Posted: 21 Apr 2015 07:53 AM PDT
Scientists have presented the geophysical impact of phytoplankton that triggers positive feedback in the Arctic warming when the warming-induced melting of sea ice stimulates phytoplankton growth.When the Arctic sea ice melts away due to greenhouse warming, the ocean surface albedo inevitably decreases, reducing the amount of solar energy reflected back from Earth and ultimately resulting in warmer ocean surface. As phytoplankton growth is subject to factors such as temperature, light, and nutrients, the explosive growth of phytoplankton follow when both the warming-induced melting and shortwave radiation penetrating the ocean increase. The new study has confirmed that it is the beginning of the geophysical feedback by which chlorophyll and the related pigments in phytoplankton absorb solar radiation and in turn raise the sea surface temperature even further. Using a coupled ocean-atmosphere model, the authors have revealed that the additional positive feedback in the Arctic can amplify Arctic warming by as much as 20%. “We believe that, given the inseparable connection of the Arctic and global climate, the positive feedback in Arctic warming triggered by phytoplankton and their biological heating is a crucial factor that must be taken into consideration when projecting future climate changes,” says Jong-Seong Kug, a professor at POSTECH’s School of Environmental Science and Engineering and one of the leaders of this study.