The
oceans and seas cover two thirds of the planet’s
surface and there is much we still have to learn
about the flora and fauna of the sea and the world
they live in. At SAHFOS we are particularly interested
in the plankton: its biology, ecology and the
role it plays as an indicator of changes in the
environment. The data collected by the CPR survey
is extremely important to the fishery industry
and scientists who study other marine life.
The oceans support the greatest
diversity of life on earth. The deepest parts
of the oceans have barely begun to be explored,
and new life forms are being discovered every
year by deep-sea submersibles. In a world where
human induced effects are thought to be accelerating,
it is very important that we monitor changes that
could alter the marine world we are only just
discovering.
Plankton are important as indicators of the health
of our oceans. They are also a key factor in climate
change. Plant plankton (phytoplankton) produce
~50% of the total photosynthesis of plants on
Earth, sucking the greenhouse gas carbon dioxide
(CO2) from the atmosphere (Reid and Edwards, 2001).
Through a process called the biological pump,
much of this CO2 is trasfered to a store in the
deep ocean. As plankton float freely in the ocean
they are difficult to study, and it was this that
prompted Alister Hardy to devise a self contained
sampler.
The Continuous Plankton Recorder (CPR) survey
has been running for 70 years and in that time
almost 4 million nautical miles of the oceans
have been sampled. The CPR is a plankton
sampling instrument which is towed behind
merchant ships at a depth of approximately 10
metres. Plankton is filtered onto a band of silk
that moves past an aperture at a rate that is
proportional to the speed of the ship. The silks
are brought back to the lab where they are cut
into 10 nautical mile sections and the phytoplankton
and zooplankton species counted and identified
under a light microscope.
Want to know more about
the survey?
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| Diagram showing how the CPR
is towed behind a 'Ship of Oppurtunity' |
Photograph showing a CPR ready to launch
at the stern of a 'Ship of Oppurtunity' |
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