Interactive effects of global climate change and pollution on marine microbes: the way ahead

Abstract

Global climate change has the potential to seriously and adversely affect marine ecosystem functioning. Numerous experimental and modeling studies have demonstrated how predicted ocean acidification and increased ultraviolet radiation (UVR) can affect marine microbes. However, researchers have largely ignored interactions between ocean acidification, increased UVR and anthropogenic pollutants in marine environments. Such interactions can alter chemical speciation and the bioavailability of several organic and inorganic pollutants with potentially deleterious effects, such as modifying microbial-mediated detoxification processes. Microbes mediate major biogeochemical cycles, providing fundamental ecosystems services such as environmental detoxification and recovery. It is, therefore, important that we understand how predicted changes to oceanic pH, UVR, and temperature will affect microbial pollutant detoxification processes in marine ecosystems. The intrinsic characteristics of microbes, such as their short generation time, small size, and functional role in biogeochemical cycles combined with recent advances in molecular techniques (e.g., metagenomics and metatranscriptomics) make microbes excellent models to evaluate the consequences of various climate change scenarios on detoxification processes in marine ecosystems. In this review, we highlight the importance of microbial microcosm experiments, coupled with high-resolution molecular biology techniques, to provide a critical experimental framework to start understanding how climate change, anthropogenic pollution, and microbiological interactions may affect marine ecosystems in the future.

Keywords: Climate change; interactive effects; microbial communities; molecular biology; pollution.

Figure 1

Interactions between ultraviolet radiation, ocean acidification, anthropogenic pollution, and microbial communities. Climate change has the potential to influence pollutant toxicity by acting directly on pollutant chemistry or indirectly by affecting microbial-mediated detoxification.

Figure 2

One hundred years scenario of forms of iron in surface ocean waters considering the 0.4 pH units decrease modeled by Caldeira and Wickett (2003), at 25°C and salinity of 35. Adapted from Millero et al. (2009). As coastal and estuarine areas are very different between them, modeling on speciation of metals in these areas is needed for a more complete and accurate scenarios.

Figure 3

Microbial microcosm coupled with “omics” technologies can provide an excellent tool to gain mechanistic insights into climate change and anthropogenic pollution interactive effects at several levels of biological organization.