[5] During his first year at the institution, Karl was a member of the Galapagos Rift Biology Expedition and was among the first to observe and sample deep sea hydrothermal vent communities from a submersible.
[6] He was recognized for his research studying marine microecology by President Ronald Reagan who granted him an Presidential Young Investigator Award in the oceanographic and atmospheric fields in 1984.
"[12] He was also appointed the Chancellor‘s Distinguished Lecturer at Louisiana State University in September 2005 followed in November by the David Packard Medal from the Monterey Bay Aquarium Research Institute, given in recognition of outstanding achievements and leadership in the field of Marine Science.
[13] Using data collected from the HOT program, Karl and added the manmade chemical methylphosphonate to samples of seawater, which immediately started making methane.
[17] Karl continued his research in the field of marine microbial ecology with Edward DeLong, using funding from the Gordon and Betty Moore Foundation,[18] and was appointed to the National Academy of Sciences Gulf of Mexico program advisory group.
[21] He later led a research team in collaboration with Chalmers University of Technology to develop a computer model to study the survival of Prochlorococcus, an abundant photosynthetic microbe.