From this literature review emerge the following issues:
• Concurrent to analytical developments, studies dealing with bioaccumulation in
microbial biofilms have been applied mainly to metal contaminants, and there is
still only limited knowledge on the accumulation of organic contaminants in these
microbial assemblages.
• A large variety of metals and organic contaminants has been found in natural
periphytic biofilms, which grow on inert surfaces like cobbles exposed to light. In
contrast, due to technical limitations, data on the bioaccumulation of contaminants in submerged microbial communities associated with sediments, leaves, or
drift particulate matter has always included both biotic accumulation and abiotic
sorption on the substratum.
• Microbial biofilms represent an important food resource in freshwater ecosystems, yet their role in dietary contaminant exposure has been neglected for a long
time, and the importance of biofilms in trophic transfer of contaminants is still
understudied, leaving a critical lack of knowledge especially but not exclusively
concerning biofilms attached to sediments or organic substrates such as leaf litter.
These issues pose a set of challenges that need to be overcome in order to better:
• Characterize the accumulation of contaminants in sediment and organic-substrate
biofilms
• Evaluate the role played by biofilms in contaminants fluxes within aquatic
ecosystems and aquatic food webs
• Assess how different environmental pressures such as shifts in water contamination, climate change, or the presence of invasive species (i.e., top-down versus
bottom-up effects) may affect contaminant bioaccumulation in biofilms and the
resulting consequences in food webs
References
Aguilera A, Souza-Egipsy V, Martin-Uriz PS, Amils R (2008) Extraction of extracellular polymeric
substances from extreme acidic microbial biofilms. Appl Microbiol Biotechnol 78:1079–1088.
https://doi.org/10.1007/s00253-008-1390-9
Alvarez M, Peckarsky BL (2005) How do grazers affect periphyton heterogeneity in streams?
Oecologia 142:576–587. https://doi.org/10.1007/s00442-004-1759-0
Ancion PY, Lear G, Lewis GD (2010) Three common metal contaminants of urban runoff (Zn, Cu
& Pb) accumulate in freshwater biofilm and modify embedded bacterial communities. Environ
Pollut 158:2738–2745. https://doi.org/10.1016/j.envpol.2010.04.013
Ancion PY, Lear G, Dopheide A, Lewis GD (2013) Metal concentrations in stream biofilm and
sediments and their potential to explain biofilm microbial community structure. Environ Pollut
173:117–124. https://doi.org/10.1016/j.envpol.2012.10.012
Arini A, Feurtet-Mazel A, Maury-Brachet R et al (2012) Field translocation of diatom biofilms
impacted by Cd and Zn to assess decontamination and community restructuring capacities. Ecol
Indic 18:520–531
Role of Biofilms in Contaminant Bioaccumulation and Trophic Transfer in Aquatic. . .
143
• Concurrent to analytical developments, studies dealing with bioaccumulation in
microbial biofilms have been applied mainly to metal contaminants, and there is
still only limited knowledge on the accumulation of organic contaminants in these
microbial assemblages.
• A large variety of metals and organic contaminants has been found in natural
periphytic biofilms, which grow on inert surfaces like cobbles exposed to light. In
contrast, due to technical limitations, data on the bioaccumulation of contaminants in submerged microbial communities associated with sediments, leaves, or
drift particulate matter has always included both biotic accumulation and abiotic
sorption on the substratum.
• Microbial biofilms represent an important food resource in freshwater ecosystems, yet their role in dietary contaminant exposure has been neglected for a long
time, and the importance of biofilms in trophic transfer of contaminants is still
understudied, leaving a critical lack of knowledge especially but not exclusively
concerning biofilms attached to sediments or organic substrates such as leaf litter.
These issues pose a set of challenges that need to be overcome in order to better:
• Characterize the accumulation of contaminants in sediment and organic-substrate
biofilms
• Evaluate the role played by biofilms in contaminants fluxes within aquatic
ecosystems and aquatic food webs
• Assess how different environmental pressures such as shifts in water contamination, climate change, or the presence of invasive species (i.e., top-down versus
bottom-up effects) may affect contaminant bioaccumulation in biofilms and the
resulting consequences in food webs
References
Aguilera A, Souza-Egipsy V, Martin-Uriz PS, Amils R (2008) Extraction of extracellular polymeric
substances from extreme acidic microbial biofilms. Appl Microbiol Biotechnol 78:1079–1088.
https://doi.org/10.1007/s00253-008-1390-9
Alvarez M, Peckarsky BL (2005) How do grazers affect periphyton heterogeneity in streams?
Oecologia 142:576–587. https://doi.org/10.1007/s00442-004-1759-0
Ancion PY, Lear G, Lewis GD (2010) Three common metal contaminants of urban runoff (Zn, Cu
& Pb) accumulate in freshwater biofilm and modify embedded bacterial communities. Environ
Pollut 158:2738–2745. https://doi.org/10.1016/j.envpol.2010.04.013
Ancion PY, Lear G, Dopheide A, Lewis GD (2013) Metal concentrations in stream biofilm and
sediments and their potential to explain biofilm microbial community structure. Environ Pollut
173:117–124. https://doi.org/10.1016/j.envpol.2012.10.012
Arini A, Feurtet-Mazel A, Maury-Brachet R et al (2012) Field translocation of diatom biofilms
impacted by Cd and Zn to assess decontamination and community restructuring capacities. Ecol
Indic 18:520–531
Role of Biofilms in Contaminant Bioaccumulation and Trophic Transfer in Aquatic. . .
143