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2000 Annual Science Report

Marine Biological Laboratory Reporting  |  JUL 1999 – JUN 2000

Protist Diversity in Extreme Environments

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

In the past year we have continued to test and refine methods for examining the protist populations from natural environments. Our full-length small subunit ribosomal gene libraries are now screened using group-specific oligonucleotide probes that we have designed for diatoms and dinoflagellates. We have also designed oligos to several other groups, such as the Chrysophytes, the Pelagophytes and the Bodonids, and are in the process of testing them. Most of the methods were developed in collaboration with our LExEn program, which is directed towards the study of protistan diversity in Antarctic environments. These methods are now being applied to several types of samples from different (and somewhat extreme) environments.

We collected anaerobic sediment samples from a tidal creek (called Trunk River) in Cape Cod, MA, in late September of 1999. Water samples from the strongly sulfidic layers of Blue Holes on Andros Island were also collected. (These layers can occur anywhere from 20 to 70 feet below the surface, with temperatures around 25oC and sulfide concentrations ranging from 10 micromolar to 10 millimolar.) Preliminary sequence analysis of the Trunk River samples has identified ciliates, apicomplexans and an acantharian (very surprising— we are pursuing this sequence in order to identify whether it is real or something only related to acantharia). During the next year, we will generate full-length ribosomal clone libraries and screen them using probes made from DGGE gel bands in order to correlate the bands with full-length sequences rather than sequence all of them first. This will help us in our work this summer in which we will use DGGE to monitor the protistan community changes in Trunk River as the environment becomes anaerobic (see Fieldwork below). For the Andros samples, we will attempt to recover protistan cultures from the samples, as well as extract and analyze DNA from the original samples to examine the protistan populations and determine whether deep/early branching eukaryotes can be identified from these environments.

    David Caron
    Project Investigator

    Rebecca Gast
    Project Investigator

    Mark Dennett

    David Beaudoin
    Research Staff

    Dawn Moran
    Research Staff

    Objective 6.0
    Define how ecophysiological processes structure microbial communities, influence their adaptation and evolution, and affect their detection on other planets.

    Objective 7.0
    Identify the environmental limits for life by examining biological adaptations to extremes in environmental conditions.