Dr Stephen SUMMERS
Senior Research Fellow
Biofilm Biology cluster, SCELSE

Dr Stephen Summers joined SCELSE as a research fellow under A/Prof. Scott Rice within the Microbial Biofilms cluster. Prior to joining SCELSE, he was a research associate at Heriot-Watt University in Scotland. In his previous role, Dr Summers investigated the microbial communities associated with nano- and micro-plastic marine debris. As plastic debris enters the marine environment, it rapidly becomes encapsulated in exopolymers, originating from bacteria and algae. This interaction between the plastics and exopolymers results in the aggregation of the plastics into marine snow. This has repercussions on the fate of the plastics, through changes to buoyant density and increasing the capture efficacy of the smallest nano-plastics. However, it also may play a role in the microbial communities within the marine snow aggregates, as some plastics have been observed to alter the microbial biofilm community composition. Moreover, the plastic particles are known to be hydrophobic and adsorb a myriad of pollutants (e.g. PAHs and PCBs) to their surfaces. Therefore, the adsorped pollutants may play a role in the natural microbial diversity and processes commonly seen in marine snow as it sinks to the benthos.

In addition to his plastics research, Dr Summers has been investigating the microbial response when oil droplets become incorporated into marine snow, generating marine oil snow. This has resulted in the enrichment of bacteria capable of degradation this type of hydrocarbon as well as exopolymer producers, further enhancing the formation of marine oil snow. These experiences of microbial ecology and biofilm formation in the marine environment compliment Stephen's work within SCELSE as his current project is to examine the biofilm formations on man-made materials in the marine environment. By exposing a series of materials to a natural microbial community, he will be monitoring the growth and diversity of microbial films as they colonise the surfaces. Furthermore, he can examine what processes are occurring within the biofilms to promote a more stable and productive ecosystem.