Kind: captions
Language: en
is there anything more festive than a
christmas tree
worm
known as spirobrancus or spiral gills
when roughly translated from the latin
the christmas tree worm is a marine
animal distantly related to earthworms
though you might notice it looks a lot
different from your garden variety night
crawler
instead of slithering through soil the
christmas tree worm inhabits coral reefs
and might even help protect them against
destruction and unlike a nightcrawler's
average lifespan of 6 to 9 years or even
20 years in some recorded cases a
christmas tree worm has an average
lifespan of 10 to 20 years and can even
live up to 40 years in an unpolluted
habitat another major difference is this
worm's uniquely shaped headgear two
projections covered in gill-like organs
called radials which the worm uses for
feeding and breathing these crowns
resemble a twin pair of brightly colored
fur trees sprouting from the reef and
they actually help protect corals from
encroaching predators but more on that
in a minute first let's look at what
this creature eats
the christmas tree worms radials are
lined with small hair-like projections
called cilia which the worm uses to snag
plankton drifting by in the ocean
current
these cilia carry unlucky riders
straight to the worms hungry wading
mouth of course the christmas tree worm
doesn't want to get eaten itself so it
comes equipped with a handy escape hatch
literally when it encounters a predator
the christmas tree worm quickly retracts
into its burrow and blocks the entrance
with a piece of its own body a modified
radial called in aperculum sealed shut
and surrounded by a coral fortress the
worm forces would-be predators to look
somewhere else for a meal this strong
defense is very important since adult
christmas tree worms have nowhere to run
unlike nearly every worm they don't
wiggle they don't move
they just stay put the lava finds a
little
niche on the coral on the living coral
and very quickly it metamorphoses into a
tiny worm and secretes a little tube
that it then inhabits
and then as the coral grows which is at
about a centimeter or so a year
the worm builds its tube inside the
growing coral and so you end up with
this coral living right up to the edge
of the tube of the worm and so as the
corals are increasing it's its height
the worm increases its height with it
these are really really successful
animals so successful that they thrive
in tropical ocean environments worldwide
from the pacific to the caribbean the
christmas tree worm also acts as an
aquatic guard dog protecting its coral
reef home from voracious predators like
the crown of thorns starfish a roughly
foot and a half long spine-covered
behemoth
like a herd of heavily armored undersea
cows
these starfish graze their way through
coral reefs in just one year each crown
of thorns starfish can graze up to about
108 square feet
that may not seem like much but each
female can produce up to 50 million eggs
it's no wonder that along with cyclones
and climate change related warming
temperatures these starfish outbreaks
have led to an estimated loss of 50
percent of coral in the great barrier
reef since 1995.
this is where the christmas tree worm
comes in as the crown of thorns starfish
makes its way across the reef it runs
into the worms radials which
instinctively push away the starfish's
encroaching appendages and stomach
i think the the fact that they protected
against the crown of thorns wasn't a um
you know wasn't a particularly conscious
decision on the part of the worms is
just that the worms by being there are a
sufficient irritation to the starfish
that it discourages the starfish from
eating on top of the worm because the
worm can you know can open and could
push and it can irritate the feeding
stomach that the starfish spreads out
across the corals lyndon de vanta even
wonders if these worms might
inadvertently help insulate corals from
rising sea temperatures with their
radials providing shade and increasing
water circulation
certainly a potential avenue of future
study
so let's recap we have an unintentional
marine bouncer that eats with its
tree-shaped lung-like organs that's
certainly not something santa would
expect to encounter on a cold christmas
eve but thanks to its role protecting
coral reefs this colorful worm has
probably secured a spot on the jolly
man's nice list
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