Hallock, P. ., University of South Florida, St Petersburg, USA, pmuller@marine.usf.edu
Robbins, L. L., U.S. Geological Survey, St Petersburg, USA, lrobbins@usgs.gov
Peters, M. ., University of South Florida, St Petersburg, USA, mpeters@marine.usf.edu

ARE SUBTROPICAL CALCAREOUS GREEN ALGAE RESPONDING TO OCEAN ACIDIFICATION?

Atmospheric CO2 concentrations are increasing faster than experienced on Earth for the last 650,000 years. Within this century, atmospheric CO2 will be double pre-industrial levels. Because the oceans are the largest natural reservoir for CO2, ocean chemistry will change more dramatically than in the last 20 million years. Indeed, pH values of the open ocean have decreased by 0.1 since 1980 and are predicted to decrease 0.3-0.5 in the next 80 years. Ocean acidification will likely affect fundamental geochemical and biological processes including calcification and carbonate sediment production. The east and west Florida shelves provide natural gradients from temperate to subtropical carbonate sedimentation; these gradients provide natural laboratories to examine the effects of ocean acidification on aragonite production by calcareous green algae. Scanning electron microscopy can reveal ultrastructural details of calcification. Comparison of Halimeda spp. from archived samples collected more than 40 years ago, with specimens collected in ongoing studies, are indicating the influence of declining carbonate saturation over this time span; both sets of samples will provide data for future comparisons.

Poster presentation

Presentation is given by student: No
Session #:003
Date: 03-04-2008
Time: 17:30 - 19:30

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