Participants
Christoph Held & Florian Leese
My research is centered around speciation of benthic invertebrates in
Antarctic waters. It used to be thought that low temperatures (down to -2oC in the
Southern Ocean) are detrimental to the development of organisms thus
enabling only a handful of highly specialized species to survive.
Taxonomic research throughout the last 150 years, however, has gradually
overcome this entirely anthropocentric view and made clear that at least
the marine life around Antarctica is surprisingly rich in species. In
contrast to the much younger Arctic Ocean the fauna around Antarctica
had much more time to adapt to these polar conditions. One of the most
notable adapations to polar conditions is the prevalence of brooding
species. But although speciation certainly needs some time and more time
is usually corellated with more speciation taking place, it is not at
all clear what processes are actually involved and which characteristics
of Antarctic waters were instrumental in the evolution of the rich fauna
that we encounter today.
The objective of my group during the ICEFISH cruise is based on the hypothesis that brooding and the lack of pelagic larvae in peracarid crustaceans facilitate genetic isolation of different population of the same species. In contrast to the relatively contiguous habitats on the high Antarctic shelf, the peri-Antarctic islands are to varyiing degrees isolated from one another, by distance and oceanographic features.
I will sample benthic invertebrates from the by-catch around the islands. These will have to be examined taxonomically first because my previous research has shown that there is molecular evidence for a high incidence of cryptic species. New species - if present - will be described on the basis of morphology and genetic data. Concentratin on species which are truly widely distributed I will then estimate the amount of gene flow within and between the islands of widely distributed species using a variety of molecular markers (AFLP, microsatellites). These data are needed to help us understand the evolution of insular faunas and speciation in the Southern Ocean.