On the projection of future marine primary productivity in mid-latitudinal marginal seas

Abstract

The magnitude of marine primary production (PP) is projected to change in response to future climate variability and the changes in PP will also influence the structure and dynamic of the marine ecosystem and food web interaction. Studies have shown that the global PP appears to have decreased over the past several decades, the PP is expected to decrease in the mid-latitudinal marginal seas. However, the challenges in understanding and predicting PP in response to climate variability is quite complex, particularly the change of PP in the SCM is not well addressed. In this study, we examined characteristics (thickness, depth, and peak) of SCM in the midlatitudinal marginal seas which include East Seas, East China Sea, and Yellow Sea. We also analyzed how thephysical factors (temperature, salinity, sigma-t, etc.) affect the SCM variability using the in-situ data collected from CTD profiler. Our results showed that the depth of SCM layers highly correlates with MLD, as SCM being formed at or above the base of the thermocline. As global warming continues, stratification will be strengthened which will alter the depth and density gradient of the thermocline. This, in turn, will change the formation and depth of SCM and subsequently primary productivity of the upper mixed layer ocean. In this context, we will also discuss the further implication of such potential changes in SCM dynamics in the mid-latitudinal marginal seave shown that the global PP appears to have decreased over the past several decades, the PP is expected to decrease in the mid-latitudinal marginal seas. However, the challenges in understanding and predicting PP in response to climate variability is quite complex, particularly the change of PP in the SCM is not well addressed. In this study, we examined characteristics (thickness, depth, and peak) of SCM in the midlatitudinal marginal seas which include East Seas, East China Sea, and Yellow Sea. We also analyzed how thephysical factors (temperature, salinity, sigma-t, etc.) affect the SCM variability using the in-situ data collected from CTD profiler. Our results showed that the depth of SCM layers highly correlates with MLD, as SCM being formed at or above the base of the thermocline. As global warming continues, stratification will be strengthened which will alter the depth and density gradient of the thermocline. This, in turn, will change the formation and depth of SCM and subsequently primary productivity of the upper mixed layer ocean. In this context, we will also discuss the further implication of such potential changes in SCM dynamics in the mid-latitudinal marginal se