You may also like these photo galleries
The news from the Great Barrier Reef is catastrophic, and has made headline news around the world.
In March, scientists from the Great Barrier Reef Marine Park Authority and the Australian Institute of Marine Science announced that – for the first time – the only living organism on Earth that can be seen from outer space has suffered two consecutive summers of coral bleaching.
The worst bleaching last year hit the northernmost, least-visited third of the reef. Since the reef is roughly the same size and shape of Italy, imagine the underwater equivalents of the Dolomites, Venice, Milan, Turin and the Italian lakes being affected.
But this year the bleaching has reached the Cairns/Townsville central section of the reef – think Rome, Florence, Siena and Pisa – the heart of a $6 billion tourist industry.
Then, just weeks later, Cyclone Debbie destroyed parts of the reef near the Whitsunday Islands. Think Sicily.
At a time like this, there are only two things you can do.
Book a trip to see the reef while it is still one the planet's primary travel experiences.
Or join the growing number of visitors who want to help save it for future generations.
Which explains why I'm diving 15 metres beneath the ocean surface on Flynn Reef filling in my underwater homework.
Yep, I've become "a voluntraveller". A member of that growing brigade – from teenagers to grandparents – who would rather spend their time doing something useful on holiday than merely lazing on a beach.
I've told my divemaster, Simon Uren, that I'll follow behind the three women in our dive party because I've got to count every sea cucumber and every Nemo I see – then record it on my "Citizen Science" ReefCheck board which I received through the post when I paid my $25 and signed up, online, as a REEFSearcher.
Fortunately, Uren comes back several times to point out things I've missed, writing idiot-proof explanations on his own underwater white board.
We do three dives that day to Coral Gardens, Gordon's Mooring and Tracy's Bommie, and thanks to Uren's patience – and my REEFSearcher role – I see things I've never noticed before, despite three decades of diving.
Not everyone is impressed though. Over lunch I join three co-divers on the outside deck of SilverSwift (part of the Quicksilver Cruises fleet). One Japanese and two Dutch backpackers confess they are a bit underwhelmed, having had more colourful diving experiences in Thailand, the Maldives or Hawaii. "It's so brown," they complain. "Why do they call it 'Great'?"
So let's remind ourselves why the Great Barrier Reef is of global significance.
Well, apart from its sheer size at roughly 345,000 square metres, no other reef has so much biodiversity. It has more coral species, more fish species, more turtle species than anywhere else on earth.
Unlike Hawaii or the Maldives, for example, (where coral atolls have grown up around huge underwater volcanoes providing a buffer against the ocean's might), the current Great Barrier Reef has endured for at least 6000 years.
Tiny brainless animals, mostly the size of a rice grain, have formed "colonies", lived, died, and formed a massive, self-perpetuating undersea cemetery of their calcium carbonate skeletons.
It may be the world's largest reef system, but it actually consists of over 2900 individual reefs, and 900 islands from Cape York in the north to Bundaberg in the south. That's around 2600 kilometres – roughly the same distance from Adelaide in South Australia to Katherine in the Northern Territory.
As for the brown, earthy colours of most of the coral here on the reef, that's how healthy coral should look (more of which later).
Yet there's no doubt the reef is facing unprecedented challenges – all linked to human activity.
The coral bleaching is a reaction to higher water temperatures, caused by global warming. Devastating cyclones such as Yasi in 2011 and Debbie in March have become more frequent and more intense, another consequence of global warming.
Finally, the Great Barrier Reef is subject to an infestation of coral-devouring crown-of-thorns starfish and the less well-known Drupella snail, which is more of a problem on Western Australian reefs. Scientists say the starfish have reached plague proportions because of the nutrients from agricultural fertilisers being washed into the ocean.
So if you're just as anxious to save the reef as you are to see it before it disappears, what can you do?
EXPERT WITNESS 1: RICHARD FITZPATRICK
Marine biologist at James Cook University. Multi-award winning documentary director and underwater cameraman. He's worked for the BBC, National Geographic and Discovery. And shot "the animal sequences" in Sir David Attenborough's "final" documentary series, David Attenborough's Great Barrier Reef broadcast on ABC in 2016.
"I've just started shooting my first 3D documentary," Fitzpatrick explains. "It's for IMAX. The market now wants Great Barrier Reef films desperately."
He's already shown me the swimming pool-sized coral aquarium he built for the Attenborough series and the purpose-built mangrove filter pumping system that ensures the water quality in the aquarium is as perfect as possible ("See that baby crocodile among the mangrove roots? He's here for some footage I need to shoot next week.")
Nearby are the tanks where he captured the first slo-mo sequences of "Nemo and friends" hatching (and Mantis shrimps mating) for the Attenborough series.
