Microbes Docking in Port

Monitoring environmental health and identifying factors which affect the health of an ecosystem is very important if we want to continue to facilitate the use of these areas. Marine sediments and water near ports are often polluted through leakages of toxic pollutants from the ships coming into port. Little work has been done on the impacts of ports on marine environments; however since the development of high-throughput sequencing technologies (like barcoded pyrosequencing) the ecology of sedimentary microbes has been extensively studied. What this study aimed to do was to identify bacterial communities in and around a busy port and hopefully use the bacterial community composition as a biomarker for environmental health.

They chose 5 sampling sites, two in high port activity, two in medium port activity, and one control with no port activity. The toxicity of surface sediments (from an unpublished paper) was found to be significantly more than the control site and bacterial species richness decreased as port activity increased. There was a marked difference in bacterial communities among sites; Proteobacteria were the dominant phylum in all sediment samples, and significant differences were seen in the relative abundance of; Acidmicrobiia, Bacteroidia, δ-proteobacteria, Flavobacteriia, ˠ-proteobacteria, Sphingobacteriia, Acidmicrobiales, Desulphobacterales, and Rhodobacterales. The Delsulfobacterales which contain Sulphate-reducing bacteria are important in the degradation of oil hydrocarbons in the sediments (as well as anaerobic mineralisation of organic compounds), they were found to have the most difference between port sites and the control site suggesting the use of this genus as a biomarker for anthropogenic activities. Conversely, the relative abundance of the Rhodobacterales was higher in the control site and moderate port activity. Perhaps a ratio between the relative abundances of Delsulfobacterales and Rhodobacterales could be used as a monitoring system or basis for a model? More work would have to be done in a wider variety of sites and over time in the same sites to establish whether this is a ubiquitous relationship.

This paper is a good read, very easy to follow and understand. As far as I can tell they are the first group to use pyrosequencing to study the effects of an antropogenic influence on bacterial diversity. It could lead to the development of cheap-easy-to-use methods for the detection of generic surface antigens common to orders/genera of bacteria.

Gomes, N.C.M., Manco, S.C., Pires, A.C.C., Goncalves, S.F., Calado, R., Cleary, D.F.R. & Loureiro, S. (2013) Richness and composition of sediment bacterial assemblages in an Atlantic port environment. Science of the Total Environment, pp. 172-180.