Effect of COVID-19 Pandemic on Oceans

Abstract

The novel corona virus (COVID-19) has slowed down a lot of human activities in the world. A lockdown for a period of 2 months, due to the pandemic, was enough to cause a drop of 7% of the anthropogonic CO2 in the atmosphere. In addition to the world in general, the excess of the anthropogonic CO2 emission in the atmosphere has always been a threat to the oceans as well. Oceans play a key role to buffer the greenhouse effect, but in the process, it becomes warmer, more acidic, and less oxygenated. While there have already been investigations done on the effect of pandemic on atmosphere, the question what happens to oceans during the pandemic remains unanswered. The aim of this paper is to study the pandemic's effect and the resultant reduction in CO2 emissions on the productivity of the global oceans. Often Chlorophyll-a (Chl-a), Particulate organic and inorganic carbon (PIC:POC) and sea surface temperature(SST), are used to indicate the productivity of oceans. Herein, satellite-derived estimates of the aforementioned parameters are used. Based on these estimates, a drop in Chl-a (0.5 mgm-3) is observed off Alaska, North Europe,South China and Southeast USA during the pandemic. CO2 reduction of 123 MtCO2 during the pandemic in China might have caused reduction in mean Chl-a by around 5% (2.5 to 1.6 mgm-3). Reduction of Chl-a during the pandemic is mostly associated with the reduction of PIC:POC. The pandemic demonstrates noticeable effect on Chl-a and/or SST. A cooling response of 0.5 oC in mean SST is observed over most of the coastal areas, especially off Alaska,north Indian ocean and eastern Pacific. The decrease in the CO2 emissions in India by 30% during the pandemic translates into a drop of mean SST in the north Indian ocean by 5% (from 29.95 to 28.46 oC). All these suggest that maintaining global activities as sustainable as the pandemic period, can help to recover the oceans.