"There are lots of things to see in the water; white-tip reef sharks, turtles, humpback whales, manta rays - but don't worry, the turtles won't hurt you."
I have time before dinner to walk the beach circuit around the island.
The tide is ebbing, exposing a broad expanse of coral heads running out to the fringing reef.
It's a peaceful scene dominated by the dazzlingly white sand and the grand spectacle of the sea, which changes from aqua to turquoise to deep blue as I turn each corner on the 30-minute walk.
Then, as night falls, the full moon lays out a pathway of gold across the sea. But slowly, inexorably, a dark crescent of Earth shadow creeps over the golden lunar surface. I watch the eclipse grow to engulf half the moon, then retire to my comfortable bungalow under the beachfront palms.
I can't escape the sublime feeling that I'm cast away on a desert island, yet living in tropical bliss and luxury.
Next morning there's excitement in the air as the research team and its eight Earthwatch volunteers prepare to locate and identify more giant manta rays to add to their data base of 390 individuals.
I step off the dive boat with divemaster Kim and immerse myself in the ambience of a kaleidoscopic coral reef outcrop known as the Lighthouse Bommie.
"Bommie" is a nickname for a submerged sandback or mound of coral.
We settle on the bottom at 24m, kneeling gently in the powdery, white coral sand. While we wait in the silent depths we become conscious of eerie-sounding music, clearly audible but muted by the dense seawater.
It dawns on me that the high-pitched sound is the hauntingly beautiful song of a humpback whale somewhere out in the ocean.
Sure enough, an answering call comes back from another whale.
It's a novel experience having piped cetacean background music to enhance the dive.
The minutes pass by ever so slowly.
I swivel around, staring into the distant haze, straining to catch a glimpse of movement at the periphery of vision.
A 2m white-tip reef shark suddenly appears as a sleek, menacing silhouette, livening up the proceedings before vanishing into the blue.
In this ecosystem of big muscle fish running on steroids I'm starting to feel a little insecure.
Later, the Aussies will make fun of the white-tips, calling them the "men in grey suits" and the black-tips "men in black".
But for now I'm in an alien world without a Mother Ship close by.
Suddenly, my heart leaps as a great white blanket of glistening underbelly passes over my head. The manta ray is huge, almost 4m from wingtip to wingtip, and it appears to move with the merest twitch of its upturned fins.
The "stealth bomber" of the ocean hovers motionless over the bommie, where it is instantly besieged by a bevy of hyperactive cleaner fish, the barbers and groomers of the reef.
In this undersea metropolis, the Lighthouse Bommie is Grand Central Station, the foremost fish-cleaning base on the reef.
As the manta ray hovers like an intergalactic spaceship, the assorted nibblers quickly remove every trace of dead skin and parasites from his - or her - mouth and gills.
When the work is done the manta ray manoeuvres its body into a wide sweeping arc and turns away, one black eye focused intensely, and I suspect curiously, on me, an unusual intruder in his world.
The encounter with this graceful winged angel has left me with an intense feeling of being alive but also of being insignificant in the undersea world's ebb and flow of life.
I've had a brief glimpse of the connectedness of all creatures, particularly the great aquatic mammals.
Humans have an intriguingly close affinity with dolphins, killer whales, whales and the giant manta rays.
Manta Project scientist Kathy Townsend gives an evening talk in the Education Centre, providing further insight into the manta ray's lifestyle. These creatures are the largest and least-known of all the rays, easily recognised by their paddle-like cephalic lobes projecting out from the head. Unlike most rays they have no stinging barb in their tail.
Most of those encountered are around 4m wide, but the largest specimen recorded was 9m wide and weighed 1.4 tonnes.
On the next day's snorkel excursion with divemaster Oko, I meet a green turtle called Buddy.
This juvenile has really taken a shine to homo sapiens and interacts with divers with unsuppressed glee. He turns in the water and backs up to us to have his shell scratched as if we are his personal cleaner fish.
He quivers appreciatively like a domestic kitten.
Around the coral outcrops, schools of tiny damsels and demoiselles form a shimmering curtain of silver, which divides and reforms in one fluid motion as if choreographed by some unseen hand.
Clusters of Nemos, proudly displaying the bright orange livery that made them a Hollywood box office attraction, dart in and out of their host anemone as if it's the Clown Fish Hilton.
The scene is captivating beyond belief; iridescent blue fusiliers parade below me, flighty butterfly fish and cheeky-beak parrotfish dive under the coral.
A brightly costumed harlequin tusk fish cavorts like a true comedian, as gorgonian fans sway gently in the current.
After this surfeit of natural wonders, I cannot expect more excitement, but Lady Elliot has one last surprise up her sleeve.
Breakfast on the terrace next morning is enhanced by an impromptu humpback whale show just beyond the reef.
A pod of barnacle-encrusted humpbacks breach and begin tail slapping, pectoral fin slapping and spy-hopping to get a view of the coral cay and its curious human observers.
Surging white foam and spray fills the air as the whales crash back into the water and sunlight flashes off their sleek, wet backs.
It's a memorable spectacle to conclude my island sojourn.
Lady Elliot Island is the perfect destination for dive junkies who seek encounters with the megafauna of the oceans.
It's also a pleasant place to simply lie back and relax under the tropical sun in a pristine, peaceful setting.
Jenni Fox, guest relations manager on the island, sums up the Lady Elliot experience: "This place grows on you. I've spent a total of nine years on the island.
"Where else can you discover the mysteries of the Great Barrier Reef by simply stepping off the beach into the ocean?"
Where else, I might add, can you listen to whale song, tickle turtles and swim with divinely graceful winged angels?
Oh, and watch a lunar eclipse as well.
