Underwater waterland

Wonder of the world under threat

Covering 344,400 km2, the conservation area around the world's most extensive reef system is nearly as big as Germany. The more than 3,000 coral reefs of the Great Barrier Reef Marine Park surround natural habitats with enormous bio-diversity encompassing 600 islands, 150 mangrove swamps, sea-grass meadows and sponge reefs. As the world's largest structure made by living organisms, the reef is home to more than 1,500 species of fish including 133 shark and ray species, starfish, rare mussels and sea cows. This wonder of the submarine world has been a designated UNESCO World Heritage Site since 1981 but has been at risk of being classed as 'endangered' for many years. The delicate eco-system is under threat not only from tornados, habitat depletion and sedimentation caused by agriculture, but above all from climate change and the rising temperature of the sea. Despite this, Australia wants to avoid the 'endangered' status if at all possible because 60,000 to 70,000 jobs depend on the Great Barrier Reef tourist trade. It is a sector of the economy worth roughly €3.6 billion. The fear that the tourists could stay away is so great that in May 2016 the government had every reference to endangered Australian biodiversity struck out of a UNESCO report on climate change. It was a move that, if anything, had the opposite effect. The attempted censorship actually put the reef right in the spotlight.

"35% of the northern reef is dead"

High water temperatures at the beginning of 2016 resulted in extreme coral bleaching effects. Only 7% of the 2,300-km reef system was completely spared the 'heat shock' of the hottest summer on record. The northern regions between Cairns and Papua New Guinea suffered particularly badly. "35% of the northern reefs we have inspected are dead,” concluded Professor Terry Hughes, director of the ARC Coral Reef Studies Centre at James Cook University, in June following his observations in the region. He found that the corals in the south had recovered distinctly better: “There, only about 5% has been permanently destroyed.”

The causes of the worst coral bleaching seen to date can be found in an El Niño year and the higher water temperatures produced by global warming. The heat initially affects the tiny algae, zooxanthellae, that live symbiotically with the corals. Under heat stress they produce toxins which cause the mollusks to reject them. Without the zooxanthellae, however, the coral reefs lose their color and turn white. If the temperature subsequently drops, new algae can colonize the reefs and the coral may survive. Long-term studies following similar bleaching events in 1998 and 2002 showed that some corals develop resistance to the temperature stress and learn, so to speak, to cope with it. However, constant rises in temperature increase the risk of permanent damage.

On the Opal Reef east of Port Douglas, small waves lap over the outboard steps of the Calypso Ten. “Normally the water would only be 22° by now in June,” says Lisa MacLeod, who has just spent a good 1,000 hours at sea for her captain's license. She is now standing barefoot on the stern deck keeping an eye on the divers. “But we are still registering 26° here.” Pleasant for the snorkelers flippering away from the catamaran – not so nice for the corals, which need cooler water to regenerate. The fish population at the spot the divers call 'Bashful Bommie' where the boat is anchored so far appears hardly diminished. Some of the snorkelers follow Rhiannon Percival over the broad plate corals to an enormous giant clam and wait for its corrugated shell to open. The diving instructor explains to the astonished party how the clam filters suspended matter though its turquoise-patterned mantle lobes. Escorted by a respect-demanding Napoleon fish, the snorkelers swim back to the boat.

mtu Series 2000 on board

Marie Claude, Christophe and the scuba divers are back on board as well. Over lunch they compare their experiences of their first underwater excursions. Captain Tony Jones and his team do a head count to make sure all 45 members of the party are present. Only then does the skipper give the order to start up the two 720-kW mtu Series 2000 engines for the onward journey to the third dive site. With its modern common-rail fuel injection that allows injection timing, volume and pressure to be infinitely varied, the engine uses substantially less fuel than its predecessor. That is important to Captain Jones because fuel consumption is the major factor that determines the cost-effectiveness of his boat.

For Jones and his team, the working day starts well before they cast off from the quayside. On this particular day, the crew includes seven qualified diving instructors who also cater for the guests, explain to first-timers how to use a mask and snorkel, and point out the special characteristics of the reef. They start preparing the yacht at seven in the morning, checking oxygen tanks and equipment. Rob Francis climbs down into the hulls of the 24-m catamaran to check the levels of the coolant, fuel and oil on the two 8-cylinder mtu engines. Each one burns 320 l of fuel on the day trip to the reef and back. "At our speeds that is very efficient," says Jones. In the mornings, he slowly steers the boat out of the marina before opening up to 22 knots once clear of the shore. Jones has been a captain for 18 years with Calypso Reef Charters, the business that his father Graham established more than 22 years ago out of a passion for sailing. Apart from Tony, the 'Calypso & Tropical Journeys' family business that also organizes excursions to the rainforest and sailing trips to the coastal islands, and includes his two brothers and a sister-in-law.

Two UNESCO heritage sites close together

“North Queensland is the only place in the world where there are two regions protected by UNESCO world heritage status so close together,” says Rhiannon Percival. The dense vegetation of the Daintree rainforest grows right down to the shore in many places and often only a narrow beach separates palm forests or fern jungles from the sea. Daintree north of Port Douglas is where many visitors to Australia see their first crocodile. They hear the tuneful song of tropical birds, which are often as colorful as the parrot fish that nibble on the coral limestone a couple of kilometers further east. Rhiannon is also fascinated by the fauna and flora of the rainforest but, like most diving enthusiasts, she prefers the trips to the coral beds and the tropical fish. Her colleague Rob Francis even has hammerhead sharks, whale sharks and divers tattooed on his upper arm. “I couldn't imagine a better job,” beams the Englishman. “What could beat being actually paid to inspire other people about ocean diving?”

Penske Power Systems on hand
After the last snorkeling trip on the Opal Reef, the passengers stretch out exhausted on the sunbeds on deck. Dive master David Eriaud sits between his divers in the cabin stamping PADI cards and helping to identify the fish species they have seen down below. One deck above them, Tony Jones starts up the mtu engines and sets course for the shore. Since Tropical Journeys commissioned the Calypso Ten in March 2015, she has been in service virtually every day covering 50 to 60 km each way through the often heavy Pacific breakers and back to the marina. Reliability is the most important requirement. “If there is a problem, the people from Penske Power Systems in Cairns are on hand,” says Jones, referring to the company that sells and services mtu engines in Australia. “They come to the marina regularly to do the major services and also check the engines under load at sea if necessary.”

In the afternoon there is a fresh wind blowing between the coast and the outer reef. “The best days are when there is only a light breeze ruffling the water. Today we have nearly 15 knots, an average wind speed out here,” explains Lisa MacLeod as she ducks to avoid a splash of saltwater shooting over the deck railings. Only if there is a storm force of over 30 knots blowing does the Calypso stay in the harbor. “It's no fun then, and after all, the passengers are here to enjoy themselves, not to suffer an endurance test.”