The Smithsonian Institution calls coralline algae “the unsung architects of coral reefs.” These pink-colored seaweed, with a skeletal structure that resembles honeycomb, live in harmony with coral.
They strengthen the corals’ foundation by growing over and between gaps in coral reefs, essentially gluing sections of coral together. They provide a surface for baby corals to settle, and serve as food for marine life, including sea urchins, parrot fish and mollusks.
“They promote biodiversity and coastal protection,” said Chiara Lombardi, a scientist with the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). “Also, they play an active role in the carbon cycle.”
The bad news, however, is that, like coral, they are vulnerable to the ravages of climate change and and ocean acidification.
“They become more fragile, and they bleach, and they aren’t able to create a healthy habitat for biodiversity,” Lombardi said. “Thus, their survival and, as a cascading effect, the survival of the associated species, is at risk.”
Lombardi and her colleagues, including Federica Ragazzola, a marine biologist at the University of Portsmouth in the UK, initiated an unusual experiment recently to try to protect these algae — scientific name Ellisolandia elongata — from increasing harm.
Last month, they installed the first of several artificial coralline algae reefs — made of highly elastic rubber material — near real coralline algae reefs in the Gulf of La Spezia, in northwest Italy. The goal is that these plastic mimics — as the artificial reefs are known — which look and move like the real thing, will shelter and host the tiny creatures who typically live on the algae, and also will become scaffolds for real coralline algae to grow.
The 60 synthetic mini reefs, each with 20 fronds, are just 10 centimeters in diameter, making them easy to place in a natural reef. Snorkelers attached the artificial reefs using epoxy resin. Hampered by bad weather, they had to make three separate runs to finish the job. “The resin needs 24 hours to become hard, so if waves occur during this period, the risk of detachment is very high,” Lombardi said.
The material’s properties are similar to that of the algae and non-toxic to the marine ecology. The mimics won’t ultimately become plastic ocean litter. “After one year of exposure, they will be removed and brought to the laboratory,” for further experiments, Lombardi said.
The research will “clarify the function of the coralline algae reef as a buffer for diversity, abundance, reproductive, ecological and structural characteristics of the associated fauna,” Lombardi said. The results “will be important for the planning of future protection and management strategies.”
This is not the first time artificial “substrates” have been used experimentally, but they have never before been made to mimic the properties of natural algae. “The majority of the studies simulating reef are mainly focused on corals,” Lombardi said. She stressed the importance of preserving algae.
“They provide services that will benefit human lives,” Lombardi said. “They are a resource, not only for marine life. We tend to consider protection of nature very far from human beings — but we are all connected, and it is important to understand this connection. Protecting the natural ecosystem will benefit the lives of all future generations.”