Planktonic foraminifera and their proxies for the reconstruction of surface-ocean climate parameters

Abstract

Planktonic foraminifera are useful organisms to assess the surface oceans role in climate change, due to their upper water column habitat, calcium carbonate mineral structure, and preservation in the deep-sea sedimentary record. Carbonate sediments rich in the calcitic shells of foraminifera are abundant in both space and time, which allows their use in an array of paleoceanographic studies over time scales ranging from decadal to glacial-interglacial, as well as beyond and between. Here we review the most important proxy methods to reconstruct surface-ocean climatic variables using planktonic foraminifera. These methods include assemblage-based and geochemical-based (both isotopic and elemental) approaches. The natural emphasis is on temperature, the most important climatic parameter of the surface ocean, although related physical, chemical, and biological properties are addressed as well, such as salinity, productivity, nutrient utilization, weathering, circulation, and oceanic C-system properties including alkalinity, pH, and [CO3 2-]. In our systematic evaluation of each foraminiferal proxy, we provide the basis for each method, brief examples, and a glimpse into the future, when current research needs will hopefully be met.