Sunscreens and marine biodiversity: an invisible threat to the oceans. By Sergio Trigos Santos (VIU)
In recent years, concern for the conservation of marine ecosystems has reached a critical level due to the increasing threats facing our oceans. One of the factors, perhaps less visible and well-known, but equally destructive, is the impact of commercial sunscreens on marine life. These substances, which we use to protect our skin from the sun, are leaving a significant mark on marine biodiversity, particularly affecting vulnerable species such as mollusks and corals.
The hidden damage of sunscreensSubstances like oxybenzone, octinoxate, and homosalate aren't particularly familiar to us, but they're present in any cosmetic product with a sun protection factor. This leads us to believe that anyone who, after using sunscreen creams, shampoos, or sprays, feels like taking a dip in the sea will release these chemicals into the environment to a greater or lesser extent.
On the Mediterranean coast, for example, it has been identified that continued exposure to these chemicals is negatively impacting local fauna. Specifically, it affects a bivalve that inhabits intertidal zones and, in addition to being essential to the food chain of this ecosystem, is of significant fishing and commercial interest: the tellina (also known as coquina).
Chemical compounds have a double negative effect on the species. In adults, they inhibit their reproductive and developmental capacity, and in the larval stages, these substances alter their metabolic processes, paralyzing their development and growth and thus reducing their survival. The result is a deterioration in the populations of these organisms, which in turn impacts the stability of marine ecosystems, given that tellinas are essential for sediment balance and water filtration, and serve as food for other species of interest to fisheries, such as the sea bream.
The sunscreen problem not only harms Mediterranean mollusks but also causes broader damage globally, especially in tropical and subtropical areas. A clear example is the Caribbean, a region famous for its coral reefs. These ecosystems, vital for marine biodiversity, also represent an important economic resource thanks to tourism.
In places like the Galapagos Islands and Cozumel (Mexico), authorities have passed laws to protect coral reefs from the harmful effects of chemicals in sunscreens. In these areas, the use of conventional sunscreens has been banned, and the use of environmentally friendly, substance-free alternatives is actively promoted.
These measures respond to growing scientific evidence demonstrating how compounds such as oxybenzone and octinoxate can trigger so-called "coral bleaching." Corals depend on a symbiotic relationship with microorganisms known as zooxanthellae, which live in their tissues. These algae carry out photosynthesis and provide corals with the energy they need to survive.
However, sunscreens disrupt this symbiotic relationship. This disruption can lead to coral bleaching and, in extreme cases, death. Various studies in different regions of the planet have extensively documented this phenomenon, which constitutes one of the most serious threats to coral reefs, which are responsible for hosting nearly 25% of the world's marine biodiversity.
From an ecological perspective, other marine species such as fish, crustaceans, and mollusks also absorb these chemical compounds, either directly from the water or by feeding on contaminated organisms. This exposure interferes with their reproductive and metabolic processes and causes a loss of biodiversity by reducing the variety of species and altering the balance of marine ecosystems.
Ecological and responsible alternativesDespite the magnitude of the problem, it is encouraging to note that, in many places, measures are being taken to reduce the impact of sunscreens on marine ecosystems. In some regions of the Caribbean, as mentioned above, authorities have banned the use of traditional sunscreens in areas near reefs.
At the same time, tourists and locals are being encouraged to use eco-friendly, biodegradable sunscreens that do not contain harmful substances such as oxybenzone, octinoxate, or homosalate. These sunscreens are formulated with natural ingredients like zinc oxide and titanium dioxide, which are considerably less harmful to aquatic ecosystems.
Awareness of these effects has also led to the creation of educational initiatives and programs that seek to inform both tourists and local residents about the importance of choosing more responsible sunscreen products. Through information campaigns and legislation, the use of sunscreens that protect our skin without harming marine life is being promoted. Furthermore, many cosmetic brands are innovating and launching eco-friendly sunscreen lines that meet environmental standards, thus contributing to the protection of the oceans and marine life.
Pending challengesHowever, the challenge remains significant. The production and distribution of non-eco-friendly sunscreen products remains widespread and often unknown to many consumers. The lack of global regulation, especially in regions outside protected areas such as the Caribbean, makes controlling this type of pollution difficult. It is essential that both governments and international organizations promote stricter policies and broader awareness campaigns that educate people about the harmful effects of conventional sunscreens on the marine environment.
It is essential that we continue to learn from the examples of regions like the Caribbean and the Galapagos Islands, where the protection of marine ecosystems has been a priority and effective measures have been adopted to mitigate the damage caused by chemicals. Protecting our oceans and their ecosystems depends not only on bans and regulations, but also on a change in our mindset and our consumption habits. We must remember that the health of the seas and oceans is fundamental to life on the planet, and that small, everyday actions, such as choosing responsible sunscreen products, can make a big difference in the conservation of marine biodiversity.
Professor of the Master's Degree in Renewable Energy at the International University of Valencia (VIU) / International Doctor of Oceanography, my professional career has closely combined science with the marine environment through teaching, research, and management of public and private projects.
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