SEMINAR: MGG Student Seminar TOMORROW 12-1pm

[Angela Rosenberg <arosenberg@rsmas.miami.edu>]

Third Floor CIMAS Conference Room
Tomorrow, March 23
12-1pm

**MGG STUDENT SEMINAR**

"Past Rapid Climate Change Events in a Bahamian Stalagmite"
Monica Arienzo

Abstract:
The impact of rapid climate change events, specifically Dansgaard/Oeschger cycles (D/O) and Heinrich Events, in the subtropics is still not well understood. There are few high resolution studies from the subtropical Atlantic and this project provides a unique opportunity to ascertain whether and how these events are recorded in the subtropics and how they compare to other records. We will sample stalagmites from submerged caves in the Bahamas. We are interested in using carbon and oxygen isotope analysis coupled with trace element analysis to understand precipitation patterns in the Bahamas related to these events. Trace element variability of our speleothems is of interest because an increase in aridity associated with these events in Western Africa should lead to a greater export of iron rich dust. When deposited in the Bahamas, this will be recorded in the geochemistry of our speleothems in the form of iron. The oxygen and carbon isotope data demonstrates a significant shift in the isotopic value associated with these events, indicating a shift to a wetter climate. Iron peaks associated with Heinrich events 1,2 and 3 are thought to be due to the export of iron rich African dust due to an increase in aridity associated with these event in the Sahara region.

------------------------------------------------------------

"In sickness and in health:  Viral record in coral skeleton?"
Husain Al Sayegh

Abstract:
The record of coral calcification contains within it chemical signals useful for reconstructing past seawater composition. Ultrastructural examination of calcification has revealed evidence to suggest that viral particles may be incorporated along with calcifying matrix into the coral skeleton.  In the research program which is focusing on the effects of CO² stress in regenerating corals tissue and skeleton (Renegar et al 2009), we have observed that cellular debris and viral like particles are encapsulated along with calcifying matrix into the coral skeleton. The viral like particles observed are morphologically similar to those observed in coral tissue (Thurber et al 2009).

Ongoing research into the organic component of the coral skeleton will attempt to isolate and identify viral proteins. Current focus is on the scleractinian coral Porities asteroides and Acropora cervicornis, with special attention to growth anomalies. The rapid calcification in these species mitigates the endolithic contribution. A hypothesis that will be examined is whether growth anomalies contain higher concentration of viral proteins then does normal skeleton.  This work has important implication to paleo environmental studies. These include:

1)      1) How far back in the coral skeletal record can viral proteins be discriminated?

2)      2) Can this record be utilized as a proxy for coral health?

-- 

University of Miami, RSMAS
Marine Geology and Geophysics
4600 Rickenbacker Causeway
Miami, FL  33149

305.421.4812 x3

--------------------------------------------------------------------- Seminars and symposia at RSMAS To unsubscribe, e-mail: seminar-unsubscribe@lists.rsmas.miami.edu For additional commands, e-mail: seminar-help@lists.rsmas.miami.edu Post to: seminar@rsmas.miami.edu