One Ocean, Many Worlds of Life - Convention on Biological Diversity

flickr/pacificklaus
cap to the bar-tailed godwit, a shorebird that makes the longest non-stop
flight <strong>of</strong> any bird, almost 12,000 kilometres from the coast <strong>of</strong> Alaska to New
Zealand without once pausing for food.
With the apparent exception <strong>of</strong> hydrothermal vent and cold-seep communities,
most <strong>of</strong> the life that survives in the dark, ocean depths relies for its
survival on life near the surface—or, more specifically, the death <strong>of</strong> that life,
which decomposes and falls as detritus known as “marine snow”. When whole
whale carcasses tumble to the bottom, they are known as “whale falls”, and
support communities <strong>of</strong> creatures that have apparently evolved specifically
to feed on them and on nothing else. At the same time, as the creatures <strong>of</strong>
the abyssal plain and hadal trenches themselves die, their nutrients also enter
the water, and upwelling from currents brings those nutrients in turn to the
surface. Multitudes <strong>of</strong> marine bacteria convert those nutrients into forms that
can then be used by the microscopic marine plants known as phytoplankton.
Phytoplankton use those nutrients for energy, in combination with carbon
dioxide from the atmosphere that they assimilate through photosynthesis.
A by-product <strong>of</strong> that photosynthesis, as with plants on land, is the release
<strong>of</strong> oxygen. In fact, half <strong>of</strong> all the oxygen in our atmosphere comes from the
“breathing” <strong>of</strong> phytoplankton.41
Without life in the ocean, there would be no life
anywhere on Earth.
Tunicates are marine filter feeders
with a saclike morphology
32 Marine BiOdiversity
The sunfish (Mola mola) is the heaviest known bony fish
in the world, with an average adult weight <strong>of</strong> 1 tonne
flickr/grantuking