Contaminant adsorption, storage or sequestration, transformation, and, finally,
release in the environment are still mainly investigated in periphyton studies using
metals and a few organics as model compounds. However, there is a gap of
knowledge on the transfer kinetics of contaminants in periphytic assemblages and
their resulting toxic effects (Chaumet et al. 2019a, b). To better understand the fate of
organic contaminants in periphyton, the development and validation of sensitive and
specific high-performance analytical methods combined with the measurement of
intracellular concentrations of organic contaminants, using novel partitioning
methods (Chaumet et al. 2019a), are the first technical challenges to overcome.
Microcosm experiments have brought valuable insights into contaminant transfer
from biofilms to consumers, but future research should now aim to push beyond
these relatively simple models and attempt to address the real-world complexity, i.e.,
both contaminant transfer from biofilm to upper trophic levels and ecological
interactions with other ecosystem components (Roessink et al. 2010), as well as
the influence of environmental factors such as temperature, organic matter, and
so on.
Future studies need to consider the potential effects of global change and specifically how (1) shifts in water contamination patterns (i.e., land-use change, evolving
agricultural practices, antibiotic resistances), (2) climate change (i.e., global
warming, droughts, floods), and (3) the presence of invasive species (i.e. top-down
versus bottom-up effects) can affect contaminant bioaccumulation by biofilms and
consequences on trophic transfer – a challenge that also raises new questions
requiring further interdisciplinary research bridging environmental chemistry, ecotoxicology, and ecology.
6 Summary
Freshwater environments host microbial biomass that can aggregate and attach to
different kinds of submerged substrates (rock, sediment, leaf litter). These microbial
assemblages, which are called biofilms, can accumulate the contaminants
transported by the water flow and/or adsorbed onto the substrates where they
develop. Furthermore, due to their high metabolic activity and their role in aquatic
food webs, microbial biofilms are also likely to influence contaminant fate in aquatic
ecosystems.
Here, by focusing on metals and organic micropollutants, we provide a critical
overview of the analytical methods currently in use for detecting and quantifying
these contaminants in microbial biofilms developing in different benthic substrata,
together with a look at the state of current knowledge and future challenges
concerning the role of biofilms in contaminant accumulation and trophic transfers
in the aquatic food web.
142
C. Bonnineau et al.
release in the environment are still mainly investigated in periphyton studies using
metals and a few organics as model compounds. However, there is a gap of
knowledge on the transfer kinetics of contaminants in periphytic assemblages and
their resulting toxic effects (Chaumet et al. 2019a, b). To better understand the fate of
organic contaminants in periphyton, the development and validation of sensitive and
specific high-performance analytical methods combined with the measurement of
intracellular concentrations of organic contaminants, using novel partitioning
methods (Chaumet et al. 2019a), are the first technical challenges to overcome.
Microcosm experiments have brought valuable insights into contaminant transfer
from biofilms to consumers, but future research should now aim to push beyond
these relatively simple models and attempt to address the real-world complexity, i.e.,
both contaminant transfer from biofilm to upper trophic levels and ecological
interactions with other ecosystem components (Roessink et al. 2010), as well as
the influence of environmental factors such as temperature, organic matter, and
so on.
Future studies need to consider the potential effects of global change and specifically how (1) shifts in water contamination patterns (i.e., land-use change, evolving
agricultural practices, antibiotic resistances), (2) climate change (i.e., global
warming, droughts, floods), and (3) the presence of invasive species (i.e. top-down
versus bottom-up effects) can affect contaminant bioaccumulation by biofilms and
consequences on trophic transfer – a challenge that also raises new questions
requiring further interdisciplinary research bridging environmental chemistry, ecotoxicology, and ecology.
6 Summary
Freshwater environments host microbial biomass that can aggregate and attach to
different kinds of submerged substrates (rock, sediment, leaf litter). These microbial
assemblages, which are called biofilms, can accumulate the contaminants
transported by the water flow and/or adsorbed onto the substrates where they
develop. Furthermore, due to their high metabolic activity and their role in aquatic
food webs, microbial biofilms are also likely to influence contaminant fate in aquatic
ecosystems.
Here, by focusing on metals and organic micropollutants, we provide a critical
overview of the analytical methods currently in use for detecting and quantifying
these contaminants in microbial biofilms developing in different benthic substrata,
together with a look at the state of current knowledge and future challenges
concerning the role of biofilms in contaminant accumulation and trophic transfers
in the aquatic food web.
142
C. Bonnineau et al.