USA

David Karl

2015 Balzan Prize for Oceanography

For his fundamental contributions to the understanding of the role and immense importance of microorganisms in the ocean, and of how microorganisms and phytoplankton control the oceanic carbon, nitrogen, and iron cycles, work that has yielded significant insights into global change

David Michael Karl was born in Buffalo, New York in 1950. He earned his PhD in 1978 from the University of California, San Diego, Scripps Institution of Oceanography. He is presently Professor of Oceanography at the School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, where he is also the Director of the University Center for Microbial Oceanography: Research and Education. This is one of the leading institutions applying molecular biology and genomics to oceanography at large scale, and one of the most productive and innovative research groups in microbial oceanography.

He is internationally recognised for his contributions to microbial oceanography. He brings a deep understanding of biochemistry, microbiology and genomics to the study of ocean ecosystems and global processes. He is also a leader in the development of new methodologies in microbial ecology, molecular ecology and biogeochemistry and in the analysis of Pacific and Antarctic Ocean ecosystems. Research in his laboratory has been particularly directed at the ocean’s carbon cycle, from the photosynthetic production of organic matter to carbon sequestration in the deep sea.

Professor Karl is renowned for his development and leadership of long-term, integrated studies of chemical, physical, and biological variations in oceanic environments that have allowed the discovery of oceanic regimes (alternative stable states) and their likely causes. In 1988 he established an open ocean monitoring station in the subtropical North Pacific to collect time series data to observe the effects of climate on the structure and function of microbial communities and to act as a sentinel to warn against disruptive change. This data set is considered to be of huge value by the oceanographic community and it has already documented significant subdecadal scale changes in microbial ecology that can be tied to large-scale climate variations such as El Niño events and the Pacific Decadal Oscillation.

His work has led to a deeper understanding of how, why and when the oceans act as a global sink or source of carbon with implications for the study of ocean acidification. This is a fundamental contribution to the science of climate change and its impact on our planet.

He has also studied microbial processes in a number of extreme environments including the low-oxygen areas of the Black Sea, Lake Vostok (beneath the ice of Antarctica) and around deep-sea hydrothermal vents. He has examined in detail the microbially-mediated transformations and physical supply mechanisms of major phytoplankton nutrients in the ocean. His work has revealed the existence and importance of new classes of organisms in the sea, notably the marine archaea found at depths between 200 and 1000 meters.

David Karl has led a large number of productive research teams comprised of collaborators, staff and especially students, and has played an important role in training the next generation of scientists. He has also been generous with his time and is recognised as having made an incomparable contribution to the broader international oceanographic community. His research output has been outstanding, and he has forever changed our perspective on life in the sea.