New study measures how much of corals' nutrition comes from hunting
by The Woods Hole Oceanographic Institution 19 Sep 2019 14:57 BST
Diverse assemblages of reef-building corals make up the framework of coral reef ecosystems © Michael Fox, Woods Hole Oceanographic Institution
When it comes to feeding, corals have a few tricks up their sleeve. Most of their nutrients come from microscopic algae living inside of them, but if those algae aren't creating enough sustenance, corals can use their tentacles to grab and eat tiny prey swimming nearby.
A new study from researchers at the Woods Hole Oceanographic Institution (WHOI), the University of New Mexico, and Scripps Institution of Oceanography is revealing that more of corals' nutrients come from this sort of hunting than previously expected, information that may help predict the fate of coral reefs as global ocean temperatures rise. The study published Sept. 17, 2019, in the journal Functional Ecology.
"When you have a heat wave, corals start bleaching. Symbiotic algae, which live inside corals and provide them with most of their nutrients, are expelled from their body. If corals stay bleached for too long they basically starve to death," says Michael Fox, a postdoctoral scholar at WHOI and lead author on the paper. "But if a coral has the opportunity to eat a lot before it bleaches or while it is bleached, it can survive off its fat stores long enough to regain those symbionts when water temperatures cool off. If we can better understand when, where, or why corals are eating, we may be able to understand why they survive better in some places than others during future bleaching events."
"To my knowledge, this has never been done with corals before. It really changed our perspective," says Fox. "Our findings suggest that some corals are eating a lot more than we previously thought, which has big implications for reef survival during climate change. We've also learned that individual corals of the same species can have very different diets—this may be an important source of variation that we'll have to take into account to understand how corals will respond to future changes."
Also collaborating on the paper were Emma A. Elliott Smith of the University of New Mexico, and Jennifer E. Smith of the Scripps Institution of Oceanography. The research was conducted under special use permits #12533-14016 and #12533-14012 from the U.S. Fish and Wildlife Service, Palmyra Atoll Research Consortium (PARC). Funding was provided by the Scripps Family Foundation, private donors, and the NOAA Nancy Foster Scholarship.
This article has been provided by the courtesy of Woods Hole Oceanographic Institution.