Seasonal response of air–water CO2 exchange along the land–ocean aquatic continuum of the northeast North American coast.
- 1Department of Earth and Environmental Sciences, CP 160/02, Université Libre de Bruxelles, 1050 Brussels, Belgium
- 2Department of Earth Sciences – Geochemistry, Faculty of Geosciences, Utrecht University, 3508 TA Utrecht, the Netherlands
- 3Institut Pierre-Simon Laplace, CNRS – FR636, 78280 Guyancourt CEDEX, France
- 4Department of Bioscience – Center for Geomicrobiology, Aarhus University, 8000 Aarhus, Denmark
- 5Yale School of Forestry and Environmental Studies, New Haven, Connecticut 06511, USA
- 6Institute for Geology, KlimaCampus, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany
Abstract. This regional study quantifies the CO2 exchange at the air–water interface along the land–ocean aquatic continuum (LOAC) of the northeast North American coast, from streams to the shelf break. Our analysis explicitly accounts for spatial and seasonal variability in the CO2 fluxes. The yearly integrated budget reveals the gradual change in the intensity of the CO2 exchange at the air–water interface, from a strong source towards the atmosphere in streams and rivers (3.0 ± 0.5 TgC yr−1) and estuaries (0.8 ± 0.5 TgC yr−1) to a net sink in continental shelf waters (−1.7 ± 0.3 TgC yr−1). Significant differences in flux intensity and their seasonal response to climate variations is observed between the North and South sections of the study area, both in rivers and coastal waters. Ice cover, snowmelt, and intensity of the carbon removal efficiency through the estuarine filter are identified as important control factors of the observed spatiotemporal variability in CO2 exchange along the LOAC.