夏季桑沟湾养殖水域有机碳的平面分布特征及其来源分析

根据2012年8月对桑沟湾养殖海域18个站位取得的溶解有机碳(DOC)、颗粒有机碳(POC)和叶绿素a(Chl-a)数据,基于不同区域的养殖特点,分析了DOC和POC的平面分布特征,并对POC的来源进行了初步探讨。结果表明,整个调查海域表层DOC的浓度范围为1.70～2.82mg/L,平均值为2.03mg/L,大致呈自西向东递减的趋势。表层POC的浓度范围为0.04～1.33mg/L,平均值为0.55mg/L,大致呈自南向北逐渐递增的趋势。网箱养殖区表层DOC和POC含量最高,其次为桑沟湾近岸海域,而海带养殖区最低,这表明有机碳的含量与养殖品种和模式有直接的关系。根据POC/Chl-a比值对POC来源进行初步分析,表明贝类养殖区、海带养殖区、贝藻混养区、桑沟湾近岸海域以及外海对照点的POC主要来自活的浮游植物,而网箱养殖区存在降解的有机物质。

Distribution and source of organic carbon in Sanggou Bay in summer

Based on the analysis of dissolved organic carbon (DOC), particulate organic carbon (POC) and chlorophyll a (Chl-a) of the water samples collected from eighteen stations in Sanggou Bay in August, 2012, according to the different aquaculture characteristics, the horizontal distribution of DOC and POC, and the source of POC were discussed. The results showed that the concentrations of DOC ranged from 1.70 mg/L to 2.82 mg/L, with an average of 2.03mg/L. The DOC demonstrated a decreasing trend from the west to the east. The concentration of POC ranged from 0.04 mg/L to 1.33mg/L, with the average of 0.55mg/L. The POC demonstrated an increasing trend from the south to the north. The concentrations of DOC and POC in net-cage culture area showed the highest values, followed by the coastal waters of Sanggou Bay. The DOC and POC concentrations were the lowest in the kelp culture area, indicating a direct relationship between the concentration of organic carbon and aquaculture species. Preliminary analysis of the source of POC based the POC/Chl-a ratios, showed that the living phytoplankton were the main source of POC in the bivalve, kelp, and bivalve-seaweed aquaculture areas, the coastal water and the offshore control area, while degraded organic matter was found in the net-cage culture area.