Metabolic Niches and Biodiversity: A Test Case in the Deep Sea Benthos

Abstract

The great anthropogenic alterations occurring to carbon availability in the oceans necessitate an understanding of the energy requirements of species and how changes in energy availability may impact biodiversity. The deep-sea floor is characterized naturally by extremely low availability of chemical energy and is particularly vulnerable to changes in carbon flux from surface waters. Because the energetic requirements of organisms impact nearly every aspect of their ecology and evolution, we hypothesize that species are adapted to specific levels of carbon availability and occupy a particular metabolic niche. We test this hypothesis in deep-sea, benthic invertebrates specifically examining how energetic demand, axes of the metabolic niche, and geographic range size vary over gradients of chemical energy availability. We find that benthic invertebrates with higher energetic expenditures, and ecologies associated with high energy demand, are located in areas with higher chemical energy availability. In addition, we find that range size and location of deep-sea, benthic species is determined by geographic patterns in chemical energy availability. Our findings indicate that species may be adapted to specific energy regimes, and the metabolic niche can potentially link scales from individuals to ecosystems as well as adaptation to patterns in biogeography and biodiversity.

Climate-driven benthic invertebrate activity and biogeochemical functioning across the Barents Sea polar front

“…At the same time, our analysis confirms the presence of distinct basal infaunal communities and a faunal separation between northern (Arctic) and southern (Atlantic) assemblages at a latitude that corresponds with the operational oceanographic [66] and benthic [56] polar front. By extension, when taken together, our findings give credence to the view that Arctic dwelling benthic assemblages are more robust than physiological assessments may indicate [100], and it is tempting to speculate that a proportion of the community are adapted to maximize seasonal shifts in, for example, resource availability [101]. However, as has been highlighted before [28], detection of the influence of environmental conditions on the structure and function of benthic communities requires an overview of how functionally relevant infaunal traits covary with changing abiotic and biotic circumstance [102], and how species interactions and ecological roles vary with context [103].…”

The commonness of rarity in a deep‐sea taxon

“…Proposed biogeographic provinces (Watling et al 2013) for the deep sea have also incorporated spatial variation in POC flux. These patterns of biodiversity and biogeographic provinces reflect both the theoretical and empirical evidence that POC specificity is an important niche axis for deep-sea species (McClain et al 2012b(McClain et al , 2018(McClain et al , 2020. Here, I quantify habitat specificity as the standard deviation of POC flux following research that deep-sea bivalve niches specifically have been demonstrated to reflect POC flux (McClain et al 2012b(McClain et al , 2018.…”

Changes to benthic community structure may impact organic matter consumption on Pacific Arctic shelves

“…The relatively low respiration rate, and thus low metabolic demand, of N. pernula may leave it preadapted to the lower-productivity waters of this area, which is influenced by the Alaska Coastal Current. This low metabolic demand may confer a physiological competitive advantage over other taxonomic groups with higher carbon requirements ( Burton et al , 2011 ; McClain et al , 2020 ). Therefore, we hypothesize that species with low metabolic rates, such as Astarte sp.…”