Grethe Rytter Hasle

Grethe Berit Rytter Hasle (3 January 1920 – 9 November 2013) was a Norwegian planktologist. Among the first female professors of natural science at the University of Oslo, she specialized in the study of phytoplankton.

Personal life Hasle was born in Borre as the daughter of shipmaster Johan Kristian Rytter (1890–1966) and his wife Nicoline Olava Nielsen (1885–1976). She married Hans Martin Hasle and took his name; he died in 1971. She resided at Ekeberg in Norway and died in November 2013.

Career She graduated from Elverum Teachers' College in 1942, and graduated from the University of Oslo in 1949 where she worked with Trygve Braarud. In 1950, she published her first paper: Phototactic vertical migration in marine dinoflagellates. She took the dr.philos. degree in 1968 on the thesis An Analysis of the Phytoplankton of the Pacific Southern Ocean. The Bacillariophyceae genus Haslea has been named after her. She is also known for revising the morphological taxonomy of the genera Thalassiosira, Nitzschia and Fragilariopsis.

She was honored with a Festschrift for her seventieth birthday, and she received the Award of Excellence from the Phycological Society of America in 2000 and the Yasumoto Lifetime Achievement Award from the International Society for the Study of Harmful Algae in 2003.

Selected publications