Quantifying
the Impact of Anthropogenic Atmospheric
Nitrogen Deposition on the Generation of Hypoxia under Future Emission
Scenarios in Chinese Coastal Waters
posted on 2020-03-11, 14:53authored byYu Yan Yau, David M. Baker, Benoit Thibodeau
Atmospheric
deposition is an important source of nitrogen to coastal
waters. In nitrogen-limited waters, the atmosphere can contribute
significantly to eutrophication and hypoxia. This is especially true
in China, where nitrogen emissions have increased dramatically and
are projected to further increase in the future. Here, we modeled
the potential future impact of change in atmospheric nitrogen deposition
on hypoxia in Chinese coastal seas. We used changes in nitrogen deposition
under two IPCC scenarios that included emission regulation and climate
change (representative concentration pathway (RCP) 4.5 and 8.5) to
evaluate the impacts of such deposition on hypoxia in the 2030s and
2100s. We found that by 2030 the extent of hypoxic areas would increase
up to 5% in China seas under RCP 8.5 due to the projected increase
in nitrogen deposition. However, the hypoxia extent was projected
to decrease by up to 9% by 2100 once emission regulations included
in RCP 4.5 and 8.5 are implemented. The South China Sea was found
to be the most sensitive region to changes in nitrogen loads, which
indicates that more effort in emissions control is needed to avoid
expansion of the hypoxic zones in that specific region.