Pantanal Basin Sediments: Unlocking Environmental Histories with Dr. Edward Lo
Unlocking Ocean Secrets: How Global Researchers Are Rewriting Earth’s Climate Story
A Conversation with Dr. Sarah Friedman and the Scientists Exploring the Deep History of Our Oceans
By Oluwatunmise Akanmu
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.
Conversation with Dr. Sarah Friedman
In my recent Voice from the Field conversation, I interviewed Dr. Edward Lo about his groundbreaking research, Pantanal Basin River Muds from Source to Sink: Compositional Changes in a Tropical Back-Bulge Depozone.
Why the Pantanal Basin Matters
Covering nearly 175,000 square kilometers, the Pantanal is the world’s largest tropical wetland and a textbook case for understanding back-bulge basins geologic depressions formed by the immense forces of plate tectonics. Its sediments provide a rare opportunity to study long-term weathering processes under tropical conditions, knowledge that can inform research in South America, Africa, Asia, and beyond.
Dr. Lo emphasizes:
“This basin is an exemplary setting for understanding back-bulge processes and improving global models when we encounter similar basins in the geologic record.”
Novelty in Methods
What sets this study apart is its integration of large-scale sampling with advanced lab techniques. Out of 97 identified sites, the team collected 74 fine-grained sediments, carefully chosen to capture the basin’s full mineralogical diversity.
Back in the lab, tools such as:
Grain size analysis
Total Organic Carbon (TOC)
X-ray fluorescence (XRF) geochemistry
were applied to disentangle how climate, soils, and parent rocks shape clay mineral composition from the basin’s uplands to its outlet.
Key Findings: Kaolinite as a Tropical Signature
The study found a dominance of kaolinite in the north-central Pantanal, consistent with intense weathering in the tropics. Other minerals, vermiculite, illite, and smectite were present only in rivers tied to specific parent rocks. Yet, kaolinite’s abundance eventually overwhelmed these local signals, making it the defining mineral of the basin.
This finding has broad implications: tropical weathering not only governs soil fertility and water quality, but also affects sediment generation and evolution along the path of transport.
This work raises crucial unresolved questions, such as:
When did the Pantanal Basin first form?
How do sand-rich deposits record distinct geologic “pulses” through time?
By integrating sedimentary analysis with scientific drilling and long-term records, Dr. Lo’s next phase of research could provide an improve model for interpreting other back-bulge basins in the geologic record.
For geologists, climate scientists, and environmental researchers, this study offers both data and a framework that can be cited and extended in future work on basin evolution, tropical weathering, and clay mineralogy.
Personal Reflection
Beyond the science, Dr. Lo shared that his most rewarding moments came from traveling over 1,000 kilometers across the basin:
“Seeing the diversity of geologic environments and the relationships communities have with the land was deeply moving. A lot of us do this work not only for the science, but for the people that we care about.”
Read the Work
Dr. Lo’s paper is a valuable contribution to the literature on tropical basins, clay mineralogy, and tectonics. I encourage colleagues and fellow researchers to read and cite this important study, which is open access and free to anyone to download:
https://oap.unige.ch/journals/sdk/article/view/1342
Reference
Lo, E. L., McGlue, M. M., Matocha, C. J., Silva, A., Rasbold, G. G., Kuerten, S., Louzada, R. O., & Haller, K. C. (2024). Pantanal Basin river muds from source to sink: compositional changes in a tropical back-bulge depozone. Sedimentologika, 2(1), 1-24. DOI: 10.57035/journals/sdk.2024.e21.1342
In conversation with Dr. Edward Lo on how Pantanal Basin sediments unlock Earth’s geologic and climatic history
Innovative Study Led by Dr. Helen Rosko (Department of Geography) Reveals Disconnect Between Water Quality
In a groundbreaking interdisciplinary endeavor, led by Dr. Helen Rosko, a team of researchers delved into the complexities of water quality in central Appalachia, shedding light on a crucial but often overlooked aspect of environmental justice. Their mission? To bridge the gap between publicly available data and the everyday realities faced by communities grappling with poor water quality. Led by Dr. Rosko, a diverse interdisciplinary team with backgrounds ranging from geography, hydrology, and Geographic Information Systems, the study aimed to challenge conventional narratives surrounding environmental justice. Rather than focusing solely on high-profile cases like Flint, Michigan, or Cancer Alley in Louisiana, the researchers sought to uncover quieter, yet equally significant, instances of water quality issues affecting communities.
Their methodology was as innovative as it was insightful. By leveraging existing data from the Environmental Protection Agency (EPA), coupled with advanced spatial analysis techniques, they identified "hot spots" of poor water quality in the region. These hot spots, often overlooked in mainstream discourse, served as focal points for further investigation. But the team didn't stop there. Recognizing the interconnectedness of ambient water quality with broader societal issues, they embarked on a journey to understand the lived experiences of affected communities. Through meticulous collection of news articles, public meeting minutes, and other sources, they unearthed a startling revelation: many instances of poor water quality were going unnoticed or unaddressed.
Their findings underscored the importance of rethinking traditional approaches to environmental justice. While existing literature often focuses on minority and low-income communities, this study revealed that vulnerability to poor water quality transcends demographic boundaries. Even in predominantly white, low-income areas, residents were disproportionately affected.
The implications of this research extend far beyond Appalachia. Led by Dr. Rosko, the team has developed a replicable method that harnesses publicly available data, opening doors for communities worldwide to identify and address environmental injustices in their midst. This bottom-up approach empowers local organizations and decision-makers to take action, even in the absence of extensive resources.
Dr. Rosko's vision for the future includes a world where interdisciplinary collaboration is the norm. By integrating human geography and other fields, she aims to deepen our understanding of the complex relationships between water quality, health, and community well-being.
Dr. Mary Collins, whose prior work explored socio-environmental intersections in air pollution, played a pivotal role in connecting Dr. Rosko and her team with valuable insights. This collaboration facilitated a more comprehensive understanding of environmental issues, emphasizing the interconnectedness of various factors.
Ultimately, their work showcases the power of synthesis and collaboration in addressing pressing environmental challenges. In a world where access to clean water remains a fundamental human right, studies like this offer hope and inspiration. Led by Dr. Helen Rosko and her team, the amplification of marginalized communities' voices and challenging of the status quo move us one step closer to a future where environmental justice is truly attainable for all.
Reference
Neville, J. A., Guz, J., Rosko, H. M., & Owens, M. C. (2022). Water quality inequality: a non-targeted hotspot analysis for ambient water quality injustices. Hydrological Sciences Journal. https://doi.org/10.1080/02626667.2022.2052073
Interview with Dr. Helen Rosko (Department of Geography Georgia Southern University).