Study Challenges Assumptions About Melting Glaciers and Climate Change

Rutgers scientists find Antarctic glacial meltwater contributes less iron than previously thought

Published on Feb. 27, 2026

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A new study by marine scientists from Rutgers University-New Brunswick challenges a long-held assumption that melting glaciers in Antarctica provide a significant amount of iron to the surrounding waters, which could feed blooms of microscopic algae and pull carbon dioxide from the atmosphere. The researchers found that the meltwater from an Antarctic ice shelf actually supplies far less iron than previously believed, with the majority of iron coming from deep ocean waters and sediments instead.

Why it matters

This study could significantly alter how climate change predictions are modeled and forecasted, as the theory of 'iron fertilization' from melting glaciers has been seen as a potential silver lining in the gloomy outlook of climate change. The findings raise questions about the true sources of iron in the Southern Ocean near Antarctica, which is a highly productive region for phytoplankton growth and a major carbon sink.

The details

The Rutgers team traveled to the Dotson Ice Shelf in West Antarctica to collect melting glacial water at the source and analyze its iron content. They found that the meltwater contributed only about 10% of the dissolved iron coming out of the ice shelf cavity, with the majority coming from deep ocean waters (62%) and shelf sediments (28%). The iron isotope ratios also suggested that a liquid meltwater layer beneath the glacier, which lacks dissolved oxygen, is a larger source of iron than the ice shelf melting itself.

  • In 2022, the researchers traveled aboard the U.S. icebreaker Nathaniel B. Palmer to the Dotson Ice Shelf in the Amundsen Sea.
  • The findings were published in the journal Communications Earth and Environment in February 2026.

The players

Rob Sherrell

A professor in the Department of Marine and Coastal Sciences at the Rutgers School of Environmental and Biological Sciences and the study's principal investigator.

Venkatesh Chinni

A postdoctoral scholar at Rutgers and the lead author of the study.

Jessica Fitzsimmons

A professor and chemical oceanographer at Texas A&M University.

Janelle Steffen

An assistant research scientist at Texas A&M University.

Tim Conway

An associate professor at the University of South Florida.

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What they’re saying

“It has been widely assumed that glacial melting underneath ice shelves contributes considerable bioavailable iron to these shelf waters, in a process of natural glacier-driven iron fertilization.”

— Rob Sherrell, Professor (Rutgers University-New Brunswick)

“Roughly 90% of the dissolved iron coming out of the ice shelf cavity comes from deep waters and sediments outside the cavity, not from meltwater.”

— Venkatesh Chinni, Postdoctoral Scholar (Rutgers University-New Brunswick)

What’s next

The researchers say additional research is needed to better understand how the subglacial processes are involved in contributing iron to the Southern Ocean.

The takeaway

This study challenges a long-held assumption about the role of melting glaciers in providing iron to the Southern Ocean, which could have significant implications for how climate change models and predictions are developed. The findings suggest the sources of iron in this region are more complex than previously thought.