scholarly journals Whole-stream metabolism: strategies for measuring and modeling diel trends of dissolved oxygen

2013 ◽  
Vol 32 (1) ◽  
pp. 56-69 ◽  
Author(s):  
Alyssa J. Riley ◽  
Walter K. Dodds
Keyword(s):  
Dissolved Oxygen ◽  
Stream Metabolism

scholarly journals Large spatiotemporal variability in metabolic regimes for an urban stream draining four wastewater treatment plants with implications for dissolved oxygen monitoring

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256292
Author(s):  
Sarah H. Ledford ◽  
Jacob S. Diamond ◽  
Laura Toran
Keyword(s):  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Ecosystem Function ◽  
Ecosystem Respiration ◽  
Incident Light ◽  
Treatment Plant ◽  
Spatiotemporal Variability ◽  
Urban Stream ◽  
Water Quality Criteria ◽  
Stream Metabolism

Urbanization and subsequent expansion of wastewater treatment plant (WWTP) capacity has the potential to alter stream metabolic regimes, but the magnitude of this change remains unknown. Indeed, our understanding of downstream WWTP effects on stream metabolism is spatially and temporally limited, and monitoring designs with upstream-downstream comparison sites are rare. Despite this, and despite observed spatiotemporal variability in stream metabolic regimes, regulators typically use snapshot monitoring to assess ecosystem function in receiving streams, potentially leading to biased conclusions about stream health. To address these important practical issues, we assessed the spatiotemporal variability in stream metabolism at nine sites upstream and downstream of four WWTPs in a suburban stream. We used one year (2017–2018) of high-frequency dissolved oxygen (DO) data to model daily gross primary productivity (GPP) and ecosystem respiration (ER). We found that GPP was 1.7–4.0 times higher and ER was 1.2–7.2 times higher downstream of the WWTPs, especially in spring when light was not limited by canopy shading. Critically, we observed that these effects were spatially limited to the kilometer or so just downstream of the plant. These effects were also temporally limited, and metabolic rates upstream of WWTPs were not different from sites downstream of the plant after leaf-out at some sites. Across sites, regardless of their relation to WWTPs, GPP was positively correlated with potential incident light suggesting that light is the dominant control on GPP in this system. Temporal windowing of DO to proposed regulatory monitoring lengths revealed that the violation frequency of water quality criteria depended on both the monitoring interval and start date. We conclude that spatiotemporal variability in metabolism and DO are crucial considerations when developing monitoring programs to assess ecosystem function, and that evidence of WWTP effects may only arise during high light conditions and at limited scales.

Improvements to the Diurnal Upstream–Downstream Dissolved Oxygen Change Technique for Determining Whole-Stream Metabolism in Small Streams

1994 ◽  
Vol 51 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Erich R. Marzolf ◽  
Patrick J. Mulholland ◽  
Alan D. Steinman
Keyword(s):  
Dissolved Oxygen ◽  
Forest Canopy ◽  
Gross Primary Production ◽  
Community Respiration ◽  
Stream Metabolism ◽  
Order Stream ◽  
Small Streams ◽  
Measured Change ◽  
Nutrient Spiralling ◽  
Chamber Measurements

Whole-stream metabolism in a first-order stream was measured using upstream–downstream changes in dissolved oxygen (DO) concentration measured at 1-min intervals over a 40-h period. The measured change in DO was corrected for reaeration flux using a reaeration coefficient determined from injections of conservative and volatile tracers. The whole-stream metabolism measurement was compared in the spring with in situ chamber measurements performed a few days later in the same stream reach. Chamber measurements of community respiration extrapolated to a 24-h period (CR24) were about one third the whole-stream measurements, while gross primary production (GPP) measured at midday in the chambers was roughly 20% less than the whole-stream estimate. Whole-stream GPP was higher during the spring just prior to forest canopy closure than in summer or autumn. Community respiration exceeded whole-stream GPP on all dates and was greatest during the summer. Our results suggest that this whole-stream approach provides a measure of total stream metabolism that is relevant to other stream ecosystem processes measured on reach scales, such as nutrient spiralling.

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