Growth rates of coastal phytoplankton from time-series measurements with a submersible flow cytometer
Growth rates of coastal phytoplankton from time-series measurements with a submersible flow cytometer
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DOI：
10.4319/lo.2003.48.5.1756
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发表时间：
2003-09-01
影响因子：
4.5
通讯作者：
Solow, AR
中科院分区：
文献类型：
--
作者：
Sosik, HM;Olson, RJ;Solow, AR
我们对浮游植物群落动态的了解受到与传统监测方法相关的空间和时间尺度的限制。为了克服其中的一些限制，我们开发了一种潜水式流式细胞仪(FlowCytobot)，旨在扩展对浮游植物丰度、细胞大小和色素沉着的自主监测。FlowCytobot于2001年7月下旬至10月停泊在新泽西州海岸外的长期环境观测站的海底，通过该仪器连续抽出5米深的水样。对细胞光学性质的分析揭示了聚球藻和隐藻的不同种群，以及混合分类的其他微藻和纳米浮游植物的组合。对于这些组中的每一组，在采样期内观察到细胞浓度的巨大变化。细胞散射的昼夜变化表明细胞大小的变化，这与光照期间细胞生长和一天中晚些时候细胞分裂的模式一致。我们开发了一个适应同时生长和分裂的大小结构矩阵种群模型，然后使用该模型和来自FlowCytobot的大小分布数据来估计聚球藻的每日特定生长率；这些估计与细胞浓度无关，也不包括死亡率。结果表明，秋季聚球藻浓度的急剧下降可以归因于比生长速度的下降，而不是物理运输过程或营养相互作用的影响。
Our understanding of the dynamics of phytoplankton communities has been limited by the space and timescales associated with traditional monitoring approaches. To overcome some of these limitations, we have developed a submersible flow cytometer (FlowCytobot) that is designed for extended autonomous monitoring of phytoplankton abundance, cell size, and pigmentation. FlowCytobot was moored on the seafloor from late July to October 2001 at the Long-term Environmental Observatory study site off the coast of New Jersey, and water samples from 5 m depth were pumped continuously through the instrument. Analysis of cells' optical properties revealed distinct populations of Synechococcus and cryptophytes, as well as an assemblage of other pico- and nanophytoplankton of mixed taxonomy. For each of these groups, dramatic variations in cell concentration were observed within the sampling period. Diel variations in cell scattering, which are indicative of changes in cell size, were consistent with patterns of cell growth during the light period and cell division late in the day. We developed a size-structured matrix population model that accommodates simultaneous growth and division and then used the model and size distribution data from FlowCytobot to estimate daily specific growth rates for Synechococcus; these estimates are independent of cell concentration and do not include mortality. The results show that a dramatic autumn decline in the concentration of Synechococcus can be attributed to a decrease in the specific growth rate rather than to effects of physical transport processes or trophic interactions.