Biological Productivity in the Eastern Equatorial Pacific Through the Pliocene-Pleistocene Transition
Abstract
The Pliocene-Pleistocene transition is significant in paleoclimate studies because it represents a major change from a warm global climate to a cooling climate. The Early to mid Pliocene warm period was followed by a transition to a cooling climate, with the eventual onset of the Northern Hemisphere Glaciation and latest ice age during the Pleistocene. Ocean sediment records from this period provide accessible data from a major climate transition, leading to reconstructions of past climate conditions via biogeochemical proxies. The Eastern Equatorial Pacific is of particular interest for biogeochemical studies because it is a region with strong nutrient upwelling patterns and high biological activity. Previous studies indicate the presence of an El-Nino like SST pattern across the Equatorial Pacific during this time, as well as a shoaling of the thermocline, accompanied by concomitant changes in ocean circulation and heat transport patterns. Such changes in physical oceanic and atmospheric properties are inextricably linked to chemical and biological changes. In this study, we investigate paleoproductivity in the Eastern Equatorial Pacific using a variety of biogeochemical proxies. The samples analyzed are from ODP Leg 138, Site 853 (7 12.655'N, 109 45.078'W). P/Ti, Ba/Ti, and nitrogen isotope data will be used to explore nutrient availability, biological productivity levels, and nutrient utilization/partitioning. The goal of this work is to compare several nutrient proxies at one site, and in light of existing micropaleontology evidence, attempt to gain new insights into productivity variations in this region. The intent is to combine this biogeochemical information with established knowledge of sea surface temperatures and other physical ocean parameters, in order to explore how nutrient cycling patterns respond to climate change over the Pliocene-Pleistocene time scale.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP33C1577R
- Keywords:
-
- 4825 Geochemistry;
- 4870 Stable isotopes (0454;
- 1041);
- 4912 Biogeochemical cycles;
- processes;
- and modeling (0412;
- 0414;
- 0793;
- 1615;
- 4805);
- 9355 Pacific Ocean