Dyeing waters: Does indiscriminate dye use threaten aquatic ecosystems?

Aquatic ecosystem conservation is imperative to reaching global biodiversity and sustainability targets. However, the ecological status of waters has been continuously eroded through mismanagement in the face of existing and emerging anthropogenic stressors, such as pollutants. There has been an emerging trend towards the use of dyes to manage algae and plants as well as to alter aesthetics within various aquatic environments. This artificial colouring has potential ecological implications through reductions in light levels and disruptions to thermoclines (i.e., temperature regime changes with depth). Abiotic regime shifts could in turn drive ecological cascades by depowering primary production, hampering top-down trophic interactions, and affecting evolved animal behaviours. Despite commercial dyes being marketed as acutely non-toxic, very little is known about the chronic effects of these dyes across ecological scales and contexts. We thus call for greater research efforts to understand the ecological consequences of dye usage in aquatic environments, as well as the socio-cultural drivers for its application. This emerging research area could harness approaches such as biological assays, community module experiments, remote sensing, culturomics, and social surveys to elucidate dye effects, trends, and perspectives under a pollution framework. A greater understanding of the potential effects of dye in aquatic ecosystems under relevant contexts would help to inform management decisions and regulation options, while helping to mediate ecocentric and anthropocentric perspectives.