Insights into Macroinvertebrate burrowing Activity and Methane Flux in Tidal Flats

The CH4 flux was examined preliminarily in tidal flats using a circular closed-chamber method to understand the effects of macroinvertebrate burrowing activity. The chamber was deployed over decapods (mud shrimp, Laomedia astacina and crab, Macrophthalmus japonicus) burrows for similar to 2 h, and the CH4 and CO2 concentrations were continuously monitored using a closed, diffuse CH4/CO2 flux meter. It founds that Laomedia astacina burrow (which is relatively long) site afforded higher-level CH4 production, likely due to diffusive emission of CH4 in deep-layer sediments. In addition, the proposed CH4-oxidation process (i.e., reverse methanogenesis) was supported by the decrease in the delta C-13 of headspace CO2 during the chamber experiment. Therefore, macroinvertebrate burrows appear to be an important ecosystem environment for controlling atmospheric CH4 over tidal flats.