A large temperature anomaly, milling over the central Pacific and wending its way inexorably towards the Indian Ocean, promises to be the biggest in recorded history.
It has all the elements of a made-for-media catastrophe – a monster that destroys everything in its path and leaves coastlines and marine ecosystems ravaged, and the underlying suspicion that this mutant is one we have nurtured with our greed.
This age of fleeting attention spans demands hyperbole, and so this patch of hot water has been christened “The Blob", caused by nothing less than "The Godzilla El Niño".
And yet, for all the extravagant headlining, this attempt at grand narrative feels suspiciously like a rather tired sequel. We have been here before. Eighteen years ago, a similar monster patch of hot water swirled its way across the oceans. By early summer, it had taken hold in the Arabian Sea.
In its wake, once vibrant coral reefs across the tropics turned smurf-blue, then brilliant white, then died. Corals are ancient animals that live in close symbiosis with a photosynthetic dinoflagellate (think tiny algae) that provide most of its food and give corals their rainbow of colours. Under stressful conditions, this relationship breaks down and the dinoflagellates leave, causing the coral to bleach ghostly white and die if the adverse conditions continue unabated.
Temperature is one such stressor, and the El Niño of 1997-'98 saw temperatures in Indian waters rise by more than two to three degrees Celsius. The reefs in Lakshadweep died within a matter of weeks, leaving behind scorched deadscapes. Corals form the living architecture of the reef; when it died, so did most of the other animals, including fish that depend on these structures for a home. Many long-living species disappeared; only the hardiest, most adaptable species continued to thrive in these transformed reefs.
Getting it wrong
While diving in those brown barren reefs as a young marine biologist, I thought that if proof were still needed that climate change was real, this was as tangible a sign as we were ever likely to get. Surely now, we could stop wrangling and get on with fixing things.
I was wrong, and for more reasons than one. The catastrophe of 1998 did not stop the bickering. Eighteen years on, the Paris conference on climate change in December stitched together a too-little-too-late deal, in which every nation can maximise its own short-term self-interest while patting each other on the back for showing global resolve in tackling climate change.
It has taken our team of marine scientists the best part of the last decade-and-a-half to unpack these responses, and it is a far more fascinating and complex story than the sad epitaph I was convinced I would write when I first dived on those dead reefs in 1998.
Understanding reef responses
The Lakshadweep reefs show such complex responses to climatic stress for a combination of reasons. While it is too early to claim complete understanding, we have tantalising clues about why these reefs are responding the way they have been over time, and this may in turn create a hope that was not apparent in 1998.
Fish play vital roles in the recovery of the reef after a major disturbance. Herbivores are particularly important, as they mow down all the algae that could otherwise overtake the reef and prevent new coral from growing. In Lakshadweep, local fishermen have been fishing very lightly on these reefs, with the result that they are not yet overfished. Also important are the monsoon storms that clear reef areas of the unstable dead coral structures that accumulate on them, leaving these locations “clean” for new coral to grow and prosper. Pollution and sediment-free reefs also tend to recover quicker.
The reefs are now midway through a recovery cycle from the last mortality event, the El Niño in 2010. In 2014, we saw the first signs of young coral recruits (little baby coral, freshly settled and ready to start life on the reef) begin to push and shove each other for a space in the sun. Given a few more years without disturbance, some of these reefs will be be bustling, chaotic reef metropolises again. But then there’s the Godzilla on the horizon – and with it the question, how will the reefs respond this time?
I don’t know. Lakshadweep has shown the value of nurturing doubt as a virtue, not a failing. The reefs may prove to be more resilient and sturdy than I gave them credit for two decades ago, or this upcoming event could be the undoing of the reefs, which may keel over and never recover.
Why we should care
Why should any of this matter? Again, I don’t quite know, but I will hazard a guess. For the people of Lakshadweep, it matters a great deal. The Lakshadweep islands depend on healthy reefs for their existence and the atolls within which they sit form a fortress, protecting the land against the worst storms the ocean can brew. The framework of the reef is a rampart of living cement, produced in vast quantities by the coral as it grows.
In a healthy reef, the forces of daily erosion are constantly repaired as the coral grows, and behind these walls, the lagoon is calm no matter how strongly it blows outside. If this fortress loses its ability to self-repair and grow, it will not be long before the tiny slivers of sand that make up the the Lakshadweep are also swept away.
More critically, these islands remain habitable because they have fresh water. Every rain replenishes the tiny aquifers beneath most islands. As the reef declines, sea water begins to seep into these freshwater sources, making them unpotable and the island inhabitable. At that point we are looking at the prospect of having to relocate more than 70,000 inhabitants to the mainland – a catastrophe of fairly large proportions.
