Seminar Series 2012
4th of July, 2012
Living on the edge: organism performance at species range limits. Questions surrounding species range limits have been a focus for ecologists and evolutionary biologists. Whilst obvious boundaries (e.g. land-sea interface) constrain distributions for some groups, for others, distributions often end abruptly and for no apparent reason. Environmental conditions contribute to species distributions with successful expansion of boundaries relying on a dynamic mix of dispersal ability, adaptation and organism performance. Indeed, the ability to balance the trade-offs among life history traits often sets the stage for how well a species performs across variable habitats. Established paradigms, central to niche theory, suggest that optimal habitats support centres of abundance with movement towards the periphery (into sub-optimal conditions) requiring higher investment in physiological maintenance, leading to poorer organism performances and declining abundances. Beyond such peripheries, conditions are assumed to be beyond species physiological tolerances, and hence species simply do not persist. Reproductive processes are key life history traits and important characters of individual and population performance. To establish a complete understanding of reproductive (geographic) variability, larval supply and ultimately population demographics it is important to determine reproduction across a broad spectrum of environmental conditions. Equally important is establishing dispersal and settlement capabilities of larvae. In this talk I will illustrate a classic case of life history tradeoffs in a sponge across its cross-shelf species range. The results are discussed under the proposal that sponges exposed to turbid coastal waters face heavier maintenance requirements than sponges located on offshore reefs resulting in marked differences between reproduction, larval recruitment, and ultimately population dynamics for this sponge.
18th July, 2012
Professor Peter Harrison: "More sex on the reef: asynchronous and pulsed spawning patterns in Maldives corals"
Liz Deschaseaux (PhD candidate): Are DMS and precursors used as antioxidants in corals"?
A/Professor Graham Jones: "DMS production from coral reefs and its influence on the atmospheric aerosol over Heron Island"
Updated: 24 July 2012