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River ecosystems are highly biodiverse, influence global biogeochemical cycles, and provide valued services. However, humans are increasingly degrading fluvial ecosystems by altering their streamflows. Effective river restoration requires advancing our mechanistic understanding of how flow regimes affect biota and ecosystem processes. Here, we review emerging advances in hydroecology relevant to this goal. Spatiotemporal variation in flow exerts direct and indirect control on the composition, structure, and dynamics of communities at local to regional scales. Streamflows also influence ecosystem processes, such as nutrient uptake and transformation, organic matter processing, and ecosystem metabolism. We are deepening our understanding of how biological processes, not just static patterns, affect and are affected by stream ecosystem processes. However, research on this nexus of flow-biota-ecosystem processes is at an early stage. We illustrate this frontier with evidence from highly altered regulated rivers and urban streams. We also identify research challenges that should be prioritized to advance process-based river restoration.
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This content will become publicly available on May 20, 2026
A novel, self‐contained benthic chamber design for conducting freshwater ecosystem experiments
Abstract We present a newly developed design for a self‐contained benthic chamber for conducting in situ ecosystem experiments in streams, with a focus on biogeochemical processes such as ecosystem metabolism and nutrient cycling. Our design expands upon smaller, portable chamber designs and is meant to answer questions at larger scales. These new chambers allow for a high level of experimental control in the field and can be used to generate spatially explicit data regarding ecosystem processes and to test mechanistic hypotheses. They are built to be deployed within the stream over periods of weeks to months and to withstand natural hydraulic forces of the benthic zone. First, we describe the materials and steps that are needed to construct these chambers in detail. Then, we report the methods and results of a multi‐part, diagnostic field study meant to demonstrate the performance and utility of the design. We quantified solute dynamics using a conservative tracer injection, then we estimated ecosystem metabolism across the study site and performed nutrient additions. We detected asymptotic declines in tracer concentrations, calculated nutrient removal rates, and mapped hotspots of ecosystem metabolism. Flow velocity and water depth imposed limitations, but with appropriate methodological forethought these limitations can be minimized. The capacity of our design to accommodate complex, three‐dimensional habitats and macrofauna, along with the capability to generate spatially explicit data, are the main advances we present. These advances provide a novel method whereby motivated users can connect mechanistic hypothesis testing with natural ecological processes through ecosystem‐level field experiments.
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- Award ID(s):
- 2305574
- PAR ID:
- 10592000
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Limnology and Oceanography: Methods
- Volume:
- 23
- Issue:
- 7
- ISSN:
- 1541-5856
- Format(s):
- Medium: X Size: p. 451-466
- Size(s):
- p. 451-466
- Sponsoring Org:
- National Science Foundation
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