[3] Her PhD, supervised by George Knox at the University of Canterbury,[4] developed new observations in copepod taxonomy but also produced insights into the processes affecting zooplankton in Kaikōura submarine canyon.
[9] Publishing under surnames Grieve, Bradford and Bradford-Grieve, she has made a significant contribution to the fields of biological oceanography in New Zealand and internationally.
She has researched topics such as ocean food webs and ecology, and is regarded as the global expert on copepod biosystematics.
[12] Grieve was a key researcher involved in the environmental survey work that underpinned and guided the development of the Maui oil and gas production facilities within the Taranaki Bight.
[15] In the 2007 Queen's Birthday Honours, she was appointed an Officer of the New Zealand Order of Merit, for services to marine science.