Til bevillingsoversigt

Deep sea biotic responses during ocean anoxia in the Southern high latitudes

Carlsbergfondets internationaliseringsstipendier

What

The project will focus on micropalaeontology, the study of microscopic fossils. The microfossils chosen for this project are the Foraminifera: small, single-celled, shell-bearing organisms living in aquatic environments around the world. Foraminifera evolved approximately 544 million years ago and have been used extensively by micropalaeontologists to study ancient climates and ecological responses to changes therein. The specific aim of this project will be to study the bottom dwelling (benthic) foraminifera extracted from samples collected during the expedition. Sampling focus will be on the time leading up to, and across the globally recognised Ocean Anoxia Event 2 (OAE2).

Why

The high latitudes (60°-62°S) of the Earth are of critical importance for the regulation of global climate, oceanographic currents and biogeochemical cycles both today and in the past. Yet, the history of these regions is poorly known particularly from past high-CO2 time intervals such as during the Cretaceous period (145 to 65 million years ago), including the globally recognised Ocean Anoxia Event 2 (OAE2; ~94 million years ago). This represents a fundamental gap in our understanding of how high-CO2 worlds operate, and ultimately hinders our ability to predict the effects of current and future anthropogenic climate change.

How

I will apply traditional palaeontological methods such as taxonomy (the study of species) and assemblage characterisation to study the changes across the OAE2 interval. Known benthic responses to ocean anoxia include decreases in both diversity and abundance or even complete absence. Other responses to expect could include a higher relative abundance of juvenile forms and/or a prevalence of thinner shell walls. As benthic foraminifera live directly on or within the ocean floor, they are as such, excellent indicators of ecological conditions, such as the general stability of the environment, water temperature, salinity, concentration of dissolved oxygen, availability of calcium carbonate and other nutrients, substrate type,and wave and current activity.

SSR

In a time of changing global climate, it seems more important than ever to document how ancient high-CO2 worlds operated to understand the mechanisms and feedbacks of climatic changes, to better predict the effects of current and future changes. This project will enable generation of palaeotemperature and biotic records that span the OAE2, providing insight to resultant changes in deep-water and surface water circulation that can be used to test predictions from earth system models. This will allow us to address key outstanding questions regarding the mechanisms, feedbacks, and climate dynamics in the high latitudes, and thereby further our understanding of rapid climate changes in the past, how they impact deep ocean life and diversity; and hence improve predictions for the future.