The Great Barrier Reef

As part of my Masters degree I had the opportunity to undertake research at the Great Barrier Reef in January 2018. We stayed on an island called Heron Island (there are no Herons on the island, the bird it was named after is actually an Egret and whoever named the island was ignorant of this fact) which homes the university research station and tourist resort only. It was amazing swimming with all the turtles, sharks and rays and occasionally getting stung by small Jellyfish. We snorkelled around half the island on our last day which took about 4 hours. Unfortunately even though we were in the southern-most part of the GBR there was evidence of coral bleaching.

The island is dominated by a plant called Pisonia which homes a bird called the White- capped Noddy. There are close to 15,000 of these birds on this tiny island. They feed on fish, but nest in these trees building very unstable nests. They breed annually with a single chick each year. On many occasions the chick falls out and dies, but with the high numbers and lack of predators this means the population is in no danger of decline. The trees that home them have very sticky seeds which stick onto the birds (as a means of seed dispersal), hindering its movements if the number of seeds stuck is high and ultimately kill them. This way the seed has enough nutrients to germinate and survive as the dead bird acts as fertiliser. A harsh, but very interesting strategy of nature. I was able to save two of these birds by removing the stuck seeds, but it’s impossible to save them all from this gruesome death as this is nature’s way of keeping the bird population in check.

A bird species called Burrowing Shearwater is also found on the island. They live in tunnels underground. They have a wailing cry (a cross between a child crying and the ghost sounds from movies) which kept us awake at night. They are amazing fliers, but horrible at landing and they collided with me on two occasions, once with my shoulder and once with my knee while one crashed directly into the face of a friend.

Our aim was to assess the health of the reef using various proxies to measure the health. I focused my study on mainly assessing the factors affecting the distribution of sea cucumbers on the reef flats. Sea cucumbers are the equivalent of earthworms on the reefs and they play a big role in nutrient cycling by feeding and excreting organic matter. Their faeces is mostly sand and I had to collect and weigh it for the six species we found and also see how each species of sea cucumber was distributed at different depths on the reef flat and see if there was a correlation between the weight of their faeces and their length. I found that the sea cucumbers were bigger in deeper waters as expected, but the weight of faeces was higher closer to shore. This could be because they were smaller individuals and were eating more frequently and with smaller guts were defecating more often.

I had the privilege of watching baby turtles making their way back to the sea while my batch mates and I aided them as much as possible by keeping the sea gulls away - not an easy task. One of my batch mates saved a hatchling from the beak of a sea gull and all of us ensured it made its way back to the sea whilst even acting as body guards going into the sea till it was safe.