Book: Growth & Decay of Coral Reefs
Corals make good press. If not in dramatic tales of divers exploring their exquisite structures and colourful habitats – homes for myriads of species– one reads accounts of their rapid demise under the toxic shadow of such draculin creatures as the infamous crown-of-thorns starfish. Feast or famine, wherever corals take centre stage, they usually command a sense of awe and wonder. And its not to say they don't deserve the headlines – they are after all our 'rainforests of the oceans', but it would do no harm to inject the odd fact-check into the almost breathless narrative.
My first encounter with corals was around the Micronesian atoll reef of Tarawa in what was then (in 1964) the 'Gilbert & Ellice Islands' but is now Kiribati and Tuvalu. I was there as a teacher on VSO (Voluntary Service Overseas) – a somewhat bizarre situation in which a recent 'A Level' student of just 18 years was appointed as senior science, maths, English, geography and health science to a giggly but charming mass of 16 to 18 year old school girls! And that was only the start of my adventures in the "South Pacific" for whose background knowledge I depended on not much more than Rogers & Hammerstein's musical of that name.
After arriving at my new island home, a thatch-roofed house with its own coconut palms, I was enthralled by the dazzling breakers rhythmically pounding at my doorstep. There was no escaping the vivid mottled tapestry of blues, greens, reds and browns of the near-by reef-top and it was not long before I was snorkelling over the shallows, imagining I was Jacques Cousteau or Hans Hass. It was what you might call : "a year well spent."
Just about keeping my head above water for nine months as a school teacher, I determined to follow my dream, devouring a bachelor's degree at Swansea University. There followed countless underwater adventures in Australia (Great Barrier Reef or GBR), Sudan, Seychelles, New Zealand, New Guinea, New Ireland, New Hebrides, Hawaii, and the Caribbean. They were formative years during which coral reefs were the magnetic attractionof my biological interests.
The GBR enraptured me from the moment of my first visit and, as a research student, I was lucky enough to join a coastguard service vessel, diving at over 80 locations as she made her way along the outer reefs and channels of Australia's east coast. Much of the talk on board focussed on the crown-of-thorns- starfish (CoTS) and the devastation it was causing to formerly pristine reefs and their mesmerising arrays of marine life. A stop-over at Lizard Island in the north and a couple of visits to Heron Island, at the southern end of the GBR, held me in its spell.
Meanwhile, back ashore the newspapers were full of doomsday stories of the damage being wreaked by CoTS. My year in Australia flew by and my arrival back in UK called for some rapid adjustments. Reflecting on all I had seen, I began to challenge the premise that the voracious aggregations of starfish may have been more of a natural event in the life of the reefs than many scientists and involved members of the public believed to be the case. It was not a popular view among academic and commercial entities seeking large grants to study the coral-eating CoTS. There was no denying the intensity or scale of CoTS invasions, nor of the impact of global warming on coral bleaching but the full story had not yet been written. A chance to join the Cambridge Coral Starfish Research Group's long-running expedition to the Sudanese Red Sea, provided an opportunity for some in-depth studies of marine life in these magnificent waters, rather than more superficial rewards of paying occasional brief visits. It was a transformative experience and one that shaped my own views of coral reef ecology.
Instead of a walk in the garden I took my exercise with gentle swims across the increasingly familiar coral reef, coming to know my aquatic neighbours by names and characteristics. I was becoming accepted by the coral reef community, less as threatening intruder than as harmless visitor and my underwater notepad's pages were filling with questions and possible answers.
Despite my privileged access, several questions persisted in my head. One was whether the physical structure of the reefs could be the result of biological behaviour rather than the other way around, with fish choosing attractive habitats whose form was defined by purely physical forces.. I found the answer through some experiments using settlement plates and wire netting cages and published the work in the Journal Marine Biology in 1980.
Another question was harder to answer: what was the enigmatic toxic organism that was spreading across coral reefs – laying a pall of death wherever it occurred – killing corals with similar efficiency to CoTS aggregations but remaining hidden under the 'biological radar?'Whilst the crown-of-thorns starfish and coral bleaching were two of the most efficient and widely recognised coral killers this was a 'new' weapon threatening coral reefs: an insipid,tissue-thin cyanobacteria sponge known as Terpios hoshinota.
My studies on the growth and decay of coral reefs led me, 50 years later, to write this book. An overwhelming theme was coral reefs' unexpected resilience to the multiple and widespread threats to their very survival. There was also one more revelation that I took with me when I left my coral home. It was that words like 'new', 'outburst' or 'spread' imply that these are unprecedented phenomena, first happening on the reef or habitat that divers visit. It became increasingly clear to me that it was more likely that the observations themselves were previously unrecorded than the event itself being unique. Thanks to tourism, SCUBA diving and the spread of Citizen Science, our eyes have been opened to the wonders of nature and it behoves us to create conditions where reefs are truly alive with the 'sound of music', enchanting visitors for decades to come.
