Methyl Bromide and Selected Halocarbons: Response of the Ocean to the Montreal Protocol and Subsequent Amendments
The Halocarbon Air Sea Transect – Pacific (HalocAST-P) cruise is part of an effort to study the spatial/temporal variability of methyl bromide (CH3Br) and other halocarbons in the upper ocean in response to the implementation of the Montreal Protocol and its amendments. Assuming that rates of biological production in the ocean have not changed, our CH3Br model predicts that CH3Br should be less undersaturated than it was before the phaseout of non-quarantine and preshipment uses. The anthropogenic CFCs and HCFCs should still be near equilibrium with regard to surface ocean saturation. However, the CFC surface ocean concentrations should be lower and the HCFC surface ocean concentrations should be higher than before the implementation of the protocol. Spatial and temporal trends in the very short-lived species (VSLS) should not be impacted by the Montreal Protocol or its amendments as they are not currently regulated, and many VSLS are thought to be mostly biogenic. During this project, we will gain information on the natural temporal and spatial variability in these species through measurements made in regions and seasons where we made them a little over10 years ago.
The cruise will commence in Punta Arenas, Chile on March 29 and end in Seattle, WA on April 28, 2010. There will be eleven scientists from four different institutions and five countries engaged in surface water, shallow water column, and atmospheric measurements during. The track for this cruise involves a short 4 day run up the Inland Passage from Punta Arenas followed by a long transect through the eastern Pacific Ocean. There will be one shallow (750 m or bottom in the coastal regions) station each day. At all of the stations CTD/Rosette operations will occur using 24, 10-L bottles that will be filled consecutively over the water column from the bottom in the coastal region and 750m in the open ocean to the surface. Extensive measurements will be taken from the scientific seawater line during the entire cruise. Air sampling from the bow will occur continuously in conjunction with physical micro-meteorological efforts.
This material is based upon work supported by the National Science Foundation under Grant No. OCE-0927874.