Microplankton community structure and the impact of microzooplankton grazing during an Emiliania huxleyi bloom, off the Devon coast
Microplankton community structure and the impact of microzooplankton grazing during an Emiliania huxleyi bloom, off the Devon coast
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德文郡海岸埃米利亚尼亚·赫胥黎藻华期间微型浮游动物群落结构和微型浮游动物放牧的影响
DOI：
10.1017/s0025315402005593
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发表时间：
2002
影响因子：
1.2
通讯作者：
C. Llewellyn
中科院分区：
文献类型：
--
作者：
Elaine S. Fileman;D. Cummings;C. Llewellyn
摘要1999年7月，对英国德文郡近海一次赫胥黎藻华进行了为期一天的研究，研究了浮游植物和微型浮游动物群落结构及其放牧对浮游动物群落的影响。在卫星图像上，沿着从低反射率到高反射率区域交叉的样带，在四个站点进行了垂直剖面。在其中两个站点进行了微型浮游动物稀释放牧实验，并结合色素分析来确定类特定放牧率。在高反射率区域，叶绿素-a和辅助色素的浓度最高（5.3 mg m−3）。浮游植物总存量在1588 ~ 5460 mg C m−2之间，且在高反射率区最高。浮游植物群落在低反射率水域以球石藻和硅藻为主，在高反射率水域以光合鞭毛藻为主。小型浮游动物的存量在905 ~ 2498 mg cm - 2之间。原生动物在微型浮游动物群落中占主导地位。在低反射率水域，原生动物群落由异养鞭毛虫、非鞭毛虫和鞭毛虫的相对均匀的混合物组成。而在高反射率区内，非舞毛纤毛虫占主导地位。在异养纤毛虫中，掠食性纤毛虫Askenasia sp.在非富纤毛虫丰度和生物量上均占主导地位。放牧实验结果表明，每天有60-64%的叶绿素-a生物量被微型浮游动物消耗。最高的放牧死亡率与草鞘素（鞭毛藻）和异黄质（隐生植物）有关。对岩藻黄素（硅藻和原藻）的放牧率较低。结果表明，在遥感高反射率区域，赫胥黎草的放牧量较低，放牧量最大的是光合鞭毛藻和隐生植物。
Phytoplankton and microzooplankton community structure and the impact of microzooplankton grazing were investigated during a one-day study of an Emiliania huxleyi bloom off the coast of Devon during July 1999. Vertical profiles were undertaken at four stations, along a transect which crossed from a low reflectance to a high reflectance area as seen by satellite imagery. Microzooplankton dilution grazing experiments, coupled with pigment analysis to determine class specific grazing rates, were performed at two of these stations. Highest concentrations of chlorophyll-a (5·3 mg m−3) and accessory pigments were measured inside the area of high reflectance. Phytoplankton standing stocks ranged between 1588 and 5460 mg C m−2 and were also highest in the area of high reflectance. The phytoplankton community was dominated by coccolithophores and diatoms in low reflectance waters and by photosynthetic dinoflagellates in high reflectance areas. Microzooplankton standing stocks ranged between 905 and 2498 mg C m−2. Protozoa dominated the microzooplankton community. The protozoan community comprised a relatively even mixture of heterotrophic dinoflagellates, non-choreotrich and choreotrich ciliates in low reflectance waters. However, non-choreotrich ciliates dominated the communities inside the high reflectance area. Of the heterotrophic ciliates, a predatory ciliate Askenasia sp. dominated both non-choreotrich abundance and biomass. Results from grazing experiments showed that 60–64% of the chlorophyll-a biomass was consumed daily by the microzooplankton. Highest grazing mortality was associated with peridinin (dinoflagellates) and alloxanthin (cryptophytes). Lower grazing rates were found on fucoxanthin (diatoms and prymnesiophytes). Our results indicate that grazing on E. huxleyi in the area of remotely sensed high reflectance was low and highest grazing was on photosynthetic dinoflagellates and cryptophytes.