Biofilm responses to marine fish farm wastes

Abstract

The structural, trophic and element accumulation changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation was quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems.

Effects of organic pollution on biological communities of marine biofilm on hard substrata

“…Our results indicate that organic pollution influenced carbon and nutrient accumulation of biofilms as it has been previously reported (Sanz-Lazaro et al, 2011b). Nutrient excess may have promoted the growth of photosynthetic organisms (Nixon, 1995), resulting in an increasing levels of chlorophyll a.…”

“…Primary productivity increase did not translate into a proportional increase of biofilm biomass in any location. A plausible explanation could be that the organic load was not enough to produce a significant increase in biofilm biomass (Sanz-Lazaro et al, 2011b). Same, polysaccharide content of biofilm in both locations showed a trend that was not proportional to TOC content.…”

“…We used microscope glass slides as the artificial surface for biofilm growth, in order to avoid confounding factors due to possible differences among natural substrates on sampling sites (Webster and Negri, 2006;Sanz-Lazaro et al, 2011b). Glass is a suitable artificial substrate since biofilms growing on this surface are similar to biofilms growing in natural substrates (Jackson et al, 2001).…”

“…Biofilms have key functions in stabilizing sediments (Stal, 2003), providing food for higher trophic levels (Decho and Moriarty, 1990;Abreu et al, 2007;Kuwae et al, 2008), favouring the settlement of marine invertebrate larvae (Crisp and Ryland, 1960) and affecting geochemical cycles and climate change at a global scale (Forney et al, 2004). Biofilms can accumulate pollutants (Morin et al, 2008;Sanz-Lazaro et al, 2011b), which is proven to induce changes in the biological assemblages in freshwater systems (Dorigo et al, 2007;Sabater et al, 2007). In marine environments, metal and pesticide pollution alter the species composition of biofilm communities (Magnusson et al, 2012;Licursi and Gomez, 2013), but these effects have been much less studied compared to freshwater systems (Sabater et al, 2007).…”

Implications of Extracellular Polymeric Substance Matrices of Microbial Habitats Associated with Coastal Aquaculture Systems

“…Divalent ion concentrations in the aquatic environment will promote biosorption processes, permitting functional group interactions between EPS and NOM. Likewise, the implications of biofilms in metal pollution derived from fish farming [136] has been examined. It was found that fish feed waste enhanced the accumulation of organic matter and metal contamination in biofilm communities, suggesting the role of biofilms as a sink for contaminants, with implications for metal transfer in the cultured species and surrounding coastal habitats.…”