The approaching Godzilla may not spell the end of the reef as we know it. Or it might. The Lakshadweep atolls may still hold surprises for us in the way they respond. This season, as The Blob slouches its way through the Pacific, our team at the Nature Conservation Foundation will mount an expedition to survey the entire Lakshadweep archipelago – 12 atolls, some 60 reefs, two full months.
Chronicling the second coming
We will document what’s there before El Niño wipes the slate clean once again. Once it has passed, we will visit these reefs again, with a firm baseline against which to measure the damage. We hope to be able to identify how different reefs respond to this and future events. In an age of climate change, these tired sequels are our new normality, and understanding how ecosystems are likely to cope with repeat events is the first step to keeping them healthy.
This is the intent, and then there is serendipity. The last time we did this, in 2010, we chanced upon one of the biggest and most spectacular aggregations of grouper recorded anywhere in the Indian Ocean. On one of the southern reefs, close to the Maldives, we dived in reefs so full of predators that we put away our data slates and watched in silent awe.
Perhaps even more rewarding are the little things: an infinite minute spent with a tiny pipefish, exploring the universe of its coral home. Or swimming past the pink floating egg-cases of a deep-sea squid, the adults of which you may never see in your lifetime. Every dive holds its wonders, and we plan to leave ourselves open as to be surprised.
Rohan Arthur is a scientist part of the Oceans and Coasts programme of the Nature Conservation Foundation, which can be followed on Twitter @Oceans_ncf (The Arthur Lab).
It has all the elements of a made-for-media catastrophe – a monster that destroys everything in its path and leaves coastlines and marine ecosystems ravaged, and the underlying suspicion that this mutant is one we have nurtured with our greed.
This age of fleeting attention spans demands hyperbole, and so this patch of hot water has been christened “The Blob", caused by nothing less than "The Godzilla El Niño".
And yet, for all the extravagant headlining, this attempt at grand narrative feels suspiciously like a rather tired sequel. We have been here before. Eighteen years ago, a similar monster patch of hot water swirled its way across the oceans. By early summer, it had taken hold in the Arabian Sea.
In its wake, once vibrant coral reefs across the tropics turned smurf-blue, then brilliant white, then died. Corals are ancient animals that live in close symbiosis with a photosynthetic dinoflagellate (think tiny algae) that provide most of its food and give corals their rainbow of colours. Under stressful conditions, this relationship breaks down and the dinoflagellates leave, causing the coral to bleach ghostly white and die if the adverse conditions continue unabated.
Temperature is one such stressor, and the El Niño of 1997-'98 saw temperatures in Indian waters rise by more than two to three degrees Celsius. The reefs in Lakshadweep died within a matter of weeks, leaving behind scorched deadscapes. Corals form the living architecture of the reef; when it died, so did most of the other animals, including fish that depend on these structures for a home. Many long-living species disappeared; only the hardiest, most adaptable species continued to thrive in these transformed reefs.
A reef carpeted with live acropora corals.
Source: Rohan Arthur
Getting it wrong
While diving in those brown barren reefs as a young marine biologist, I thought that if proof were still needed that climate change was real, this was as tangible a sign as we were ever likely to get. Surely now, we could stop wrangling and get on with fixing things.
I was wrong, and for more reasons than one. The catastrophe of 1998 did not stop the bickering. Eighteen years on, the Paris conference on climate change in December stitched together a too-little-too-late deal, in which every nation can maximise its own short-term self-interest while patting each other on the back for showing global resolve in tackling climate change.
Yet for all the congratulatory rhetoric, most climate scientists and ecologists will agree that the nebulous but high-sounding "well-below 2°C limits" agreed to are nowhere close to preventing irreversible change in the world’s complex climate systems. For coral reefs, certainly, it is far from enough to save them from their current trajectories of decline. The Paris deal does not represent an ecological turning point even if it is a high watermark of global political negotiation.
I should have expected this if I were not so naïve. The competing rationalities of societies, ecosystems, economies and polities could hardly have resulted in anything very different from what transpired in Paris. What I could not be prepared for back in 1998 was the reefs themselves.Rather than staying dead as I expected, the Lakshadweep reefs responded in much more complex ways. Some, of course, declined. But there were other reefs that showed sturdy recovery and have remained stable through the years. Yet others went through cycles of boom and bust with every subsequent disturbance. The fish that I saw disappear in many reefs back then made surprising comebacks at some locations. And within less than a decade, it was difficult to tell that these reefs had experienced the worst disaster in recent history.
