The planktonic foraminifera exhibit the best species-level fossil record available to science. Decades of work have led to an extensive breadth of knowledge of their functional ecological and morphological traits, as well as the ability to collate their occurrences into global occurrence datasets with the potential to explore these functional roles from the global to the regional perspective. Following the collation of the Triton planktonic foraminifera occurrence dataset, efforts have been focussed on leveraging this incomparable archive to better understand the evolutionary and biological response of the planktonic ecosystem to Cenozoic climate change. This presentation highlights some of the key novel discoveries that have come to fruition with the Triton dataset and showcases exciting projects in preparation:
Firstly, new work looking into compositional variability to assess the temporal and spatial heterogeneity of planktonic foraminiferal communities shows that the Cenozoic was a period of punctuated volatility with high turnover post K-Pg mass extinction and during the Late Neogene cooling. Using a new statistic called FAVA, this work highlights key features of global communities including equatorial regions stabilizing over time, whereas polar communities, especially in the Southern Ocean, destabilized; and equatorial regions homogenizing from initially high heterogeneity, whereas polar communities showed the opposite pattern, including a “latitudinal seesaw” of spatial heterogeneity over the past 30 million years.
Secondly, by assessing the planktonic foraminiferal record to track changes in their functional ecological groups through the Cenozoic greenhouse-icehouse transition at the Eocene-Oligocene Boundary (~34 million years ago), it was found that warm-water-adapted species, especially photosymbiotic taxa occupying the surface mixed-layer, gradually declined in richness. In contrast, cool water dwellers, such as the thermocline and sub-thermocline species, showed steadier speciation through the Eocene, followed by post-EOT diversification across the globe. These patterns may represent protracted and transient cooling events across the greenhouse-icehouse transition laying the foundation for early colonization of the oceanic “twilight zone”. This may have ultimately set the stage for many of the biodiversity patterns that are still present in the modern day.
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