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SEMINAR: GEOTOPICS Presents: Human Modification of Carbon Delivery to the San Francisco Bay-Delta System

From: orash sharifi <osharifi@rsmas.miami.edu>
Subject: SEMINAR: GEOTOPICS Presents: Human Modification of Carbon Delivery to the San Francisco Bay-Delta System
Date: Mon, 6 Feb 2012 10:21:20 -0500




Monday, February 6, 2012
3:15, SLAB Seminar Room, S/A 103
Refreshments at 3:00 PM


Our upcoming speaker is one of the well known scientists and authors in the field of Biogeochemstry from Virginia Institute of Marine Science (VIMS): Dr Elizabeth A. Canuel

The title of her talk is "Human Modification of Carbon Delivery to the San Francisco Bay-Delta System".


SUMMARY

Anthropogenic activities, including climate change, influence connections between the hydrologic and carbon cycles as well as the exchange of materials between terrestrial and aquatic systems.  This presentation will present results from San Francisco Bay-Delta, California (Delta, hereafter), which was used as a model system for understanding how human activities influenced delivery and composition of organic carbon (OC) over the past 50+ years. Sediment cores from the Delta were used to examine human impacts on carbon sources, amounts, and ages. Sediment and carbon accumulation rates were four to eight-fold higher pre-1972 relative to post-1972, coincident with completion of several large reservoirs and increased agriculture and urbanization in the Delta watershed.  Organic biomarkers provided insights about the sources of organic matter.  Biomarkers demonstrate that terrigenous OC has decreased since the 1940s while algal OC increased. In addition, radiocarbon isotopes of TOC and fatty acids in surface sediments indicate that much of the OC is highly reworked (900-1400 years BP) and vascular plant biomarkers have the oldest ages suggesting erosion of soils.  Together, these data suggest that human activities have altered the amount, sources, and ages of carbon accumulating in the Delta. Projected increases in aridity and changes in the timing of freshwater delivery associated with anthropogenic climate change are likely to exacerbate these modifications to the delivery of carbon and water with implications for downstream ecosystems.


We hope to see you all there!

Your GEOTOPICS Coordinators,
Keri Vinas and Arash Sharifi
        
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