OCEAN ECOSYSTEM TRANSFORMATION CAUSED BY RAPID WARMING AND SEA LEVEL RISE IN THE PLEISTOCENE CARIACO BASIN (MIS 9-7)
Open Access
- Author:
- Rizzo, Adriana
- Graduate Program:
- Geosciences
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 06, 2019
- Committee Members:
- Timothy Bralower, Thesis Advisor/Co-Advisor
Katherine Haines Freeman, Thesis Advisor/Co-Advisor
Mark E Patzkowsky, Committee Member - Keywords:
- paleoceanography
coccolithophores
phytoplankton
paleoecology
organic geochemistry
Pleistocene
Climate Change
harmful algae bloom
productivity
sea level
ITCZ
Cariaco Basin
micropaleontology
UK37
nutrients
Emiliania huxleyi
Florisphaera profunda
dinoflagellates
Margalef's Mandala
MIS 8 - Abstract:
- Local phytoplankton community structure has implications for larger ocean ecosystems and the global carbon cycle. Understanding the response of these ecosystems to warming in the tropics is important for understanding future global change. We examined changes in phytoplankton community composition over a full glacial cycle in MIS 9-7 (330-230 kya) in the sediments from the Cariaco Basin (ODP Site 1002). Phytoplankton communities were reconstructed using both calcareous nannoplankton assemblages and sterol and alkenone biomarkers. These data were integrated with alkenone, microfossil, and sterol proxies for temperature and circulation. Emiliania huxleyi occurred definitively in the Cariaco Basin for the first time between 250 and 240 kya, possibly due to increased connectivity caused by rising sea level. At the same time, environmental variability increased during a period of rapid warming from 250-240 kyr, inducing ecological turnover at both species- and larger clade levels. In general, during interglacials, the basin was more productive and more stratified, suggesting higher nutrient fluxes from land and greater rainfall associated with a more northerly ITCZ. This suggests that current warming may cause similar species introductions, productivity changes, and disruptions to phytoplankton populations.