Title: Functional Changes Across Marine Habitats Due to Ocean Acidification

Published in Global Change Biology, Jan 2024

Overview:
This study examines how ocean acidification (OA), caused by increased CO2 levels, affects marine ecosystems. Using natural CO2 vents as models, researchers observed changes in marine communities across various habitats and depths. The findings highlight significant changes in species diversity and ecosystem functions due to acidification.

Key Takeaways:

• Decreased Diversity: Both species and trait diversity tend to decrease under ocean acidification. This reduction in biodiversity can lead to less resilient marine ecosystems.
• Habitat-Specific Responses: The impact of OA varies significantly across different habitats and depths. For example, some areas see a greater loss of calcifying species, which are crucial for building marine structures like reefs.
• Changes in Ecosystem Functions: Essential functions within the ecosystems, such as nutrient cycling and habitat provision, are altered due to shifts in species traits and interactions.
• Use of Natural Vents: Studying natural CO2 vents helps scientists predict and understand the future impacts of ocean acidification on marine life. These vents mimic the conditions expected in the oceans at the end of this century under high CO2 scenarios.
• Implications for Conservation: The study underscores the need for strategies to mitigate the effects of ocean acidification and protect marine biodiversity.

This infographic from the research paper provides a great summary of the findings:

The infographic presents a comparative analysis of the impact of ocean acidification (OA) on four different marine habitats: Deep Reef, Reef, Cave, and Shallow Reef. The information is organized into two main categories: changes in biodiversity (top) and changes in cover of specific functional groups (bottom). Here’s the main takeaways:

Changes in Biodiversity (top):

• Each habitat is analyzed for changes in species richness, functional entity richness, and functional dispersion, with percentage changes indicated on the horizontal axes.
• A red circle denotes a decrease and a blue circle indicates an increase.
• The “Deep Reef” and “Cave” habitats show significant decreases in all three biodiversity metrics, while the “Reef” shows an increase, and the “Shallow Reef” shows a mix of increases and decreases.

Changes in Cover of Functional Groups (bottom):

• These are measured as changes in the percentage cover of different ecological roles: autotrophs, filter feeders, herbivores, habitat-forming species, and calcifiers.
• Red bars indicate a decrease in cover percentage, while blue bars indicate an increase.
• Notably, “Deep Reef” shows a decrease in filter feeders, habitat-forming species, and calcifiers, while “Cave” demonstrates declines across all categories except autotrophs.
• The “Reef” habitat shows slight changes, and the “Shallow Reef” exhibits increases in autotrophs and calcifiers but decreases in other categories.

pH Values:

• Each habitat panel lists the average pH value measured, which is a primary indicator of acidity. Lower pH values signify higher acidity.
• The average pH is followed by a range in parentheses, representing the variability.

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Did you know that the sunscreen you apply doesn’t always stay on your skin? In fact, when we swim (or even shower), the sunscreen you’ve applied throughout the day washes off into waterways and often ends up in the ocean. In fact, around 6000 tons of sunscreen washes off into reef areas every year, according to scientists. That’s equal to the weight of nearly 50 blue whales!

While we depend on sunscreen to protect us from skin damage and disease, many sunscreens actually cause great harm to marine ecosystems. And with 80% of corals in the Caribbean lost in the last 50 years, in part due to pollution, it’s more important now than ever before to ensure we take steps to avoid damaging these important organisms further.

But how exactly does sunscreen damage coral reefs, and what can we do about it? Let’s dive in.

Protection for People, Harm to Marine Life

Researchers estimate that approximately 10%, if not more, of coral reefs around the world are threatened by sunscreen. The areas feeling the brunt of the damage are highly-tourested areas like Hawaii and the Caribbean, where thousands of tourists swim every day, leaving sunscreen behind them. 

So, how is sunscreen killing coral reefs? There are two main types of sunscreen: physical and chemical. Unfortunately, both types of sunscreen can cause harm to coral and other types of marine life.

Physical sunscreen is made of minerals that sit on top of your skin and reflect the sun’s rays. The main minerals used for this purpose are titanium dioxide and zinc oxide, which can wash off into the water. In fact, studies estimate that the average tourists on a Mediterranean beach release 4kg of titanium dioxide in a single day. When these minerals are very small (called “nanoparticles”), they can be absorbed by coral and cause severe damage.

A 2018 study found that zinc oxide nanoparticles cause extreme coral bleaching. This is because the zinc interferes with symbiosis between coral and other organisms, which leads to bleaching over time. Zinc oxide and titanium dioxide nanoparticles in the ocean may also cause chemical reactions to occur that result in hydrogen peroxide, which bleaches coral.

Chemical sunscreens contain chemicals that absorb into the skin, and then absorb UV rays before they can hit your skin. The active ingredients include “UV filtering” chemicals avobenzone, octinoxate, and oxybenzone. These are extremely potent and toxic to marine animals including coral.

New Research: How Does Sunscreen Harm Coral Reefs?

While scientists have known that oxybenzone damages coral reefs for a while, they did not know exactly how the chemical was causing harm. In May 2022, researchers at Stanford released a study that explored oxybenzone’s effects on sea anemone, an organism that’s closely related to corals. 

