User:Ethanmoss10/Marine habitats

Sea Surface Microlayer
The surface microlayer of the ocean serves as the transitional area between the atmosphere and the ocean. It covers around 70% of the Earth’s surface as it covers most of the ocean waters on the planet. The microlayer is known for its unique biological and chemical properties which give it a small ecosystem of its own and serves as a distinct habitat from the deeper ocean waters. The surface microlayer is not in fact entirely aqueous like the rest of the ocean, but is closer to a kind of hydrated gel composed of concentrated nutrients forming a biological film over the water it covers. This film is rich in microbes which mediate the interactions between the sun, the atmosphere, and the waters below.

Although thin, the surface microlayer is critical for life beneath it. Because of the environment rich in microbes and nutrients, larvae of fish and other aquatic animals are often laid in the microlayer to incubate. The plankton in the microlayer are distinctly adapted to withstand high levels of radiation, and serve as buffers to prevent this potentially harmful radiation from reaching the deeper water. Environmental changes such as aerosols or dust storms can cause these surface plankton to become overproductive, leading to blooms. Because of the unique properties of the microlayer, pollutants often accumulate within and use it to reach other parts of the ocean. Hydrophobic compounds, such as petroleum, flame retardants, and heavy metals, have a particular affinity for the surface microlayer. Recently, the abundance of aerosols and microplastics has also had an impact on the SML and their accumulation has lead to many problems, such as animal ingestion of these compounds leading to widespread disruption of balance and spread of these compounds among marine communities.

The surface microlayer is also critical to gas exchange between the atmosphere and the ocean. Because the microlayer is filled with microbes, it is widely theorized that it plays a critical role in gas exchange and uptake of nutrients, but relatively little data on this has been collected. The central feature of the microlayer is the temperature, as it is an indicator of how pollutants and human activity affects the ocean.

Main article: Sea surface microlayer