Molecular Assessment of Salp Gut Content - an improved method to determine phytoplankton biodiversity in the Southern Ocean?

浮游生物群落结构随气候变化的变化和物种对气候的敏感性目前正在推动海洋生态学的主题。预计与气候有关的环境变化可能会导致浮游生物物种的丰度、空间分布、生物地理或优势地位发生变化。这将极大地影响生物地球化学循环，也会影响到鱼类或鸟类等顶级捕食者的海洋食物网。浮游植物是海洋食物网的基础，它由微微浮游生物、纳米浮游生物和微型浮游生物的细胞组成。为了评估气候变化对南极海洋生态系统的影响，有必要掌握关于海洋浮游植物丰度、生物多样性或群落结构的全面信息。通过应用自动化核糖体RNA基因间隔区分析(ARSA)、18S rDNA克隆文库的PHYLOCHHIP分析和测序，对拉扎雷夫海不同季节的两种南大洋咸鱼Salpa thompsoni和Ihlea racovitzai的肠道内容物进行了分析和测序，研究了浮游植物的季节性和空间变异性。在同一个站点上同时出现的Salpa thompsoni和Ihlea racovitzai将被用来检验这一假设，即Salp内脏确实给出了整个水柱浮游植物多样性的综合信号。对浮游生物多样性的详细研究将进一步深入了解南大洋的盐类饮食，特别是在浮游植物稀少的冬季。

Changes in plankton community structures in response to climate change and the climatic sensitivity of species are currently driving topics in marine ecology. It is expected that climate related environmental change could result in changes in the abundance, spatial distribution, biogeography or dominance of plankton species. This would strongly influence biogeochemical cycling, and also marine food-webs up to top predators like fish or birds. Phytoplankton is the base of marine food webs, it consist of cells from the pico-, nano-, and microplankton. In order to evaluate consequences of climate change for marine ecosystems in the Antarctic, it is necessary to possess comprehensive information on the abundance, biodiversity or community structure of marine phytoplankton. By applying Automated ribosomal RNA intergenic spacer analysis (ARISA), PHYLOCHHIP – analysis and sequencing of 18S rDNA clone librarieson on the gut content of two Southern Ocean salps, Salpa thompsoni and Ihlea racovitzai from various season of the Lazarev sea, we will investigate the seasonality and spatial variablility of phytoplankton. The co-occurrence of Salpa thompsoni and Ihlea racovitzai on the same stations will be used to test the hypothesis, that salp guts truly give an integrated signal of phytoplankton diversity over the entire water column. Detailed studies of the plankton diversity will give further insights in the diet of salps in the Southern Ocean, particular during winter time, when phytoplankton is scare.