Because the neuston potentially covers the 70% of the Earth's surface, its structure is particularly important in the exchange between the ocean and the atmosphere.
This paper focuses on neuston structure supporting Sieburth's proposal of a gelatinous microlayer film.
Recent works showed that samples of sea-surface microlayer have a higher content of transparent exopolimer particles (TEPs) compared to sub-surface samples (1m) collected in the same area. TEPs derive from the coagulation of biogenic polysaccarides,particularly those produced by phytoplancton, and are critical in the formation of marine aggregates as they are the matrix that holds the aggregate together.
As the structure of sea-surface microlayer and sub-surface water is different,the communities within them are greatly distincted.
For example, Franklin et al. (2005) showed that the bacterioneuston at a site in the North Sea was distinctly different compared with subsurface water just 0.4 m below the surface. The bacterionesuton was dominated by Vibrio and Pseudoalteromonas, both organisms with physiological adaptations to biofilm survival.
This means that there is a selection in the community composition of sea-surface microlayer possibly due to the gelatinous strucuture of the biofilm.
Surface microlayer films occur also in freshwater, where biofilm derives from the aggregation of bacterial cells attached to TEP-based gel particles, the same process described for the sea-surface microlayer.
All of these evidences support the theoretical proposal made by Sieburth that the sea-surface microlayer is a gelatinous biofilm and,as the marine gel in subsurface water, it may play a significant role in many ecological and biological processes we still don't know.
Reference: Cunliffe M & Murrell JC (2009) The sea surface microlayer is a gelatinous bioļ¬lm. ISME J 3: 1001–1003
4 comments:
Hey Valentina,
I hope you are enjoying the weather in Sicily. Interesting review. The neuston layer you described does suggest the surface layer of the marine environment may be as diverse in organisms as reef systems, vents, seeps etc. Perhaps we should start thinking of that layer as one giant biofilm as detailed in your review. I am curious as to whether there is a defined boundary for the neuston ecosystem, but I'm assuming that this layer is not symmetrical across the ocean and may vary in dimensions depending on where you are looking. I've always assumed that tropical waters would have more species diversity but I think the consensus is that temperate seas are more productive, therefore the neuston layer would be equally productive I'm assuming.
I wonder how this proposal by Sieburth impacts the concept of the microbial loop. It might be an interesting study for the future if it hasn't been done already.
The specificity of the bacterioneuston seems to also be of interest in other aquatic environments which are questioning it as a possible unique community – for example high mountain lakes. Perhaps by identifying it as an independent entity in its own right, a new perspective could ask novel questions regarding its characterisation and function.
The specificity of the bacterioneuston seems to also be of interest in other aquatic environments which are questioning it as a possible unique community – for example high mountain lakes. Perhaps by identifying it as an independent entity in its own right, a new perspective could ask novel questions regarding its characterisation and function.
Hi Vale!
I've always wondered what happens to the surface microlayer when there's rough seas. I mean, It is really easy for me to imagine a surface microlayer in a lake or in a lagoon with calm and flat waters...but it is really hard for me to imagine the existence of such a defined layer when some waves shakes the sea surface. Maybe everything get's resuspended and then when the sea is calm again is reformed? But i guess this will be very difficult to study since in my mind also sampling such a thin layer must be incredibly complicated...
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