Show-Me State Times

Researchers from the University of Missouri have unveiled new insights into early ocean life through a study of ancient reef-building organisms and fossilized sea creatures. The focus was on archaeocyathids, sponge-like organisms that constructed some of the planet's earliest reefs over 514 million years ago in what is now Nevada.

The study examined how these ancient reefs shaped their environment and the presence of "small shelly fauna," some of the earliest animals with hard shells. Unlike modern coral reefs, which are biodiversity hotspots, these early reefs did not show a consistent pattern of boosting biodiversity. Casey Bennett, a graduate student in the Department of Geological Sciences and lead author, noted, “With modern reefs, biodiversity is expected to decrease as you move away from the reef structure due to reduced shelter and food access... However, we didn’t find a consistent pattern with these ancient reefs.”

The research challenges assumptions about ecosystem development around reef structures and offers insight into how life evolved in early oceans. It also suggests that ancient ocean currents played a significant role in shaping these communities. Sarah Jacquet, an assistant professor of paleontology at Mizzou and co-author of the study, stated that hydrodynamics likely influenced which faunas were preserved or removed.

Additionally, sediment conditions impacted fossil preservation quality. Bennett explained that different rock types represented sub-environments that preserved specific organisms better than others.

The team highlights the importance of ongoing fieldwork and fossil analysis to understand early reef habitats' influence on life distribution in Earth's oceans. Jacquet remarked, “Just because we know how the world works today doesn’t mean it worked the same way back then.”

The findings were published in Palaeogeography, Palaeoclimatology, Palaeoecology under the title “Small shelly fauna biodiversity from reef-adjacent facies of the lower Cambrian Harkless Formation, Nevada.” Clare Mate, a Mizzou graduate student, also contributed to this study.