Quantification of dimethyl sulfide (DMS) production in the sea anemone <i>Aiptasia</i> sp. to simulate the sea-to-air flux from coral reefs

Abstract

<p><strong>Abstract.</strong> The production of dimethyl sulfide (DMS) is poorly quantified in tropical reef environments but forms an essential process that couples marine and terrestrial sulfur cycles and affects climate. Here we used gas chromatography to quantify net DMS production and the concentration of its cellular precursor dimethylsulfoniopropionate (DMSP) in the sea anemone <i>Aiptasia</i> sp., a model organism to study coral-related processes. Bleached anemones did not show net DMS production whereas symbiotic anemones produced DMS concentrations (mean ± standard error) of 160.7 ± 44.22 nmol g<sup>−1</sup> dry weight (DW) after 48 h incubation. Symbiotic and bleached individuals showed DMSP concentrations of 32.7 ± 6.00 and 0.6 ± 0.19 μmol g<sup>−1</sup> DW, respectively. We applied these findings to a Monte-Carlo simulation of DMS flux into the atmosphere and demonstrate that net aqueous DMS production accounts for only 0.5–2.0 % of gross aqueous DMS production, and that reefs may release up to 15 μmol DMS m<sup>−2</sup> coral surface area d<sup>−1</sup> into the atmosphere with 40 % probability for rates between 0.5 and 1.5 μmol m<sup.−2</sup> d<sup>−1</sup>. Conversion to a flux rate normalised to sea surface area (range 0.3–10 with highest probability for 0.3–1 μmol DMS m<sup>−2</sup> d<sup>−1</sup>) suggests that coral reefs continuously emit DMS at lower rates than the average global oceanic DMS flux of 6.7 μmol m<sup>−2</sup> d<sup>−1</sup>. The high gross DMS-production rates in corals suggest that it is important to assess the sensitivity of DMS-consumption pathways to environmental change before addressing the impact of predicted degradation of coral reefs on DMS production in tropical coastal ecosystems and its impact on future atmospheric DMS concentrations and climate.</p>