If you've watched Blue Planet, you've already benefited from some of Professor Callum Roberts' lyrical love for the ocean. In his memoir, Reef Life (Profile Books), Britain's pre-eminent marine conservation scientist tells of how he fell in love with the 'rainforests of the ocean', and of his concerns for coral in the face of global warming. In this extract, he takes us back to the Red Sea three decades after his first encounter with coral there, and celebrates nature's miraculous ability to thrive, adapt and regenerate without human interference.
“It is 2012 and I am in the courtyard of the Sofitel Beach Resort looking across Sharm el-Sheikh's Na'ama Bay. Before me lies the same supple curve of beach and cliff that, over twenty years ago, I spent countless hours admiring from my house.
The sea is as vivid and enticing as ever, but the land before me utterly different. Gone are the khaki hues of desert sand and rock, replaced by the glint of whitewashed concrete, steel, tinted glass and manicured gardens. As far as the eye can see in both directions, a continuous belt of development extends inland, a kilometre or two from the water's edge.
This is my first time in Sharm el-Sheikh for sixteen years, an odd omission given that these are the closest coral reefs to my home in Britain. In truth, I have actively avoided the place. To return somewhere you once loved deeply in the certain knowledge that it has been so altered is to court disappointment. Sure enough, the timeless majesty of desert has been sacrificed to progress. Yet it is easy to see why a country like Egypt, struggling to make its way in the world, would make this choice.
My wife Julie and I are here to introduce our Masters students to coral reefs. Rupert Ormond, my old friend and PhD advisor, is back with us to run the course along with his wife Mauvis Gore, also a marine biologist. We have two daughters in tow, aged 12 and 13, both already qualified scuba divers. Our students chatter excitedly as we head for our first dive, but Julie and I have grave doubts.
When we published our predictions in the early 1990s about the damage that mass tourism might do to Egyptian refs, people from the Ras Mohammed Marine Park and Environment Ministry scoffed. We were alarmist, they said. Development would stop far short of the 1.2 million tourist nights per year that we forecast. In reality we were much too cautious. By 2015 there was a hotel capacity in South Sinai for over 25 million tourist nights per year. We saw in the 1980s how much damage small fraction of these tourists could do.
'What do you think it will look like?' Julie asks uncertainly as we drive to the dive site.
'I dread to think.' We are silent the rest of the way.
It isn't just the mass tourism. There have been more sinister developments for reefs worldwide. From late 1997 to early 1998 tropical oceans sweltered in unusual warmth as a vast pool of overheated water spread across the Pacific and Indian Oceans, linked to the El Niño-Southern Oscillation, the same climatic disturbance that destroyed Galápagos' coral reefs in the 1980s. Reports soon began to come in of mass coral bleaching.
As New Year 1998 came and went, the internet began to crackle with stories of overwhelming coral death and it became clear a major calamity was underway. All over the world, immense banks of coral lay in ruins which only a few months previously had pulsed with life, stifled to death by hot water. It felt like one of those disaster movies in which the first reports of the unusual soon coalesce into a deluge of terror as aliens mount their invasion or a virus spreads. By year's end, a rough accounting suggested that something like 70 % to 95 % of all corals had perished across a vast swathe of the Indian Ocean from the Seychelles to Sri Lanka, Kenya to the Maldives. Pacific and Caribbean reefs racked up additional losses of 30 % to 50 %. This catastrophe had no historical precedent.
Although mass coral death also reached the southern Red Sea, taking out mountainous coral heads hundreds of years old, here in the north it remained cool enough to spare the reefs. Still, I reasoned, as Julie and I pulled on wetsuits, even with more favourable conditions there is sure to be a lot of damage here, being under such stress from tourism. I must have been frowning because Mauvis asks what the matter is. Julie laughs and lowering her voice, so the students won't overhear, replies for both of us, 'We're hoping this won't be a disappointment! So much has changed.'
'Don't worry. I think you'll be pleasantly surprised'
Mauvis is Jamaican and in her late fifties, her dark wavy hair streaked with grey. I should trust her opinion as she has seen a lot of reefs in a long career, and she and Rupert have taught field courses here for several years. But I can't quite shake off my anxiety.
We cross the reef on a walkway made of floating plastic pontoons installed by the hotel whose dive centre we are using. The students go in first, then we jump. When the bubbles clear, it feels like l have been whisked backward in time. Corals bristle at the reef edge, some smooth and rounded, others folded like brains, or extending like shelves, all hemmed in by stubby fingered branching colonies and the ochre plates of fire coral. Splashes of purple and the gently rounded waves of coral bushes remind me of moorland heather in bloom, but here with alien smudges of blue, hot pink and apricot. A shoal of Abudefduf damselfish gravitates towards us, milling about like huge butterflies, their black and white barred bodies briefly rendering the scene in monochrome. Fish storm above the drop off, their polychrome clouds effervescing in the sunshine.
