Can seasonal and spatial variation of methyl iodide in the NW Atlantic reveal some clues to its oceanic production?
Moore, R. M.
MetadataShow full item record
The ocean is a significant source of atmospheric methyl iodide (CH sub(3)I), but the main oceanic sources of CH sub(3)I are not yet understood. The seasonal investigation of Canadian Surface Ocean Lower Atmosphere Study (C-SOLAS) in the NW Atlantic in 2003 provided an unprecedented opportunity to study the spatial and seasonal variation of oceanic methyl iodide in this open ocean area. Data collected during this field campaign have offered some clues to the oceanic production of CH sub(3)I. The concentration of CH sub(3)I in the NW Atlantic was observed to vary with season, with mixed layer levels ([CH sub(3)I] sub(ML)) being high in summer, low in spring, and moderate in fall. In the same season, the Slope, Subtropical Gyre West/East, North West Continental Shelf, Gulf Stream, and North Atlantic Drift biogeochemical provinces were generally associated with high concentration and production rate of CH sub(3)I in the surface mixed layer. In contrast, concentration and production rate of CH sub(3)I were relatively low in the Arctic Water and Boreal Polar Water provinces. No conclusive evidence for either phytoplanktonic or photochemical production pathway was obtained from this field study. However, results from some exploratory regression models that were developed from the field data in this investigation have indicated that the depth-averaged daily radiant exposure (H sub(325,ave) and H sub(PAR,ave)) and water temperature (T) can explain about 50% of the variation of CH sub(3)I concentration in the surface mixed layer. It is possible that these physical factors can influence the CH sub(3)I production rate of the unidentified biological or photochemical producers in the ocean.
Wang, L., R. M. Moore, J. Cullen, and K. Thompson. "Can seasonal and spatial variation of methyl iodide in the NW Atlantic reveal some clues to its oceanic production?." 40th CMOS Congress 2006 - Weather, Oceans and Climate, Exploring the Connections, Toronto, Ontario (Canada), May 29 - June 1, 2006.