獐子岛海域浮游植物的粒径结构及碳流途径

Size-fraction of Phytoplankton and Photosynthetic Carbon Flow Pathway in the Coastal Area of Zhangzidao Island

中文关键词: 粒径结构  浮游植物  微食物环  虾夷扇贝  獐子岛

英文关键词: ize-fraction  Phytoplankton  Microbial food loop  Patinopecten yessoensis  Zhangzidao Island

中文摘要:

      根据2011年6月、10月、12月和2012年4月4个航次对獐子岛海域水温、分粒径Chl a浓度、透明度等参数的调查数据，分析了该海域Chl a浓度的时空变化特征，探讨了浮游植物的粒径结构、光合固碳能力及碳流途径。研究结果显示，獐子岛海域表、底层Chl a浓度年变化范围分别为0.07–6.28 µg/L和0.16–5.28 µg/L，年平均浓度分别为(1.60 ± 1.38) µg/L和(1.31 ± 1.10) µg/L，存在显著的季节差异(P<0.05)和空间分布的不均匀性，表、底层Chl a含量秋、春季节差异极显著(P<0.01)。表、底层浮游植物粒径组成均以微型浮游植物(Nano-phytoplankton)为主，贡献率分别为50.85%和44.64%。典范对应分析(CCA)结果表明，NO3-、PO43-和NH4+的3种形态无机营养盐对微型浮游植物有显著的影响，而水温和NO2-对微微型浮游植物(Pico-phytoplankton)影响显著。该海域初级生产力变化范围为40.31–1017.64 mg C/(m2·d)，平均为(386.07±281.80) mg C/(m2·d)。超过38.3%的总初级生产通过微食物环向高营养级传递并入经典食物链，微食物环在獐子岛虾夷扇贝养殖生态系统中扮演着重要角色。

英文摘要:

      To investigate the seasonal and spatial distribution of phytoplankton in terms of Chlorophyll a (Chl a) in the scallop Patinopecten yessoensis aquaculture area of Zhangzidao island, northern China, four filed investigations were conducted in June 2011, October 2011, December 2011 and April 2012. Chl a was further divided into pico-phytoplankton (< 2 μm), nano-phytoplankton (2-20 μm) and micro-phytoplankton (>20 μm) size fractions. Results showed that the concentration of Chl a in the surface and bottom seawater of Zhangzidao area ranged from 0.07-6.28 µg/L and 0.16-5.28 µg/L, respectively, and the related average was (1.60±1.38) and (1.31±1.10) µg/L. There were significant differences in the concentration of Chl a among different seasons (P<0.05). The differences of Chl a’s concentration between surface and bottom seawater were highly significant during autumn and spring (P<0.01). Nano-phytoplankton was the most important size-fraction regardless of surface and bottom seawater and accounted for 50.85% and 44.64% of the total phytoplankton, respectively. CCA analysis of the main environmental factors showed that NO3-, PO43- and NH4+ contributed greatly to nano-phytop­lankton while seawater temperature and NO2- gave a great contribution to pico-phytoplankton. The annual photosynthetically produced particulate organic carbon (PPOC) in this area ranged from 40.31 to 1017.64 mg C/(m2·d) with an average value of (386.07±281.80) mg C/(m2·d). More than 38.3% of the fixed carbons by the photosynthesis were taken by the classical food web via the microbial food loop. These results highlight the important role of the microbial loop in aquaculture system of Zhangzidao coastal area.