The researchers found that when oxybenzone was exposed to light and a sugar found in anemone tissue, not only did it kill the anemone, but the chemical metabolized into another molecule, releasing free radicals that kill coral. Sea anemones exposed to oxybenzone and sunlight died around one-three weeks after exposure.

Finally, preservatives used in sunscreen to help the product last longer can also have toxic effects on both humans and coral. For example, parabens, a class of preservatives, are used in many sunscreens to prevent the growth of bacteria and mold. However, parabens can wash off into the environment, and have been found in a wide variety of organisms all over the world, from fish to marine mammals and birds. Studies show that parabens can disrupt the hormones of a variety of animals, including humans. 

Parabens can also cause viral infections in zooxanthellae, symbiotic algae that live in healthy coral tissue and provide it with nutrients. A 2008 study showed that, because of these viral infections, coral bleaching occurred within a few hours to a few days of exposure to even very small amounts of sunscreen.

Does Sunscreen Harm Other Types of Ecosystems?

It’s not just marine life that’s impacted by sunscreen. When we shower, sunscreen is often washed off into wastewater, which makes its way into fresh bodies of water. However, due to the extreme variety of aquatic ecosystems throughout the world, the specific impacts of sunscreen in aquatic environments are still unknown. 

Many experts are calling for more research into the impacts of sunscreen on non-marine ecosystems. In August 2022, the National Academies of Sciences, Engineering and Medicine published a report calling on the US EPA to conduct further studies into the risks that UV filters cause to aquatic ecosystems (including freshwater). They explain that while we know UV filters have been found in water, sediment and even animal tissue in a variety of ecosystems, we need more information to understand the extent of the impacts they’re having on a variety of aquatic organisms. 

Government attention to the issue of sunscreen killing coral reefs is not limited to scientific data gathering, however. Next, we’ll review how a few governments have taken a stab at protecting coral reefs and other marine organisms from toxic sunscreen ingredients.

Legislation: Bans on Reef-Toxic Sunscreen

In response to concerns about the toxic effects of sunscreen on coral reefs and the intense reduction in living coral reefs, several governments have passed legislation banning sunscreen containing oxybenzone and octinoxate. 

Hawaii was the first state to ban harmful sunscreens with the passage of a bill in 2018 that banned oxybenzone and octinoxate sunscreens. In 2021, the Hawaii State Legislature passed another bill that banned two more harmful chemicals in sunscreen, avobenzone and octocrylene.

Other local and federal governments have also banned harmful sunscreens, including:

• Aruba
• Bonaire
• The U.S. Virgin Islands
• Key West
• Palau

What You Can Do to Protect the Ocean from Harmful Sunscreen

There are a few things you can do to avoid putting more harmful sunscreen into the ocean.

1. Use other forms of sun protection. While sunscreen is, of course, a necessary product to protect ourselves from harmful ultraviolet rays, it should really be a last resort. Instead, use UV-protective clothing like a sun shirt to reduce the amount of sun your skin is exposed to. You can also try and spend time in the shade to protect your skin.

2. Use reef-safe sunscreen. When you do need to use sunscreen, make sure it’s a reef-safe sunscreen. First, avoid spray-on (aerosol) sunscreen, as the spray disperses into the environment much more easily than a cream, and often contains harmful chemicals. Instead, opt for a mineral sunscreen with zinc oxide and titanium dioxide that aren’t nanoparticles (if the packaging doesn’t explicitly say “micro-sized” or “non-nano,” you can be pretty sure it contains harmful nano-sized particles).

To figure out if a sunscreen is truly reef friendly, look at the label. Make sure to avoid these chemicals:

Finally, while sunscreen in the ocean is clearly harming coral reefs, we must also take into consideration the other threats to coral reefs, including overfishing and climate change’s rising temperatures. Changing to a reef-safe sunscreen may make a small dent, but we must curb climate change in order to truly protect coral reefs and other marine life.

The post How Is Sunscreen Killing Coral Reefs? appeared first on Ocean Acidification.

Ocean acidification is a worldwide problem that, according to experts, requires the same level of attention as plastic pollution and global warming. Here are some of the best quotes about ocean acidification from activists, oceanographers, and authors.

Background Information: Ocean Acidification Infographic

1. “There are ecosystems like coral reefs at risk through ocean acidification. Those are valuable things that we should protect.”

– Bill Gates

Coral reefs are one of the organisms most severely affected by ocean acidification. As acidification increases, coral become unable to build or repair their skeletons due to a lack of calcium. If ocean acidification continues, we may lose the majority of our coral reefs, as well as the important products and services that corals provide to the ecosystem and to our community and economy. Bill Gates, along with many other environmentalists, pushes for solutions to ocean acidification in order to reduce its impacts on fragile ecosystems. In particular, Gates argues in favor of a shift to clean energy in order to reduce the amount of carbon dioxide in the atmosphere. This would reduce climate change and ocean acidification.

