渤海中部海域颗粒有机碳季节性变化及碳库估算

依据不同季节的调查，对渤海水体中颗粒有机碳（POC）的时空变化特征、碳库及影响因素进行对比研究.结果表明：春、夏、秋和冬季渤海调查海域颗粒有机碳的平均浓度分别为（338±146）μg/L、（491±136）μg/L、（358±228）μg/L和（2534±2601）μg/L，其中冬季渤海水体中POC浓度最高约是春季的7倍.不同季节渤海调查海域POC分布具有相似的规律，即由近岸浅水区向远岸逐渐降低，高值区多集中在调查海域北侧近岸、黄河入海口以及渤海湾等处.不同季节影响POC分布的因素不同，春、夏和秋季影响渤海调查海域POC分布的因素主要是陆源输入和浮游植物的生长繁殖，沉积物再悬浮是影响冬季渤海调查海域POC分布的主要因素.通过C/N比值探究不同季节渤海水体中POC来源发现，春季有45.3%、52.8%样品的C/N比值分别介于2.6~4.3和4~10之间，夏季有38.7%、32.3%样品的C/N比值分别介于2.6~4.3和4~10之间；秋季有84.4%样品的C/N比值介于4~10；而冬季有72.2%样品的C/N比值大于12，可见渤海水体中POC来源具有季节性差异，春季和夏季渤海调查海域POC主要来源于海洋生物的代谢活动，秋季渤海水体中POC的主要来源是浮游植物，冬季渤海POC的主要来源是再悬浮物作用下沉积物中保留下来的有机物.渤海POC碳库呈季节性变化，春、夏和秋季渤海调查海域POC碳库在6×10⁵~7×10⁵t范围内，冬季碳库最高，为2.5×10⁶t.

Seasonal variation and reserves estimation of particulate organic carbon (POC) in the central Bohai Sea

According to the seasonal investigations in the central Bohai Sea, spatial-temporal characteristics of particulate organic carbon (POC) concentrations, POC pools in the seawater and the possible influencing factors were compared in this study. Results show that the average concentrations of POC in the study area were (338±146)μg/L in spring, (491±136)μg/L in summer, (358±228)μg/L in autumn, and (2534±2601)μg/L in winter. Affected by strong hydrodynamic forces in winter, the average concentration of POC in the study area is about 7times as much as that in spring. During different seasons, POC distributions in the study area show a similar pattern, in which POC contents decreased along the offshore direction. The POC zones with high concentrations were observed along the northern coast of the study area, nearby the Yellow River estuary and Bohai Bay. The distribution patterns of POC were affected by variable factors during the different seasons. In spring, summer and autumn, the distribution of POC was affected mainly by the terrigenous input and phytoplanktonic production. In winter, the distribution of POC was affected majorly by the resuspension of sediments. To trace the source of POC of Bohai Sea, we determined the C/N ratio of samples in different seasons, the results showed that the C/N ratio of 45.3% samples was between 2.6~4.3while 52.8% of the samples was 4~10in spring, the C/N ratio of 38.7% samples was between 2.6~4.3while 32.3% of the samples was 4~10in summer, the C/N ratio of 84.4% samples was between 4~10in autumn, and the C/N ratio of 72% samples was above 12in winter. Consequently the sources of POC in the study area varied seasonally. In spring and summer, POC in the study area mainly came from the metabolic activities of marine organisms. In autumn, the POC mainly came from the phytoplanktonic production. In winter, POC in the study area mainly came from re-suspended sediments with rich organic matters. POC pools in the study area varied seasonally as well. In winter, the POC pool was about 2.5×10⁶t, higher than the values ranging from 6×10⁵t and 7×10⁵t during other seasons.