Increase in CO2 Uptake Capacity in the Arctic Chukchi Sea During Summer Revealed by Satellite-Based Estimation

The capacity of CO2 uptake in the Chukchi Sea is particularly sensitive to rapid physical and biological changes. However, scarce field observations pose a challenge in understanding the long-term trend of CO2 uptake capacity on this continental shelf. We adopted a machine-learning-based approach to construct a 17-years (2003-2019) long-term time series of summer sea surface partial pressure of CO2 (pCO(2)) from remote sensing products. We show that the long-term increase in CO2 uptake capacity can be attributed to strong and enhanced biological uptake. In addition, the intraseasonal variability of surface pCO(2) in early summer confirms the crucial role of sea ice melt and the subsequently enhanced photosynthesis as soon as the surface ocean converts into an open system. Our results thus highlight the use of remote sensing data in interpolating/extrapolating the highly dynamic carbonate system in the continental shelf sea and shed light into future studies involving machine learning or algorithms.

Automated summary

The study constructed a 17-year time series of summer sea surface partial pressure of CO2 in the Chukchi Sea using machine learning, attributing the long-term increase in CO2 uptake capacity to enhanced biological uptake. The intraseasonal variability of surface CO2 in early summer also highlights the importance of sea ice melt and enhanced photosynthesis.