Earth

New research reveals deep-sea clues that solve the mysteries of the ice age 1 million years ago

Researchers analyzed sediment core samples collected by D/V JOIDES Resolution near Cape Town, South Africa. Their discoveries reveal details about changes in temperature and salinity in the deep ocean, as well as the history of mixing of water originating from both the Northern and Southern Hemispheres. Credit: Sophie Hines, Woods Hole Oceanographic Institution

A study recently published in the journal Science challenges theories about the origins of the Earth’s major ice age transitions.

The study, led by an international team of researchers from Woods Hole Oceanographic Institution (WHOI), Lamont-Doherty Earth Observatory, Scripps Institution of Oceanography, and Cardiff University, provides new insights into the role of the ocean in mid-Pleistocene climate. provide. transition, a period of mysterious change in climate cycles that began about a million years ago.

Although many theories have been proposed for the mid-Pleistocene transition, one important theory involves a significant weakening of the Atlantic Meridional Circulation (AMOC). But new discoveries suggest an equally important but more subtle role for the deep ocean.

The research team used climate records spanning the past 1.2 million years to reconstruct deep ocean properties important to understanding ocean currents and carbon sequestration capacity.

“The deep ocean is huge, especially when you consider its ability to store carbon dioxide (CO2) compared to the atmosphere,” said lead author and WHOI scientific assistant Dr. Sophie Hynes. “Even modest changes in ocean circulation can have large effects on Earth’s climate.”

Researchers analyzed sediment core samples collected during International Ocean Discovery Program (IODP) Expedition 361 near Cape Town, South Africa. By studying carbon, oxygen and neodymium isotopes from fossilized single-celled organisms called foraminifera, the research team revealed changes in deep ocean temperature and salinity, and the history of water mixing originating from both the northern and southern hemispheres. Revealed details about.

New research reveals deep-sea clues that solve the mysteries of the ice age 1 million years ago

Dr. Sophie Hynes (right) assists IODP-JRSO technician Sandra Herman (left) in cutting Expedition 361’s core into sections. Credit: Tim Fulton.

“Importantly, changes in various properties of the deep ocean are always the same,” said Dr. Sidney Hemming, Arthur D. Stork Professor of Earth and Environmental Sciences at the Lamont-Doherty Earth Observatory and co-principal investigator of the expedition. “We are showing that this is not the case.” A more highly resolved multi-proxy record, including the transition period, shows that ice age intensification was primarily influenced by changes around Antarctica. ”

It has been suggested that as the Antarctic ice sheet expanded, the ocean’s carbon storage capacity increased, leading to lower atmospheric CO2 levels, a cooler climate, and longer ice age cycles.

Dr Hines added: “Our research highlights the complex interactions between ocean dynamics and climate change and highlights the importance of the Southern Ocean in understanding Earth’s climate history. ” he added.

Recent studies have highlighted the urgency of anthropogenic climate change, particularly in relation to AMOC reduction. The Southern Ocean continues to warm at an alarming rate, and understanding its dynamics is important. The Southern Ocean plays a vital role in regulating global climate patterns, and changes therein can have significant impacts on ecosystems and weather systems around the world.

Further information: Sophia KV Hines et al., Reconsidering the mid-Pleistocene transition ocean circulation crisis, Science (2024). DOI: 10.1126/science.adn4154

Provided by Woods Hole Oceanographic Institution

Citation: New study reveals deep ocean clues to million-year-old Ice Age puzzle (November 8, 2024), https://phys.org/news/2024-11-deep-ocean-clues- Retrieved November 10, 2024 from million years.html

This document is subject to copyright. No part may be reproduced without written permission, except in fair dealing for personal study or research purposes. Content is provided for informational purposes only.

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button