Climate change reductions in lake ice cover duration and thickness help regulate the carbon sink potential of plateau type lakes

Abstract

Lake ice changes in winter under the influence of global climate change, but how lake ice changes will regulate water gross primary productivity (GPP) and carbon sequestration capacity is still unclear. Here, we evaluated and analyzed the geographic spatial pattern and dynamic changes of lake ice and GPP on the Qinghai-Tibetan Plateau (QTP) in the past 20 years. Results show that lake ice duration on the QTP is 123.36±2.43 d on average, although longer for lakes at higher altitudes, of moderate size, and with shallower depths. Lake ice thickness is between 55-66 cm on average, and its GPP on the QTP is between 0.17-3.35 g C m −2 d −1 . In the context of global climate change, reductions in lake ice cover duration and changes in ice thickness on the QTP increased phytoplankton GPP during the winter freeze period while decreasing Carbon dioxide (CO 2 ) emissions during the melting period.