ABSTRACT
Wetlands are characterized by a range of conditions including both drained and ooded soil conditions. Depending on the hydrologic regime and hydroperiod, wetland soils often alternate between drained and ooded soil conditions. Gas exchange between atmosphere and soils is regulated by the hydrologic regime. The most important biogeochemical reactions involving gases include microbial and plant respiration that consume oxygen and produce carbon dioxide. During the day, algae and submerged aquatic vegetation in the water column consume carbon dioxide and produce oxygen by photosynthesis. Soil respiration consumes oxygen and produces carbon dioxide during both night and day. In many ecosystems, daytime oxygen production typically exceeds oxygen consumption.
