Sun protection cosmetics – good for you, bad for the aquatic environment?

By Sabine Schultes

Most people who like the sea and the shore also enjoy a sunny day at the beach, playing in the water when the weather is warm. Luckily, the education campaigns for skin cancer protection have made us all aware of the importance of protecting ourselves from harmful ultraviolet (UV) radiation which is a part of natural sunlight. UV light is at the lower end of the light spectrum and is divided into UVA, UVB and UVC. The highly energetic UVC is absorbed by our atmosphere, but UVA and UVB reach the surface.

Wavelength spectrum of natural sunlight.

So, we all adopted the habit to regularly apply cosmetic sunscreens before sunbathing, but we are typically not as attentive when it is time to take a dip in the lake or ocean. Probably, you are just like me and are so anxious to cool off, that you rush over the hot sand and to take a wonderfully refreshing dive head first into the waves.

© worldartsme.com/

UV radiation is not only a problem for us, but for all living beings, especially if they are without protective pigmentation, feathers, fur, or scales. Single-celled organisms have it even harder, so much so that one way to kill bacteria to make a sterile environment is to expose the lab bench to a couple of minutes of UV radiation. Sunburn for a single cell is lethal!

Plankton are, in most cases, single celled or transparent, so they are very sensitive to UV light. Luckily, ocean and lake water progressively absorbs the incident sunlight. Depending on how clear the water is, UV light only reaches a few meters below the surface. Planktonic organisms have nevertheless evolved repair mechanisms to cope with the constantly occurring DNA damage.

Alternatively, plankton can avoid UV radiation by migrating to water depths with no or little UV radiation. This strategy has been adopted by the zooplankton such as some copepods . Other copepods that live in very clear alpine lakes or in the surface layer of the tropical ocean are pigmented, often orange or even blue! Instead of getting a suntan - when our skin cells produce melanin - the zooplankton simply accumulates the pigments from their algal food. One example are the beautiful blue copepods from the genus Anomalocera, in the family of the Pontellidae.

Now, what happens if you and I take our dive into the waves and the sunscreen we have applied to our skin is washed off, into the sea? Yes, large parts are washed off, even if you use waterproof lotion. Looking through the scientific literature makes it clear: sunscreen cosmetics are a source of pollution with growing concern. Waters of popular beaches all show high concentrations of the organic molecules used as chemical UV filters in sun protection creams. Very low concentrations (10µg/L) are sufficient to promote coral bleaching. The chemicals persist in the aquatic environment and accumulate in mussels, fish and dolphins. Lakes and rivers are also subject to this type of contamination.

This is why I have decided to do at least two things:

1. Before taking a swim I will try to get rid of most of the cream on my skin. Many modern beach facilities have showers connected to a wastewater system. So why not have a quick wash before you dive? If showering is not an option, I bring baby wipes and rub off the excess.
2. I started to do my own research into the question. I am interested in learning how plankton growth and diversity is affected by sublethal concentrations of sunscreen. Is the pelagic food web disturbed? Are there alternative cosmetics available with potentially less harmful effects for the aquatic environment?

Sunscreen cosmetics are complex mixtures of organic UV-filters (e.g. oxybenzone, octocrylene, …), oils, perfumes, stabilizers and often nanoparticles. Our experiments also try to find out, which of the components are particularly harmful, and if sunscreen cosmetics that are solely based on natural oils may be a better option for the aquatic environment. I will tell more about this in my next post - so wait and see!

Preliminary results show that plankton growth can either be enhanced or reduced when the water is polluted with conventional sunscreen, depending on the concentration we add and whether the water comes from an oligotrophic or eutrophic environment. The community composition of the phytoplankton is modified because some algal groups are more sensitive to sunscreen pollution than others. The use of sunscreen may even be one of the causes of cyanobacterial blooms in recreational lakes leading to skin irritation in summer swimmers.

We need recreation, and we need to protect ourselves from UV radiation to prevent skin cancer. How can we fulfill the needs of human society without totally spoiling our environment?  This question is exemplary for many issues in nature conservation!  So, I am passing this question on to others and will make an opinion poll at the beach...

Beach life in Ubatuba, Brazil (left). Beach life in Munich, Germany (right).

    

Further reading:

Balmer, M., Buser, H.R., Müller, M.D., Poigner, T. 2005. Occurrence of some organic UV

filters in wastewater, in surface waters, and in fish from Swiss lakes. Environ. Sci. Technol. 39: 953-962

Cunha, C.,  Fernandes, J.O.,  Vallecillos., L.,  Cano-Sancho, G., Domingo, J.L., et al. 2015. Co-occurrence of musk fragrances and UV-filters in seafood and macroalgae collected in European hotspots. Environ. Res.143: 65–71

Danovaro, R., Bongiorni, L., Corinaldesi, C., Giovannelli, D., Damiani, E., et al. 2008. Sunscreens cause coral bleaching by promoting viral infections. Environ. Health Perspect. 116:441–447

Gago-Ferrero, P., Alonso, M. B., Bertozzi, C. P., Marigo, J., Barbosa, L., et al. 2013. First determination of UV filters in marine mammals. Octocrylene levels in Franciscana Dolphins. Environ. Sci. Technol. 47: 5619−5625

Sánchez Rodríguez, A., Rodrigo Sanz, M., Betancort Rodríguez, J.R. 2015. Occurrence of eight UV filters in beaches of Gran Canaria (Canary Islands). An approach to environmental risk assessment. Chemosphere 131: 85–90

Tovar-Sánchez, A., Sánchez-Quiles, D., Basterretxea, G., Benedé, J.L., Chisvert, A., et al. 2013 Sunscreen products as emerging pollutants to coastal waters. PLoS ONE 8(6): e65451.

