Science Centres: Coasts, Oceans

All aquatic ecosystems are strongly driven by physical processes, and nowhere is this more true than in Antarctica. On land, the very presence of liquid water is dependent on short periods when ice can melt, and in the ocean the presence of annual and multi-year sea ice is a powerful influence on primary production. Regional and year-to year differences in climate (operating through these physical constraints) may be responsible for broad-scale patterns seen in inland and marine ecosystems.

By studying the climate-related environmental processes which influence the spatial structure of populations and community dynamics, as well as the community composition and its spatial and temporal variability, we are better placed to understand the potential impacts of regional climate variability on aquatic ecosystems, as well as to separate natural fluctuations from ongoing anthropogenic changes.

In collaboration with a national and international network of researchers, we investigate a series of ecosystems within the Ross Sea Region, from inland lakes and ponds to the shallow continental shelf.

Inland ponds and streams

Streams are surprisingly abundant in the ice-free parts of the continent, occurring wherever melting of snow or ice is regular enough to allow consistent, year-on-year occurrence of liquid water. Ponds are known from as far south as the La Gorce Mountains (87°S) where they may be ice covered all summer. Our pond research focuses on how the extreme physical conditions, including complete freezing to –30°C or below in winter, affect community composition and activity.

This work is primarily funded by FRST.

Contact: Dr Ian Hawes [ i.hawes@niwa.co.nz ]

Dry Valley Lakes

The lakes of the McMurdo Dry Valleys have fascinated scientists since they were discovered by Scott's expedition in the early 20th Centrury. They are extraordinary systems, permanently ice covered, permanently stratified and mostly closed basins that are highly responsive to small changes in local climate. They are end members in any limnological continua, and have been foci of research for forty years. Our Dry Valley lake research at the moment centres on the role of benthic processes in the ecology of these closed basin lakes, and how this may respond to a changing environment.

This work is primarily funded by FRST.

Contact: Dr Ian Hawes [ i.hawes@niwa.co.nz ]

Coastal benthic communities

Antarctica's coastal marine environments support diverse benthic communities. These are structured by a hierarchy of physical and biotic factors, Principal amongst these are substrate type and food. The strong seasonality in environmental conditions, in terms of sea ice cover and light regime, exerts a strong influence on primary production and the subsequent food supply to benthic animals. The sea ice itself provides a substrate for growth of some algae, but inhibits growth of others by depriving them of light. Our research investigates coastal benthic communities along the coast of the Ross Sea and uses the ice conditions and food supply that this natural gradient encompasses to examine the processes underlying broad and local-scale patterns in biodiversity

This work is primarily funded by MFish.

Contact: Vonda Cummings [ v.cummings@niwa.co.nz ]