Hobart

Seminar Abstract

Wednesday 26 August, 11.30am (Tas time)
CSIRO Auditorium, Hobart

Sophie von der Heyden
Evolutionary Genomics Group
Department of Botany and Zoology
University of Stellenbosch
Matieland, South Africa

What can comparative phylogeographies tell us about southern Africa’s dynamic oceanic past?

South Africa is the meeting point of two great and dynamic oceanic currents, with the associated coastline comprising a number of highly variable bioregions that affect the distribution and abundance of marine species. In order to understand the patterns of population structure and gene flow and the processes driving these, along the 3500 kms of South African coastline, species with large geographical ranges and differing life history characteristics (i.e. broadcast spawning, brooding and live bearing) were sequenced for both mtDNA and nuclear genes. Organisms included molluscs, crustaceans, echinoderms and fishes. Results show that Cape Agulhas and the regiona round Algoa Bay play important roles in limiting gene flow between the east and west coasts for many species Other barriers to gene flow were also detected, but differ between even closely related groups of organisms and are probably linked to life history and environmental requirements, as well as historical influences of the dominant ocean currents. It is likely that some of the barriers recovered have been separating populations for at least 70,000 years. Interestingly, organisms with differing pelagic larval durations are affected by the southern African current systems in a variety of ways and that species with short larval stages are not successfully dispersed by the large-scale Agulhas Current. Coalescent analyses were utilised in order to analyse demographic changes for all species concerned in order to comprehend the effects of glacial cycles and associated changes in the Benguela and Agulhas Current systems. Colelction and analysis of multi-species data sets are shedding new light on the historical and contemporary processes influencing population structuring. This will not only influence management practices of exploited marine species, but will contribute to the management and conservation of the entire southern African coast.

Seminar recording

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Location:
CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
To schedule a seminar, contact:
Clothilde Langlais, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5399
Natalie Kelly, (Biology/Modelling seminars) CSIRO Marine and Atmospheric Research 0438 452 483
Jillian Enraght-Moony, (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5320
Communications Manager, Antarctic Climate and Ecosystems CRC (03) 6226 2265
Margaret Hazelwood, Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2971

Last updated 8/12/09