Ocean Surface Film is Important Habitat
Gelatinous Layer Between Sea and Atmosphere has Unique Organisms
Aug 10, 2009
Bubbles of air bring material to the sea surface to form a newly discovered habitat that houses an unusual set of microbes.
Bubbles Bring Jelly to the Surface
- When microbes in seawater die bubbles of air bring complex chemicals to the surface where they feed a unique group of microorganisms.
- When waves break the surface the bubbles return the film and its inhabitants to the surface.
- The layer is incredibly thin (less than the thickness of a human hair), but important for understanding how gases move between the atmosphere and the ocean.
- Unfortunately the surface layer seems to be very good at concentrating pollutants, and nobody yet knows what the effects are likely to be.
The amount of jelly-like surface is so small that it is not possible to collect samples in any container – the proportion of ‘normal’ surface water in the container is huge relative to the amount of film.
The only way to get a sample is to cool a piece of glass in liquid nitrogen and then touch it to the surface – the jelly surface sticks to the glass.
Identifying Microbes of the Surface Film
The living organisms have not yet been studied, but DNA analysis reveals that they form a community that is distinct from the normal ocean habitat – they have much in common with microbes that form thin layers on solid surfaces.
Polluting the Ocean Surface Film
Many pollutants (including pesticides) are easily trapped in the film, and presumably this has a huge impact on the organisms that live there. This weird habitat is very thin, but enormously widespread (over most of the surface of the world oceans). It influences the way gases move from air to sea (and vice versa), so polluting it could have far-reaching consequences.
Carbon Dioxide and Methane
The organisms in the ocean surface film take methane out of the atmosphere and use it as a sort of food. The surface also seems to suck carbon dioxide out of the air allowing it to dissolve in the sea. Removing these two greenhouse gasses is obviously very important in terms of climate change.
Because the ocean surface film is very difficult to study it has received little attention in the past. Now that it is becoming clear how important this microlayer is, (for any clear understanding of the way gases can move into and out of the atmosphere), more attention is being paid to it.
Reference: ‘The gelatinous nature of the sea-surface microlayer’ Oliver Wurl - Marine Chemistry 03/2008 (110:89-97)
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