Physical, resource supply, and biological controls on nutrient processing along the river continuum

Excess nutrient loading has negatively impacted the ecology of ~90% of the streams in the US and the ecosystem services these streams provide, with estimated damages to US surface and groundwater system over of 100 billion dollar per year. Thus, there is a strong need to develop methods to predict the transport, uptake, and export of nutrients along fluvial networks and their cumulative effects on surface and groundwater quality. Our project is developing a data-driven, mechanistic understanding of critical factors that largely control nutrient uptake and export: 1) interactions between transport-related processes (masstransfer to metabolically active zones), 2) resource supply dynamics (nutrient concentrations, stoichiometric constraints, etc.), and 3) biological controls (microbial community structure and function), and how these key factors drive nutrient uptake along a river continuum. This work is designed to address current knowledge gaps in understanding lotic nutrient dynamics that include a paucity of data for high order streams, a lack of studies assessing stoichiometric controls on nutrient uptake due to a traditional focus on solute-specific analyses (e.g., nitrogen only), and a scarcity of data that links microbial diversity and function with nutrient uptake dynamics along fluvial networks. Resolving these limitations will promote scientifically based restoration projects to reduce the burden of eutrophication costs. To meet our goals, we are pursuing three specific research objectives: RO1) Investigate how changes in river sediment texture control mass-transfer to metabolically active zones, colonizable surface area, and biological nutrient uptake along the river continuum; RO2) Investigate nutrient uptake kinetics along the river continuum considering limiting vs. non-limiting (i.e., stoichiometrically balanced) conditions, and labile vs. recalcitrant organic matter sources; and RO3) Investigate differences in microbial diversity, community structure, and genomic potential along the river continuum and how differences interact with resource supply to impose fundamental controls on nutrient uptake.

• Publication year

  2022

• Venue

  Unknown venue

• Publication date

  2022-03-30

• Fields of study

  Not labeled

• Identifiers
  DOI 10.2172/1860260
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

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