Diurnal Fluxes of Carbonyl Sulfide (COS) in a Subtropical Salt Marsh
Abstract
The atmospheric sulfur budget has been greatly perturbed, with anthropogenic contributions exceeding natural emissions. Carbonyl sulfide (COS) is the most abundant, longest-lived reduced sulfur compound in the atmosphere, and COS concentration changes could have a significant effect on the global climate and the natural biogeochemical sulfur cycle. Measuring fluxes of COS presents a methodological challenge, and in situ measurements from terrestrial ecosystems are sparse. Terrestrial plants are considered to be the largest sink for COS in the troposphere, although specific species have been reported to act as sources. Here we describe production rates of COS from salt marsh plants on a Texas Gulf coast subtropical barrier island (27.8 °N, 97.1°W). In July 2009, static flux chamber measurements were performed on three sites over the course of 24 hours to capture the temporal and spatial variation of fluxes. Two of the sites were dominated by B. maritima, a common salt marsh plant, while one was a control plot with only marsh soil and no vegetation. Fluxes from the two sites were measured within an hour of each other and showed a very similar pattern with time, indicating that the COS emissions responded to the same environmental factors. Of the environmental parameters measured, fluxes correlated best with soil temperatures at 5 cm depth. The site with the drier of the two soils consistently yielded a 20-30% larger flux. The control plot produced an order of magnitude less COS, but still exhibited a positive flux. These results are part of an ongoing study on how subtropical salt marshes contribute to the global atmospheric sulfur budget.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.B51A0288W
- Keywords:
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- 0315 ATMOSPHERIC COMPOSITION AND STRUCTURE / Biosphere/atmosphere interactions;
- 0426 BIOGEOSCIENCES / Biosphere/atmosphere interactions;
- 0488 BIOGEOSCIENCES / Sulfur cycling;
- 0490 BIOGEOSCIENCES / Trace gases