Citation by Sheri Fritz, University of Nebraska – Lincoln and Paul Baker, Duke University
We are delighted to introduce Tom Johnson as the recipient of the 2019 Israel C. Russell Award in limnogeology. Tom, an expert on biogenic silica and carbonate dissolution in the ocean, was a pioneer in applying the approaches of paleoceanography to lakes. In the 1990s, he spearheaded the International Decade of East African Lakes (IDEAL), which helped catalyze investigations of Africa’s large lakes. He also mobilized support for lake drilling and later was PI on the ambitious Lake Malawi Drilling Project. He was Founding Director of the Large Lakes Observatory at University Minnesota-Duluth, which rapidly became a leading center for interdisciplinary lake research.
Some of Tom’s earliest limnological work dealt with sedimentation and silica cycling in Lake Superior, but he is best known for research on climate history in Central and Eastern Africa. With Bruce Rosendahl, he was one of the first to undertake single and multi-channel seismic reflection profiling in African lakes. His studies documented profound late-Pleistocene lake-level changes, including desiccation of Lake Victoria, with important implications for speciation of the endemic cichlid fauna. Studies of Lake Malawi drill cores, extending back over a million years, demonstrated the role of insolation and Indian Ocean SST in pacing precipitation and temperature variability in East Africa, as well as a surprising long-term evolution to progressively wetter conditions. Together with students and colleagues, Tom also promoted new organic geochemical techniques, generating some of the first long continental reconstructions of temperature in tropical East Africa. In short, Tom has been a leading figure in African paleoclimatology.
Tom has been an excellent mentor of graduate students and postdocs, and many have gone on to highly successful careers of their own. He has led and served on multiple committees and advisory boards, including as co-founder of the GSA Limnogeology Division in 2002.
We congratulate Tom on this well-deserved recognition of his many accomplishments!
Response by Thomas C. Johnson
Thank you, Sheri Fritz and Paul Baker, for your flattering and very kind words. I am truly honored to be receiving the Israel C. Russell Award, especially when nominated by such eminent scientists as yourselves.
One’s path through life is truly fickle – Twists and turns along the way may lead to joy and stimulation, or to tedium, or even to tragedy. I am one of the lucky ones. I knew from quite an early age that I wanted to do something on the oceans. Despite growing up in a small mining town in northern Minnesota, I managed to head out to Seattle to major in oceanography at the University of Washington. What followed was 4 years at UW, 3 years in the Coast Guard, and 5 years at Scripps Institution of Oceanography, followed by over 40 wonderful years in academia, at the University of Minnesota (Twin Cities and Duluth), Duke University, and now, somewhat retired, at the University of Massachusetts Amherst.
I want to acknowledge a few of the many people who particularly influenced my career – those lucky encounters that led to such a rewarding, professional life. Dick Sternberg at the UW, who taught me the attraction of a life in academia, and how to calmly respond to the challenges of science at sea. Wolfgang Berger, my Ph.D. advisor at Scripps, whose keen mind taught me to think globally, to write professionally, and yes, to take a break at noon once in awhile for some body surfing and a run on the beach. Herb Wright, who led the Limnological Research Center in Minneapolis, home of a most impressive stream of graduate students and post-docs from whom I gained so much insight into Quaternary geology and limnology. Bruce Rosendahl at Duke University, who drew me to Duke and into the great lakes of East Africa, where I subsequently focused most of my research, on the climate history of the African tropics. Kerry Kelts, who convinced me to return to Minnesota, to set up the Large Lakes Observatory on the Duluth campus. Kerry and I co-conspired to set up IDEAL (the International Decade for East African Lakes). We had embarked on a productive collaboration on Lakes Victoria and Edward, which most unfortunately ended when he passed away at too early an age. Joe Werne, who established an organic geochemistry lab at LLO and soon led to our co-advising several excellent graduate students who were the first to use TEX86 as a paleo-thermometer in lakes, and to obtain leaf wax isotopic records of past precipitation. Eric Brown, who set up an excellent core scanning XRF facility at LLO, at the time just the second one in the United States. Captain Mike King and the crew of LLO’s R/V Blue Heron, which has become a most capable research vessel in the Laurentian Great Lakes, now used by scientists from many universities in the region. To the many excellent graduate students I have had over the years, some of whom are in the room tonight, I extend my warmest regards and gratitude for your very important contributions to our science, and for the pleasant environment in which we collaborated. Finally, I thank my dear wife, Kate Whittaker, for contributing so often as a graphic designer, social organizer, and field companion, and for adding such a warm and artistic dimension to my life.