In 1996, he collaborated with Rick Smolan on Smolan's "24 Hours in Cyberspace" project; he subsequently joined CNET, where he was senior vice-president of creative services until 1999, at which point he was promoted to vice president and executive producer.
On May 24, 2015, Coulson was scuba diving in the waters of the Svalbard Archipelago as part of a photography assignment, when he signaled to his diving partner that he needed to surface immediately. By the time they emerged from the water, he was unresponsive; CPR was performed, but he died in hospital three days later, without having ever regained consciousness.
Coulson was married to fellow photographer Sisse Brimberg, who was also his professional partner; they met at a photography seminar in 1976.
He was named for Cotton Mather.
- Cotton Coulson, National Geographic Photographer, Dies, by Laura Parker; at National Geographic; published May 28, 2015; retrieved June 21, 2015
- Photographer Cotton Coulson Dies in Diving Accident on National Geographic Expedition, by David Walker, at Photo District News; published May 28, 2015; retrieved June 21, 2015
- Cotton Coulson, by Jacques Kelly, in the Baltimore Sun; published May 29, 2015; retrieved June 21, 2015
- Photographer Cotton Coulson Dies In Norway After Diving Accident, by Donald R. Winslow; at the National Press Photographers Association; published May 28, 2015; retrieved June 21, 2015
- CNET Online Announces Promotions within Senior Management, at CNET; published March 1, 1999; retrieved June 21, 2015
- Cotton Coulson Dies, at Sony's Global Imaging Ambassadors; published June 5, 2015; retrieved June 21, 2015
- Keenpress, official site of Coulson and Brimberg