The effect of substratum type, orientation and depth on the development of bacterial deep-sea biofilm communities grown on artificial substrata deployed in the Eastern Mediterranean

Abstract

An increasing number of deep-sea studies have highlighted the importance of deep-sea biofouling, especially in relation to the protection of deep-sea instruments. In this study, the microbial communities developed on different substrata (titanium, aluminum, limestone, shale and neutrino telescope glass) exposed for 155 days at different depths (1500 m, 2500 m, 3500 m and 4500 m) and positions (vertical and horizontal) in the Eastern Mediterranean Deep Sea were compared. Replicated biofilm samples were analyzed using a Terminal Restriction Fragment Length Polymorphisms (T-RFLP) method. The restriction enzymes CfoI and RsaI produced similar total numbers (94, 93) of different T-RFLP peaks (T-RFs) along the vertical transect. In contrast, the mean total T-RF number between each sample according to substratum type and depth was higher in more samples when CfoI was used. The total species richness (S) of the bacterial communities differed significantly between the substrata, and depended on the orientation of each substratum within one depth and throughout the water column (ANOVA). T-RFLP analyses using the Jaccard similarity index showed that within one depth layer, the composition of microbial communities on different substrata was different and highly altered among communities developed on the same substratum but exposed to fouling at different depths. Based on Multidimensional Scaling Analyses (MDS), the study suggests that depth plays an important role in the composition of deep-sea biofouling communities, while substratum type and orientation of substrata throughout the water column are less important. To the authors' knowledge, this is the first study of biofilm development in deep waters, in relation to the effects of substratum type, orientation and depth.

In situ environment rather than substrate type dictates microbial community structure of biofilms in a cold seep system

“…So far, only a few studies have been devoted to biofilm development on artificial surfaces in deep-sea environment. Nevertheless, a recent study reported that substrate types and orientation were less important than depth in shaping the microbial composition of deep-sea biofilms at 1,500–4,500 m depth in the eastern Mediterranean Sea9. Our results also support the importance of environments, rather than substrata, in shaping the microbial structures of biofilms.…”

“…So far, there has been only one study that reported biofilm formation on artificial substrata in water column from surface water to deep-sea waters9 but there has been no study to reveal formation mechanisms of biofilms in deep-sea extreme environments, such as cold seeps and brine pools. Cold seeps are formed by subsurface fluid expulsions to the seabed, due to differential pressure gradients and tectonic activity at both active and passive continental margins1011.…”

Life under flow: A novel microfluidic device for the assessment of anti-biofilm technologies

“…The parameters fluid density (q) and dynamic viscosity (l) of 1024.75 kg m À3 and 1.08 Â 10 À3 Pa s, respectively, correspond to values of seawater at laboratory temperature of 20 C. 31 Velocity boundary condition was imposed at the flow inlet section, while a constant pressure (101 325 Pa) was imposed at the outlet boundary. Finally, no-slip conditions were applied at the solid walls of the modelled device.…”

Effects of substratum type on bacterial community structure in biofilms in relation to settlement of plantigrades of the mussel Mytilus coruscus

“…Bellou et al (2012) found a difference in colonization of microbial communities on substratum types and suggested that substratum type may influence the microbial community. Similarly, microbial communities developed on artificial substrata, i.e., granite and petri dish (Chung et al, 2010), glass slides, ceramic tiles, coral skeletons and reef sediments (Witt et al, 2011) have also been shown to be influenced by substratum type.…”