Affiliation:
1. School of Marine Science and Policy, University of Delaware, Newark, DE 19716, USA.
Abstract
The ocean has absorbed anthropogenic carbon dioxide (C
anthro
) from the atmosphere and played an important role in mitigating global warming. However, how much C
anthro
is accumulated in coastal oceans and where it comes from have rarely been addressed with observational data. Here, we use a high-quality carbonate dataset (1996–2018) in the U.S. East Coast to address these questions. Our work shows that the offshore slope waters have the highest C
anthro
accumulation changes (ΔC
anthro
) consistent with water mass age and properties. From offshore to nearshore, ΔC
anthro
decreases with salinity to near zero in the subsurface, indicating no net increase in the export of C
anthro
from estuaries and wetlands. Excesses over the conservative mixing baseline also reveal an uptake of C
anthro
from the atmosphere within the shelf. Our analysis suggests that the continental shelf exports most of its absorbed C
anthro
from the atmosphere to the open ocean and acts as an essential pathway for global ocean C
anthro
storage and acidification.
Publisher
American Association for the Advancement of Science (AAAS)