Fig. 1.

Spatiotemporal patterns in ROL from the roots of Zostera muelleri and Halophila ovalis. a Oxygen loss from Z. muelleri roots over 9 days of growth. A second new root can be seen leaking oxygen in day 8 and 9. b Oxygen loss in roots of Z. muelleri during light (250 µmol photons m⁻² s⁻¹) and dark transitions (30 min darkness). c Oxygen loss from H. ovalis root over 3 days. d Oxygen loss in H. ovalis root during light and dark transitions. Images are overlays of transparent optode images on bw images of the roots. Nine replicate plants were measured for each species. Days are relative to when ROL was first observed (i.e., when the root grew to the optode wall). Scale bar is 5 mm