Kelp to help understand human impact on marine ecosystems

Rebecca Neumann is examining whether environmental stressors affect the chemical defences and microbial communities occurring on kelp.
Wednesday, 1 June, 2011

Research at the Sydney Institute of Marine Science (SIMS) is focusing on kelp to find out how human-induced environmental stresses might affect the health of our marine ecosystems.

Environmental changes due to anthropogenic processes such as climate change and pollution have been associated with the emergence of diseases in marine habitats.

These negative impacts are particularly important when habitat-forming species, such as kelp, are affected. Evidence already obtained from corals, sea grasses and seaweeds indicates these increases in environmental stress may lead to increased disease.

Marine environments near Sydney are subjected to stress from coastal development, urbanisation and rising ocean surface temperatures caused by the more southerly extent of the East Australian Current.

The highly productive and species-rich marine ecosystems founded there on the habitat-forming kelp Ecklonia radiata may therefore be at risk if this keystone species becomes more vulnerable to disease. E. radiata is the most abundant seaweed on sub-tidal rocky reefs of Australia and New Zealand.

Thyne Reid Doctoral Fellow and PhD candidate Rebecca Neumann is examining whether environmental stressors (changes in temperature and pollutants) affect the chemical defences and microbial communities occurring on this kelp, and whether these effects lead to a greater incidence of disease.

Previous studies have shown the local red seaweed, Delisea pulchra, suffers decreases in chemical defences, facilitating infection by pathogenic bacteria, when subjected to environmental stress.  These chemical defences play an important role in the interactions between these organisms and their environment. Their reduction can affect responses to natural enemies ranging from herbivores to pathogens to fouling organisms.

If the kelp is found to have increased susceptibility to disease due to reduced chemical defences, then the effects of any resulting disease on the health of the kelp will also be evaluated.

Supervised by SIMS director Professor Peter Steinberg and Dr Tilmann Harder of the Centre for Marine Bio-Innovation, the project is being conducted along the coast of Sydney, with controlled laboratory assays at UNSW.

This research aims to help determine underlying mechanisms affecting the susceptibility of this key habitat-forming macroalga to environmental stress and assist predicting how anthropogenic processes might affect marine ecosystems on the Australian east coast.