"I've been snorkelling on the reef since I was six," says the Cairns local.
"We've definitely seen the death of our inner reefs. As a kid I'd snorkel on the inshore reefs. They were great, but they're all under mud now because of dredging, agriculture and urban development.
"The outer reef has survived, but it is being assaulted on so many fronts. Cyclones, crown-of-thorns starfish, and now global warning which is causing these unprecedented bleaching events.
"David thought he was coming to the end of his career, and wanted to finish where he'd started – on the reef.
"But he was also determined to spell out the threats to the reef. He's been very active in the past few years filling in the background to his documentaries. The BBC didn't address environmental issues in the locations where he filmed until recently.
"But David has realised those documentaries suggest to viewers that nature is doing fine. So he's insisting now that his films have a healthy dose of reality.
Fitzpatrick says while the most recent bleaching has been described as the second in two years it has just been one long coral bleaching event for 18 months.
"We didn't have a winter, so the water temperature hardly dipped below 25C in winter and below 30C in summer which meant the coral didn't have any respite.
"People don't realise that when corals are bleaching, they're still alive.
"Corals get their colour, energy and food from a form of photosynthetic plant called zooxanthellae, which is why so many corals are autumnal colours – browns and greens.
"But when the water temperature stays too hot for too long, the corals expel the zooxanthellae. So the corals start to starve to death."
There are four stages of coral bleaching. Amazingly the second stage is when the corals are at their most colourful and vibrant.
Sadly, the third stage is the forced evacuation of all the zooxanthellae, leaving the corals devoid of colour, with only their transparent "skeletons" showing brilliant white in the underwater depths.
And the fourth stage? After a week or two, death.
TIP ON HOW YOU CAN HELP THE REEF
Not everyone can afford a trip to Cairns, but Fitzpatrick recommends signing on for a new initiative, Citizens of the Great Barrier Reef, which will launch in July. Headed by Andy Ridley (the founder of Earth Hour) and backed by the federal government, Queensland government, GBRMPA and James Cook University, the new body will co-ordinate an array of ways people across the globe can take action to protect the reef. See citizensgbr.org
EXPERT WITNESS 2: SIMON UREN
Dive master on SilverSwift (owned by Quicksilver Cruises) which employs an on-board marine biologist to brief guests, plus a diver dedicated to collecting crown-of-thorns starfish and Drupella snails.
Admittedly Uren is at a disadvantage because we're conversing underwater, and I am so pre-occupied with filling in my REEFSearch chart I sometimes fail to spot his diving checks. You don't need to be a diver: snorkellers and reef walkers can also take part in REEFSearch.
So let's keep it simple.
When you enrol online as a REEFSearcher, you'll be sent a pack containing a cool underwater identification chart and a REEFSearch field guide.
The field guide makes fascinating reading. There are six categories of organism a REEFSearcher needs to identify: anemone fish; fish larger than 20 centimetres long; giant clams; sea cucumbers; sea urchins and crown-of-thorns starfish.
Who knew "Nemos" are endangered because they are harvested outside Australia for the aquarium trade, and that the anemones they hide in are one of the first indicators of coral bleaching?
Or that giant clams are so sensitive to changes in water quality that they're an ideal indicator of reef health.
As for sea cucumbers? Apparently they are a delicacy in many countries, but taste of fish poo – because that's the core diet of these "vacuum cleaners of the ocean".
Uren also points out other environmental challenges on our three dives.
Look, there's our first Drupella snail. "It's Shaun's job to collect these, but it's his day off. In a normal day he could collect 1000."
And that triggerfish tearing away at that plate coral? "He's a parrot fish, a big beak with crushing plates behind. He's a natural predator of Drupella snails. Yet, in searching for the snails, he's destroying the coral."
TIP ON HOW YOU CAN HELP THE REEF
Sign up as a REEFSearcher, run by Reef Check Australia. A 10-minute video explains how it works (reefcheckaustralia.org). The registered charity also offers full or part-time (heavily subsidised) courses in Cairns, Townsville, Port Douglas, the Sunshine Coast and Brisbane for both snorkellers and scuba divers who want to take their commitment a stage further. Plus an EcoDiver course that is internationally recognised.
EXPERT WITNESS 3: GARETH PHILLIPS
South African-born Phillips runs ReefTeach in the Cairns CBD. Another marine biologist with a Masters degree, his primary service is a passionate, two-hour illustrated and highly entertaining presentation explaining the intricacies of the reef ($23 per adult, $60 per family). He also offers an Underwater Naturalist Program with private marine biologist guide ($450 per day, plus the cost of the reef excursion). See reefteach.com.au/
Saturday evening in Cairns and I'm the only Australian who has signed on for the ReefTeach information show whose motto is "With learning comes appreciation".
