Metabolic tradeoffs control biodiversity gradients through geological time.
Current biology : CB
The latitudinal gradient of increasing marine biodiversity from the poles to the tropics is one of the most conspicuous biological patterns in modern oceans.1-3 Low-latitude regions of the global ocean are often hotspots of animal biodiversity, yet they are set to be most critically affected by anthropogenic climate change.4 As ocean temperatures rise and deoxygenation proceeds in the coming centuries, the volume of aerobically viable habitat is predicted to decrease in these zones.5,6 In contrast to the slightly asymmetrical modern latitudinal biodiversity gradient,7 compilations of fossil occurrences indicate peaks in biodiversity may have existed much further away from the equator in the past, with transitions between climate states hypothesized to explain this trend.8-13 We combine a new compilation of fossil mollusc occurrences, paleotemperature proxies, and biogeographic data to reveal a non-monotonic relationship between temperature and diversity in the paleontological record over the last 145 million years. We derive a metabolic model that integrates the kinetic effects of temperature on biodiversity14 with the recently described Metabolic Index that calculates aerobic habitat availability based on the effect of temperature on hypoxia sensitivity.5,15,16 Although factors such as coastal habitat area and homeothermy are important,17,18 we find strong congruence between our metabolic model and our fossil and paleotemperature meta-analysis. We therefore suggest that the effects of ocean temperature on the aerobic scope of marine ectotherms is a primary driver of migrating biodiversity peaks through geologic time and will likely play a role in the restructuring of biodiversity under projected future climate scenarios.
View details for DOI 10.1016/j.cub.2021.04.021
View details for PubMedID 33961786
- Global marine redox evolution from the late Neoproterozoic to the early Paleozoic constrained by the integration of Mo and U isotope records EARTH-SCIENCE REVIEWS 2021; 214
Persistent global marine euxinia in the early Silurian.
2020; 11 (1): 1804
The second pulse of the Late Ordovician mass extinction occurred around the Hirnantian-Rhuddanian boundary (~444Ma) and has been correlated with expanded marine anoxia lasting into the earliest Silurian. Characterization of the Hirnantian ocean anoxic event has focused on the onset of anoxia, with global reconstructions based on carbonate delta238U modeling. However, there have been limited attempts to quantify uncertainty in metal isotope mass balance approaches. Here, we probabilistically evaluate coupled metal isotopes and sedimentary archives to increase constraint. We present iron speciation, metal concentration, delta98Mo and delta238U measurements of Rhuddanian black shales from the Murzuq Basin, Libya. We evaluate these data (and published carbonate delta238U data) with a coupled stochastic mass balance model. Combined statistical analysis of metal isotopes and sedimentary sinks provides uncertainty-bounded constraints on the intensity of Hirnantian-Rhuddanian euxinia. This work extends the duration of anoxia to >3 Myrs - notably longer than well-studied Mesozoic ocean anoxic events.
View details for DOI 10.1038/s41467-020-15400-y
View details for PubMedID 32286253
- Oxygen, temperature and the deep-marine stenothermal cradle of Ediacaran evolution PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 2018; 285 (1893)
- The Temporal and Environmental Context of Early Animal Evolution: Considering All the Ingredients of an "Explosion" INTRODUCTION INTEGRATIVE AND COMPARATIVE BIOLOGY 2018; 58 (4): 605–22