Chapter 12 - Mega-challenges of nano-metals on micro-decomposers in freshwaters

Abstract

The rapid growth of nanotechnology-based research has led to an escalated production and application of metal-based nanoparticles (MNPs). Due to their characteristic mechanical, electrical, thermal, and optical properties, MNPs are widely used, resulting in significant releases to the environment, especially to aquatic systems. Freshwaters are generally the primary interface between terrestrial and aquatic systems that serve as conduits or reservoirs for MNPs. Considering the potential toxicity and persistence of MNPs in the environment, they may pose an enormous threat to freshwater organisms, ecosystem processes, and consequently human health. In freshwaters, the decomposition of organic matter is a pivotal ecosystem process mediated primarily by microbial decomposers, allowing the transfer of nutrients and energy to higher trophic levels and contributing to nutrient cycling. MNPs have the potential to impact freshwater microbial communities thereby disrupting important ecological processes such as decomposition and nutrient cycling. This chapter aims to provide comprehensive insights into the responses of microbial decomposers to MNPs, emphasizing different levels of biological organization—from molecules to freshwater ecosystem processes. This multilevel perspective may provide new insights for management and policy regarding the discharge of MNPs into freshwater ecosystems and inspire protective measures for these less recognized groups of freshwater microorganisms.