Diurnal variations in photosynthetic rates: comparisons of ultraphytoplankton with a larger phytoplankton size fraction
Diurnal variations in photosynthetic rates: comparisons of ultraphytoplankton with a larger phytoplankton size fraction
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DOI：
10.1093/plankt/7.4.519
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发表时间：
1985
影响因子：
2.1
通讯作者：
H. Glover;Andrew E. Smith;L. Shapiro
中科院分区：
文献类型：
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作者：
H. Glover;Andrew E. Smith;L. Shapiro
1983年8月，我们在从缅因州海湾到马尾藻海的航行中比较了两种大小级浮游植物的组成和光合活性。在每一个站位和每一个深度，超浮游生物（这里定义为通过过滤器中3 μm孔隙的细胞）对叶绿素的现存量和初级生产率都做出了重大贡献。超浮游植物组合占主导地位的藻蓝蛋白丰富的蓝藻。总体而言，超浮游生物对总初级生产力的贡献是最大的低光子通量：（一）在光周期的开始和结束;（二）随着透光层深度的增加;（三）当每日辐照度低。超浮游植物的组成随深度而变化。表层（2 m）超浮游植物群落几乎完全由富含藻蓝蛋白的蓝藻组成，其中以较小的（0.2-0.8 μm）蓝藻为主。在表层混合层以下，大、小蓝藻的比例增加，超浮游植物的真核成分往往变得重要。在两个马尾藻海站，最大数量的蓝藻低于混合层在1%的光照水平，而最大数量的真核ultraphytophytoterters发生更深，在0.5%的光照水平，与叶绿素最大值。在马尾藻海真光层的底部。真核生物在数量上占优势的超浮游植物，并作出了重大贡献的叶绿素最大值。
We compared the composition and photosynthetic activity of two size fractions of phytoplankton during a cruise from the Gulf of Maine to the Sargasso Sea in August 1983. At every station, and at every depth, ultraplankton (defined here as cells passing through 3 μm pores in filters) made a major contribution to both the standing crop of chlorophyll and the rate of primary production. Ultraphytoplankton assemblages were dominated by phycoerythrin-rich cyanobacteria. Overall, the ultraplankton contribution to total primary production was greatest at low photon fluxes: (i) at the beginning and end of the photoperiod; (ii) with increasing depth in the euphotic zone; and (iii) when daily irradiance was low. The composition of ultraphytoplankton varied with depth. Surface (2 m) ultraphytoplankton assemblages were almost exclusively composed of phycoerythrin-rich cyanobacteria with smaller (0.2–0.8 μm) cyanobacteria predominating. Below the surface mixed-layer, the proportion of larger (0.8–3 0 μm) to smaller cyanobacteria increased and the eukaryotic component of the ultraphytoplankton often became important. At two Sargasso Sea stations, the greatest numbers of cyanobacteria were below the mixed layer at the 1% light level, while the maximum numbers of eukaryotic ultraphytoplankters occurred deeper still, at the 0.5% light level, coincident with the chlorophyll maximum. At the bottom of the euphotic layer in the Sargasso Sea. eukaryotes numerically dominated the ultraphytoplankton and made a major contribution to the chlorophyll maximum.