Journal Article

How humans alter dissolved organic matter composition in freshwater

Butman, David, Williams, Clayton J., Barnes, Rebecca T., D’Amario, Sarah C., Spencer, Robert G. M., Kothawala, Dolly N., Wilson, Henry F., Xenopoulos, Marguerite A., Solomon, Christopher T., Fasching, Christina, Boodoo, Kyle S., Catalán, Núria, Pisani, Oliva

2021

Overview

Dissolved organic matter (DOM) is recognized for its importance in freshwater ecosystems, but historical reliance on DOM quantity rather than indicators of DOM composition has led to an incomplete understanding of DOM and an underestimation of its role and importance in biogeochemical processes. A single sample of DOM can be composed of tens of thousands of distinct molecules. Each of these unique DOM molecules has their own chemical properties and reactivity or role in the environment. Human activities can modify DOM composition and recent research has uncovered distinct DOM pools laced with human markers and footprints. Here we review how land use change, climate change, nutrient pollution, browning, wildfires, and dams can change DOM composition which in turn will affect internal processing of freshwater DOM. We then describe how human-modified DOM can affect biogeochemical processes. Drought, wildfires, cultivated land use, eutrophication, climate change driven permafrost thaw, and other human stressors can shift the composition of DOM in freshwater ecosystems increasing the relative contribution of microbial-like and aliphatic components. In contrast, increases in precipitation may shift DOM towards more relatively humic-rich, allochthonous forms of DOM. These shifts in DOM pools will likely have highly contrasting effects on carbon outgassing and burial, nutrient cycles, ecosystem metabolism, metal toxicity, and the treatments needed to produce clean drinking water. A deeper understanding of the links between the chemical properties of DOM and biogeochemical dynamics can help to address important future environmental issues, such as the transfer of organic contaminants through food webs, alterations to nitrogen cycling, impacts on drinking water quality, and biogeochemical effects of global climate change.

• Publisher: Springer Science + Business Media,Springer International Publishing,Springer Nature B.V,Springer Verlag
• Subject: Allochthonous deposits / Aquatic ecosystems / Biogeochemistry / Biogeosciences / Browning / carbon / Chemical properties / Chemicophysical properties / Climate change / Climate effects / Composition / Contaminants / Continental interfaces, environment / Cultivated lands / Dissolved organic matter / Drinking water / Drought / Earth and Environmental Science / Earth Sciences / Ecosystems / Environmental Chemistry / Eutrophication / Food chains / Food contamination / Food webs / Fresh water / Freshwater / Freshwater ecosystems / Global climate / humans / Inland water environment / Land pollution / Land use / land use change / Life Sciences / Metabolism / Metals / Microorganisms / nitrogen / Nitrogen cycle / Nutrient cycles / Nutrient pollution / Ocean, Atmosphere / Organic contaminants / ORIGINAL PAPERS / Outgassing / Permafrost / Permafrost thaws / pollution / Sciences of the Universe / Toxicity / Water quality / Wildfires