A coral-on-a-chip microfluidic platform enabling live-imaging microscopy of reef-building corals

Coral reefs, and the unique ecosystems they support, are facing severe threats by human activities and climate change. Our understanding of these threats is hampered by the lack of robust approaches for studying the micro-scale interactions between corals and their environment. Here we present an experimental platform, coral-on-a-chip, combining micropropagation and microfluidics to allow direct microscopic study of live coral polyps. The small and transparent coral micropropagates are ideally suited for live-imaging microscopy, while the microfluidic platform facilitates long-term visualization under controlled environmental conditions. We demonstrate the usefulness of this approach by imaging coral micropropagates at previously unattainable spatio-temporal resolutions, providing new insights into several micro-scale processes including coral calcification, coral-pathogen interaction and the loss of algal symbionts (coral bleaching). Coral-on-a-chip thus provides a powerful method for studying coral physiology in vivo at the micro-scale, opening new vistas in coral biology.

Errata: Previous work by Venn et al. describing live imaging of coral mounted on cover slips in miniaturized flow cells and live imaging of coral calcification was inadvertently omitted from the reference list of this Article. This work should have been cited in the second paragraph of the introduction, where previous work describing microscopic examination of coral and coral culture systems are referred to, as follows: ‘Previous work by Venn et al. described live imaging of coral calcification using the lateral skeleton preparation in combination with miniaturized flow chambers (Venn et al. 2011)’. A reference to this work should also have been provided in the section discussing the use of calcein for in vivo imaging of coral calcification.