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Gross production exceeds gross consumption of methyl halides in northern California salt marshes
Author(s) -
Rhew Robert,
Mazéas Olivier
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl044341
Subject(s) - salt marsh , environmental science , marsh , primary production , ecosystem , sink (geography) , temperate climate , atmospheric sciences , ecology , wetland , geography , biology , geology , cartography
Coastal salt marshes are sources of CH 3 Br and CH 3 Cl to the atmosphere, but the wide range of reported emission rates illustrates the need to understand better the factors controlling net fluxes. Here we demonstrate the use of a stable isotope tracer method to separately evaluate gross production and consumption fluxes to determine their relative roles in the overall net flux. At two salt marshes in northern California, gross production exceeds gross consumption at all measured sites, leading to a large net source overall. Emission rates are within the range observed at other temperate salt marshes. By evaluating the consumption component separately, we explain how a typical salt marsh source might convert into a temporary net sink by exposing the ecosystem to uncharacteristically high concentrations of methyl halides. This circumstance may account for the reported net uptake of methyl chloride during the growing season at a coastal salt marsh in China.