2016年春季西太平洋M2海山浮游植物粒级结构与初级生产力研究

BIOAMASS OF SIZE-FRACTIONATED PHYTOPLANKTON AND PRIMARY PRODUCIVITY AT M2 SEAMOUNT IN TROPICAL WEST PACIFIC IN SPRING 2016

2016年3月对西太平洋马里亚纳区域M2海山浮游植物粒级结构和分粒级初级生产力进行了观测,同时结合温度、盐度和营养盐浓度,研究了M2海山的总叶绿素a浓度的分布规律,不同粒级浮游植物对总叶绿素a的贡献率及其与环境因子的关系,初级生产力结构和分布特征。结果表明:M2海山各水层叶绿素a浓度变化范围分别为0.004—0.304mg/m^3,平均叶绿素a浓度为0.094mg/m3。微微型浮游植物在整个调查区域内为最优势类群,对总叶绿素a浓度的贡献率达到了85%,微型浮游植物和小型浮游植物的贡献率均较低,分别为10%和5%。M2海山的叶绿素a浓度最大层均在100m深度附近的次表层,其中西南部和东南部为叶绿素a浓度高值区。M2海山的平均初级生产力为71.31mg C/(m^2×d),初级生产力的主要贡献者为微型和微微型浮游植物,其中微型浮游植物贡献率达到了72%,微微型浮游植物贡献率为28%。M2海山的海山效应不明显,浅海山(<200m)可能对浮游植物的生长存在促进作用。

The distribution and concentration of size-fractionated chlorophyll a（chl a） and size-fractionated primary productivity at Seamount M2 in the western Pacific were investigated in spring 2016. The results show that the average chl a concentration was 0.094 mg/m^3, of which pico-phytoplankton chl a was dominant for occupying 85%. The deep chlorophyll maximum layer（DCML） was observed at 100 m in depth. The primary productivity was about 71.31 mg C/（m^2×d）, and composed of mainly nano-and pico-phytoplankton productivity. The nano-phytoplankton productivity contributed 72% to the primary productivity, although the biomass of nano-phytoplankton was only about 10% of the total. The pico-phytoplankton productivity contributed 28% to the primary productivity. Therefore, no obvious ＂Seamount Effect＂ was found in Seamount M2, and a shallow seamount（200 m） may promote the growth of phytoplankton.