(Editor’s note: Alison Green, senior marine biologist at The Nature Conservancy, is spending the next two weeks diving and exploring Palmyra Atoll as part of the first marine assessment of the atoll. Follow her posts from Palmyra on Cool Green Science…and learn more about the expedition.)
Climate change presents a huge threat to coral reefs, particularly warming seas that have already caused mass coral bleaching and mortality worldwide, including at Palmyra. In 1998, the world’s reefs experienced the worst coral bleaching event on record, which led to the loss of nearly 20 percent of the reefs of the world.
Rod Salm, who leads our Asia Pacific marine team, has spent the last two decades studying the effects of coral bleaching — and helping marine-resource managers understand how to respond to this threat.
Rod’s role in this expedition is to determine the impact of climate change on the reefs of Palmyra, and the prognosis for their long term survival.
Rod told me today: “Over the last week, I’ve seen a mosaic of healthy, lush, resilient reefs and some that have been heavily impacted by both coral bleaching and WWII dredging and coastal construction.”
“Looking forward, the uplifting feature is that there are still areas of vibrant, vigorous coral growth that have the strong indicators of resilience that reefs need to recover from past disturbances and survive into the future.”
But how does he know that? What are the ingredients of coral reef resilience so apparent here at Palmyra?
There are several: big, old coral colonies that can produce masses of larvae to replenish the reef; evidence that the larvae are settling and growing successfully; and healthy fish populations that keep the reef clean, providing great settling habitat for baby corals.
“Palmyra provides a wonderful opportunity for us to watch a reef heal itself,” says Rod, “and to understand the long term effects of climate change in the absence of stresses like overfishing.”
(Image: Vibrant coral communities at Palmyra. Credit: Rod Salm/TNC.)