Keeping corals alive

Studying something that his children’s children may never see adds a certain urgency and poignancy to Simon Davy’s daily routine.

The United Kingdom-born associate professor in Victoria’s School of Biological Sciences is New Zealand’s only active coral symbiosis physiologist. His research focus is on the symbiotic relationship between algae and invertebrates, such as corals, and coral bleaching and disease.

Coral reefs cover just a fraction of the planet—estimated to be an area about the size of New Zealand—but are a vital part of the marine eco system and the economies of communities that rely on them for food, fish, building materials and tourism dollars.

"It’s old news to us that the reefs are going to die within 50 to 100 years,” says Dr Davy. “Climate change is the longer term threat but pollution and practises such as dynamite fishing are, if anything, a bigger problem because they are working much faster."

Some years back, Dr Davy and a colleague were the first scientists to discover viruses in corals and the breakthrough sparked his interest in the broader topic of coral diseases.

He says corals are highly complex. They contain tiny algae which process light energy and provide the host with essential nutrients. When water temperatures rise, the micro-algae are expelled and the coral loses its colour and may die.

Dr Davy is using a Marsden Fund grant to better understand the pathways that lead to losses of these micro-algae.

"We know temperature and light are crucial factors in coral bleaching but there’s a lot of detail to investigate such as why some corals bleach and others don’t. There can be mass bleaching events covering large areas, patches of bleaching or two neighbouring corals that look identical but one bleaches and the other doesn’t."

A lot of his research is done at Victoria using sea anemones which contain similar micro-algae and are easier to keep alive in the laboratory.

But Dr Davy and his students also have access to living labs not too far from New Zealand. Victoria is the only non-American member of the Palmyra Atoll Research Consortium (PARC) which is studying natural systems on one of the most isolated and pristine areas in the world.

Located in the Central Pacific just north of the Equator, Palmyra Atoll is made up of small islands and islets encircling three lagoons and surrounded by nearly 6500 hectares of coral reef. Although there have never been permanent residents on the atoll, it was used as a US military base during the Second World War and the landscape was dramatically modified with the construction of a causeway.

"It’s an amazing resource for coral research because it is pristine enough to be able to study the drivers of natural levels of disease in corals while also showing us what happens to a coral reef when there are major changes to the surrounding environment," says Dr Davy.

The Victoria research team is also relatively near to Lord Howe Island, which lies between Australia and New Zealand and is surrounded by the world’s southernmost coral reef.

"It’s also an outstanding research resource because there are corals living in colder waters and more variable weather patterns than they would cope with in other places.

"As coral reefs disappear, it could become a refuge for some species while understanding how the corals around Lord Howe Island have adapted could provide insights to help protect corals in other areas."

Dr Davy sees his role as providing fundamental understanding of what is happening to coral populations "so managers and policy makers can think about how to respond".