The other 25 in the audience vary in age, scientific knowledge and nationality.
Most are backpackers or honeymooners, though a retired Canadian couple and an older Dutch woman ask Phillips the most insightful questions.
He goes on to describe the bad science in the Finding Nemo movie. Once Nemo's mum died, his hermaphrodite dad, Marlin, would have turned female – one of eccentricities of clown fish.
Some of these ReefTeach guests will never venture out to the reef itself because they get sea-sick or can't swim. Others want to learn more about the reef before they choose which of many reef adventures to book out of Cairns.
I'm doing his Underwater Naturalist Program so we meet at 8.45am on Sunday at the Cairns Esplanade Reef Fleet Terminal. As we walk along the pier towards our vessel, he quizzes me on what I remember from the lecture.
Sure, I now know a coral polyp is a living animal – an upside-down jelly fish that can vary from the size of an "angel on a pinhead" to a saucer-sized mushroom.
Yes, I recall there are no great white sharks this far north as the water temperature is too balmy (as it was even before global warming).
And yes, I remember that those tiny cleaner wrasse keep the fish on the reef healthy by eating all the parasites on fish, big and small.
Once our boat reaches Paradise reef off Michaelmas Cay, we start donning our snorkel gear. "My job as a marine biologist is to show my clients what I am looking for, and share those insights with them," Phillips says.
It's high tide when we start snorkelling, with a strong wind blowing. It can reach up to 30km/h – worse in a cyclone. Phillips prefers to guide snorkelling trips rather than diving trips because it's easier to bob to the surface and exchange information.
So what do we see? "The depth of the coral bleaching is alarming me now. Last year it was confined to the top six metres," Phillips says. "This year, it is already deeper."
Yet there's so much to see. That fire coral? I now know not to touch it after the lecture last night: "It's like sticking your hand into a roaring fire."
That unicorn fish? I didn't notice it until Phillips pointed it out.
That coral war – with three different types of coral communities competing for the same patch of territory? Who knew coral could be so belligerent?
ReefTeach is also launching its first Great Barrier Reef Marine Discovery Program for volunteers who want to work with professional marine biologists to conduct science on the reef. See reefteach.com.au
TIP ON HOW YOU CAN HELP THE REEF
Phillips recommends you choose a company which displays the Eco Certified Advanced Ecotourism logo (not just Eco Certified logo). See ecotourism.org. You might have to pay $30 more than the cheapest Great Barrier Reef trips, but you'll learn so much more.
EXPERT WITNESS 4: RUSSELL HOSP
Denver, Colorado, is about as far as you can get from the ocean in the US, but he's lived in Australia for the past 11 years and now has a Masters in Public Relations and Sustainable Tourism. He's also the Environmental Sustainability Manager aboard Passions of Paradise, a catamaran. passions.com.au/
Hosp is giving me an introductory course into the Eye On The Reef checklist – the underwater citizen science program run by the GBR Marine Park Authority (a similar checklist to REEFSearch, but more intensive).
"Gobies are the Tim-Tams of the Reef," Hosp tells me before we snorkel off the bird sanctuary that is Michaelmas Cay. "They're a quick snack. The bottom of the food chain. They have three functions in life: eat, make more little gobies, and avoid being eaten."
Hosp is making the point that visitors to the reef are often disappointed they don't see bigger, more colourful fish.
"But without gobies, there would be no bigger species."
We go through the checklist again before we venture into the water.
Since I've passed the online volunteer test, I'm already up to the second level of the Eye On The Reef qualification. (Of course, Hosp is much higher on the EOTR food chain – he's often sent out on special missions to check out the results of the data non-scientists like me are recording).
But this afternoon we have two missions to complete.
Our first joint exercise is to snorkel for 10 minutes and record what we witness.
Then Hosp points out a giant clam, "a sign of how good the water quality is", those grazing butterfly fish, "the kangaroos of the sea, keeping the plant life under control", and that Maori wrasse, "the biggest reef fish in the world".
Ten minutes later, we're doing the Eye On The Reef 360 degree test. Essentially, this means picking an area roughly the size of a tennis court and checking the condition of the coral.
It's a lot more complicated to describe than it is to do it.
TIP ON HOW YOU CAN HELP THE REEF
Join the Eye On The Reef program. See gbrmpa.gov.au
EXPERT WITNESS 5: STEVE MOON
Project manager for the crown-of-thorns-starfish control program run by the Association of Marine Park Tourism Operators which has culled 460,000 of the pests since 2012.
