A grocery store in Detroit
Melvin Ellis Calvin was born in St. Paul, Minnesota, on April 8, 1911. His parents, Elias Calvin and Rose Herwitz, were Jewish immigrants from the Russian Empire; his father came from Lithuania and his mother from Georgia, in the Caucasus. When Melvin was young the family moved to Detroit, where his parents ran a small grocery store to make a living.
The store was his first laboratory. As a boy he worked behind the counter and spent hours looking over the products on the shelves, wondering what they were made of. Later accounts of his life trace his interest in chemistry to that habit of curiosity about ordinary things. He graduated from Detroit’s Central High School in 1928.
From a mining college to Manchester
Calvin studied at the Michigan College of Mining and Technology, now Michigan Technological University, where he was the school’s first chemistry major and earned its first bachelor’s degree in chemistry in 1931. He took his doctorate at the University of Minnesota in 1935 with a thesis on the electron affinity of the halogens, supervised by George Glockler.
He then spent two years, from 1935 to 1937, as a postdoctoral researcher with the chemist and philosopher Michael Polanyi at the University of Manchester in England. There he became interested in phthalocyanines and related ring-shaped molecules that hold metal atoms, cousins of the chlorophyll that makes plants green. His Nobel biography notes that this interest in how such molecules capture and use energy stayed with him for life, and it pointed directly toward the problem that would make him famous.
Berkeley and a new radioactive tool
In 1937 Calvin joined the University of California, Berkeley, as an instructor, at the invitation of the great chemist Gilbert N. Lewis. He would stay at Berkeley for the rest of his life. Lewis introduced him to the physicist Ernest Lawrence, inventor of the cyclotron, and Calvin became one of the first chemists to join Lawrence’s Radiation Laboratory. In his first Berkeley years he worked on the theory of organic molecules, writing The Color of Organic Substances with Lewis and The Theory of Organic Chemistry with G. E. K. Branch. From these men, he later wrote, he took a lasting interest in how organic molecules behave in the finest detail.
The key to his later work was carbon-14, a long-lived radioactive form of carbon discovered at Berkeley in 1940 by Sam Ruben and Martin Kamen using Lawrence’s cyclotron. Because it behaves chemically like ordinary carbon but can be detected by its radiation, carbon-14 can be used as a tracer, a tag that shows where carbon atoms go. According to a story Calvin told, on the day Japan surrendered in 1945 Lawrence told him that it was time to do something worthwhile with radioactive carbon. From 1946 Calvin directed the laboratory’s bio-organic chemistry group, and he decided to use the new tracer to solve one of biology’s oldest puzzles.
Following the trail of carbon
Everyone knew in outline what photosynthesis did: plants use the energy of sunlight to turn carbon dioxide and water into sugar, releasing oxygen. But no one knew the chemical steps by which carbon dioxide from the air became part of a sugar molecule. Calvin assembled a team that included the biochemist Andrew Benson, who set up the photosynthesis laboratory, and James Bassham.
Their method was simple in principle and fiendishly hard in practice. They grew single-celled green algae, fed them carbon dioxide containing carbon-14 for very short, carefully timed periods, then killed them instantly and analysed which compounds had picked up the radioactive label. Using paper chromatography, a technique for separating mixtures on sheets of filter paper, they could resolve the products formed in as little as about five seconds. The very first stable product turned out to be a three-carbon compound, phosphoglyceric acid. Experiments in which algae were moved from light to darkness showed that the capture of carbon dioxide itself does not need light; it runs on chemical energy that the light reactions have already stored. As Berkeley Lab later summarized it, sunlight acts on chlorophyll to power the making of organic compounds, rather than acting directly on carbon dioxide as had been believed.
The finding was not accepted at once. A rival laboratory at the University of Chicago could not confirm that phosphoglyceric acid came first and attacked the Berkeley results in print. The dispute was aired at a symposium of the American Association for the Advancement of Science, where Calvin and Benson persuaded a sceptical audience that their data were right.
