Diane Littler is a leading U.S. phycologist at the Smithsonian Institution, Washington. With her husband, Mark Littler, she carries out deep-scuba collections in habitats of exceptional diversity and produces studies that contribute towards the conservation of tropical marine ecosystems.

Diane Littler's two key research interests are Relative Dominance Theory and monographic and field guide treatments of coral reef plant life. Developed by Mark and Diane Littler, Relative Dominance Theory takes a rigorous experimental approach to assessing the effects of destructive fishing and pollution in the phase shifts of coral to algal communities occurring on coral reefs worldwide.

Littler received her bachelor's degree from the University of Hawaii (1968) and her PhD (1985) in marine botany from Pacific Western University, California. From 1994-2008 she was a senior scientist (later adjunct senior scientist) at Harbor Branch Oceanographic Institution, prior to which she was based at the University of California, Irvine. She is currently a research associate at the Smithsonian. After joining the Smithsonian Institution in 1982, Mark and Diane Littler began working as a team of three with Barrett Brooks (1958-). All three are certified to dive to a depth of 65 metres, allowing them great flexibility in their underwater work.

The Littlers' contributions to marine science include quantitatively documenting the importance of coralline algae in tropical coral reefs and discovering the first reported pathogen of reef-building algae in the Cook Islands (followed by two more in the tropical Pacific and Atlantic). Their discovery prompted a new discipline: biotic-reef pathology. They have also been major architects in forming a model of marine algal functional morphology and evolution, helping ecologists to interpret patterns and predict biotic relationships within complex marine communities. In 1985 Mark and Diane Littler described the deepest known plant communities, opening up a new area of biological oceanography.

In response to increasing awareness of the degradation of coral reefs due to human activities, the Littlers developed what has become a leading theory of tropical reef biogenesis, the Relative Dominance Model, offering predictive capabilities to those managing reef systems. They have been the foremost researchers of macrophyte species in tropical seas, doubling the number of known taxa for the Bryopsidale genera Anadyomene, Avrainvillea and Udotea with their monographic treatments of 1990-1992 and producing much-needed identification guides to reef plants. In 2000 they published the guide Caribbean Reef Plants and in 2003 South Pacific Reef Plants. They then turned their attentions to the submersed plants of the Indian River Lagoon, producing their most sophisticated taxonomic work to date in 2008. They have also published a floristic field guide for Pacific Panama and are working on guides for several other areas including Caribbean Panama and Islas Aves. Major works on marine flora by other scientists invariably rely upon the Littler guides and on examples from the tens of thousands of specimens they have added to the U.S. National Herbarium. As curators they have also added considerable collections to the herbarium including freshwater diatoms, blue-green algae and European seaweeds.

Mark and Diane Littler have been awarded numerous honours for their work, which has shaped the management policies of environmental agencies as well as spurring new fields of academic research (such as deep-sea botany). Most recently, Diane Littler was nominated for the Women Divers Hall of Fame. The couple are frequently called upon to carry out surveys and inventories, and to assess damage caused by ship groundings such as the 1984 Wellwood freighter incident in the Largo Marine Sanctuary off the coast of Florida.

With many regions still unexplored and no fewer than 20 new classes of algae being described in the last 30 years, there is no doubt a wealth of marine plant biodiversity still to be discovered, offering Mark and Diane Littler vast scope for future work. However, they are keen to stress that fieldwork in exotic places is no easy ride: "We have endured a dislocated shoulder in Martinique, a badly lacerated and nearly destroyed eye in the Florida Keys' backcountry, experienced sever ciguatera poisoning on the Great Astrolabe Reef, contracted malaria in the Solomon Islands, overcome amoebic dysentery while dry-suit diving in the Galapagos and suffered through innumerable, mandatory kava ceremonies in Fiji. For the uninitiated, kava is a traditional and locally revered drink (pounded from a plant root) that looks like muddy river water but tastes much worse."

Sources:
Personal communication, April 2009.