The Mediterranean Sea is a world of impressive diversity where ocean sunfish and whales live side by side, and colourful corals provide a home for smaller creatures. But human beings have left their mark here for thousands of years: ancient shipwrecks and fighter planes from the Second World War litter the ocean floor, while until recently raw sewage was fed straight into the sea. The impact has been devastating – today the Mediterranean is an ecosystem on the edge. But there is a glimmer of hope as measures to protect the sea from pollution and excessive disturbance are being put into place. Sandrine Ruiton from the University of Marseille specialises in research on artificial reefs to build up the lost marine biodiversity near cities like Marseille, one of the Mediterranean’s busiest ports. Until recently it was responsible for seriously polluting the surrounding Mediterranean Sea. Christian Petron himself has been instrumental in raising awareness of this ecosystem in dire straights. His own 30-year-old archive footage shows the extent of the pollution in graphic detail. Both Sandrine Ruiton and Christian are involved in the hugely successful ‘Prado Reef 2006’ project, which is designed to repopulate the local waters by encouraging the colonisation of new reefs. Even old shipwrecks and fighter planes turned into artificial reefs and first indications offer grounds for cautious optimism. But to be able to accurately assess the success of these artificial reefs, detailed population counts are absolutely essential. But their accuracy is questionable when carried out by divers with conventional equipment – reef creatures are notoriously shy and many are likely to hide at the approach of a noisy diver. So Sandrine Ruiton wants to find out if Frederic can achieve more accurate population counts on these fragile reefs by being less intrusive. His ability to move and behave almost like a fish without any cumbersome diving equipment allows him closer access without frightening the wildlife off. His first destination is the wreck of an freighter, sunk after world-war 2, closely followed and observed by Christian Petron. The collection of creatures found here are delicate and extremely cautious. But this dive also poses real challenges for Fred: diving in a wreck brings particular dangers with it, especially for a freediver. Nevertheless, he is determined to press on with his attempt to evaluate the state of Mediterranean marine wildlife. The artificial reef population surveys are only part of the reason why Frederic has come to the Mediterranean. He also works together with Dr. Pierre Chevaldonne, a scientist at the ‘Station Marine D’Endoume/Marseille’. Both are interested in an underwater cave that could be invaluable to modern science. Organisms and animals that are usually associated with much deeper waters thrive in this deep dark cave. In particular a collection of sponges could be of interest, not just because they provide an endless supply of biomarkers that are very sensitive to environmental changes: they are also highly relevant for modern medicine. Sponges are known to provide AZT (Azido-Thymidin) – currently one of the most used medications for the treatment of AIDS and in the fight against cancer. The sponges generate these substances as dangerous chemical weapons against predators or as a defence against harmful bacteria. The research team is renowned for their work on sponges, but the breathing bubbles emitted by conventional drivers would collect at the cave ceiling and gradually kill the cave dwellers. But Frederic’s approach is very different. By holding his breath, he can ensure that the sponges and other cave organisms are not threatened. He is able to explore the cave in detail and report his findings and bring samples back to the research group. This research can provide ground-breaking insights into modern medicine, as well as giving an indication of the health of the Mediterranean waters by examining the sponges’ biomarkers. Together, Frederic’s involvement in the artificial reef projects as well as the underwater cave exploration are extremely valuable contributions to the quest to document and protect the diversity of Mediterranean marine wildlife. He is in a unique position to access and approach the wildlife, that cannot be replicated by using conventional diving methods, and as such is an incredible opportunity for the scientists to gain a new window to the underwater life of the Mediterranean.

• published: 13 Nov 2015
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