Measuring light and substrate movement
The first five months in the life of a baby coral can be stressful, even for those that have been outplanted to the reef on our settlement substrates. During this time, they must attract symbiotic algae to start energy production via photosynthesis, they have to fight aggressive algae for space to grow, and they need to survive intense waves from storms that are sometimes strong enough to loosen and move the substrates.
For these reasons, SECORE and its partners in The Bahamas closely monitor the environmental conditions and changes on reef sites in the waters surrounding Eleuthera Island, where last October the team outplanted substrates with settled Mountainous Star Corals (Orbicella faveolata) and Symmetrical Brain Corals (Pseudodiploria strigosa).
A composite image of the reef floor at an outplanting site. The inset reveals the high resolution of the composite: each SECORE substrate is about four inches wide. (by John Parkinson/SECORE & Kory Enneking/UNCW)
Since then, SECORE Research Biologist John Parkinson has returned to Eleuthera twice to check in on the baby corals, together with local researcher Lily Haines from the Perry Institute for Marine Science (PIMS/CEI). During his visits, John mapped the locations of each substrate by taking a series of overlapping photographs of the reef floor. The images were sent to Kory Enneking, a collaborating graduate student in Nicole Fogarty’s lab at the University of North Carolina - Wilmington, to stitch them together into a high-resolution composite. “These baseline maps will prove invaluable for tracking how the substrates move over time, and determining which designs are best at sticking around on the reef,” John says.
Top) John Parkinson installs a light meter at an outplanting site in the waters surrounding Eleuthera Island, The Bahamas. Bottom: left) This light meter records the amount of photosynthetically active radiation striking its sensor. It can be used to monitor how much light is available for coral symbionts to create energy; middle) A tagged colony of the Rigged Cactus Coral (Mycetophyllia ferox), another restoration candidate; right) A tagged substrate in the field (all by Lily Haines/PIMS/CEI).
Additionally, John installed instruments at the two outplant sites to better characterize local light conditions. Light is a critical factor for coral growth, as the algal symbionts within coral cells rely on the sun’s rays to photosynthesize and produce energy to feed their hosts. Differences in growth on the substrates at the two sites could be driven by light availability, so it’s an important environmental factor to monitor. The light meters are provided by Rebecca Albright and Raphael Ritson-Williams at the California Academy of Sciences, who work with SECORE as part of the joint Global Coral Restoration Project.
Top: A 5-month-old Mountainous Star Coral (left) and a 5-month-old Symmetrical Brain Coral (right), settled onto SECORE substrates. The view is through a stereo microscope at 400X magnification. (John Parkinson/SECORE); Bottom: left) Counting settled corals in the field is hard! Some of the SECORE substrates are brought back to the laboratory and observed under a microscope to confirm field-based counts; middle) beneath a yellow filter, Mountainous Star Coral settlers glow green under a fluorescent light, while algae on the substrate tile glow red; right) even without a filter, this Symmetrical Brain coral settler glows brightly (all by Savannah Ryburn/CEI).
Finally, it was important to examine the corals themselves, even though after five months they were still rather small. Thanks to the provision of a state-of-the-art stereo microscope from partner Craig Dahlgren at the Perry Institute for Marine Science (PIMS), John and Lily collected some of the substrates and examined them under high magnification. “We are happy to report that the settlers are doing well and have already acquired their symbionts. As you can see, it takes a village to raise coral babies, but they’re in good hands in The Bahamas,” Lily says.
Our joint research and reef restoration efforts in the Bahamas are part of the Reversing the Decline of Bahamian Coral Reefs program, led by the Perry Institute for Marine Sciences and supported by the Disney Conservation Fund. We implement the program locally in cooperation with the Bahamas National Trust, Bahamas Reef Environment Educational Foundation, and the Cape Eleuthera Institute. Further partners include the Shedd Aquarium, The Nature Conservancy in the Caribbean, as well as Nicole Fogarty and her team.
Reef restoration is team work: John Parkinson (left), CEI Research Assistant Sam Russell (middle) and local researcher Lily Haines. (Lily Haines/PIMS/CEI)