JAMS September 2011 meeting report by Justin Seymour

A keen crowd of about 35 braved the rain to attend the September JAMS, which this month was held within the more spacious setting of the 4th floor at the Australian Museum. This month’s presentations all had a marine flavour, with the audience enjoying three entertaining talks focussed on the community dynamics and biogeochemical capabilities of marine microorganisms.

Mark Brown, a QEII Research Fellow at UNSW, kicked things off with a very interesting insight into the community dynamics of the ocean’s most abundant and ubiquitous bacterial clade, SAR11. This important group of bacteria often represents up to 50 % of the bacterial community in ocean surface waters.  Mark’s presentation showed us that the distributions of discrete SAR11 ecotypes are not uniform across the global ocean, but vary with changes in seawater temperature. This ecological niche differentiation may provide new insights into how the SAR11 clade has become so dominant in the global ocean. Mark closed his presentation by demonstrating that potentially important shifts in SAR11 ecotypes may occur as a result of predicted increases in seawater temperature associated with global warming.

Next up was David Wilkins, also from UNSW. His presentation took us to the cold waters of the Southern Ocean, where microbial assemblages are demarcated by the Polar Frontal Zone, a region where temperatures drop by up to 2° C and salinity varies substantially over a distance of only 30 Km. David sequenced several metagenomes from both north and south of the Polar Front and found that the disparate environmental conditions between these regions support very different microbial assemblages. The warmer waters north of the Polar Front hosted a community rich in SAR11 and the dominant marine cyanobacteria Synechococcus and Prochlorococcus. On the other hand, south of the Polar Front, uncultured chemolithoautotrophic bacteria and ammonia oxidising archaea were over-represented. David’s work provides a nice example of how physical oceanography can structure microbial community characteristics in the ocean.     

Finally, Lev Bodrossy from the CSIRO Marine and Atmospheric Research group in Hobart gave us an exciting and detailed insight into the use of microarrays as affordable high throughput tools to examine microbial community function. Lev described the use of microarrays used to probe for ammonia oxidation and methanotrophy, and described the application of these tools in both aquatic and terrestrial ecosystems. He closed his presentation by describing the extremely exciting potential of using microarray technologies within in situ sensing equipment deployed in the marine environment.

This month’s JAMS continued to encourage the engagement of Sydney’s microbiology community within a relaxed and enjoyable setting.   The JAMS organisers would like to thank each of the speakers, as well as the Australian Museum for providing the meeting venue and the Australian Society for Microbiology for providing funds for pizza and drinks.