Oceanic oxygen in a warming climate: mechanisms, patterns, and timescales
Abstract
The oxygenation of the ocean reflects a balance of physical O2 supply and biological O2 demand, both of which are strongly influenced by climate. The processes governing changes in O2 supply and demand are spatially heterogeneous and involve multiple time scales, leading to complex pattern of O2 variability. We present an analysis of model simulations, historical observations, and the recent sedimentary record that reveal fundamental differences between the O2 response of the tropics and high latitudes to rising greenhouse gases. Whereas the reduction in O2 solubility and a slowing of ocean circulation act in concert to deoxygenate the mid- and high-latitudes, these processes tend to counteract one another in the tropics. Emerging evidence from the sedimentary record and model reconstructions in the Pacific Ocean indicates that oxygen demand is the dominant control on oxygenation in the eastern tropical anoxic zones on decadal to centennial time scales. This reduction is closely linked to the strength of the tropical trade winds and upwelling, providing a mechanism for transient contraction of anoxia during climate warming.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2014
- Bibcode:
- 2014AGUFMPP11D..01D
- Keywords:
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- 0459 Macro- and micropaleontology;
- BIOGEOSCIENCES;
- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES;
- 1050 Marine geochemistry;
- GEOCHEMISTRY;
- 9610 Cretaceous;
- INFORMATION RELATED TO GEOLOGIC TIME