Expedition update: Osprey Reef

Osprey Reef is an amazing coral "mountain" - a large reef sitting in ocean waters around 2km deep - you can take a short swim at Osprey and go from being in waters 1-2m depth on the reef edge to the deep blue ocean 1-2km depth - all within a few strokes. Needless to say when you are diving here you need to make sure you don't make too many strokes in the wrong direction! After a long sleep - very nice to be in a calm anchorage - we started early, doing a quick dive with the ROV to look for a good worksite at 40m depth (the mesophotic zone). Having found a good site we readied out equipment and took our first dive at Osprey. After a few days of being confined to the shallows by the poor weather everyone was very, very keen to "get mesophotic"! We were not disappointed: the coral cover and sheer number of coral species was very high - much more than we have found at our other coral sea sites. Exactly why this is so will be the subject of continuing work but the amazingly clear waters of the Coral Sea probably play a part, they allow the light which corals need to grow to penetrate to great depth. We placed several quadrats on the reef- marked off areas which we can return to each year and measure the progress of the corals- their growth, death, birth, their competition for space and long term changes in the reef. The quadrats were meticulously photographed twice and numerous small samples of corals taken. Finally we used the ROV to place temperature and light recorders down to depths of 100m - these will be left in place for a year. Dr. Paul Muir, Coral Taxonomist, Deep Reef Team