Researchers stunned by beauty of Kingman Reef in the South Pacific

This is what a coral reef should look like - and finding another one as pristine and healthy left anywhere on the globe would be hard.

An international team of researchers including Elizabeth Dinsdale, a marine scientist at James Cook University, explored one of the least visited places on Earth, Kingman Reef in the South Pacific, as part of a study into how human activity has degraded these wonders of the ocean.

It was exhilarating to see such an untouched place, Dr Dinsdale said. "The water was very clear, the sharks were very curious and the coral was very vibrant."

At night more than 50 sharks circled their boat, chasing fish, which brought home to her why early sailors feared these creatures so much.

"They were so aggressive, they'd flip out of the water. I saw one do a somersault."

During the day the mostly grey reef sharks were calmer but it took courage to go into the water: "They basically looked over your shoulder, to see what you were doing, which was pretty off-putting."

Dr Dinsdale, whose role was to study coral diseases, recalled hammering repeatedly at the reef on one occasion to collect specimens.

"I looked up to make sure I hadn't attracted too many sharks and I couldn't count the number swimming around me," she said.

Dolphins were also inquisitive, sitting motionless on their tails watching the scientists.

Large fish, unfamiliar with people, bit at the divers to see what they were.

"You would go underwater nervous of the sharks and end up being bitten by a snapper," she said.

The expedition to the Line Islands, about 2600 kilometres south-west of Hawaii, concluded last month and was led by the Scripps Institute of Oceanography in the US. Dr Dinsdale said it was unique in exploring such remote areas and examining the whole ecosystem, including all the main reef organisms such as microbes, algae, corals, sponges, sea stars, clams and small and big fish.

A range of reefs was surveyed from the highly degraded and over-fished reefs near Kiritimati, also known as Christmas Island, to the rarely visited Kingman Reef. The worst sight was at Tabuaeran, also called Fanning Island, where a shipwreck had released iron into the water, promoting algal growth that turned the reef black.

Dr Dinsdale said it was important to find a reef like Kingman, to act as a baseline for comparison with reefs affected by over-fishing, pollution, climate change and disease.

"On reefs where the sharks and large fish had been removed and effluent from the land was flowing into the marine environment, up to 28 per cent of the corals were affected by disease symptoms," she said.

Source: www.smh.com.au