Below us the reef plunges vertically, losing itself in shadows that darken into a blue grey abyss. It feels so natural and familiar, a sharp contrast to the foreign world above water.
It isn't the same of course. Some of the larger stony corals are dead and overgrown by ephemeral soft corals. There is more tourist damage too – shattered clumps of coral, severed branches trampled sponges – but it has the feel of a place that is coping, not a reef struggling to survive. It remains vibrant, beautiful and uplifting, like a favourite country walk.
Our students bombard us with questions from the moment our heads break the surface. Most have never seen so many different creatures in one place or felt so accepted by wild animals. I never did solve the enigma of this extraordinary richness, nor, so far, has anyone else. Many ideas attempt to explain the eruption of life. One holds that because coral reefs are tropical, they haven't suffered the Ice Age extinctions of higher latitudes, so they have accumulated species from long, uninterrupted stretches of evolution. The tropics are also highly productive and relatively stable, so they can support specialist species that more finely divide available resources than is possible in seasonal temperate and polar seas. An example from land makes the point well. It would be impossible for a species to eat nothing but fruit in temperate latitudes because fruit is seasonal. But it is a simple matter in the rainforest where there is always fruit to be had from some plant or other.
These explanations of high diversity all involve biology, by which I mean that the interactions among species and with their environments are important. However, in the last decade some theorists have pursued a different line, suggesting the greater richness of the tropics is an effect of chance. If you were to drop a bunch of species with different geographic range sizes onto the surface of the planet at random, they argue, more of their ranges will overlap in the middle than at the polar edges of the habitable world. This happens because while small ranges can fit anywhere, big ranges would be constrained by barriers at the edges so lots of them overlap in the middle. Middle regions therefore have lots of species and the margins fewer. In other words, richness would be high on coral reefs for purely prosaic reasons of geometry. The same thing works longitudinally. The boundaries here are supplied by Africa and the Americas bracketing the Indian and Pacific Oceans, so South-East Asia, which is midway between them, has the most species. I recoil instinctively from this idea, as do many colleagues. Such an explanation feels like someone pulling a well-loved rug from underneath our feet. How can it be possible for nature in all its splendour to be explained by mere mechanical assembly rules? Fortunately, recent thinking has shifted again to the idea that biology plays a role and that patterns seen in nature do not conform exactly to this joyless prediction; nonetheless, the match is close.
In 1994, four years after I [last] left Egypt, my pursuit of an answer to the secret of reef diversity took me to Palau. This tiny archipelagic nation lies at the edge of the global epicentre of coral reef diversity, 900 km east of the Philippines. So rich are the reefs of South East Asia the region is dubbed the 'Coral Triangle'. While the Red Sea hosts about a thousand species of fish, Indonesia and the Philippines have over three thousand. More than five hundred of the world's eight hundred plus shallow water coral species occur in the Coral Triangle. Compared to Egypt, Palau's reefs support a mind-corrupting turmoil of species. By the time I went there I had begun using a different method to count fish. Instead of swimming for a set distance or time and counting all the fish in a belt several metres wide, I now counted them for fifteen minutes in a ten-metre diameter circle. This was better in the Caribbean, where I then worked, because reef habitat there is patchy and long-distance counts aren't practical. But when I tried it in Palau, my brain nearly jammed.
TO MAKE THINGS TOUGHER, CURRENTS POURED ACROSS THE PALAUAN REEF SLOPES LIKE A LIQUID TREADMILL. I HAD TO SWIM HARD JUST TO STAY PUT. IT FELT LIKE ONE OF THOSE MAD ENDURANCE TESTS A TELEVISION GAME SHOW MIGHT DEVISE.
