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Marilyn Fogel, ‘isotope queen’ of science, dies at 69

She helped develop the field of biogeochemistry and showed its power in making discoveries about nature, ecology, the long-term history of living things and the possibilities of life on other worlds

Marilyn Fogel in 2018. ( Natasha Metzler/Carnegie Institution for Science)

Marilyn Fogel, a scientist dubbed the “isotope queen” for illuminating fundamental scientific questions through analysis of atomic isotope ratios, died May 11 at her home in Mariposa, Calif. She was 69.

The cause was amyotrophic lateral sclerosis, often known as Lou Gehrig’s disease, said her husband, Chris Swarth.

Dr. Fogel spent much of her career at the Carnegie Institution for Science in Washington, where she pioneered the use of isotope ratios in the relatively new field of biogeochemistry. She helped show the value of knowing stable isotope ratios and of blending biology, chemistry and geology in the study of nature, ecology, the long-term history of living things and the possibilities of life on other worlds.

Important aspects of her work involved mastery and development of precision techniques to measure quantities on the atomic scale. But much involved field work that included expeditions to far places under hazardous conditions.

In addition to being lashed to the deck of a small ship at sea in a hurricane, one of her assignments on an Arctic expedition was to carry the rifle intended to fend off any marauding polar bears.

In addition, from her earliest days in research, Dr. Fogel observed and overcame many difficulties and indignities confronting women in science. Her interest in a sophisticated version of an instrument vital to her work was once met with a dismissive comment by an engineer: “This is not a mass spectrometer for a housewife.”

As she achieved status and recognition, she encouraged and mentored other women. She also became, she once said, a “pesty, persistent voice” on committees that bestowed awards.

At the outset, she found the world of geoscience akin to the proverbial Old Boys Club. As she advanced, she was transformed, she said, from a shy and quiet researcher to an outspoken laboratory director and a leader among scientists. It could be said that she became herself an Old Boys Club member.

But she made a distinction: “I am now old, but have never been and will never be a boy.” In the wit therein displayed may be seen a flash of the zest and humor that led her to call her blog “Isotope Queen.” She also published a book titled “Advice from the Isotope Queen: Building a Meaningful Career While Enjoying a Full Life.”

In her work, Dr. Fogel inferred the story of significant events in the history of living creatures through changes in the ratios of the isotopes of their atoms.

Measuring such changes, discerning almost infinitesimally small, disparities in weight, required a precision that might not long before her have been regarded as impossible to achieve. Using such seemingly abstruse measurements to reach broad conclusions about nature demanded an uncommon blend of talents. It required harnessing great technical skill to knowledge of many disciplines and a creative ability to conceive of possibilities.

Behind many of her findings lay the concept of the isotope. Isotopes of a chemical element are atoms that differ from each other in small ways. They each have the same number of protons and electrons. That gives them the same chemical properties. But two isotopes of the same element differ in the number of neutrons in their nuclei. Although they are still atoms of the same element the difference in the number of neutrons means that they differ in mass or weight.

Different isotopes of an element all have the same number of electrons, and so in theory will bond to other atoms in the same way. But in actual chemical reactions, a slightly heavier atom of a given element may have slightly less mobility. That may cause it to participate in a chemical reaction in a slightly different way from other atoms of the same element.

The history of a living thing may be regarded as an account of the chemical reactions that affected it. Facts about these reactions may be deduced from changes in the isotope ratio.

Chemical reactions in living cells, for example, may result from changes in diet. Such changes may in turn point to population movements or migrations; they may also show variations in climate or other living conditions. So stories of vast historical sweep may be told by the tiniest shifts in the balance of atomic isotopes.

“Marilyn has had a deep and lasting impact on important questions in Earth and planetary sciences,” Carnegie Institution President Eric D. Isaacs said earlier this year when Dr. Fogel received the Geochemical Society’s highest honor.

Marilyn Louise Fogel was born in Camden, N.J., on Sept. 19, 1952, and grew up in Moorestown, N.J. Her father was an engineer, and her mother was a homemaker. She graduated with bachelor’s degree in biology from Penn State in 1973 and received a doctorate in botany and marine science from the University of Texas at Austin in 1977.

She joined the Carnegie Institution as a fellow in 1977. Two years later she became a staff scientist, a position she held until 2012, when she left to become chair of the life and environmental sciences unit of the University of California at Merced School of Natural Sciences. In 2016 she was named director of the EDGE (environmental dynamics and geoecology) Institute at the University of California at Riverside, where she was an emeritus professor after retiring about two years ago.

She was a fellow of the American Association for the Advancement of Science and was elected a member of the National Academy of Sciences, among other professional honors.

Her first marriage, to Jack Estep, ended in divorce. In addition to Swarth, her husband of 35 years of Mariposa, survivors include two children from her second marriage, Dana Swarth of Mariposa and Evan Swarth of Riverside, Calif.; her mother, Florence Fogel of Cherry Hill, N.J.; and a brother.