Title: Coral bacteria associations; the role of chemotaxis
Supervisor: Dr Justin Seymour (UTS) and Professor Peter Ralph (UTS)
Recent studies have revealed the presence of a dynamic microbial biota living on the surface and in the tissue of many coral species (Shnit-Orland & Kushmaro, 2009). Yet the specific role which bacteria partake in, not only in coral health, but also in the overall reef ecosystem remains uncertain. What is clear from previous research is that bacteria play a fundamental role within reef ecosystems through:
• Driving nutrient cycling process that support the productivity of the reef ecosystem,
• They are a food resource for corals,
• Being either symbiotic or pathogenic to a coral.
Little is known about the dynamics involved in establishing coral-bacteria spatial associations within the environment. It has been proposed that chemotaxis is one potential mechanism that enables bacteria to establish associations with coral. Bacteria move towards favourable conditions and away from hostile surroundings through sensing of chemical gradients. Using chemotaxis bacteria may establish and maintain symbiotic relationships, colonise surfaces such as the mucosal layer of corals as well as gain access to nutrient patches throughout the water column.
The fundamental aim of my honours project is to determine:
• How are coral-bacteria associations developed?
This will be assessed by determining if the coral species Pocillopora damicornis has an elevated microbial community associated with it, as well as establishing if bacteria are chemotactically attracted to coral and how the environment affects this.