Protistan diversity in the Ross Sea, Antarctica: linking genotype, morphology and physiology

• Published in: The Journal of Eukaryotic Microbiology
• Main Authors: GAST, REBECCA J., MORAN, DAWN M., DENNETT, MARK R., ROSE, JULIE M., CARON, DAVID A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2005
• Subjects: Ross Sea; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1111/j.1550-7408.2005.05202003_1_28.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1550-7408.2005.05202003_1_28.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1550-7408.2005.05202003_1_28.x

Traditional microscope‐based studies of protistan assemblages in the Ross Sea, Antarctica have contributed significantly to our understanding of the microbial biogeography and food web structure in this extreme cold‐water environment. However, these investigations have neither been able to characterize the genetic diversity of the communities, nor have they necessarily determined the abundances or trophic contribution of the dominant organisms. Resolution of the latter issue is hindered by the fact that physiological studies are often conducted on opportunistic species that respond to enrichment culture rather than species truly representative of intact communities. Therefore, we sought to determine the genetic diversity of microbial eukaryotes in ice, water and slush samples from the Ross Sea, and establish both morphologic and physiologic links between enrichment cultures and the genetic data. Denaturing gradient gel electrophoresis and ribosomal clone library analyses indicate that the protistan communities are very diverse, but those present in similar habitats are more alike than those in different habitats at the same site. We have been able to identify several protists from our enrichment cultures as being genetically represented in the original samples. General studies of their physiology have been initiated and methods for determining their abundances are being developed.