Testing Energy Biodiveristy Theories on Marine Species

Energy–biodiversity hypotheses aim to explain the mechanistic relationships between energy availability in the environment and the processes that generate and maintain species richness. These hypotheses propose that the amount, variability, and minimum levels of available energy can influence speciation, extinction, and the overall capacity of ecosystems to support diverse biological communities. The Available Energy (Cumulative) Hypothesis suggests that ecosystems receiving greater annual cumulative energy inputs can support more species because higher energy availability increases resource production. This hypothesis is supported by both in situ field observations and controlled in vivo studies. The Environmental Stability (Variation) Hypothesis proposes that lower intra-annual variability in energy promotes species richness by providing predictability and reducing physiological stress, which enables more species to coexist. In contrast, the Environmental Stress (Minimum) Hypothesis emphasizes the role of minimum energy thresholds, suggesting that regions maintaining higher minimum levels of energy throughout the year can support more species by exceeding the baseline physiological requirements necessary for survival and reproduction. These three hypotheses (cumulative, variation, and minimum energy) collectively explain between one-half and two-thirds of the geographic distributions of amphibians, mammals, and birds in terrestrial systems, demonstrating their broad explanatory power. Importantly, the mechanisms underlying these hypotheses are not inherently restricted to land-based ecosystems. In this study, we extend these ideas to the marine environment to assess whether similar energy–biodiversity relationships emerge in the ocean. Using satellite-derived observations, we developed two radiative energy indices (photosynthetically active radiation and sea surface temperature) and three metabolically based indices (primary production and benthic particulate organic carbon flux). We paired these indices with species richness data for marine fish, mammals, reptiles, lobsters, abalone, conus species, corals, and seagrasses. Our results show that radiative energy indices explained up to 63% of the variation in species richness for certain taxa, whereas metabolic indices were generally less predictive. As in terrestrial ecosystems, cumulative energy was most important offshore, while energy variation more strongly influenced coastal biodiversity, likely reflecting the dynamic and productive nature of coastal habitats. Collectively, our findings demonstrate that energy availability is closely linked to global patterns of marine species richness.