Life In The Ice: Microbial Diversity and Function in Antarctic Sea Ice Ecosystems

Our hypothesis is that ‘spatial and temporal variations in diversity and ecosystem function of the sea ice microbial community are sensitive indicators of changing climatic conditions’. The research will develop baseline long-term data on microbial biodiversity and community structure in the “grass” of ice-covered regions – the primary and secondary producers at the base of the food web. We will do this using both conventional methods and molecular technology, and will quantify abundances and species identifications using a range of traditional and modern techniques including DNA fingerprints, high throughput sequencing and single cell genome amplification. We will develop an understanding of the functional role of various components of the sea ice microbial community using ecophysiological methods we have developed over nearly 20 years of Antarctic research coupled with new technologies brought together with our international collaborators on this project.

Microorganisms are the most diverse and by far the most abundant biological entities in marine environments and they are often sensitive indicators of environmental change because of their rapid lifecycles. Given the projected changes to the volume and extent of annual sea ice, SIMCO or ‘sea ice microbial communities’ provide an ideal model system to measure the effects of environmental change in Polar Regions. This research will generate a bio-inventory of the microorganisms in sea ice using both conventional methods and molecular technology, and will quantify abundances to generate community fingerprints for each field site.

In 2010-2011 our research was conducted at Cape Evans. The following data was collected.
- CTD (conductivity/temperature/depth) casts of temperature, conductivity, salinity, depth, live chlorophyll were made each day at solar noon through the sea ice to bottom (25m).
- PAR recorded at 5m above sea ice, using Skye light sensors. (units of microeinsteins /m2/s for PAR and microW per cm2 for UVB. Data were recorded daily at solar noon.
- HOBO data loggers embedded in sea ice at approx 300mm intervals through the depth of the ice (2m). Recording continuously at 10 min intervals.

In 2011-2012 our research was conducted at Turtle Rock and Cape Evans. The following data was collected.
- Turtle rock: CTD casts of temperature, conductivity, salinity, depth, live chlorophyll were made each day at solar noon through the sea ice to bottom (25m).
- Air temperature, solar visible and UVB irradiances were recorded each day at solar noon (approx 1330)
- Cape Evans: CTD casts of temperature, conductivity, salinity, depth, live chlorophyll were madeon selected days at approximately solar noon through the sea ice to bottom (30m)