Comparison of genetic diversity and ecophysiological performance in the colony-forming polar prymnesiophyte species Phaeocystis antarctica and Phaeocystis pouchetii

棕囊藻是一种世界性的、具有重要生态意义的水华浮游植物属，包含两种冷水性的菌落形成物种：北极的P. pouchetii和南大洋的P. anaustica。核糖体RNA（rRNA）和ITS（Internal Transcribed Spacer）序列的初步分子生物学分析表明，P.pouchetii具有显著的种间和种内多样性，可能存在种间复合体，并试图追溯南极沿岸沃茨中P.anastritica菌株的地理学历史。在此基础上，对两种极地物种的种群结构进行了详细的分析，旨在将遗传数据与环境参数以及生理生态反应模式联系起来。微卫星是一种高度多态性的短重复序列，已被设计并成功应用于南美原教旨主义，但仍有待统计分析。我们现在将能够研究来自不同地点的种群内部的遗传多样性以及它们之间的基因流动。对P.pouchetii也进行了同样的研究，但如果对P.anastritica设计的标记的适用性测试失败，微卫星仍有待开发。选择两种具有较大遗传差异的棕囊藻克隆，在不同非生物条件下比较研究光合作用和生长，以确定各自的最适和耐受限度。主要目的是通过实验评估遗传差异是否反映在不同的生理生态反应模式中，这些模式可以很好地解释特定的地理分布模式。此外，这种新方法首次提供了将人口遗传学与两个极地地区的预测气候变化联系起来的机会。

The prymnesiophyte Phaeocystis is a cosmopolitan, ecologically important and bloom-forming genus of the phytoplankton containing two colony-forming cold water species: P. pouchetii in the Arctic and P. antarctica in the Southern Ocean. Preliminary molecular biological analyses of the ribosomal RNA (rRNA) and ITS (Internal Transcribed Spacer) sequences indicated substantial inter- and intraspecific diversity, the possibility of a species complex in P. pouchetii and tried to trace the biogeographic history of P. antarctica strains in Antarctic coastal waters. Based on these results, a detailed analysis of the population structure of both polar species is intended to link genetic data to environmental para-meters as well as to ecophysiological response patterns. Microsatellites, short, repetitive sequences that are highly polymorphic, for P. antarctica were designed and successfully applied but still await statistical analysis. We will now be able to study the genetic diversity inside populations from different locations and the gene flow between them. The same approach is also planned for P. pouchetii al-though microsatellites have still to be developed if applicability tests with markers designed for P. antarctica fail.Selected clones of both Phaeocystis species with large genetic differences will be comparatively studied in terms of photosynthesis and growth under different abiotic conditions to outline the res-pective optima and tolerance limits. The main goal is to experimentally evaluate whether genetic differences are reflected in different ecophysiological response patterns which could well explain specific biogeographic distribution patterns. Moreover, this new approach offers for the first time the opportunity to relate population genetics to predicted climatic changes in both Polar Regions.