Page 11 - BBC Wildlife Volume 36 #04

WILD APRIL
Hidden
alkastorm-blown
strand-line and
Wmingled with the
flotsam and jetsam of humanity
you’ll find a tangle of natural
treasures. If you’re lucky, these
will include a strange creature NICK
called the sea mouse, Aphrodita
aculeata. It’s a psychedelic fuzz of BAKER
fur and spine, and can look like REVEALS A
both something and nothing.
From one angle it resembles a FASCINATING
sandy fur-ball. But from another, WORLD OF
it catches the lightand your eye. WILDLIFE THAT
Pop it in some seawater and
ittakes on a completelynew WE OFTEN
vibrance. It becomes a splash of OVERLOOK.
fibre-optic brilliance.
The sea mouse simply doesn’t
conform to what you might SE A MOU SE
expect a ‘worm’ to be. Far from
being a slim tube it is quite
chunky: up to 20cm long and
5cm wide. The body is covered
in a velveteen pelage, and its
perimeter is trimmed with a
wide skirt of long glassy hairs
(setae) amongst which are
embedded a palisade of much
thicker, stouter spines, making
the creature quite prickly.
Turn the worm and you’ll
get a hint as to its place in the
animal kingdom. It is a kind
of segmented (annelid) worm,
with its body divided up into
sections. Each has a pair of
WONDERFUL WORMS
Polychaetes are among the most diverse of all marine organisms.
ustrat ons by Peter Dav d Scott/The Art Agency they also go by the name of f become flattened into little oars, nano-structure of the bristles u he worm overcomes these
burrow.In some species,such as
Most polychaete worms are
green paddle worms,they have
covered in hair-like bristles,so
o
name
bec
ome
fl
the
bristle worms.TThey usually have
enabling th
e worms to actively
well-developeddjaws and each
nd.With over 10,000
swim aroun
body segment has a pair
species
s of polychaete known,
ding the fearsome
of limb-like muscular
inclu
bit worms of BBC’s
Blue Planet II,it’sa boddy
B
‘limbs’can be
used to crawl and
p
plan that works well.
I protrusions.Thhese bobb
April 2018
Physicists can
learn a lotfrom
theseamouse
and its ability to
reflect light.
hollow hexagonal tubes, which
fleshy ‘feet’ called parapodia, h
complete with a bundle of ru
un parallel to the length of the
more spines at the tip. The sea b
bristle. A cross-section therefore
g
y
mouse uses these as it p ploughs lo l ooks a little like a honeycomb.
through the seabed sediments, When light hits this precise
matrix of tubes, it splits and
as deep as 3,000m, where it m
hunts other worms, molluscs r eflects back those portions
andcrustaceans. in
n a specific part of the light
Most ofthe sea mice washed s pectrum. Amazingly, this
up are dead, or lethargic at s tructure is very similar to
he artificial structures being
best, but if you do place one in th
a clear-sided vessel of seawater, d
developed by physicists in
he exciting field of photonic
you will hopefully observe its th
real magic. Natural light falling c ommunications, which uses
on the worm’s veil offluff li ight instead of electricity
n telecommunication and
creates a kaleidoscopic in
DID YOU rainbow of colour c omputing. For this we need to
be able to amplify and control
KNOW ? –a phenomena b
The scientific name termed pseudo- photons. The sea mouse has
p
for seamice refers to birefringence. b
been doing this all along.
Aphrodite. To see why, Thischromatic Not only did this worm get
here first, it exhibits almost 100
turn one over and use shimmering of th
p
your imagination. blues, reds, greens per cent reflectivity – much better
han anything our technology has
and yellows seems to th
emanate from the finer c ome up with.What’s more, it
strands, whilethethicker a chieves this using nothing more
han a simple arrangement of
spines glow ember-red,making t th
hexagonal crystal-like structures
for a garish opulence rare in a h
creature of the deep. e xuded fromitsskin. Buthow
d
does theworm benefit?
Light show One theory is that the light
The purpose of these colours s in how deters other predators
has long been debated, but
n the dimpsy darkness of the
s
u
recent investigations into the
underwater world.Ifour worm
used normal pigmented colours,
much of the light hitting its fur
and hairs have revealed the
m
first known instance of natural
w
would simply become absorbed.
By deploying photonics
B
photonic engineering. Under
th
an electron microscope,each
imitationsonthe seabed.
hollow tube whose walls in turn
NICK BAKER
N
comprise some 88 layers of
is
filament is shown to be a li s a naturalist, author and TV presenter.
BBC Wildlife 11