Although the study of resource subsidies has emerged as a key topic in both ecosystem and food web ecology, the dialogue over their role has been limited by separate approaches that emphasize either subsidy quantity or quality. Considering quantity and quality together may provide a simple, but previously unexplored, framework for identifying the mechanisms that govern the importance of subsidies for recipient food webs and ecosystems. Using a literature review of > 90 studies of open-water metabolism in lakes and streams, we show that high-flux, low-quality subsidies can drive freshwater ecosystem dynamics. Because most of these ecosystems are net heterotrophic, allochthonous inputs must subsidize respiration. Second, using a literature review of subsidy quality and use, we demonstrate that animals select for high-quality food resources in proportions greater than would be predicted based on food quantity, and regardless of allochthonous or autochthonous origin. This finding suggests that low-flux, high-quality subsidies may be selected for by animals, and in turn may disproportionately affect food web and ecosystem processes (e.g., animal production, trophic energy or organic matter flow, trophic cascades). We then synthesize and review approaches that evaluate the role of subsidies and explicitly merge ecosystem and food web perspectives by placing food web measurements in the context of ecosystem budgets, by comparing trophic and ecosystem production and fluxes, and by constructing flow food webs. These tools can and should be used to address future questions about subsidies, such as the relative importance of subsidies to different trophic levels and how subsidies may maintain or disrupt ecosystem stability and food web interactions.

An experiment in >1000 river and riparian sites found spatial patterns and controls of carbon processing at the global scale.

We performed two experiments to examine how temperature and nutrients interact to control dinitrogen (N 2 ) fixation, chlorophyll a (Chl a) biomass, and community composition of periphyton in subalpine oligotrophic streams in the Sawtooth Mountains of Idaho. We grew periphyton on nutrient-diffusing substrata (NDS) in a cold lake inlet (7uC) and a warm lake outlet (18uC). We then switched substrata between the two stream sites to test the effect of incubation temperature on N 2 -fixation rates. Periphyton on substrata grown at both sites exhibited greater N 2 -fixation rates when incubated in the warm outlet, which indicates physiologic temperature control. Periphyton on P-enriched NDS grown in the warm outlet had the greatest N 2 -fixation rates, largest Chl a biomass, and largest percentage of N 2 -fixing taxa of any treatment, which indicates that temperature and P interact to influence the community. In the second experiment, colonized rocks and uncolonized NDS were placed in cold (13uC) and warm (18uC) mesocosms. Within 2 days, warm temperature stimulated N 2 fixation by the rock periphyton community two times above cold temperatures, which indicates physiologic temperature control. After 45 days, warm temperatures and P enrichment led to Anabaena sp. in the periphyton community and the greatest rates of N 2 fixation observed in the experiment, which also indicates temperature and nutrient control at the community level. This study indicates that N 2 fixation and periphyton community composition in oligotrophic streams are controlled by both temperature and P supply, with temperature modulating the response to P.

The issues facing academic mothers have been discussed for decades. Coronavirus Disease 2019 (COVID-19) is further exposing these inequalities as womxn scientists who are parenting while also engaging in a combination of academic related duties are falling behind. These inequities can be solved by investing strategically in solutions. Here we describe strategies that would ensure a more equitable academy for working mothers now and in the future. While the data are clear that mothers are being disproportionately impacted by COVID-19, many groups could benefit from these strategies. Rather than rebuilding what we once knew, let us be the architects of a new world.