In-vivo imaging of O2 dynamics on coral surfaces spray-painted with sensor nanoparticles

We describe a new method for imaging O-2 dynamics on heterogeneous biotic and abiotic surfaces using optical nanosensors. The method can overcome limitations of commonly used optodes or microsensors. To show the potential of the method, the O-2 dynamics on the surface of living corals were studied. Small coral fragments were spray-painted with O-2 sensor nanoparticles using a conventional airbrush and O-2 imaging was done with a simple SLR camera setup. Good coverage of the coral surface was achieved without significantly compromising the coral wellbeing as shown by measuring photosynthetic activity of the photosymbionts at different light levels. The method enabled analysis of spatial heterogeneities in O-2 concentration over the coral surface linked to different tissue types. Oxygenic photosynthesis and O-2 consumption could be followed at a temporal resolution of <10 s. (C) 2016 Elsevier B.V. All rights reserved. vertical bar