Source: “The Bill Gates Interview:  An energy miracle is coming, and it’s going to change the world”, Business Insider, February 2016

2. “Nothing is as daunting as the threats associated with global warming. That’s the biggie. Everyone bangs on about rising sea levels but the real challenge of a warming planet is ocean acidification. An acid ocean spells the end of life on earth.”

– Tim Winton

In this interview with famed Australian author and environmentalist Tim Winton, he argues that the issue of ocean acidification is often overlooked as many people are still unaware of the consequences of ocean acidification. As Winton states, the acidity of our oceans may result in the extinction of all species. This is due to the fact that ocean acidification has the potential to trigger a negative domino effect, resulting in an ecological imbalance that will harm both marine and terrestrial ecosystems and life, transforming our world into a place not applicable for life. 

Source: “Tim Winton Interview,” Surfers Against Sewage, December 2014

3. “As an explorer, I know firsthand there are many places in the ocean so full of life that they should be protected. Coral reefs and mangrove coastlines are stressed already by climate change and ocean acidification, and poor planning will just make their plight worse.”

– Philippe Cousteau Jr.

Philippe Cousteau Jr. is an environmental activist and nature-television host whose work focuses primarily on the ocean. This quote emphasizes the significance of proper planning in minimizing ocean acidification in order to maintain the remaining pristine marine ecosystems. This is why it is critical to develop a comprehensive global solution capable of properly addressing the worsening consequences of climate change and ocean acidification.

Source: “A blueprint for our blue home”, Huffington Post, July 2011

4. “Past, present and future CO₂ emissions will have a cumulative impact on both global warming and ocean acidification. The laws of physics are non-negotiable.”

– Michel Jarraud

Michel Jarraud is a meteorologist and former secretary general of the World Meteorological Organization (WMO). In this quote, Jarraud emphasizes that our emissions in the past, present, and future will push forward global warming and ocean acidification. This is due to the fact that ocean acidification and global warming are triggered by an excess of atmospheric carbon in the atmosphere, a result of human greenhouse gas emissions. We cannot address these problems unless we reduce global CO₂ emissions. With his phrase, “the laws of physics are non-negotiable,” Jarraud emphasizes the fact that our only real solution to ocean acidification and climate change is reducing carbon dioxide emissions.

Source:  “Greenhouse gas concentrations hit yet another record,”, World Meteorological Organization Greenhouse Gas Bulletin, September 2014

5. “Global warming is the foreboding thunder in the distance. Ocean acidification is the lightning strike in our front yard, right here, right now.”

– David Horsey

David Horsey is an editorial cartoonist and political commentator for the Los Angeles Times. This quote argues that we have yet to see the worst of global warming’s impacts. On the other hand, we’re already seeing the impacts of ocean acidification. Horsey implies that ocean acidification is a pressing matter that must be addressed urgently.  Additionally, ocean acidification can be seen as a wake-up call, indicating that the consequences of global warming are already harming the ocean today, and will continue to damage the world faster than we may realize.

Source: “Ocean acidification is killing sea life, and we are the culprits,” Los Angeles Times, November 2012

6. “Our biggest challenges for the ocean and for the planet are problems of perception. People need to understand that species extinctions, habitat destruction, ocean acidification, and pollution are all chipping away at the resilience of the thin layer of life that sustains us on Spaceship Earth.”

– Edith Widder

Edith Widder is an oceanographer, marine biologist, and the CEO of the Ocean Research & Conservation Association. This quote emphasizes that our planet suffers as a result of people’s lack of awareness about environmental problems that threaten our existence, such as ocean acidification and pollution. These problems are having a severe impact on the limited natural products and services we receive from the environment, as well as diminishing the capacity of life on Earth to adapt and survive.

Source: ORIGIN Magazine Issue 25, August 2015

7. “With our evolved busy hands and our evolved busy brains, in an extraordinarily short period of time we’ve managed to alter the earth with such geologic-forcing effects that we ourselves are forces of nature. Climate change, ocean acidification, the sixth mass extinction of species.”

– Kate Bernheimer

Kate Bernheimer is an American author focusing on fiction and specifically, fairy tales. This quote describes how human technologies and activities are causing our world to face environmental issues at an alarming rate. We have caused climate change, global warming, and ocean acidification as a result of our carbon emissions and excessive pollution, which might lead to the sixth mass extinction. This quote relates closely to the idea of the anthropocene, or the stage of geologic history in which humans act as a shaping force on the environment.

Source:  Xo Orpheus: Fifty New Myths, September 2013

8. “Ocean Acidification is sometimes referred to as Global Warming’s Equally Evil Twin.”

– Elizabeth Kolbert

Elizabeth Kolbert is a journalist and author of the award-winning book, The Sixth Extinction: An Unnatural History. This quote emphasizes the fact that ocean acidification and global warming have similarly destructive impacts on life on Earth. Both environmental problems are triggered by an excess amount of carbon in the atmosphere, and both may lead to a mass extinction in both terrestrial and marine ecosystems. Kolbert goes on to say that in the past, ocean chemistry has been a good predictor of mass extinction, and has played a role in mass extinctions throughout the Earth’s history. 

Source: The Sixth Extinction: An Unnatural History, February 2014

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