Abstract
Samples from a recent 15-year time-series of sediment trap experiment in the North Pacific subpolar region, reveal that both the opal flux (OP) and organic carbon flux (OC) mainly had significant linear decreasing trends in the first half of year (OP: -6 to -47 mg/m2/yr; OC: -1 to -9 mg/m2/yr). Furthermore, OP/CaCO3 flux(OP/CC) also had diminished with -0.2 to -0.6/yr, which are the largest decreasing rate in the world ocean. These facts suggest a evidence that occurrence of recent shift in the marine biological species from diatom to coccolithophorids with the decrease of biological activities in the North Pacific, which consequently would cause the reduction of efficiency of absorption of CO2 between air and sea.