For those who love coral reefs, Palau is close to heaven on Earth. Like Egypt, this country has reefs above and below water, although rather than the rufous layers of the Red Sea's fossil cliffs, Palau's fossil reefs are gleaming pinnacles of limestone shaggy with tree ferns, elephant ears, lianas and dripping moss. Over tens of thousands of years, rainwater has etched these raised reefs into a labyrinth of islets, passages and cul-de-sacs. We approached the dive site through this maze, following winding water trails between soaring cliffs and along shadowed gorges, emerging at last into hard sun glare and the borderless immensity of mid ocean. The boat driver steered toward a serpentine ridge of reef visible only as a malachite smear on the dark sea, crossing it through a channel. A swift current slapped the gunnels as he threaded the narrows to a small bay that opened on the ocean side where we would dive. Below the surface in the sharp-edged clarity of pure oceanic water, the reef fell away in an amphitheatre of breathtaking scope. Rounded corals looked like velvet pillows heaped on the terraces, while seafans rusted on the slopes, bent and quivering in the current. Descending to fifteen metres, I picked a spot directly beneath the boat, started my stopwatch and wrote down the first fish: 'Monotexis grandoculis, the bigeye emperor, 7 individuals at 50 to 70 cm long'. Broad-finned, with large forked tails and three dark squares on their leaden flanks, these fish are almost always the first counted because by day they hang above the reef in full view, nearly motionless. Glancing up, there were ten other species, at least, milling about within the space of a metre or two. Before I could decide which to record next, several others took their places: parrotfish green and maroon as their jungle namesakes, barracuda like silver ingots, gobies with red-striped faces glimpsed in their burrows. I scribbled them down, freezing the moment in my mind's eye, before looking up for more. The minutes ticked by in a feverish ordeal of species identification and counting. By the end of fifteen minutes, my board crammed with coded-names, strings of numbers and cryptic sketches, I had recorded 95 species of fish in my ten-metre cylinder of reef.
Within a handful of dives, I discovered that the leisurely simplicity of Caribbean fish counting was supplanted by a head-spinning, pencil-busting burst of speed writing. To make things tougher, currents poured across the Palauan reef slopes like a liquid treadmill. I had to swim hard just to stay put. It felt like one of those mad endurance tests a television game show might devise.
I had already amassed similar counts from reefs all over the Red Sea and Caribbean. When I plotted the number of fish species counted against the total number reported from a region, there was a straight-line relationship angled at roughly 45 degrees: the more fish present in a region, the more there were in the snapshots of my counts. Put simply, in richer regions, the species packed more tightly into the available space. When I added the Palau data to the plot, the straight line just sailed on upwards. I had been expecting it to bend and level of like the rise to a hilltop, as a limit was reached on the number of species that could share a given amount of space. There must come a saturation point, I reasoned, when the available resources can no longer be subdivided further,
Our students bombard us with questions from the moment our heads break the surface. Most have never seen so many different creatures in one place or felt so accepted by wild animals. I never did solve the enigma of this extraordinary richness, nor, so far, has anyone else. Many ideas attempt to explain the eruption of life. One holds that because coral reefs are tropical, they haven't suffered the Ice Age extinctions of higher latitudes, so they have accumulated species from long, uninterrupted stretches of evolution. The tropics are also highly productive and relatively stable, so they can support specialist species that more finely divide available resources than is possible in seasonal temperate and polar seas. An example from land makes the point well. It would be impossible for a species to eat nothing but fruit in temperate latitudes because fruit is seasonal. But it is a simple matter in the rainforest where there is always fruit to be had from some plant or other.
THE SHEER WONDER OF THIS IDEA WAS THRILLING. LEFT ALONE FOR ENOUGH TIME, CORAL REEFS MIGHT JUST CARRY ON GETTING RICHER AND RICHER AS EVOLUTION ADDS MORE SPECIES.
But the straight line of my graph said there was no ecological limit to coexistence at this scale. What limited the number of species in my counts was the number available from the regional pool.
All this time I had been looking for the secrets of co-existence at small scales, but this panoramic view said that the processes that set the number of species present operate at far larger scales and over very long periods. It is the balance between evolution and extinction that fixes the variety of fish in a region and this in turn dictates diversity on the reef. The sheer wonder of this idea was thrilling. Left alone for enough time, coral reefs might just carry on getting richer and richer as evolution adds more species. In fact, palaeontologists already had this figured out. Plotting the number of species on Earth over time shows that life has been getting more varied for the last 200 million years. Over the long creep of geological time, the world has been filling up with new species in a slow-motion evolutionary explosion. There was a brief setback 66 million years ago when there was trouble with an asteroid that dinosaurs and many others didn't enjoy. But this mass extinction aside, for a very long time, the rate at which new species have been added to Earth has been greater than that at which they have been erased. The struggle for life has propelled nature to ever greater creativity. What could be more wonderful!
Looking back, I am glad that coral reefs have guarded their mysteries. The structure of DNA can only be solved once. The complexity of the living world will keep us probing, guessing and arguing for centuries to come.”
Edited extract, from Reef Life by Callum Roberts (Profile Books, 2019)
Image credits: TheOceanAgency.org
Fill in your details below to get regular updates through our newsletter.
The Lewis Pugh Foundation is a registered charity in England & Wales.
Charity Registration no. 1168977.
.png)
