Saving Coral Reefs for Humankind

When it comes to climate change, coral reefs are like “the canary in the coalmine” says Dr Manuel Aranda, Associate Professor of Marine Science at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. “Corals have an intimate and symbiotic relationship with dinoflagellate algae which live inside their cells,” he explains. “These algae photosynthesise and pass on sugars to the coral host covering most of their energetic needs.” Corals stressed by changes in their local environment, like high temperatures due to climate change, forcibly evict the algae and turn white – a process known as coral bleaching. Without their algal energy source, the corals are at dire risk of starvation and disease.  

As an evolutionary biologist, Manuel was intrigued by this 200 million-year-old relationship. On the surface, it seems altruistic, but in evolutionary terms, it doesn’t make sense that the algae would give away vital nutrients for free when all organisms are under selective pressure to proliferate and survive. Manuel and his team are digging deeper to understand this partnership and determine why it’s so sensitive to stress. “We’re looking specifically at the molecular mechanisms these organisms have to respond to changes in their environment by means of acclimation, so short-term responses, as well as adaptations, so long-term evolutionary responses,” he says. Their goal is to develop human interventions to help corals survive climate change, or at least mitigate some of its impacts so that the ecosystem will be preserved.

Manuel appreciates the many advantages of working at KAUST, like the guaranteed baseline funding for his research group and access to additional grants for projects. KAUST is research-focused so faculty members have a low teaching load. The Core Labs are a particular strength as all of the routine analyses can be carried out internally without the need for external service providers. He says, “We have workshops that build things to our design, for example, a structure for a marine project to deploy, let’s say, a CTD sensor array [conductivity, temperature, depth oceanography instrument]. We have coastal and marine research labs which provide ships and boats, and aquarium facilities where we can keep organisms and do experiments. Everything is basically in a compact package.”

All of this allows Manuel to focus on what he really loves doing – his research on coral reefs. They are one of the most biodiverse ecosystems on our planet. About 30 percent of all known marine animals depend on coral reefs at some point either for their main habitat, for procreation, or as a hunting ground. This is remarkable considering they only cover 0.1–0.2 percent of the ocean floor. They’re also of huge economic importance as more than 600 million people directly or indirectly depend on them for their livelihoods through fisheries and ecotourism. What’s more, they protect coastal areas from flooding and storm damage. He says, “At the end of the day, it’s not about saving corals because they're nice and beautiful – it’s retaining the ecosystems they built because they provide essential services for humankind.”

Recently, Manuel’s group published some exciting results. They took corals from the Arabian Gulf, the hottest region in the world for reef-building corals, to see if they could transfer their heat tolerance to offspring from the same species from a colder environment. “We show that yes, in a single generation, we can increase the resilience of these offspring by three to four degrees, which in terms of climate change would buy us several decades,” he says. As a proof of concept experiment, it shows that there’s the potential to actively combat the effect of global warming on coral reefs.

Manuel came to KAUST as a postdoc in 2009 and was subsequently promoted to Assistant and then Associate Professor. He’s full of praise for the advice and support he received at KAUST as a young faculty member which encouraged him to focus on one area and develop his research. The dean believed in his potential and gave him time to build his lab and establish himself in the field. Now he has a full professorship in his sights. He says, “A lot of the research that I've been doing is unique and most of the high-impact papers I’ve published are first in the field. This is because I got support on all levels, so I don't need to rush or publish things before they reach the maturity they require to really make an impact. I don't see where I could have done this other than at KAUST.”