Environmental Genomics And Transcriptomics Of Salpa thompsoni And Population Genetic Variation Of Euphausia superba In The Southern Ocean

The Western Antarctic Peninsula (WAP) region, which is experiencing increased sea surface temperatures, is a highly productive region of the Southern Ocean, supporting dense populations of the salp Salpa thompsoni and krill Euphuasia superba. Ecological data suggest that important species like salps and krill are being affected by climate change and that this effects on these planktonic species will have considerable consequences for the balance of the Southern Ocean ecosystem. The Antarctic krill E. superba is one of the best-studied marine zooplankton species in terms of population genetic diversity and structure. However few studies have discriminated life stages and examined sub-regional scale population genetic variation. Analysis of molecular variation revealed no significant differentiation between years, however larger levels of differentiation were observed among samples when furcilia larval stages were analyzed separately, and among life stages in the 2001 collection from Marguerite Bay. On the other hand the Southern Ocean S. thompsoni is subject to variable environmental and biological conditions, as well as the marked seasonal variability and long-term climate change. Knowledge of the physiology and molecular biology is imminent; one of the approaches that can be used is whole genome and transcriptome sequencing. The draft genome provided the first basis for the construction of an annotated gene catalog for S. thompsoni, a much-needed tool to understand the physiological response to environmental condition at a molecular level. Transcriptome analysis showed clear differentiation of gene expression patterns for a wide diversity of genes in salp samples from different regions, seasons, and samples.