Small Samples, Big Benefits
As the climate crisis accelerates, the need to understand and protect coral reef ecosystems grows ever more urgent. One important element of this quest to unravel the inner workings of reefs is mapping reef biochemistry, which reveals far more about the stress the reef is under than visual surveys do. This is especially useful as visual surveys are slow to detect problems, which can be far more swiftly identified by examining the coral holobiont (the coral and its associated microorganisms).
Previously, coral sampling usually involved collecting entire fragments of coral, or collecting small parts of coral known as “nubbins”, processes that damage the coral. This is rather ironic given that the purpose of such sampling is often to determine the exact issues faced by the reef. However, researchers at the University of Hawai’i have come up with a new sampling technique that allows them to map out biochemistry within the reef while leaving a minimal impact on the reef itself, meaning more samples can be collected more often.
Instead of sampling whole fragments, the team used a probe needle to collect individual polyps, a technique far less invasive than collecting fragments. In the study, they collected six polyps from each branch, as described in the image below; collecting from three branches of each of the 19 Montipora capitata colonies in the reef. This means they can analyse the biochemistry of the corals on many different scales using just one set of samples.
This sampling technique has a lot of potential, as Ty Roach, one of the authors of the paper said: “We plan to use this approach in future studies to map the temporal and spatial distribution of coral biomolecules in ways that were not previously possible without damaging whole coral colonies.” This is important, because the previous inability to do that made it nearly impossible to quantitatively link changes in the coral holobiont to environmental conditions, a huge hindrance to the understanding of coral diseases and the health of reefs.
Having the ability to rapidly establish, and quantify, causal relationships between factors such as climate or contaminants and the health of coral would allow us to much more effectively protect and restore reef ecosystems, and react to threats more quickly.
