Environmental Geology & Geochemistry Seminar (EGGS)

Date
Sep 16, 2021, 12:30 pm1:30 pm
Location
Guyot 220 & via Zoom

Speaker

Details

Event Description

Abstract
Relationships between body size and temperature are widely observed in laboratory experiments and the geological record of marine species, but a predictive theory is lacking. We derive a mechanistic model to predict this ‘Temperature Size Rule’ from organismal O_2 supply and demand across the range of ocean temperatures and body sizes. The model predicts a magnitude and variability of inter-generational size reductions consistent with laboratory experiments and fossil evidence of diverse aquatic species, supporting O_2 limitation as the underlying mechanism. Stronger temperature-size responses among larger species arise from convergent trends in allometric dependence of metabolic rate and diffusive O_2 supply, consistent with both theoretical scaling and measured species traits across the size spectrum from microbes to macrofauna. Without rapid physiological adaptation, accelerating ocean warming and O_2 loss in this century will cause >20% reductions in the body mass of the smallest animal species, with larger and more variable shrinkage at higher trophic levels, compounding the direct impact of human harvesting on size-structured ocean food webs.