Christina
Persico, RNZ Pacific Bulletin Editor
An
expedition in Tuvalu’s waters is using a submersible to
study the ocean – some parts of which have never been
studied in-depth.
The National Geographic Pristine
Seas project is studying the health of Tuvalu’s marine
environments. The expedition is a partnership between
Pristine Seas and Tuvalu government.
Expedition leader
Keiron Fraser said they will be deploying a range of
scientific equipment in the sea and the tech will help them
get an idea of the health of the ocean in that
area.
“The leg we’re on at the moment is a deep sea
leg. So, a lot of the work that we’re doing at the moment is
centred around our submersible, the Argonauta, and
that’s a three-person submersible which is rated to go down
to 1300 metres,” he said.
“We can put scientists in
that with a driver to record scientific observations, count
fish, look for species and things like that.”
Fraser
said the submersible has a variety of tools on it, including
a manipulator arm enabling the scientist to reach out and
grab things.
It also has capability for a process
called environmental DNA, or E-DNA.
“When an
organism’s floating around in the water or swimming, it
releases very, very small fragments of DNA, which is
obviously from the bodies and that can be released in a
variety of ways.
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“Using those DNA fragments you can
actually sequence them.
“So instead of swimming around
looking for the fish species that you can see, you can
collect water and to some degree you can identify – without
seeing the actual organism, from their DNA in the water –
the species that lives there.”
They also use BRUVs –
baited remote underwater videos.
“The idea of these is
that you put them in the water and basically they record
what species turn up.
“They’ve got a bait can on
them…the various organisms in the area smell the the scent
of the bait and come to the cameras and then from that you
can work out what species live in that area and to some
degree the density of them.”
Fraser said the area they
are working in is fairly unexplored.
“In some of the
shallower waters, there’s been some really good work done on
scientific diving – shallow water surveys on fish and corals
and things, but certainly in the area we’re working for the
next month in the deep sea, there’s been I’m pretty sure
next to nothing done.
“The sort of data that we’re
collecting will help the Tuvalu government and the
communities understand what lives in their seas and identify
areas which are really prime for protection.”
The team
will also conduct bird surveys, and after this expedition a
second one is planned.
“On that one there’ll be
scientific diving, looking at fish distributions using a
technique called underwater visual census, and species that
live on the bottom, such as coral and invertebrates, so
things like sea
cucumbers.”
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