[Intra- and inter-annual variabilities of particulate organic matter in the Mirs Bay from 2000 to 2010]

Based on the data obtained from monthly cruises from 2000 to 2010, temporal and spatial distributions of the particulate organic matter (POM) in the Mirs Bay were briefly presented and discussed. The POM composition and residence time were approached by combining with the chlorophyll a (Chl-a) measurements. It has been shown that the hydrodynamics in the Mirs Bay only pose a weak impact on the POM distributions. The POM concentration was (1.1 +/- 0.8) mg x L(-1), which was not much different from those in both the Pearl River Estuary and the Daya Bay, but higher than that in the northern South China Sea. A notably positive correlation was found between the POM and Chl-a in the surface-water. The ratio of the phytoplankton POM (PPOM): Chl-a was about 70 g x g(-1), based on which the PPOM concentration was calculated to be (0.31 +/- 0.39) mg x L(-1), accounting for about 28% of the POM. The primary productivity (PP) and integrated POM (IPOM) were used for estimating the POM residence time, which was found to be about 6.5 days in the Mirs Bay, close to that for POC in the coastal continental shelf waters in the southern East China Sea. During the 11-year investigation, the PP inter-annual variability showed a decreasing trend, but both the POM and IPOM underwent a trend of increase, which suggested that the refractory detritus POM had been gradually acumulated in the Mirs Bay.