Identifying the biodiversity of Southern Ocean protist populations

New organisms are being found and described every year. Antarctic Marine Protists, a guide to more than 500 Antarctic protists with photographs and descriptions was published in 2005, as an aid to the identification of these organisms. An online taxonomic key, based on the book, was published in 2014.

Determining the distribution and abundance of protists in the Southern Ocean

The distribution, abundance and types of phytoplankton present are being determined using their photosynthetic pigments, by light and electron microscopy, and using electronic particle counters. Factors that control population abundance are being studied in relation to oceanography, nutrients and grazers — information vital to models of global carbon budgets. We are also investigating associations between species and ecological processes or oceanic regimes.

Determining the abundance and activity of marine bacteria

Scientists are measuring phytoplankton production, carbon dioxide uptake, carbon sedimentation, nutrient concentrations and oceanography to build an integrated picture of the smallest, but the most important, components of the marine food web.

To find out how Southern Ocean phytoplankton and microbial communities will change as atmospheric CO2 concentrations increase scientists are:

  • Characterising the effects of enhanced CO2 on key species, in particular the carbonate producing coccolithophorids and key diatoms.
  • Characterising the effect of enhanced CO2 on taxonomic composition and cell size of microbial communities and the processes of photosynthesis, respiration, grazing and biogenic sedimentation.