Recovering the Coral Reef Communities of the Gulf
NYUAD Assistant Professor of Biology John Burt works with the Environment Agency — Abu Dhabi (EAD) on a two-year project to develop a monitoring program to determine the current state of Abu Dhabi's coral reefs.

Recovering the Coral Reef Communities of the Gulf

It wouldn't be a stretch to surmise that a childhood of summers spent on the water had something to do with NYU Abu Dhabi Assistant Professor of Biology John Burt's chosen profession.

The marine biologist, who grew up in Nova Scotia, Canada, stayed on the family boat for two months each year. "It gave me an appreciation for living along coastlines and the marine environment," he said. Initially focused on fresh water ecology — using river- and lake-dwelling larval insects as indicators of pollution for his master's degree — Burt switched to marine biology while working toward his PhD. "I was still interested in the environmental genre," he explained, "but just changed direction." And, he laughed, "I must say that it's much more attractive to work in tropical coral reef environments than hanging off the side of a boat in the middle of the Great Lakes in November."

Joking aside, what Burt has already accomplished in his three years at NYUAD is no small feat. Working with the Environment Agency — Abu Dhabi (EAD) on a two-year project to develop a monitoring program to determine the current state of Abu Dhabi's coral reefs following degradation in the late 1990s, the processes driving differences in recovery among reefs, and what might be done to improve the situation, Burt's research has helped lead to the development of a marine-protected area around a formerly unprotected reef. As he said, "Developments like this make a huge difference in terms of knowing that the contribution you are making is having an impact on the local community."

Using the Arabian Gulf as a natural laboratory, Burt studies the process of recurrent mortality and recovery in its corals and is examining the resilience of coral reef communities in the region. "Throughout the Gulf there has been widespread degradation of coral reefs in the last 20 years," he explained. "Some of it is the result of coastal development, pollution, and other anthropogenic factors, but a lot of it has to do with the naturally elevated sea-surface temperatures that occurred in 1996 and 1998." According to Burt, the Gulf lost more than 90 percent of its reefs during the summer of 1998, when water temperatures in Abu Dhabi reached 37.7 degrees Celsius. "Using the Great Barrier Reef as an example, if you put the corals there in water at 31 or 32 degrees Celsius, the entire reef — the largest reef on earth — would be dead," Burt said. "Here we're going well in excess of that naturally every summer."

As well as discovering that reef communities had become increasingly degraded traveling west from Dubai to the border of Qatar — this due to western waters being somewhat shallower and having lower circulation, thus exposing the coral to a more extreme environment of higher water temperatures and salinity — Burt also noticed that a branching coral called Acropora, almost entirely lost in 1998, was showing limited recovery in Dubai and the eastern reefs of Abu Dhabi, but not in the west. Questions of degradation turned to those of recovery. Specifically, why the Acropora, a once-dominant and important reef-building coral that provides important three- dimensional structure for fish and other reef fauna, was recovering in some areas but not others.

This extraordinary ecosystem may also provide insights into the possible impacts of future climate change on reefs worldwide and what physiological processes the individual corals, fish, and other fauna are using to adapt to extreme conditions.

John Burt, NYUAD Assistant Professor of Biology

Despite the presence of source populations of Acropora that were not destroyed in 1998, and the fact that they are indeed sending out larvae in order to reproduce, the reefs, especially those in the west, show few signs of improvement. Additionally, Burt found that some of the most degraded reefs in Abu Dhabi actually have the highest number of juvenile corals landing on them, suggesting that local environmental conditions are hampering the reef's chances of recovery. "There's not much you can do about local conditions," Burt said, "so our plan is to draft a proposal for the next two-year phase of the project, which will look at using management intervention in the form of propagating the corals." A task he will complete with colleagues at the EAD, as well as a physical oceanographer who will develop models for water circulation in the southern Gulf using satellite imagery and meters placed around the Gulf.

As Burt explained, reefs can reproduce in two ways: vegetative propagation, during which pieces of the coral's branches break off in a storm and attach to substrate elsewhere to start a new colony, or broadcast spawning and sexual propagation, during which the corals release eggs and sperm at the same time to form planktonic larvae. Usually occurring in April or May, a couple of days after a full moon, broadcast spawning creates spawn slicks (large red slicks of fertilized eggs that float above the reefs), which spread out for a period of about a week, allowing the larvae to develop swimming behavior before they start searching for a place to settle down and start their life. "There are literally billions and billions of eggs floating there," said Burt, "however, more than 99 percent die. They get eaten by fish and other organisms, or they get advected offshore and eventually die of 'old age,' but some of them do successfully find a bottom." That "bottom" could be concrete, a rock, or dead coral skeleton, as corals will not start their life on a mobile substrate such as sand.

In order to propagate the corals for reef recovery, Burt could use fragmented pieces of coral or actually artificially seed the reef by collecting larvae, raising them in situ or in aquaria, and putting them onto artificial substrates that would then be placed on the reef. "If there's some way that researchers can facilitate the number of successful larvae that are landing on reefs, that's going to enhance recovery patterns," said Burt. "The question is whether or not it is economically and logistically feasible."

This year, Burt heads a team of four researchers in the NYUAD Marine Biology Lab, one of whom is examining the molecular responses of coral, specifically looking at what physiological mechanisms corals are using to protect themselves from dangers including extreme summer temperatures. "Be it swapping out the algae they have inside their tissue or the production of stress proteins or green fluorescent protein — a protein corals produce which acts as a sunscreen — together, we'll be conducting a multi-faceted approach in trying to develop an understanding of the physiology that allows corals to survive in this really unique and interesting ecosystem we have right off of our shore."

This extraordinary ecosystem may also provide insights into the possible impacts of future climate change on reefs worldwide and what physiological processes the individual corals, fish, and other fauna are using to adapt to extreme conditions. "It provides a proxy, a predictor of what's going to happen elsewhere," said Burt. "It is already experiencing temperatures that will be felt by the rest of the world, the tropics at least, probably in the next 100 years."