In a groundbreaking study led by researchers from University College London, the pristine waters of the Mediterranean have revealed a silent crisis unfolding beneath the waves.
For the first time, evidence of industrial pollutants embedded in the region's corals has come to light, raising alarming questions about environmental conservation and human health.
This revelation not only underscores a new method to track pollution history but also unveils an urgent need for global action against environmental degradation.
The pollutants, known as fly ash or combustion-derived particles (SCPs), are microscopic spheres of carbon and metals that are emitted by coal-fired power plants, factories, and vehicles.
They can travel long distances in the air and settle in various environments, including the ocean.
The researchers collected coral samples from different depths and analyzed them using a scanning electron microscope. They found SCPs in all the samples, indicating that the corals had been exposed to pollution for decades.
The SCPs were mostly concentrated in the outermost layer of the coral skeleton, suggesting that they had accumulated over time as the corals grew.
The study, published in the journal Science of Total Environment, is the first to report the presence of SCPs in corals. Previous studies have found SCPs in lake sediments, ice cores, and soil, but not in marine organisms.
"This is a novel way of using corals as natural archives of pollution," said Dr. Diego Kersting, the lead author of the study and a research associate at UCL. "By looking at the SCPs in the corals, we can reconstruct the history of pollution in the Mediterranean and see how it has changed over time."
The presence of SCPs in corals is indicative of human influence on marine ecosystems. It serves as a historical marker of pollution and offers insights into its long-term impacts on biodiversity, marine life health, and potentially human populations relying on these ecosystems.
The researchers estimated that the corals in Illa Grossa Bay had been exposed to an average of 0.42 SCPs per gram of coral skeleton per year since the 1950s.
This is comparable to the SCP levels found in lake sediments in Europe and North America, where pollution is known to have caused ecological damage and acidification.
The effects of SCPs on corals are not yet fully understood, but the researchers suspect that they could have negative consequences for their growth, reproduction, and resilience. SCPs could also affect the symbiotic algae that live inside the corals and provide them with energy and nutrients.
"SCPs are foreign bodies that the corals have to deal with," said Dr. Kersting. "They could cause stress, inflammation, or infection in the corals, or interfere with their calcification process. They could also alter the balance of the coral-algae symbiosis, which is essential for the survival of the corals."
The researchers also warned that SCPs could pose a threat to human health, as they could enter the food chain through the consumption of seafood. SCPs contain toxic metals such as arsenic, lead, and mercury, which can accumulate in the tissues of marine animals and cause various diseases in humans.
"SCPs are a hidden danger that we need to be aware of," said Dr. Kersting. "They are not only a problem for the environment, but also for our health. We need to reduce our reliance on fossil fuels and switch to cleaner sources of energy, before it is too late."
The study was funded by the European Union's Horizon 2020 research and innovation program and the Spanish Ministry of Science and Innovation.
It involved researchers from UCL, the University of Barcelona, the Spanish Institute of Oceanography, and the Columbretes Marine Reserve.
