The importance of the Surface Microlayer: When it comes to tackling climate change, on the whole, we’ve been particularly focused on cutting carbon dioxide emissions. However, there’s an often-ignored aspect of our planet that plays a crucial role in climate control—the ocean. That’s why Ocean Integrity is devoted to cleaning it up.

In our blog post, we explore an eye-opening report that sheds light on the surface microlayer (SML) of the ocean and its profound impact on climate change. This newly discovered layer not only affects our climate but also holds the key to fighting pollution and protecting marine life.

The Unsung Hero of the Ocean: The SML Layer

Covering a whopping 71% of the Earth’s surface, the ocean plays a vital role in regulating climate. The SML layer, which is between 1 to 1000 micrometres deep, is made up of lipids and surfactants* produced by marine phytoplankton. This layer serves several crucial functions—it helps form clouds, prevents water from evaporating too quickly, and slows down the transfer of heat to the atmosphere.

The Surface Microlayers Role in Climate Control

One of the most fascinating discoveries is that the increasing concentration of water vapor in our atmosphere is solely due to evaporation from the ocean surface. This means that the oceans bear the primary responsibility for climate change. The SML layer regulates atmospheric water vapor pressure, temperature, cloud formation, and rainfall. Any changes in this layer can have significant effects on our climate system.

Pollutants in the SML Layer

Unfortunately, the SML layer acts like a magnet for various harmful substances. Toxic forever chemicals, microplastics, and hydrophobic black carbon soot from burning fossil fuels build up in this layer. Shockingly, the concentration of toxic chemicals in the SML layer is around 500 times higher than in the underlying water. These pollutants, combined with tiny particles like submicron and microplastics, pose a serious threat to plankton—the primary producers in marine ecosystems.

Implications for Marine Life and Ecosystems

Pollution and ocean acidification have led to a decline in marine biodiversity, causing significant damage to our oceans. Reduced growth of phytoplankton weakens the SML membrane, decreases carbon absorption, and increases the concentration of dissolved carbon dioxide in surface waters. This worsens ocean acidification and disrupts the delicate balance of marine ecosystems. If the pH reaches 7.95 by 2045, it could trigger a regime shift, dangerously affecting key species and potentially causing a collapse in the entire marine ecosystem.

Consequences for Climate and Humanity

As the SML layer shrinks, evaporation rates and atmospheric water vapor concentrations rise. This altered condition impacts the formation of cloud cover, rainfall patterns, humidity, and temperature. The result could be disastrous climate change, characterized by heavy rainfall, flooding, and other extreme weather events.

Meanwhile, the collapse of the marine ecosystem and ocean acidification may result in the loss of countless species, affecting the food supply for billions of people.

While reducing carbon emissions remains crucial in the fight against climate change, we must also recognize the role of the ocean and the surface microlayer in climate regulation. Understanding the importance of the SML layer allows us to develop comprehensive solutions that tackle pollution, safeguard marine biodiversity, and mitigate climate disruptions. By taking action to reduce plastic pollution in our ocean we can help to conserve marine ecosystems. There’s hope for a future that protects our planet and everyone who calls it home.

*Surfactants are organic compounds produced by marine plankton and bacteria that form an oily film on the surface of the water.

Read about our other effects of microplastics in the ocean

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