GEOTRACES tribute to Dr. Thomas M. Church

It is with deep sadness that we inform you of the passing of Dr. Thomas M. (Tom) Church on 11 February 2021 due to complications from COVID-19. He is survived by his wife Karen, eldest daughter Dorothy (Daisy), son Thomas Edward (Ted), and youngest daughter Aimee.

Tom was many things in his superb professional career as a chemical oceanographer at the University of Delaware. Among these were academician, mentor, spokesman, holistic thinker, collaborator, and visionary to name a few. Tom’s work was very well received throughout his career, and he was driving chemical research at the air-sea interface for over forty years. He contributed to writing the atmospheric input section of the GEOTRACES Science Plan and developed and tested the methods used to collect trace element-clean aerosol and rainfall samples on cruises since 2002.

Tom published over 160 papers in prestigious journals that include Science and Nature. However, Tom was much more than the excellent scientific content, which is in these papers…. Below is an abstract of a tribute from his colleague Dr. George Luther summarising Tom’s career.

“Tom always used fundamental chemistry to understand earth and ocean processes, and he was always rigorous in his approach to major questions and problems. He was instrumental in showing the importance of iron and sulfur chemistry and cycling in the salt marsh. However, the organic sulfur contribution was unknown until his group in collaboration with my group showed that 50% of the reduced sulfur in the salt marsh was in the organic fraction. His group’s salt marsh papers are still highly cited because of their creativity and importance to biogeochemical processes. The field of biogeochemistry is a broad one which merges the fields of biology, chemistry and geology to understand earth and ocean processes, and Tom was one of the first to link these fields in an understandable way.

Tom knew that the transport of the elements from land to the ocean cannot occur in significant amounts from river transport. He along with other visionaries began to show in the 1970s that atmospheric transport of dust [as well as the conversion of some of the elements (for example iron) in dust during rain events into soluble chemical species] can actually fertilize surface ocean waters so that phytoplankton can grow.

Tom understood the need for time series data earlier than most scientists and as a result he set up a rain water sampling site in Lewes Delaware, which still provides important data on pH and ions in rain water that can be compared with other sites around the world (e.g., Bermuda and Ireland); thus, giving us an idea on how the atmosphere responds to global change and anthropogenic effects. An example of the importance of this work is that the burning of coal with less sulfur resulted in an increase of rainwater pH; a very good thing.

Tom always used natural radionuclides to understand the cycling and transport of elements in the environment. One of his favorite radioactive elements was polonium. His early research on polonium at the air-sea interface indicated that it can be volatilized, and this led to a study with Tom Hanson of UD showing that dimethyl polonium can be formed during reduction of oxidized polonium by marine microbes just as sulfur is volatilized from salt marshes and the ocean as dimethyl sulfide. The use of polonium as a tracer in oceanographic and atmospheric biogeochemical processes (including volcanic activity) is more important than previously recognized.

Tom has been an exquisite and effective spokesman for the field of chemical oceanography. His spokesman status started early in his career and is exemplified by his love for the history of chemical oceanography, which he gave at the biennial Gordon Research Conference in chemical oceanography.

Throughout his entire career, Tom took a rigorous academic approach to both research and education. As Tom mentored his students and collaborators, he always challenged them to do their best. At the same time, he showed how generous he was.”

With respect to generosity, the oceanographic community knew Tom as someone who would freely share his knowledge, samples, sampling equipment and even his labor to help them achieve their scientific goals. And more than this, while doing great science he made sure everyone was having fun, either with bad jokes, weird costumes, or funny stories, but also with food and wine. And when travelling, he delighted in every culture’s food, clothing and customs; everyone was smiling when Tom was there. His novel and important science will continue through those he inspired and educated, but many of us will miss the fun of science he catalyzed.

On behalf of GEOTRACES,
George Luther, Greg Cutter, Bill Landing, Bob Anderson and Catherine Jeandel

We invite you to watch this video including a French GEOTRACES SWINGS cruise dedication to Tom Church:

GEOTRACES SWINGS cruise’s tribute to Tom Church. Presenter: Bill Landing.
Videographer: Sybille D’Orgeval