"Shellfish Face Uncertain Future in High CO2 World:
Influence of Acidification
on Oyster Larvae Calcification and Growth in Estuaries"
Dr. Whitman Miller
Smithsonian Environmental Research Center
Monday, April 6, 2009
3:30 PM
Room 3200, Research Innovations Building I
Abstract
Human activities have increased atmospheric concentrations of carbon
dioxide by 36% during the past 200 years. One third of all anthropogenic
CO2 has been absorbed by the oceans, reducing the pH by about
0.1 pH units and significantly altering their carbonate chemistry. There
is widespread concern that these changes are altering marine habitats
severely, but little or no attention has been given to the biota of
estuarine and coastal settings, ecosystems that are less pH buffered
because of naturally reduced alkalinity. To address
CO2-induced changes to estuarine calcification, veliger larvae
of two oyster species, the Eastern oyster (Crassostrea virginica),
and the Suminoe oyster (Crassostrea ariakensis), were grown in
estuarine water under four pCO2 regmines, 280, 380, 560
and 800 µatm, to simulate atmospheric conditions in the pre-industrial era,
present, and projected future concentrations in 50 and 100 years
respectively. CO2 manipulations were made using an automated
negative feedback control system that allowed continuous and precise
control over the pCO2 in experimental aquaria. Larval
growth was measured using image analysis, and their calcification was
measured by chemical analysis of calcium in their
shells. C. virginica experienced an 18% decrease in shell area and
a 32% reduction in calcium content when pre-industrial and end of
21st century pCO2 treatments were
compared. C. ariakensis showed no change to either growth or
calcification. Both species demonstrated net calcification and growth,
even when aragonite was under-saturated, a result that runs counter to
previous expectations for invertabrate larvae that produce aragonite shells.
Biography
Dr. Miller received a Ph.D. degree from the University of California, Los
Angeles. He currently serves as the assistant Director of the Marine
Invasions Research Laboratory (headed by Gregory Ruiz) and is the Director
of the National Ballast Information Clearinghouse, a cooperative effort of
SERC and U.S. Coast Guard. Research interests center on marine and
estuarine invasion ecology, and more recently, he has embared on research
that investigates the biological and ecological effects of
CO2-induced acidification in coastal habitats.
Reception before seminar at 3:00 PM
Research Innovations Building I
Old Dominion University
Norfolk, VA 23529
757-683-5548
Last updated 03/25/2009.
This page is maintained by
Julie Morgan
Copyright Info: Old Dominion University 2009
