SELECTIVE EXTINCTION BASED ON LIFE HABIT IN DECAPODS OVER THE CENOMANIAN-TURONIAN OAE2

We are facing an environmental and biodiversity crisis in the modern day due to anthropogenic climate change. Projected crises in the oceans include rising water temperature, ocean acidification and anoxia. In particular, large provinces of anoxia can cause species relocation or extinction, and destabilize ecosystems. However, the exact outcomes of ecological disruption are unclear. How have species reacted to widespread anoxia in the past? Can we predict which life habits will give species an advantage with respect to anthropogenic climate change?

Several ancient mass extinctions were also associated with widespread anoxia. The Permian-Triassic extinction, Triassic-Jurassic extinction, as well as the Cretaceous Ocean Anoxic Events (OAE) 1 and 2 show stratigraphic and isotopic evidence of anoxia. This project uses the Paleobiology Database to assess changes in life habit irrespective of taxonomy over the course of the Cenomanian-Turonian Ocean Anoxic Event (OAE 2). The Cenomanian-Turonian OAE was a period of abrupt warming and severe anoxia created by the abrupt release of CO₂ into the atmosphere. It was also associated with an extinction of 27% of marine invertebrates, as well as several marine reptile groups. Widespread anoxia during the Triassic-Jurassic OAE, as well as the Torarcian OAE, led to selective extinction of infaunal bivalves.

However, what about decapods, a common modern warning taxon for low oxygen conditions? Decapods in the Cretaceous filled a variety of niches, including infaunal burrowing, predation, herbivory, filter feeding, and many more. They also lived in a great diversity of life habits, which we will simplify to epifaunal and infaunal. In addition, studies of modern decapods show that they require more oxygen as compared to similarly sized invertebrates, and therefore may be more sensitive to anoxia. This project uses the Paleobiology Database to evaluate several measures of decapod extinction throughout the Cretaceous to see if infaunal versus epifaunal status has an effect on survivorship. This can tell us about how Cretaceous decapods responded to increasingly stratified and anoxic water, as well as what niches decapods filled to survive this stressful period in earth’s oceans.