Biofilms are important in the settlement of larvae and each biofilm can contain different microorganisms. This is a major problem in antifouling as the different mechanisms used in biofilm settlement makes it difficult to isolate and replicate. In return this does mean that it is expensive and very difficult to produce antifouling agents used in industry. It is therefore vital to understand the differences between biofilms and the microorganism structure. This study investigates biofilms and any site specific variation in Antarctic marine biofilms on artificial surfaces.
The authors used glass surfaces (microscope slides) lowered into the Antarctic sea on the base of PVC frames in three different locations at two depths (12 m and 18 m), then were left for twelve months. The three locations were Cape Armitage (CA), Pram Point Scott Base (SB-1) and McMurdo Station (MM-1). Each of the site locations had a multitude of parameters measured from sediment contamination to characterising macroorganisms, they also recorded for any anthropogenic debris.
Once the glass plates were recovered they were frozen at -80°C until analysed. The authors used two methods in community analysis; Fluorescent in situ hybridization (FISH) and Denaturing gradient gel electrophoresis (DGGE). They also sequenced a large proportion of the bands in the DGGE analysis. The authors used a series of 16 different probes in the FISH analysis encompassing many different microorganisms.
The authors used Analysis of similarities (ANOSIM), Non-metric multidimensional scaling (nMDS), Principal component analysis (PCA) to analyse the data statistically. The nMDS revealed a greater variability in community composition between the different sites than within a single site and this was confirmed by the PCA of quantitative FISH data. This analysis revealed the majority of bacterial sequences present were affiliated to Gammaproteobacteria, Cytophaga/Flavobacteria of Bacteroidetes (CFB), Verrucomicrobia and Planctomycetales. With each of the sites dominated by different bacterial groups; SB-1 by green sulphur and sulphate reducing bacteria, CA by Alphaproteobacteria, Gammaproteobacteria and CFB, finally MM-1 by Planctomycetales and sulphate reducing bacteria. The highest abundance of Archaea was found near SB-1 (2.5% of total bacteria).
Each of the sites selected were impacted by different levels of anthropogenic activity, CA the least impacted and MM-1 being the highest impacted. As this is the first investigation of Antarctic biofilm structure and with the current results the authors have concluded; the results suggest that anthropogenic impacts may influence the complex composition of microbial communities.
A review of: Webster, N. S., & Negri, A. P. (2006). Site-specific variation in Antarctic marine biofilms established on artificial surfaces. Environmental microbiology, 8(7), 1177-90.
1 comment:
Interesting topic and enjoyed the review.
The anthropogenic impact upon microbial communities seems to be well represented in the literature; however this paper appears to offer a new avenue of enquiry into how microbial community structure with a direct relevance to the complex relationships associated with biofilm formation may respond to anthropogenic pressures. High levels of anthropogenic activity have been regularly linked with marine habitat degradation and the homogenisation of microbial composition, structure and their processes in the marine environment. Perhaps the pattern of homogenisation would be emulated in biofilm structure in the Antarctic during further analysis, possibly attributing to larger implications upon the marine habitat and its biodiversity assimilated with the mass productivity of the Southern Ocean – I couldn’t find much on this from a preliminary search in the literature.
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