Predicting Dissolved Organic Matter Lability and Carbon Accumulation in Temperate Freshwater Ecosystems

BASTIDAS NAVARRO, M.,; SCHENONE, L.; MARTYNIUK, N; VEGA, EVELYN; MODENUTTI, B; BALSEIRO, E

Ecosystems

Springer

Año: 2021 vol. 25 p. 795 - 811

Dissolved organic matter (DOM) dynamics influenceaquatic ecosystem metabolism with ecological andbiogeochemical effects. During microbial degradation,certain DOM molecules accumulate in the environmentsconstituting the residual refractory carbon (C)pool that has a key role in the global carbon cycle inlakes and oceans. The present study aims to model thefactors driving bacterial C-consumption, thus predictingthe potential residual carbon accumulation. Wedeveloped mechanistic models to represent bacterialC-consumption, considering the contribution ofDOMquality and phosphorus (P) and nitrogen (N) concentrationsin the total carbon pool. Based on 59 differentenvironments, we established DOM components andnutrient concentration for deep lakes, shallow lakes,high-altitude lakes, and wetlands from North-AndeanPatagonian glacial lake district (around 41S).We appliedBayesianmethods to estimatemodel parametersfrom laboratory C-lability experiments performed in26 environments.We tested the statistically predictiveaccuracy of our models with an external dataset consistingof C-lability experiments with natural lakewater enriched with organic matter from differentsources.Wefound a model that performed excellentlyin both fit to training data and prediction to externalexperiments. The selected model showed that an increasein P concentration stimulates C-consumption,and an increase in the proportion ofDOMprotein-likecompounds reduces the amount of residual C. Basedon the statistically predictive accuracy,we showedthatourmodel is very useful to anticipate C-accumulationdue to changes in the inputs to water bodies.