Trygve Braarud was born in Verdal, Norway. He had ten older siblings as well as a twin sister. He received his early schooling at a private teaching institution founded by his father, finished his secondary education at Trondheim Cathedral School in 1921, and graduated from the University of Oslo with the cand. real degree in 1927. In his early career he published the work The 'Øst' Expedition to the Denmark Strait 1929 in two volumes. The first volume, Hydrography, was published together with J. T. Ruud in 1932. The second volume, The Phytoplankton and its Conditions of Growth was completed in 1935 and earned Braarud the Dr philos. degree.

Professional Career

Braarud was affliated with the University of Oslo for most of his career. He had taken up planktology as a research assistant of Prof Gran the botanical laboratory, a position he held from 1926 to 1933. From 1934 to 1936 he was a research fellow of plant physiology; in 1935 he spent time working with Prof Krogh in Denmark. In 1936, Braarud joined the permanent staff of the University of Oslo as a lecturer in general botany. This placed an enormous burden of teaching and other administrative work on him that was not lessened during the war years 1940-45. It was only in 1947, when a personal Chair of Marine Botany was created for him, that he could concentrate on building up a department devoted to his own research interests. This gradually grew to the size where he could encourage younger collaborators to specialize in different disciplines under his general direction. Up to his retirement in 1973, he saw it as the long-term goal of the department to cover all branches of phytoplankton research. Braarud co-founded Norske havforskeres forening in 1949, and was its spokesperson from 1962 to 1965. He was also a vice president of the Scientific Committee on Oceanic Research (SCOR). He died in 1985 in Oslo at the age of 81.


Braarud was a member of the Norwegian Academy of Science and Letters from 1942, the Royal Swedish Society of Sciences and Letters in Gothenburg from 1959 and the Royal Danish Academy of Sciences and Letters from 1963. He was a member of the British Phycological Society for many years and was given the rare honor of an Honorary Membership in 1974.

Key contributions

After starting his scientific career as a student of higher plants, in 1927 under the guidance of Professor Gran he switched to marine phytoplankton. Oslo was already then one of the centers of phytoplankton studies, and Braarud joined in large-scale investigations of phytoplankton growth in Norwegian coastal waters and on the American east coast. This led to the discovery of the importance of water column stability for net phytoplankton growth. This achievement still stands as a landmark in the development of the field of phytoplankton ecology. In 1929 he joined on a polar expedition to the Denmark Strait on board a sealer, and Braarud earned his doctorate from this work that aimed at an understanding of the dynamics of phytoplankton growth from observations of hydrographical features.

Braarud was a keen microscopist and the material collected from American and Greenland waters demonstrated the deficiencies of taxonomical knowledge of important groups such as dinoflagellates and coccolithophorids. Consequently, systematic sections with descriptions of several new taxa were included in his reports. In 1935, he went to the laboratory of the zoophysiologist Prof Krogh in Copenhagen in order to do quantitative growth studies on diatom cultures. The product of this work and its continuation in Oslo was a set of growth rate measurements on a considerable number of species of common planktonic diatoms, grown under controlled conditions. This work marks the beginning of experimental phytoplankton ecophysiology as a quantitative discipline. It led to the important conclusion that temperature alone does not govern the spring succession of diatoms in temperate coastal waters. Braarud also took up an intensive study of the polluted waters of the Oslofjord and he was able to conclude that uncontrolled discharge of plant nutrients does not select for "saprophytes" but rather causes an excessive growth of selected phytoplankton.

Dinoflagellates and coccolithophorids remained particularly close to his heart. His department was the first to make use of electron microscopy in the study of coccolithophorids. Corresponding work on diatoms and other groups was soon to follow. Braarud's department soon began to attract foreign students, something that helped to cement the numerous contacts he had already established with institutions and colleagues abroad. Being a trained botanist, he always choose as a starting point the biology of the individual species in the plankton. Elsewhere during the 1950s and 1960s, the tendency in biological oceanography was to reduce phytoplankton to some simple value in terms of chlorophyll or 14C uptake, The more recent resurgence of interest in the complexity of interactions at the species level to some extent has its roots in the "Oslo School", and must have caused Braarud a great deal of personal satisfaction.

Braarud produced 8 publications on “red tides”. His first 1937 paper described different types and causes of water discolorations in freshwater and marine environments. Only 8 month later the first red water bloom of Gonyaulax (nowLingulodinium) polyedra occurred in Norwegian waters. Other bloom papers focused on “Gymnodinium galatheanum” (now thought to be a Karlodinium species) in Walvis Bay, milky-green Emiliania huxleyi blooms in the Oslofjord, and possibly his best known 1970 paper is on the mass occurrence of Gyrodinium aureolum (now Karenia mikimotoi) along the southern Norwegian coast. He also examined variability of toxin production by Alexandrium tamarense (as Gonyaulax excavata) and already mentioned the possible role of bacteria. Braarud will always be recognized as a pioneer of quantitative biological oceanography, and all those who met him in person were impressed by his courteous and friendly, though at the same time slightly reserved manners. Science had placed him in a position of tremendous responsibility and he was always aware that this extended beyond the duty to promote human knowledge and included an obligation to look after the well being of those who worked around him.

Notable students

Grethe Hasle, Berit Heimdal, Eystein Paasche, Olav Skulberg, Theodore Smayda, Ingrid Solum, Karl Tangen, Jahn Throndsen.

10 Key publications

Braarud, T., Nygaard I. 1980. Phytoplankton observations in offshore Norwegian coastal waters between 62 ºN and 69 ºN. 2. Diatom societies from More to Vesteralen, March-April 1968-1971. Sarsia 65, 93-114.

Braarud, T., 1976. Natural history of Hardangerfjord.13. Ecology of taxonomic groups and species of phytoplankton related to their distribution patterns in a fjord area. Sarsia 60, 41-62.

Braarud T., Heimdal B, 1970 : Brown water on the Norwegian coast in autumn 1966. Nytt Mag Bot (Oslo) 17, 91-97.

Braarud, T. 1957. A red water organism from Walvis Bay. Galathea Rep. 1, 137- 138.

Braarud, T., Nordli E. 1952. Coccoliths of Coccolithus huxleyi seen in an electron microscope. Nature 170, 361-362.

Braarud, T., 1951. Salinity as an ecological factor in marine phytoplankton. Physiologia Plantarum 4, 28-34.

Braarud, T. 1945. Morphological observations on marine dinoflagellate cultures (Porella perforata, Goniaulax tamarensis, Protoceratium reticulatum). Avh. norske Viensk. Akad. Oslo I. Mat.-Naturv.Klasse 11, 18pp.

Braarud, T., 1939. Microspores in diatoms. Nature 143, 899-899.

Braarud, T. 1935. The ØST Expedition to the Denmark Strait 1929. II. The phytoplankton and its conditions of growth. Hvalrådets Skrifter Nr. 10, 1-173.

Gran, H.H. & T. Braarud 1935. A quantitative study of the phytoplankton in the Bay of Fundy and the Gulf of Maine (including observations on hydrography chemistry and turbidity). J. Biol. Bd. Canada 1, 279-467.

(Partially based on: Paasche, E. 1986. Trygve Braarud (1903-1985). Europ. J Phycol.21, 1-3; Smayda, T. 1993. Flagellates and their blooms in the sea: Trygve Braarud’s contributions to our knowledge. In:TJ Smayda & Y.Shimizu (eds), Toxic phytoplankton blooms in the sea. Elsevier., pp.3-12.)