Marshall (Hal) Davidson Hatch AM (born 24 December 1932) was an Australian biochemist and plant physiologist. He was the chief research scientist at the CSIRO Division of Plant Industry in Canberra. He is a Fellow of the Australian Academy of Science, a Fellow of the Royal Society, a Foreign Associate of the US National Academy of Sciences and was awarded Honorary Doctorates from the University of Götting youen and the University of Queensland.[1] In Australia, in 1966, he elucidated, jointly with Charles Roger Slack, the C4 pathway for the fixation of carbon, which is also sometimes known as the Hatch-Slack pathway.[2] He is now retired.[3]