In a special issue of Science magazine, a team of 160
scientists has published a series of papers detailing the findings of the
Tara expedition. What did they discover? A massive world of microscopic creatures dwelling in seas all around the globe.
Comb jellies are the largest animals that
use combs of hair-like cilia
for swimming. This is one of the smaller species, which start at just a
millimetre or so in length, but larger species range up to 1.5 metres.
Caption:Michelle StarrPhoto:Christian Sardet, "Plankton -- Wonders of the Drifting World", University of Chicago Press, 2015
The queen of the Xenomorphs?
This semitransparent prawnish-looking creature is an amphipod
-- a type of crustacean with no carapace.
The female of the species feeds on jelly-like salps,
leaving just a hollow gelatinous shell behind. It will then climb inside and
use the empty barrel-shaped shell of the salp as a sort of mobile home, sailing the seas
and snagging food, keeping her young safe inside.
These little fish in the genus Cyclothone grow to just 6 centimetres long, and live at ocean depths
greater than 300 metres.
This makes them difficult to catalogue,
but the numbers found are extremely abundant. Although it is a small fish,
ichthyologists theorise that the Cyclothone genus contains more individuals,
and possibly more biomass, than any other fish genus in the world.
At 200 microns (0.2 millimetres), Lauderia annulata is one
of the largest known kinds of single-celled algae. This one
was found in the Indian Ocean.
The green and yellow speckles are chloroplasts,
the algae's food-producing organelles;
the entire organism is encased in a shell of silicon dioxide, a type of
naturally occurring glass, similar to quartz or sand.
The Lyriopemedusa is a very small jellyfish, measuring just 10 to 30 millimetres across. This individual has caught and devoured a
juvenile fish in its tentacles. Photographer and Centre National de la Recherche Scientifique research director Christian Sardet captured the
Published:Caption:Michelle StarrPhoto:Christian Sardet, "Plankton -- Wonders of the Drifting World", University of Chicago Press, 2015
On the right, with what
looks like butterfly wings, is what is known as a sea
butterfly (funnily enough).
Sea butterflies are a type of sea snail, that, unlike their mollusc cousins,
can swim, using a foot that forms a pair of wing-like flaps. It lives close to
the sea's surface and doesn't usually get bigger than 10 millimetres long.
Marine ragworm Platynereis dumerilii isn't your ordinary
ragworm. It's considered a living fossil, having survived for millions of years in
the same environment, still with many of the same features as its ancestors.
This makes it a very good study case for evolution -- in
particular its eyespots. Eyespots are the most primitive form of eyes, able
only to detect the presence of light, which allows the worm to navigate. Everything else, it
performs using touch. These eyespots, scientists theorise, are the nearest existing formation to
the earliest evolution of eyes.