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Review article - Peer-reviewed, 2021

Cryptic Constituents: The Paradox of High Flux-Low Concentration Components of Aquatic Ecosystems

Olofsson, Malin; Power, Mary E.; Stahl, David A.; Vadeboncoeur, Yvonne; Brett, Michael T.


The interface between terrestrial ecosystems and inland waters is an important link in the global carbon cycle. However, the extent to which allochthonous organic matter entering freshwater systems plays a major role in microbial and higher-trophic-level processes is under debate. Human perturbations can alter fluxes of terrestrial carbon to aquatic environments in complex ways. The biomass and production of aquatic microbes are traditionally thought to be resource limited via stoichiometric constraints such as nutrient ratios or the carbon standing stock at a given timepoint. Low concentrations of a particular constituent, however, can be strong evidence of its importance in food webs. High fluxes of a constituent are often associated with low concentrations due to high uptake rates, particularly in aquatic food webs. A focus on biomass rather than turnover can lead investigators to misconstrue dissolved organic carbon use by bacteria. By combining tracer methods with mass balance calculations, we reveal hidden patterns in aquatic ecosystems that emphasize fluxes, turnover rates, and molecular interactions. We suggest that this approach will improve forecasts of aquatic ecosystem responses to warming or altered nitrogen usage.


turnover rates; inorganic nutrients; carbon; nitrogen; primary production

Published in

2021, volume: 13, number: 16, article number: 2301
Publisher: MDPI

Authors' information

Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Power, Mary E.
University of California Berkeley
Stahl, David A.
University of Washington
Vadeboncoeur, Yvonne
Wright State University Dayton
Brett, Michael T.
University of Washington

Sustainable Development Goals

SDG6 Clean water

UKÄ Subject classification

Oceanography, Hydrology, Water Resources

Publication Identifiers


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