Late Cenozoic cooling restructured global marine plankton communities

Area of Science:

• Paleontology
• Marine Biology
• Climate Science

Background:

• Marine organisms' geographic ranges are shifting poleward due to climate change.
• Understanding past biodiversity patterns is crucial for contextualizing current trends and potential extinctions.
• Planktonic foraminifera fossils offer a rich dataset for studying marine biogeography dynamics.

Purpose of the Study:

• To analyze planktonic foraminifera diversity, latitudinal specialization, and equitability over the past eight million years.
• To investigate the relationship between ancient climate changes and marine biogeography.
• To understand the development of marine biodiversity patterns and their drivers.

Main Methods:

• Application of a bipartite network approach to quantify diversity metrics.
• Utilized the Triton dataset, a high-resolution global record of planktonic foraminiferal occurrences.
• Analyzed data spanning the last eight million years.

Main Results:

• A global, clade-wide shift towards the Equator in ecological and morphological community equitability over the past eight million years was observed.
• This shift is linked to temperature changes during late Cenozoic bipolar ice sheet formation.
• A latitudinal equitability gradient among planktonic foraminiferal functional groups was identified, coupled to the biodiversity gradient only in the last two million years.

Conclusions:

• Higher latitudes promoted community equitability across ecological and morphological groups before the last two million years.
• Past and present range shifts suggest significant poleward expansion of marine communities under warming scenarios.
• The study provides insights into long-term marine biodiversity responses to climate change.