Choose your friends wisely

When you're a tiny creature in a vast ocean it pays to hang out with the right crowd, regardless of whether they are related to you or not, a new study into the amazingly diverse world of marine microbes has found.

For bacteria at least, it seems that what matters more than your species identity is whether you have specific genes that let you work with other species to form a functioning community.

The study looked at the rich communities of bacteria that form on the surface of a common seaweed known as sea lettuce (Ulva australis) and found surprisingly large variations in the 400 or so member species that make up each community.

Despite this great variety and high species diversity within them, each community has similar core functions, such as the ability to attach to the seaweed's surface and gather nutrients from the host, says a new study in the journal Proceedings of the National Academy of Sciences, led by Dr Catherine Burke of the UNSW Centre for Marine Bio-Innovation (CMB) and School of Biotechnology and Biomolecular Sciences (BABS).

"I guess this shows that for bacteria it matters less who you are - that is, your species - than what you can do and who you hang out with," says co-author Dr Torsten Thomas, a BABS senior lecturer and CMB member.

For ecologists, the finding challenges long-held theoretical ideas about how communities of organisms are established, says co-author Professor Peter Steinberg, Director of the Sydney Institute of Marine Science.

"Species are usually the fundamental unit by which communities are characterised in higher organisms," says Professor Steinberg, who is also on staff at UNSW's School of Biological, Earth and Environmental Sciences and the CMB.

"But in these systems the important thing is to know what genes the bacteria have, not what species those genes are packaged in. This flies in the face of a hundred years of studies of the community ecology of higher organisms."

The team also included scientists from the J. Craig Venter Institute and the Singapore Centre on Environmental Life Sciences Engineering.

Read the full story at the Faculty of Science newsroom.

Media contact: Bob Beale UNSW Faculty of Science 0411 705 435