Corals for Climate: Restoring Resilient Reefs

The temperature is dropping, the waves are getting bigger, and diving conditions are becoming more extreme. There is only one explanation for all of this: winter. With winter, corals get a reset and a breather; finally, the bleaching stress subsides, and color slowly starts to reappear on the reef. Winter is challenging for divers in Punta Cana, as visibility is limited and currents get stronger, making work risky. Fortunately, we experience small windows when the ocean allows us to get back in the water. 

This was the case for our most ambitious target of microfragments to outplant. After having to reschedule due to weather and dealing with a motor malfunction on the exact day of the activity, a team of 16 citizen scientists, along with divers from the Marine Innovation Center, achieved a new outplanting record. We outplanted 2,707 microfragments of 8 species back onto the reef. This activity was not only for coral conservation but also aimed to involve the community in learning and active participation. We had teenagers, fishermen, diving instructors, biologists, photographers, parents, and interns all doing their part to secure 205 biodegradable nets with these corals. 

Winter symbolizes unity, support, and family. That day, our goals aligned to restore the coral reefs of Punta Cana.  

At the Puntacana Foundation Center for Marine Innovation, we use a popular technique in our restoration practices called micro-fragmentation. This consists of dividing larger donor colonies into smaller fragments of about 2 – 3 cm² to promote faster growth rates in these fragments, as opposed to the natural growth rate of larger colonies. It is a technique that has been proven to be effective, however there are some challenges to be overcome, especially when out-planting individual fragments onto bare substrates on the natural reef. 

One of the potential solutions we have been testing out, as part of our continued partnership with Sea Foundry, is their biodegradable nets. These nets are used in our day-to-day management of the coral micro-fragments in our land-based nursery, and for out-planting onto our underwater nurseries or natural reef sites. The materials that the nets were made with needed to withstand wave energy, while also providing stability for the corals and biodegrade in place once the corals started growing. Hence the need to explore the best combination and type of material that fulfills these requirements.

To determine which concentrations were the most appropriate for coral growth we conducted an experiment to test for the best combination of different concentrations of calcium carbonate (CaCO₃) and polymer plastic. For this, we tracked the growth rates for each coral fragment (i.e., area and volume) for two genotypes of coral species Montastraea cavernosa during 5 months. We found than fragments growing on meshes with a 20% concentration of calcium carbonate (CaCO₃) tended to exhibit higher growth rates compared to counterparts situated on alternative nets. This finding highlights the importance of the composition of substrates for coral growth. This study can be used as an example of how important the role of technological innovation and AI use can be in advancing our understanding of reef restoration practices.

Links:

• Dominican Marine Innovation Hub
• Puntacana Foundation website