2-6th May 2006

Meike Vogt, Greencycles Early-Stage Researcher at UEA, Norwich, UK, presented her recent results on measuring and modelling DMS emissions at the 4th International Symposium on Biological and Environmental Chemistry of DMS(P) and Related Compounds (DMSP) in Norwich, UK. She gave a talk entitled "Factors controlling DMS production under different pCO2 regimes during a microcosm experiment" (see abstract below):

Factors controlling DMS production under different pCO2 regimes during a microcosm experiment

Meike Vogt^a,b, Michael Steinke^b, Sue Turner^b, Peter Liss^b & Corinne Le Quéré^b,c
a Max-Planck-Institut für Biogeochemie, Postfach 100164, D-07701 Jena, Germany
b School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
c British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK

In the past 200 years, the oceans have absorbed half of the CO2 emitted by human activities such as fossil fuel burning. This uptake has lead to a reduction of the pH of the surface water. The effects of ocean acidification on marine ecosystems are mostly unknown. To understand how marine DMS fluxes will respond to ocean acidification we have conducted measurements of DMS, DMSP and the enzyme DMSP-lyase during a mesocosm experiment (PeECE III) in spring 2005. An E. huxleyii bloom was studied for 24 days under present, double and triple pCO2. Our results indicate very similar DMSP and DMSP-lyase patterns for all treatments. However, DMS concentration showed different temporal development in the low versus the high pCO2 treatments, hence a reaction of the ecosystem to simulated ocean acidification. The cumulative DMS concentration over the whole study period were similar, but the release in the low CO2 scenario occurred during a shorter period with a more pronounced peak. Thus, under bloom conditions where the maximal gradients in DMS between the sea-air interface are crucial for the amount of DMS transferred to the atmosphere, the observed pattern differences could lead to altered sea-air fluxes.