Zoology Department Seminar
Structural Weakening of Corralline Algae Skeleton in Response to Ocean Acidification
School of Earth Science, University of Bristol
TUESDAY 6th March,
Neil Chalmers Science Seminar Room (DC.LG16)
Since the beginning of the industrial revolution, carbon dioxide concentrations in the atmosphere have risen by over 100 μatm (from 280 μatm to 390 μatm) due to anthropogenic input. The ocean has absorbed about one-third of the anthropogenically derived CO2 which has resulted in a lowering of the carbonate saturation and a reduction of the average global surface ocean pH by almost 0.15 units, a process termed "ocean acidification". These chemical changes are suggested to have direct implications for physiological processes such as photosynthesis, calcification or internal pH regulation in a wide range of marine organisms. To test these effects on marine calcifiers living in high latitude, the coralline alga Lithothamnion glaciale was cultured for 3 months at different pCO2 concentrations. Here we show continued calcification of L. glaciale in undersaturated/high pCO2 conditions but with major changes in the ultrastructure leading to an increase in the total strain energy of nearly an order of magnitude and an uneven distribution of the stress inside the skeleton. This weakening of the structure is likely to reduce the ability of the alga to resist boring by predators and wave energy with severe consequences to the benthic community structure.
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