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Abstract Freshwater ecosystems are under immense pressure from global environmental change. These stressors have led to biogeochemical alterations, rapid rates of defaunation and losses of associated animal‐driven ecosystem functions.Zoogeochemistry provides a unique perspective on the dual challenges of global change and defaunation in freshwater ecosystems, but zoogeochemical frameworks that explicitly link conservation biology with biogeochemistry have not yet been fully embraced by freshwater ecologists.We conducted a systematic review and meta‐analysis of the mechanistic roles that animals play in freshwater biogeochemistry, with the aim of advancing the application of zoogeochemistry in freshwaters.We reviewed 14 major mechanisms of freshwater zoogeochemistry. Our review shows that a diversity of taxa impact ecosystem‐level elemental pools and fluxes, within and across freshwater ecosystem boundaries. However, these effects are not always placed in context at the ecosystem level, which limits the scope of our meta‐analysis.Zoogeochemical impacts tended to be stronger in wetlands and lakes than in streams and estuaries. Consumption, excretion, and respiration had the strongest direct impacts on elemental pools and fluxes; bioturbation, consumption, and egestion had the strongest indirect impacts. These mechanisms often interacted, generating complex influences on elemental pools and fluxes. However, creative experimental designs can be used to isolate individual mechanisms, allowing complex effects with multiple mechanisms to be incorporated into ecosystem models.Quantifying and modelling zoogeochemical effects in freshwater ecosystems will allow ecologists and managers to make informed decisions that balance biodiversity conservation with healthy ecosystem function. 

While collaborative science is becoming the norm in ecology, many ecologists participating in collaborations are less aware of the body of research that studies the processes by which collaborative teams organize and communicate.Here, we discuss how we successfully used a shared leadership model in the Dry Rivers Research Coordination Network. We discuss how this model promoted our success in different stages of the project, using the Tuckman model of team development: forming, storming, norming, performing and adjourning.Shared leadership in the forming phase helped us recruit a diverse membership from different scientific disciplines. In the storming and norming phases, shared leadership was especially useful in ensuring that all voices were heard in establishing group norms that promoted adhesion among and investment by RCN members. Shared leadership in the performing phase was crucial in providing opportunities for early career members to lead projects, and in the adjourning phase we reflected upon our entire collaboration to identify that shared leadership was crucial to our success, generating the thesis for this commentary.It is our hope that others may find this discussion of our experience in implementing a shared leadership model useful in developing their own fruitful collaborations. Read the freePlain Language Summaryfor this article on the Journal blog. 

Abstract. A comprehensive set of measurements and calculated metricsdescribing physical, chemical, and biological conditions in the rivercorridor is presented. These data were collected in a catchment-wide,synoptic campaign in the H. J. Andrews ExperimentalForest (Cascade Mountains, Oregon, USA) in summer 2016 during low-dischargeconditions. Extensive characterization of 62 sites including surface water,hyporheic water, and streambed sediment was conducted spanning 1st- through5th-order reaches in the river network. The objective of the sample designand data acquisition was to generate a novel data set to support scaling ofriver corridor processes across varying flows and morphologic forms presentin a river network. The data are available at https://doi.org/10.4211/hs.f4484e0703f743c696c2e1f209abb842 (Ward, 2019). 

Abstract. Although most field and modeling studies of river corridorexchange have been conducted at scales ranging from tens to hundreds of meters,results of these studies are used to predict their ecological andhydrological influences at the scale of river networks. Further complicatingprediction, exchanges are expected to vary with hydrologic forcing and thelocal geomorphic setting. While we desire predictive power, we lack acomplete spatiotemporal relationship relating discharge to the variation ingeologic setting and hydrologic forcing that is expected across a riverbasin. Indeed, the conceptual model of Wondzell (2011) predicts systematicvariation in river corridor exchange as a function of (1) variation inbaseflow over time at a fixed location, (2) variation in discharge withlocation in the river network, and (3) local geomorphic setting. To testthis conceptual model we conducted more than 60 solute tracer studiesincluding a synoptic campaign in the 5th-order river network of the H. J. Andrews Experimental Forest (Oregon, USA) and replicate-in-time experimentsin four watersheds. We interpret the data using a series of metricsdescribing river corridor exchange and solute transport, testing forconsistent direction and magnitude of relationships relating these metricsto discharge and local geomorphic setting. We confirmed systematic decreasein river corridor exchange space through the river networks, from headwatersto the larger main stem. However, we did not find systematic variation withchanges in discharge through time or with local geomorphic setting. Whileinterpretation of our results is complicated by problems with the analyticalmethods, the results are sufficiently robust for us to conclude that space-for-timeand time-for-space substitutions are not appropriate in our study system.Finally, we suggest two strategies that will improve the interpretability oftracer test results and help the hyporheic community develop robust datasets that will enable comparisons across multiple sites and/or dischargeconditions.