Year-end Sale % OFF 
Abstract
Abstract. Oxygen-depleted regions of the global ocean are rapidly expanding, with important implications for global biogeochemical cycles. However, our ability to make projections about the future of oxygen in the ocean is limited by a lack of empirical data with which to test and constrain the behavior of global climatic and oceanographic models. We use depth-stratified plankton tows to demonstrate that some species of planktic foraminifera are adapted to life in the heart of the pelagic oxygen minimum zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the eastern tropical North Pacific OMZ. The tests of the former are preserved in marine sediments and could be used to trace the extent and intensity of low-oxygen pelagic habitats in the fossil record. Additional morphometric analyses of G. hexagonus show that tests found in the lowest oxygen environments are larger, more porous, less dense, and have more chambers in the final whorl. The association of this species with the OMZ and the apparent plasticity of its test in response to ambient oxygenation invites the use of G. hexagonus tests in sediment cores as potential proxies for both the presence and intensity of overlying OMZs.
Highlights
Oxygenation in the oceans is temporally and spatially variable and is controlled by physical factors like ventilation as well as biotic factors such as photosynthesis and respiration
Smallscale oxygen features and their depth relative to the oxycline and oxygen minimum zone (OMZ) varied somewhat (Wishner et al, 2018, 2020b), the overall structure of the water column was consistent across tows
Stratified plankton tows taken through the eastern tropical North Pacific show that distinct assemblages of planktic foraminifera live above and within the OMZ and that a depauperate fauna occupies the upper oxycline
Summary
Oxygenation in the oceans is temporally and spatially variable and is controlled by physical factors like ventilation as well as biotic factors such as photosynthesis and respiration. Oxygen minimum zones (OMZs), where dissolved oxygen can reach undetectable levels, are found in mid-waters (i.e., water depths of hundreds to thousands of meters) in some regions of the global ocean. They are often associated with eastern boundary currents, and other upwelling regions, where surface productivity, and sub-surface respiration, is high and ventilation of intermediate waters is low. Proxies for marine oxygenation currently fall into three broad categories: (1) those that are indicative of productivity, nu-
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
