Corals Reclassified

New study highlights the importance of Brazilian corals

Brazil's coral reefs are finally getting the recognition they deserve. A recent study by researchers at Scripps Institution of Oceanography at UC San Diego offers new insight into the unique family history of Brazilian corals and their relationship to their better-known Caribbean cousins. This research has important implications for coral reef conservation worldwide.

Corals have deep genealogy roots, yet scientists are only just beginning to skim the surface of study. Flavia Nunes, a post graduate researcher at Scripps Oceanography and native of Brazil, found an opportunity to reconnect with her homeland when it became apparent to her that there was a growing need for research on Brazilian corals.

Her study, recently published in the journal Coral Reefs, suggests that the traditional way of defining coral species is incorrect, and that many corals, including a number of species found only in Brazil, referred to as endemics, have been misclassified. Using genetic analysis of several coral genera, Nunes demonstrated that a coral genus endemic to Brazil contains more species than previously thought, and that one species of coral was genetically distinct from its Caribbean counterpart.

"What this ultimately means is that we don't have the ability to make good estimates of biodiversity and endemism in corals," said Nunes. "We don't really know how many species, genera, or families exist or how they are related to one another, and sometimes we don't even have a good idea of where they occur."

Understanding the relationship of coral reef organisms is of great importance for conservation. Only 15 species of reef-building corals have adapted to life in Brazilian waters and many are likely endemic to the region. This compares to more than 60 in the Caribbean and more than 100 in the Indo-Pacific regions.

Coral reef management and conservation measures often aim to protect areas with a large number of species, or give special attention to species that are evolutionarily unique, both criteria that require an accurate classification scheme; therefore, incorrect classification could impact the entire ecosystem. If current science classifies a species as widespread in other regions this could lower their priority for protection in a specific region, such as Brazil.

"With corals, we may be giving special attention to certain areas that appear to have high diversity yet ignoring an equally important area filled with endemic species because we didn't really know what was there," said Nunes.

Brazil's coral reefs reside on the fringes of the coral community. Brazilian corals thrive in silty offshore waters, which are typically inhospitable to most corals. However, these unique living conditions also provide researchers with a valuable opportunity to understand corals response to environmental change.

Since only a few species make up these communities, the extinction of one type could disrupt the balance of the entire ecosystem. Scientists want to know what niche these corals play in the ecosystem. Brazilian corals appear to be potentially more vulnerable to changes in the environment than corals from other places.

In the past 20 years, Brazilian corals have begun receiving attention from researchers, but the amount of work done on these species doesn't compare with the amount of work that has been done in the Caribbean and Australia, notes Nunes.

Annie Reisewitz