Life across the divide: Comparative Studies of the Ecology and Physiology of Species across the Antarctic Intertidal Zone

Waller, Catherine L (2007). Life across the divide: Comparative Studies of the Ecology and Physiology of Species across the Antarctic Intertidal Zone. PhD thesis The Open University.



This thesis describes the first detailed comparative study of Antarctic communities across the gradient of environmental conditions from terrestrial to marine zones. Sampling was undertaken at both sub-Antarctic (Scotia Arc) and Peninsula sites. This study is also the most detailed and comprehensive investigation of intertidal assemblages south of 60°S undertaken to date.

Supralittoral, intertidal and, where possible, shallow sublittoral habitats were sampled along a latitudinal gradient from the Falkland Islands through the Scotia Arc (Bird Island, South Georgia and Signy Island (South Orkney Islands)) over one austral summer. Peninsula sites, in the vicinity of Rothera Research Station (Adelaide Island 67° 34.5’S), were studied in more detail over two austral summers, and one point sample was undertaken during the austral winter at Rothera Research Station.

Contrary to the findings of previous studies, the Antarctic intertidal was found to support an unexpectedly rich and diverse community, with a total of 61 species being found at sites around Rothera Research Station, Adelaide Island. This is more than double the previous maximum richness reported in an Antarctic study. Intertidal assemblages at more northern Scotia Arc sites were less diverse and numerically abundant, the most depauperate sites being on Bird Island and South Georgia.

Many of the taxa found are permanent residents in the intertidal near Rothera Research Station. Four-year-old colonies of the bryozoan Inversiula nutrix were found alive in summer samples, and a winter excavation of only 1 m2 of the intertidal icefoot revealed 17 species of both mobile and sessile taxa alive and present under the outer layer of rocks. The taxa present were predominantly marine species with only one possibly obligate intertidal animal being found, the halacarid mite Rhombognathus gressitti.

The assemblages were virtually all located beneath the outer scoured surface of the intertidal rock matrix, in protected interstices. Both abundance and size of taxa increased with depth through the cobble boulder matrix suggesting that they are exploiting protected microhabitats in order to survive in this extreme environment.

Preliminary ecophysiological studies suggest that the limpet Nacella concinna is capable of freeze tolerance and is able to survive all of the osmotically active water freezing, whilst the nemertean Antarctonemertes validum shows evidence of the presence of thermal hysteresis proteins (THPs). As such this is the first Antarctic and only the second marine invertebrate likely to possess THPs.

Viewing alternatives

Download history


Public Attention

Altmetrics from Altmetric

Number of Citations

Citations from Dimensions

Item Actions