Aquatic ecosystem metabolism as a tool in environmental management

Abstract

Recent advances in high‐frequency environmental sensing and statistical approaches have greatly expanded the breadth of knowledge regarding aquatic ecosystem metabolism—the measurement and interpretation of gross primary productivity (GPP) and ecosystem respiration (ER). Aquatic scientists are poised to take advantage of widely available datasets and freely‐available modeling tools to apply functional information gained through ecosystem metabolism to help inform environmental management. Historically, several logistical and conceptual factors have limited the widespread application of metabolism in management settings. Benefitting from new instrumental and modeling tools, it is now relatively straightforward to extend routine monitoring of dissolved oxygen (DO) to dynamic measures of aquatic ecosystem function (GPP and ER) and key physical processes such as gas exchange with the atmosphere (G). We review the current approaches for using DO data in environmental management with a focus on the United States, but briefly describe management frameworks in Europe and Canada. We highlight new applications of diel DO data and metabolism in regulatory settings and explore how they can be applied to managing and monitoring ecosystems. We then review existing data types and provide a short guide for implementing field measurements and modeling of ecosystem metabolic processes using currently available tools. Finally, we discuss research needed to overcome current conceptual limitations of applying metabolism in management settings. Despite challenges associated with modeling metabolism in rivers and lakes, rapid developments in this field have moved us closer to utilizing real‐time estimates of GPP, ER, and G to improve the assessment and management of environmental change. This article is categorized under: Water and Life > Nature of Freshwater Ecosystems Water and Life > Conservation, Management, and Awareness

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

“…With this contrast between data and regulations, our results invite a reconsideration of the numeric stream criteria intended to regulate stream ecosystem processes. Given the rapidly growing and more spatiotemporally representative DO datasets [14], there is clearly an opportunity for adaptive management of numeric criterial to better understand when to monitor conditions that create hypoxia or algal blooms [20,68] and how to use data to determine underlying stream processes [37,43] and move beyond binary criteria.…”

“…While high temporal resolution DO monitoring has opened a new portal to understanding riverine function, it is clear that sampling frequency and window remain strong controls on subsequent inference [ 14 , 34 ]. Many current regulatory protocols—typically created to address Total Maximum Daily Load (TMDL) requirements—do not require continuous monitoring, but may include short periods of diel data (days to weeks) or sampling at a consistent time of day [ 15 ].…”

“…Stream metabolism is routinely measured via the diel dissolved oxygen (DO) method [10], which allows simultaneous estimation of gross primary production (GPP), ecosystem respiration (ER), net ecosystem production (NEP = GPP + ER, where ER is negative by convention), and physical gas exchange (K). As in-situ DO sensors increase in reliability and decrease in cost [11][12][13], many state environmental agencies are considering DO as a proxy for ecosystem metabolism to assess and regulate stream health [14][15][16]. However, poorly constrained spatiotemporal heterogeneity in DO patterns limits the informed placement of regulatory measurements that intend to capture whole river system function [17,18].…”

Resistance and resilience of stream metabolism to high flow disturbances

“…Together, ER and GPP can elucidate whether a stream is a net producer (autotrophic; GPP > ER) or consumer (heterotrophic; ER > GPP) of carbon. Ecosystem metabolism is coupled with other ecosystem processes (e.g., nitrogen uptake; Hall and Tank, 2003) and is used to monitor stream health (Young et al, 2008;Jankowski et al, 2021), as well as ecosystem responses to disturbance and restoration (e.g., Arroita et al, 2019;Blersch et al, 2019;Palmer and Ruhi, 2019).…”

Wastewater effluents affect ecosystem metabolism: an evaluation of activation energy case study from the River Wandle, UK

“…On a global scale, a major contributor to atmospheric CO2 is from the respiration of riverine organic matter (Beaulieu et al 2013;Raymond et al 2013;Jauhiainen et al 2014), while GPP is important for supporting aquatic biodiversity in river ecosystems (Strayer and Dudgeon, 2010;Ferreira et al 2020). A wide range of environmental factors affects both GPP and ER (Mulholland et al 2008;Gernot et al 2010;Jankowski et al 2021;Fig. 1a), notably stressors associated with the urban stream syndrome (Meyer et al 2005;Walsh et al 2005).…”