About Sabine:


With the goal to become a marine biologist, I studied biology and hydrobiology at Hamburg University and then earned a Master’s degree in oceanography from Université du Québec à Rimouski, in Canada. My doctoral studies in biological oceanography at the Alfred Wegener Institute in Bremerhaven were followed by various post-doc projects in Brest, France and Sao Paulo, Brazil. Since 2012, I teach ecology and zoology at LMU Munich. Growing up, my parents gave me the incentive to search new ways and to relate with people and cultures around the world. I am convinced that today, more than ever, we need to take good care of our Oceans.

A new home for Nemo

By Cathrine Boerseth

People don't like having their homes destroyed and neither do animals; bears don’t like it, birds don't like it, fish certainly don't like it and neither do the tiniest planktonic animals that people often forget even exists. Some of these tiny animals are meroplanktonic, which means they only float around in the early stages of their lives, to grow up as adults they need somewhere to settle down, a nice home with a good foundation; for many organisms that means a hard surface like rocks or a coral reef. 

Sadly, in the waters of northern Paraná state, many of these nice hard (and already rare) surfaces were destroyed by destructive fishing methods like trawling. The meroplanktonic larvae were still floating around in the water, but there were few places for them to settle down. In the biological world one thing always affects another and so did the lack of appropriate habitat in our case; fish eat the organisms living on and around rocky reefs and so the lack of hard bottom substrates meant a lack of food for the fish, and so the populations declined.

But what if we made new homes for these animals and what if those homes were so sturdy and strong that trawlers wouldn't be able to break them? Well, that’s exactly what researchers did between 1997 and 2013 when they deployed a number of artificial reefs along the Paraná coast. But what exactly is an artificial reef? An artificial reef can be made out of rocks, concrete blocks or even sunken ships. They are man-made structures, preferably with different holes and crevasses, placed under water to provide shelter for marine organisms. Bacteria and algae are usually the first organisms to arrive, meroplanktonic larvae settle and grow up to be anything from anemones to crabs; all of these animals attract fish looking for food and they in turn attract larger fish and other predators.  After a while, the ecosystem on the artificial reef grows to become a place with both food and shelter for all kinds of marine organisms.

However, even after the artificial reefs were in place, many questions were still unanswered: would meroplanktonic organisms come to settle? Would they attract fish? Would those fishes reproduce? Would the ecosystem of the artificial reefs be anything like a natural rocky reef? The answer to the two first questions was discovered to be a big YES, but what about the other questions? That's what I wanted to find out! Exiting stuff, now what?

To answer those questions, we decided to look at fish larvae and fish eggs. To capture them we used a net attached to an underwater scooter (so cool, I know), and a light-trap. With the scooter and light-trap we were able to capture larvae very close to the artificial reef; the net captured eggs and the smallest fish larvae while the trap attracted larger larvae. We also sampled at a distance from the artificial reef (would the abundance of larvae and eggs be different there?) and at a natural rocky reef habitat nearby (the beautiful archipelago of Currais). We collected as many samples as the weather and waves allowed between the July of 2014 and April of 2016.

The samples were collected using a light-trap (left) and a net attached to an underwater scooter (right).

Currais archipelago on the Paraná coast.

So what did the data show?  

The number of fish larvae and fish eggs was in fact higher on the artificial reef compared to samples taken at a distance from the reef. Furthermore, the fact that the samples contained eggs and very small newly hatched larval fish means that fish are either reproducing on the reefs or close by. Additionally, many of the fish larvae collected on the artificial reefs belonged to species that are known to live on rocky reef habitats; most of the other species found were pelagic, which means they live in the open water. What does it all mean? Well, it means that the artificial reef is beginning to act like a natural reef (great!), but it still has a way to go. Fish are still more abundant on the natural reef and many of the fishes on the artificial reef are more like visitors, like the pelagic species. They are all welcome of course! The artificial reef provides food and shelter; many of the visitors attracted by delicious food become food themselves, but that's ok, it's all part of the food network. 

It may sound like artificial reefs are the solution to all of our problems and you may want to stand up with your hands in the air shouting: let's put artificial reefs in all the seas in all the world! Then everything will be great again, right? That would be amazing, but unfortunately, as with most things in life, it's just not that simple. There are many factors to consider because deploying an artificial reef is in itself a human intervention in nature and could cause more harm than good, careful research in each individual case is essential!

What can we learn from all this? Nature finds a way. Humans are destructive; in order to get our way and build our houses, we destroy houses of so many other animals. Fortunately, given time, many ecosystems are resilient enough to come back to life. Artificial reefs may not be the answer to all our problems, but on the coast of Paraná it appears that a tiny piece of a suffering ecosystem may actually be getting back on its feet. 

About Cathrine:

Biologist and currently preparing to defend my masters’ dissertation in the field of biological oceanography at the University São Paulo. As a true Norwegian I fell in love with the ocean scuba diving in the freezing waters of the north. I have been living in Brazil for four years now and I can't wait to discover where life will take me in the future. What I know with certainty is that I want to work and live close to nature, that being in the beautiful tropics of Brazil or in the wonderful Arctic of Norway (or somewhere in between).