Two researchers from the Georgia Institute of Technology (Atlanta) are building symbiotic underwater gardens in the Pacific to show how different coral species can work together to possibly restore degraded reefs .
Coral reefs are seriously threatened. The reasons are varied: overfishing, pollution and global warming are destroying them , as well as the ecosystems that are themselves. According to the United States Environmental Protection Agency (EPA), the Caribbean has lost between 80% and 90% of its coral cover and the Indo-Pacific region 50% in the last 30 years. In the bleaching event that took place in 2015-2016, almost half of the corals that remained on the Great Barrier Reef in Australia were lost. Since corals build structures that provide living space for many other species, scientists know that the loss of corals causes the loss of other reef species .
In the study, published in Science Advances , Cody Clements and Mark Hay found that increasing coral richness by “transplanting” a diverse group of coral species improves coral growth and survival . This finding may be especially important in the early stages of reef recovery after large-scale coral loss, and in supporting healthy reefs that in turn support fishing, tourism, and coastal protection from tides. storm.
The researchers traveled to Mo’rea, in French Polynesia, and there they planted coral gardens of different species on platforms similar to chessboards. The different variants had to compete with each other, but what was seen is that they behaved better together than separately, and that is that the corals benefited from the increase in biodiversity , “but only up to a point,” Clements said. “Corals planted in gardens with an intermediate number of species – three to six in most cases – performed better than gardens with few, or one species, or many, as in the case of nine species. Without However, we still do not fully understand the processes that contributed to these observations. “
“We are still investigating the mechanisms that cause this surprising result, but our experiments consistently show that positive interactions outweigh negative ones in the reef environments where we conducted these experiments. That means that when species are removed from the system, some of the those positive interactions, and if the criticism is removed, it can make a big difference, ”Hay said.
Scientists believe further research is needed to better understand and exploit the mechanisms that produce these positive species interactions, with the dual goals of improving reef conservation and promoting faster and more efficient recovery of degraded reefs. Also, if more coral species are lost, the synergistic effects could threaten other species. It is what Clements and Hay define as “collapse of biodiversity”.
” Negative effects on corals often have cascading repercussions on other species that call coral reefs home. If biodiversity is important to coral performance and resilience, a ‘biodiversity collapse’ could exacerbate the decline of reef ecosystems that we are seeing around the world, ”said Clements.
Fuente: Cody S. Clements, Mark E. Hay. Biodiversity has a positive but saturating effect on imperiled coral reefs. Science Advances, 2021; 7 (42) DOI: 10.1126/sciadv.abi8592
