Metabolic rates of groundwater species as a function of body mass and temperature

Research on the metabolic physiology of groundwater species, particularly regarding oxygen consumption rates (OCR), has made significant advancement, revealing valuable insights into the adaptations of exclusively groundwater-dwelling (stygobitic) species. However, a comprehensive understanding of how these metabolic rates scale with body mass and respond to temperature changes remains elusive. This study aims to bridge this gap by reviewing published data on OCR across a variety of groundwater organisms to elucidate patterns of metabolic rates in relation to body size and temperature. We employed a combination of literature review and quantitative analyses, focusing on the allometric scaling of OCR with body weight and the effect of temperature on metabolic rates. Our findings indicate that OCR scales with body weight in an allometric pattern, with an inter-species slope of 0.80, suggesting non-isometric scaling. Furthermore, our analysis showed that stygobitic species' metabolic rates are less responsive to warming than those of non-stygobitic species at low to moderate temperatures. However, at higher temperatures, metabolic rates in stygobitic species decline faster than in non-stygobitic taxa, highlighting a potential vulnerability to global climate change. This study contributes to our understanding of the metabolic strategies of groundwater species, underscoring the need for further research to fully grasp the eco-evolutionary implications of these findings for groundwater conservation. Keywords: Allometry, Arrhenius equation, ectotherms, metabolism, oxygen consumption rate, respiration, stygobiont