internationale
Vereinigung für theoretische und angewandte Limnologie: Verhandlungen,
20, 514–524, 1978.
4. Apple, J., Smith, E., and Boyd, T.: Temperature, Salinity, Nutrients, and
the Covariation of Bacterial Production and Chlorophyll-a in Estuarine
Ecosystems, J. Coast. Res., 2008, 59–75, https://doi.org/10.2112/SI55-005.1, 2008.
5. Apple, J. K., del Giorgio, P. A., and Kemp, W. M.: Temperature regulation of
bacterial production, respiration, and growth efficiency in a temperate
salt-marsh estuary, Aquat. Microb. Ecol., 43, 243–254, https://doi.org/10.3354/ame043243, 2006.
Cited by
3 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献