Effects of the herbicide diuron on the early life history stages of corals from the Great Barrier Reef

This research examines the effects of herbicide on the reproduction and early life stages of coral of broadcast spawning and brooding corals. Laboratory experiements were conducted to determine the potential effects of herbicide diuron on: fertilisation rates of broadcasted coral oocytes with and without symbionts, rates of metamorphosis of coral larvae, and the photosynthetic efficiency, extent of bleaching and rates of survival of coral recruits and adult colonies.

Collections of mature collonies occured in 2002 and 2003:

Acropora millepora and Montipora aequituberculata at Lizard Island

A. millepora and P. damicornis at Magnetic Island

The oocytes of M. aequituberculata contain parentally derived dinoflagellate symbionts, whereas oocytes from A. millepora are symbiont-free. Pocillopora damicornis larvae contain symbiotic dinoflagellates.

At Lizard Island colonies were held in aquariums at the research station. After spawning in November 2002, gametes were collected and cultured.

Colonies collected from Magnetic Island were held in outdoor aquariums at the Australian Institute of Marine Science, Townsville. Following spawning, the larvae were harvested from the tank.

Following spawning of corals and collection of larvae, experiements were performed to examine the effects of diuron on:

fertilization of broadcast spawning corals, effects of diuron on

metamorphosis of broadcast spawning coral larvae

metamorphosis of brooding coral larvae

indoor exposure of recruits: survival and cleaching

outdoor exposure of recruits: bleaching and tissue retration

outdoor exposure of recuits: photosyntheyic efficency

outdoor exposure of adult colonies: photosynthetic efficiency