According to a study, sunlight improves the development of corals. Coral reefs around the tropics are under increasing stress from rising temperatures, water acidification, pollution and overfishing. However, a ray of hope for troubled reefs could come in the form of sunshine, according to US scientists.
By ensuring that the optical quality of the water in which reefs are marinated remains good, we can go a long way toward protecting them, reports Tomás López-Londoño, a postdoctoral fellow at Pennsylvania State University and lead author of the paper. to study.
“Our results suggest a key role for solar energy availability and photosynthetic production in explaining global-scale patterns of coral biodiversity and community structure along depth gradients.“, writes the expert. “Consequently, maintaining optical water quality in coral reefs is essential to protecting coral biodiversity and preventing reef degradation.”.
It has long been known that reefs get their energy from sunlight, but the extent of the sun’s impacts on reef health has not been fully explored before, say the authors.
They observed the development of corals
“Coral reefs are one of the most biodiverse ecosystems on Earth. To better understand this diversity, we looked at the role that sunlight plays in the symbiotic relationship between corals and the algae that provide oxygen for their survival.”, explains López-Londoño.
“We found that underwater light intensity plays a key role in the energy expended by symbiotic coral algae to maintain their photosynthetic activity.“, he adds.
“What is new here is that we have developed a model that provides a mechanistic explanation of biodiversity patterns in corals.“, continues. “Central to this explanation is water clarity, which means that preserving the mild underwater climate must be a priority for coral reef conservation. It is as vital as mitigating pollution, limiting ocean acidification and reducing heat stress.”.
The study of coral development and sunlight
The researchers studied coral growth in an aquarium in which they simulated depth and various gradations of sunlight. They also developed a mathematical model that can track the association between depth-dependent variations in coral photosynthetic energy and species diversity gradients in colonies.
They began examining data on reefs in the wild, comparing varying degrees of water clarity and biodiversity patterns at marine biodiversity hotspots around the world to map productivity and biodiversity. According to their results, “much of the variation in species richness with depth is due to changes in sunlight exposure“, they report.
When they applied their model against global coral datasets, the researchers found that the variation in energy produced by sunlight produced by algae living on corals greatly influences “the spatial variation of species diversity within coral communities. This means that the most productive underwater environments are those that have access to a lot of sunlight.
“The model is very elegant because it only takes into account two things”, says Roberto Iglesias-Prieto, professor of biology and co-author of the study. “Look at the productivity, the potential for an algae to extract energy from the sun, and the cost of living, the cost of fixing the photosynthetic machinery. It’s a very simple notion and we think it explains the existing empirical data.”.
Measures to be taken for the conservation of reefs
The study points the way forward for reef conservation everywhere, highlighting the need to preserve seawater clarity around coral reefs. This can be achieved by removing sedimentation and water contaminants from human causes such as coastal development and mass tourism.
“We tend to react reflexively to large-scale threats such as ocean acidification and heat stress caused by climate change. We warned: ‘This is a serious problem, but what can I really do locally?’ In the case of mitigating optical pollution, the answer is ‘everything’”, emphasizes Iglesias-Prieto.
“Unlike many of the environmental threats facing corals, this is something that can and should be managed locally.”, adds Iglesias-Prieto.
By Daniel T. Cruz. Article in English