Changes in accumulation rate of organic carbon during the last 8,000 years in sediments of Nakaumi Lagoon, Japan

Changes in the organic carbon accumulation rate (C org A.R.) and their relation to climate changes during the last 8,000 years were investigated in a 20 m sediment core from the Nakaumi Lagoon, southwest Japan. High-resolution 14C dating was possible from fifteen shell samples. The warm climate interval 8,000-6,500 cal. yr B.P. was accompanied by an increase in the C org A.R. (21–32 g m −2 yr −1) and the cool climate interval 3,000-2,000 cal. yr B.P. by a decrease (11 g m −2 yr −1). The accumulation of both terrestrial and planktonic organic matter increased during the warm interval. The lagoon seems to act as a more effective small sink for atmospheric CO 2 following the global warming climate.