CENOZOIC CLIMATE AND LARGER BENTHIC FORAMINIFERAL BIODIVERSITY TRENDS

In the modern day, coral reefs harbor a huge amount of biodiversity and ecosystem functions and services. However, numerous studies show they are currently undergoing a crisis with ocean acidification and warming seas leading to widespread degradation. Understanding the response of these shallow tropical environments to major climatic change is therefore key to managing their future. Whilst corals are the most obvious organisms in modern reef systems, equally important for carbonate production over the Cenozoic are a group known collectively as the larger benthic foraminifera. Whereas the fossil record of corals is patchy, LBF occur abundantly in shallow tropical marine deposits. The LBF, much like corals, contain photosymbionts, limiting them to nutrient poor waters in the photic zone and making them highly sensitive to environmental perturbations. They are therefore ideal fossils for tracking climate response through geological time in reef environments.

Cenozoic climate change is a major topic of current research. However, most studies are from deep sea records and shallow marine records are often fragmentary, despite the shallow marine environment frequently being of most concern for future global warming. Larger benthic foraminifera, have largely been neglected by climatic-impact studies, but have huge potential as tools to examine the effects of rapid climate change on the reef environment. The Cenozoic was a dynamic interval of Earth’s climatic history. A long term gradual cooling trend is punctuated by multiple instances of more rapid temperature change. The LBF also undergo a series of global overturning events, culminating with a rapid extinction of several long ranging genera at the Eocene-Oligocene transition. However the mechanisms behind these events are not well understood.

In this project, we use the close association between morphology and palaeoenvironment to create a global database of Cenozoic occurrences of LBF. Though in its early stages, this type of record has the potential to show whether major changes in distributions, diversity and evolution of key morphologies, reflecting function or life history traits, on a broad scale are linked to climatic events.