Aquatic Eddy Covariance: The Method and Its Contributions to Defining Oxygen and Carbon Fluxes in Marine Environments

Aquatic eddy covariance (AEC) is increasingly being used to study benthic oxygen (O-2 ) flux dynamics, organic carbon cycling, and ecosystem health in marine and freshwater environments. Because it is a noninvasive technique, has a high temporal resolution (similar to 15 min), and integrates over a large area of the seafloor (typically 10-100 m(2)), it has provided new insights on the functioning of aquatic ecosystems under naturally varying in situ conditions and has given us more accurate assessments of their metabolism. In this review, we summarize biogeochemical, ecological, and biological insights gained from AEC studies of marine ecosystems. A general finding for all substrates is that benthic O-2 exchange is far more dynamic than earlier recognized, and thus accurate mean values can only be obtained from measurements that integrate over all timescales that affect the local O-2 exchange. Finally, we highlight new developments of the technique, including measurements of air-water gas exchange and long-term deployments.

Automated summary

Aquatic eddy covariance (AEC) is a noninvasive technique with high temporal resolution and large area coverage, which provides new insights and more accurate assessments of the functioning and metabolism of aquatic ecosystems. The studies using AEC have revealed that benthic oxygen exchange is more dynamic than previously recognized, and accurate mean values can only be obtained by integrating measurements over all timescales. The technique has also seen new developments in measuring air-water gas exchange and long-term deployments.