Voices from the Field Episode 7-Unlocking Ocean Secrets: How Global Researchers Are Rewriting Earth’s Climate Story

The Deep Connection Between Oceans and Climate

Welcome back to Voices from the Field — where we uncover the work and journeys of professionals transforming the landscape of environmental science and geology.

In this edition, I had the privilege of speaking with Dr. Sarah Friedman, Assistant Professor of Geology in the School of Earth, Environment, and Sustainability at Georgia Southern University, a Structural geologist whose passion lies in unraveling how Earth's surface deforms, folds, and transforms over time, who joined a remarkable team of international scientists on a mission to understand how the deep ocean has shaped Earth’s climate for millions of years.

The research, recently published in Nature Communications, goes beyond tectonics and sediment — it tells a story of how ancient ocean circulation shaped the world we live in today.

A Landmark Discovery Beneath the Atlantic

The study, titled “The Onset of Strong Iceland–Scotland Overflow Water, 3.6 Million Years Ago,” brought together more than 30 scientists from across the globe as part of the International Ocean Discovery Program (IODP).

Their goal? To explore the Mid-Atlantic Ridge and the Iceland hotspot, and uncover how the movement of tectonic plates, ocean currents, and sediments intertwine to record Earth’s changing climate.

But what they discovered was even more profound — a major shift in ocean circulation patterns between Iceland and Scotland that occurred about 3.6 million years ago, altering heat flow, nutrient distribution, and ocean ecosystems on a planetary scale.

“Our oceans transport heat, nutrients, and oxygen — the key ingredients for life,” Dr. Friedman explained during our conversation. “When those currents shift, everything changes. Energy moves differently, ecosystems adapt or collapse, and the planet itself adjusts.”

How the Science Was Done

Through deep-sea core samples and advanced techniques like cyclostratigraphy and astronomical tuning, the team matched sediment layers and fossil evidence with Earth’s orbital cycles.

Dr. Friedman’s group focused on high-resolution paleomagnetic data, analyzed every 2.5 centimeters, revealing a stunningly detailed timeline of magnetic and environmental changes.

These records serve as Earth’s ancient memory, allowing scientists to reconstruct how oceans responded to natural shifts — a crucial step in understanding the climate patterns we see today.

Resilience and Collaboration in a Changing World

The project was not without challenges. Originally scheduled for 2020, the expedition was disrupted by the COVID-19 pandemic, forcing scientists to work remotely while technicians continued the mission at sea.

“It was unprecedented — a scientific expedition without scientists onboard,” Dr. Friedman shared.

The team reconvened in 2023, bringing in new researchers and collecting more data, demonstrating that even in times of uncertainty, science thrives through collaboration and perseverance.

Why This Matters Now

As scientists warn about potential weakening in parts of the modern ocean circulation system, studies like this offer a long-term view of change.

Understanding how ancient oceans responded to tectonic and climatic forces helps us predict how modern oceans may evolve under global warming — insights essential to both climate modeling and environmental policy.

“Our research doesn’t show collapse,” Dr. Friedman said, “but it reminds us that the ocean is dynamic. The better we understand past shifts, the better prepared we are for future ones.”

Lessons for Future Scientists

For young geologists and environmental scientists, this project underscores the power of teamwork, curiosity, and interdisciplinary thinking.

As Dr. Friedman emphasized, “Every rock, every sample tells a story. Some stories take years to uncover — but the questions you ask today can shape the science of tomorrow.”

Explore Further

The full study, “The Onset of Strong Iceland–Scotland Overflow Water, 3.6 Million Years Ago,” is available open-accessin Nature Communications (May 2025).

Final Thoughts

This conversation reminded me that geology isn’t just about the past — it’s about understanding the present and preparing for the future.

Our planet is a living archive, and the scientists studying it — from tectonics to climate — are the storytellers helping us read its pages.

Stay tuned for more Voices from the Field stories, where we highlight researchers bridging science, community, and environmental resilience.

Acknowledgment

Special thanks to the FacultyCenter GeorgiaSouthern for providing the podcast space and technical support that made this Voices from the Field episode possible.

Until next time — I’m Oluwatunmise Akanmu