Abyssal deposit‐feeding rates consistent with the metabolic theory of ecology

The Metabolic Theory of Ecology (MTE) posits that metabolic rate controls ecological processes, such as the rate of resource uptake, from the individual‐ to the ecosystem‐scale. Metabolic rate has been found empirically to be an exponential function of whole organism body mass. We test a fundamental assumption of MTE, whether resource uptake scales to metabolism, by examining detritivores accessing a single common resource pool, an ideal study case. We used an existing empirical model of ingestion for aquatic deposit feeders adjusted for temperature to test whether ingestion by abyssal deposit feeders conforms to MTE‐predicted feeding rates. We estimated the sediment deposit‐feeding rates of large invertebrates from two abyssal study sites using time‐lapse photography, and related those rates to body mass, environmental temperature, and sediment organic matter content using this framework. Ingestion was significantly related to individual wet mass, with a mass‐scaling coefficient of 0.81, with 95% confidence intervals that encompass the MTE‐predicted value of 0.75, and the same pattern determined in other aquatic systems. Our results also provide insight into the potential mechanism through which this fundamental assumption operates. After temperature correction, both deep‐ and shallow‐water taxa might be summarized into a single mass‐scaled ingestion rate. The Metabolic Theory of Ecology (MTE; Brown et al. 2004) posits that metabolic rate controls ecological processes, from the individual‐ to the ecosystem‐scale (Schramski et al. 2015), and provides a potentially valuable numerical framework for the interpretation and modeling of ecological processes. A key element in the link between individuals and the ecosystem is the relative distribution of resource use across body mass classes (White et al. 2007). These concepts, and particularly their underlying causes, remain contentious (Isaac et al. 2013). In the simple, symmetric case of this “energetic equivalence,” resource acquisition and use are approximately equivalent in each size class; metabolism is assumed to scale with individual body mass, and numerical abundance in geometric size classes is approximated by a power function. This simple case may only hold within a single trophic level (Brown et al. 2004), with herbivores, or detritivores, accessing a single common resource pool as good candidates for study. Despite being a fundamental assumption of MTE, few studies test whether such resource uptake scales with metabolism. Prior to formulation of the MTE, Cammen (1980) produced an empirical model