球形棕囊藻增加水体黏度对柱形宽水蚤的摄食抑制

Inhibitory Effect of Increase in Water Viscosity of Phaeocystis globosa on Feeding of Temora stylifera

关键词:  球形棕囊藻  柱形宽水蚤  摄食  黏度  透明胞外颗粒聚合物

Key words:  Phaeocystis globosa  Temora stylifera  feeding  viscosity  transparent exopolymer particles

摘要:

球形棕囊藻（Phaeocystis globosa）在囊体结构形成的过程中可以产生大量的溶解有机物（Dissolved Organic Carbon，DOC），随之带来的水体黏度变化对桡足类摄食活动产生的影响仍然有争议。为揭示球形棕囊藻赤潮带来的海域水体黏度增加对柱形宽水蚤（Temora stylifera）摄食的影响，利用不同浓度的球形棕囊藻培养液和海藻酸钠溶液设置黏度摄食实验，测定柱形宽水蚤对牟氏角毛藻（Chaetoceros muelleri）的摄食率，并对球形棕囊藻的生长过程中胞外颗粒聚合物（Transparent Exopolymer Particles，TEP）含量和培养液的黏度进行分析。研究结果表明，在球形棕囊藻的生长过程中，TEP含量和水体黏度均表现出上升趋势，分别为（2.63±3.72）-（677.33±34.92）μg/liter xanthan equiv.和（2.96±0.58）-（4.92±0.19） Mpa·s，且球形棕囊藻的游离细胞丰度、囊体丰度和囊体直径与TEP含量、黏度均呈显著正相关关系。在球形棕囊藻培养液和海藻酸钠溶液摄食实验组中，黏度高、低规格组的摄食率和滤水率均呈显著差异，低黏度组的摄食率和滤水率高于高黏度组的（P<0.05）。推测柱形宽水蚤的摄食率受到水体黏度的抑制。

Abstract:

Phaeocystis globosa can produce a large amount of Dissolved Organic Carbon (DOC) during the formation process of cyst structure,but the effect of water viscosity changes on the feeding activities of copepods is still controversial.To reveal the effect of increased water viscosity caused by red tide of P.globosa on feeding of Temora stylifera,a viscosity feeding experiment was set up with different concentrations of P.globosa culture medium and sodium alginate solution to determine the feeding rate of the T.stylifera on Chaetoceros muelleri.The content of Transparent Exopolymer Particles (TEP) and the viscosity of culture medium during the growth of P.globosa were analyzed.The results showed that during the growth of P.globosa,the content of TEP and the viscosity of culture medium showed an upward trend,and the variation range was (2.63±3.72)-(677.33±34.92) μg/liter xanthan equiv.and (2.96±0.58)-(4.92±0.19) Mpa·s,and the solitary cell abundance,colony abundance and colony diameter of P.globosa showed a significant positive correlation with TEP content and viscosity.In the experiment group fed with P.globosa culture medium and sodium alginate solution,the feeding rate and filtration rate of the high and low viscosity groups showed significant differences,and the feeding rate and water filtration rate of the low-viscosity group were higher than those of the high-viscosity group (P<0.05).It can be speculated that the feeding rate of T.stylifera is inhibited by the viscosity of water body.