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Photosynthetic oxygen production in a warmer ocean: the Sargasso Sea as a case study.
- Source :
- Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences; 9/13/2017, Vol. 375 Issue 2102, p1-22, 22p
- Publication Year :
- 2017
-
Abstract
- Photosynthetic O<subscript>2</subscript> production can be an important source of oxygen in sub-surface ocean waters especially in permanently stratified oligotrophic regions of the ocean where O<subscript>2</subscript> produced in deep chlorophyll maxima (DCM) is not likely to be outgassed. Today, permanently stratified regions extend across approximately 40% of the global ocean and their extent is expected to increase in a warmer ocean. Thus, predicting future ocean oxygen conditions requires a better understanding of the potential response of photosynthetic oxygen production to a warmer ocean. Based on our own and published observations of water column processes in oligotrophic regions, we develop a one-dimensional water column model describing photosynthetic oxygen production in the Sargasso Sea to quantify the importance of photosynthesis for the downward flux of O<subscript>2</subscript> and examine how it may be influenced in a warmer ocean. Photosynthesis is driven in the model by vertical mixing of nutrients (including eddy-induced mixing) and diazotrophy and is found to substantially increase the downward O<subscript>2</subscript> flux relative to physical-chemical processes alone. Warming (2°C) surface waters does not significantly change oxygen production at the DCM. Nor does a 15% increase in re-mineralization rate (assuming Q10 =2; 2°C warming) have significant effect on net sub-surface oxygen accumulation. However, changes in the relative production of particulate (POM) and dissolved organic material (DOM) generate relatively large changes in net sub-surface oxygen production. As POM/DOM production is a function of plankton community composition, this implies plankton biodiversity and food web structure may be important factors influencing O<subscript>2</subscript> production in a warmer ocean. [ABSTRACT FROM AUTHOR]
- Subjects :
- PHOTOSYNTHESIS
SEAWATER
CLIMATE change
Subjects
Details
- Language :
- English
- ISSN :
- 1364503X
- Volume :
- 375
- Issue :
- 2102
- Database :
- Complementary Index
- Journal :
- Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences
- Publication Type :
- Academic Journal
- Accession number :
- 125933535
- Full Text :
- https://doi.org/10.1098/rsta.2016.0329