Commercial dive and snorkelling operators are responsible for culling crown-of-thorns starfish and Drupella snails on the reefs they visit.
But they are reinforced by a full-time dedicated team, run by the association and funded by the Department of the Environment which go out onto the reef for 10 days at a time aboard two ships, Hero and Venus.
Divers target infestations on reefs visited by tourists, priority reefs which propagate coral larvae, and known breeding areas for the starfish.
"The biggest of these starfish we've found was 1.3 metre across – that's the size of a truck tyre," Moon explains. "And each one can eat its own body size in coral every day."
Unlike, say, the cane toad which is an introduced species, these jellyfish occur naturally in the GBR. But their numbers have swollen hugely due to heavy nutrients in the ocean caused by run-off from fertilised agricultural properties.
"The crown-of-thorns infestation is now just off the Cairns coast, but they are moving south towards Townsville. They'll eventually reach the Whitsundays.
"Our mission is to cull as many as we can to suppress their numbers before the coral spawning event in October/November."
TIP ON HOW YOU CAN HELP THE REEF
Tourism contributes around $10 million to the Great Barrier Reef Marine Park Authority via the environmental management charge which is collected by every reef operator as part of the ticket price. Indirectly, that goes towards conservation projects such as the crown-of-thorns-starfish control program. So just by taking a trip to the reef, you're helping.
EXPERT WITNESS 6: MIKE BALL
Owner of Mike Ball Dive Expeditions in Cairns, Queensland's longest-running dive operator and an inductee into the International Scuba Diving Hall of Fame.
Ball has run "shark feeding" dive trips in the Coral Sea since 1981 when he became the first operator in Cairns to have a live-aboard dive boat (his current vessel is the luxurious Spoilsport).
Shark feeding isn't allowed within the Great Barrier Reef Marine Park, so Ball offers four and seven-day trips to Osprey Reef, one of the most spectacular dive sites in the world with spectacular wall drop-offs teeming with sharks – white-tips, grey whalers, hammerheads and oceanic silver tips.
There are three types of shark interaction. For the "passive" experience, a bait crate (containing tuna heads) is lowered to a depth of around 15 metres surrounded by divers, but the food is not released. "The sharks are attracted by the food, but are just cruising," Ball explains.
The second experience is more frenetic. Once the food is released, the sharks literally go into a "feeding frenzy".
And if you're really committed you can opt for the "Shark Shooter" option, when keen underwater photographers really get up close and personal with scores of different sharks getting to within a couple of metres of the submarine snappers.
Why does this count as eco-tourism? And how does this help the reef? Because sharks are pelagic fish which cruise the oceans (and the GBR) – unlike reef fish which stay within their coral confines.
They're top of the food chain in the reef – apart from humans, obviously. So the more we know about them, the better for the long-term sustainability of the reef.
"The value of sharks to tourism in Australia is worth far more per kilo than the price they reach down at the fish markets where they're sold as flake for fish and chips," says Ball.
"Each diver commits to paying $5 a day for the time they're on Spoilsport to marine research, and the data we collect when we're diving is sent back to marine biologists at James Cook University."
If sharks aren't appealing, what about Antarctic minke whales? These wonderful mammals – the second smallest species of baleen whales – gather off Ribbon Reef, between Steve's Bombe and Cod Hole, for six weeks every June and July.
These are Ball's most popular dive trips of the year, with scientists now successfully tagging the minkes to discover their annual migration patterns.
You'd prefer something more unusual? What about the company's Nautilus Expeditions, run in conjunction with researchers from Central Queensland University? Nautilus are deep sea creatures, the size of a wheel on a kid's cycle, and deeply mysterious – related to the octopus and squid.
Or perhaps you want cute? Raine Island (named because it apparently looks like a single drop of rain) is recognised as the largest rookery of green sea turtles in the world.
There are other places on the reef to see turtles hatch and waddle to the sea, braving the birds who feed on them.
So do yourself a favour. Make your own video and pretend you're David Attenborough.
TIP ON HOW YOU CAN HELP THE REEF
Plastic bags affect many creatures, but none more than the turtle. Because they feed on jellyfish, they often mistake plastic bags for a decent meal.
The lucky ones die quickly. Most die slowly of starvation, their stomachs unable to digest the real food they've eaten.
The Port Douglas-based Tangaroa Blue Foundation (founded in 2004) is part of the Australian Marine Debris Initiative, organising beach and wetland clean-ups around the nation. There's also a citizen science aspect to the rubbish removal: with the data being used by Tangaroa Blue researchers to work out where the rubbish comes from, to address the problem at its source.
Steve Meacham was a guest of Tourism and Events Queensland.