A mixed species shoal of herbivorous fish.
Source: Pooja Rathod
It has taken our team of marine scientists the best part of the last decade-and-a-half to unpack these responses, and it is a far more fascinating and complex story than the sad epitaph I was convinced I would write when I first dived on those dead reefs in 1998.
Understanding reef responses
The Lakshadweep reefs show such complex responses to climatic stress for a combination of reasons. While it is too early to claim complete understanding, we have tantalising clues about why these reefs are responding the way they have been over time, and this may in turn create a hope that was not apparent in 1998.
A shoal of powderblue tangs and striped bristletooth.
Source: Pooja Rathod
Fish play vital roles in the recovery of the reef after a major disturbance. Herbivores are particularly important, as they mow down all the algae that could otherwise overtake the reef and prevent new coral from growing. In Lakshadweep, local fishermen have been fishing very lightly on these reefs, with the result that they are not yet overfished. Also important are the monsoon storms that clear reef areas of the unstable dead coral structures that accumulate on them, leaving these locations “clean” for new coral to grow and prosper. Pollution and sediment-free reefs also tend to recover quicker.
The reefs are now midway through a recovery cycle from the last mortality event, the El Niño in 2010. In 2014, we saw the first signs of young coral recruits (little baby coral, freshly settled and ready to start life on the reef) begin to push and shove each other for a space in the sun. Given a few more years without disturbance, some of these reefs will be be bustling, chaotic reef metropolises again. But then there’s the Godzilla on the horizon – and with it the question, how will the reefs respond this time?
Bleached Pocillopora.
Source: Shreya Yadav
I don’t know. Lakshadweep has shown the value of nurturing doubt as a virtue, not a failing. The reefs may prove to be more resilient and sturdy than I gave them credit for two decades ago, or this upcoming event could be the undoing of the reefs, which may keel over and never recover.
Why we should care
Why should any of this matter? Again, I don’t quite know, but I will hazard a guess. For the people of Lakshadweep, it matters a great deal. The Lakshadweep islands depend on healthy reefs for their existence and the atolls within which they sit form a fortress, protecting the land against the worst storms the ocean can brew. The framework of the reef is a rampart of living cement, produced in vast quantities by the coral as it grows.
In a healthy reef, the forces of daily erosion are constantly repaired as the coral grows, and behind these walls, the lagoon is calm no matter how strongly it blows outside. If this fortress loses its ability to self-repair and grow, it will not be long before the tiny slivers of sand that make up the the Lakshadweep are also swept away.
More critically, these islands remain habitable because they have fresh water. Every rain replenishes the tiny aquifers beneath most islands. As the reef declines, sea water begins to seep into these freshwater sources, making them unpotable and the island inhabitable. At that point we are looking at the prospect of having to relocate more than 70,000 inhabitants to the mainland – a catastrophe of fairly large proportions.
A healthy reef.
Source: Rohan Arthur
The approaching Godzilla may not spell the end of the reef as we know it. Or it might. The Lakshadweep atolls may still hold surprises for us in the way they respond. This season, as The Blob slouches its way through the Pacific, our team at the Nature Conservation Foundation will mount an expedition to survey the entire Lakshadweep archipelago – 12 atolls, some 60 reefs, two full months.
Chronicling the second coming
We will document what’s there before El Niño wipes the slate clean once again. Once it has passed, we will visit these reefs again, with a firm baseline against which to measure the damage. We hope to be able to identify how different reefs respond to this and future events. In an age of climate change, these tired sequels are our new normality, and understanding how ecosystems are likely to cope with repeat events is the first step to keeping them healthy.
This is the intent, and then there is serendipity. The last time we did this, in 2010, we chanced upon one of the biggest and most spectacular aggregations of grouper recorded anywhere in the Indian Ocean. On one of the southern reefs, close to the Maldives, we dived in reefs so full of predators that we put away our data slates and watched in silent awe.
Perhaps even more rewarding are the little things: an infinite minute spent with a tiny pipefish, exploring the universe of its coral home. Or swimming past the pink floating egg-cases of a deep-sea squid, the adults of which you may never see in your lifetime. Every dive holds its wonders, and we plan to leave ourselves open as to be surprised.
A large shoal of goatfish and snappers in a coral reef.
Source: Rucha-Karkarey
Rohan Arthur is a scientist part of the Oceans and Coasts programme of the Nature Conservation Foundation, which can be followed on Twitter @Oceans_ncf (The Arthur Lab).
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