Blue Community

Out in the greater Pelagic zone - in fact, on the interface between atmosphere and marine - is a floating community that taps the food from below, and lives off one another.

(New Zealand examples here: https://www.inaturalist.org/projects/blue-fleet-monitoring-nz)

A feature of this community is their exposure to predation from above and below: to this end they are predominantly blue in colour - from whence they get their name.

They either float - on floats, bubble rafts, or flotsam - or live suspended in the surface tension of the interface. Blown about by winds, they often end up in masses along the shoreline. Here Bluebottles in their death throws and beyond, encounter humans and earn their reputation as stinging hell. But the majority of species are small and not easily noticed, and after a day or two on the beach, shrivel up, die, bleach and blow away, or are eaten by whelks and other predators.

Poorly known: this page is devoted to making the Blue Community better known.

The primary component of the community is the Portuguese-Man-O-War (or Bluebottle), which is a Cnidarian, a highly developed "social Anemone" - a community - with different animals forming a float (filled with Carbon dioxide), stinging tentacles (for defense and catching prey: these may be 10-50m long, and have contractile cells to reel in any catch), feeding polyps (which surround and digest food) and reproductive zooids. The tentacles have stinging cells that produce toxins that kill prey: to humans they can be extremely painful and may blister skin.

Feeding on these are small creatures: another Cnidarian (of course), a Seaslug, a Snail, a Crab. I did say that it was a small community: it is not very diverse, although different species may occur in different oceans. All are small and blue.

Associated with them are some fish that live among the tentacles. These are immune or do not trigger the stingers in the PMOW and thus seek safety among the tentacles. Most prominent of these is the Man-O-War-Fish or Shepherd Fish, which nibbles on the smaller tentacles.

And they are joined by Goose Barnacles, when here is enough flotsam.

And dont forget the Argonaut: the Sailing or Flying Octopus, or Paper Nautilis, which constructs a sail of calcite and travels the high seas. The shell is a retreat, egg case, sail and bubble trap, the female living inside it (males are small and merely living penises, leaving their hectocotylus with sperm in the female, after which they break off and die) and sailing the seven seas. They live off seaslugs, snails, crabs, jellyfish and salps. They can change colour, produce ink as a smoke-screen, and flash silver to confuse predators. Still they are eaten by many larger fish and dolphins.

There are other members of this community, but most appear to be rare or only join occasionally. Hopefully we will find more, and find out more.

There is no reason why the Blue Community should remain obscure.

Posted on Οκτώβριος 19, 2017 1021 ΠΜ by tonyrebelo