Piece by piece, through the late 1940s and 1950s, the group identified the sugars involved, including unusual sugars with five and seven carbon atoms. When they restricted the supply of carbon dioxide, a five-carbon sugar called ribulose bisphosphate built up, showing that it was the molecule that grabs carbon dioxide from the air. By 1958 they had worked out the whole cycle: a loop of reactions in which carbon dioxide is attached to ribulose bisphosphate, turned into sugar, and the starting molecule regenerated to capture more. It is known today as the Calvin cycle or, recognising his colleagues, the Calvin–Benson–Bassham cycle.
Why the Calvin cycle matters
The cycle Calvin’s group mapped is the main route by which carbon enters the living world. Almost every crop, forest and field of grass captures carbon dioxide this way, so nearly all the food people eat, and the oxygen-rich atmosphere they breathe, depend on it. Knowing its steps made it possible to study photosynthesis as chemistry rather than as a mystery.
That knowledge underpins much of modern plant science. Researchers who try to raise crop yields, breed plants that cope better with heat and drought, or engineer more efficient photosynthesis start from the reactions Calvin’s team identified, and the enzyme that fixes carbon dioxide in the cycle is one of the most studied proteins on earth. Climate scientists rely on the same chemistry to understand how forests, crops and ocean plankton take up carbon dioxide. The tracer method itself, following radioactive atoms through living systems, also became a standard tool across biology and medicine.
Credit, controversy and a laboratory without walls
Calvin received the Nobel Prize in Chemistry alone in 1961, for his research on the assimilation of carbon dioxide in plants. The work, however, was a team effort, and the question of credit has been debated. Andrew Benson later said that Calvin had dismissed him from the laboratory and did not mention his role in an autobiography written decades afterwards, and some historians of botany have argued that Benson deserved more recognition. The modern name for the cycle, which includes Benson and Bassham, reflects that view.
Calvin did care deeply about how scientists work together. His group worked in the old wooden building that had housed Lawrence’s original Radiation Laboratory, a cramped space that pushed people into constant contact. When it was demolished in 1959, he had a new building designed on the same principle: a round structure, opened in 1963 and nicknamed the Roundhouse, with laboratory benches arranged like spokes so that chemists, physicists and biologists would keep meeting and talking. It became the home of his Laboratory of Chemical Biodynamics and was renamed the Melvin Calvin Laboratory when he retired in 1980.
Jewish roots
Calvin was the son of Jewish immigrants who had come to America from the western edge of the Russian Empire, part of the great migration of Eastern European Jews at the turn of the twentieth century. His parents’ grocery store in Detroit was a typical immigrant livelihood of that generation, and like many children of such families he rose through public schools and state universities into American science.
He did not write publicly about religious practice. In 1942 he married Marie Genevieve Jemtegaard, the daughter of Norwegian immigrants, and they had two daughters, Elin and Karole, and a son, Noel. He is counted among Jewish Nobel laureates by the Jewish Virtual Library.
Public service and the search for clean fuel
Calvin’s curiosity ranged widely. His group also studied the chemical origins of life, the causes of cancer, organic geochemistry and, after the Apollo landings, samples of moon rock. He helped NASA plan how to protect the moon from contamination by earthly microbes and the earth from anything that might return from the moon. He served on the President’s Science Advisory Committee under Presidents Kennedy and Johnson from 1963 to 1966, on the top advisory board of the U.S. Department of Energy, and as president of the American Chemical Society.
In his final years of research he returned to the energy of sunlight. He studied plants that make oil-like hydrocarbons, such as a species of Euphorbia, as possible renewable fuels that could be grown rather than drilled, and his small group worked on artificial photosynthesis, the dream of capturing solar energy the way leaves do. He survived a heart attack at 38 and worked for nearly five decades more. Colleagues remembered a fearless, restless scientist who ended each day by asking what was new. He received the National Medal of Science in 1989, and in 2011 he appeared on a U.S. postage stamp honouring American scientists.
Melvin Calvin died in Berkeley on January 8, 1997, at the age of 85. The pathway his team traced remains in every biology textbook, a map of the chemistry that feeds the world.
Sources & further reading
Melvin Calvin, Biographical, NobelPrize.org · Melvin Calvin obituary, Berkeley Lab Research News (1997) · Melvin Calvin, Biographical Memoirs Volume 75, National Academy of Sciences · Melvin Calvin, Jewish Virtual Library · Melvin Calvin, Wikipedia · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.