Dive Pacific 175 Dec2020 Jan 2021
Dive Pacific, New Zealand's Dive Magazine , captures the best of diving in New Zealand and the Pacific. with adventures, top photos and expert technical advice
Dive Pacific, New Zealand's Dive Magazine , captures the best of diving in New Zealand and the Pacific. with adventures, top photos and expert technical advice
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Tiny animals and their<br />
critical importance on<br />
entire oceanic food webs<br />
By Jean-Michel Cousteau and Holly Lohuis<br />
Ocean Futures Society www.oceanfutures.org<br />
There is an inner galaxy of alien looking organisms on our own planet. Just night dive in open water<br />
with a bright light and witness for yourself the water column coming alive with all different forms of<br />
gelatinous plants and animals, referred to as plankton. It is indeed an unknown world to most of us,<br />
a world of wandering, drifting plants and animals, which provide the base of the very complex and<br />
extremely productive oceanic food web on which we all depend in so many important ways.<br />
The word plankton comes from<br />
the Greek, planktos, means to<br />
wander, or drift. These plants and<br />
animals make up a tremendous<br />
amount of the biomass in our oceans,<br />
yet the significance of how they<br />
influence key planetary functions is<br />
only being appreciated today as we<br />
are documenting major changes in<br />
our oceans.<br />
While many of these mysterious<br />
gelatinous organisms provide<br />
important opportunities to study the<br />
link between their abundance and<br />
the health of our oceans, there are<br />
many things we do know about their<br />
importance.<br />
…Every other breath we take is a gift from the sea…<br />
Phyto (plant) plankton<br />
Phytoplankton, plant plankton<br />
thrive in nutrient rich waters and<br />
are generally found in the sunlit<br />
waters of aquatic environments. Like<br />
terrestrial plants, phytoplankton<br />
contain chlorophyll and require<br />
sunlight in order to live and grow.<br />
Through the process of photosynthesis,<br />
phytoplankton take in CO 2<br />
and release oxygen. In fact, as much<br />
as 50% of our oxygen comes from<br />
phytoplankton. We can think of them<br />
as every other breath we take as a<br />
gift from the sea. They are one of the<br />
world’s most important producers of<br />
oxygen and they provide important<br />
food for the first order of consumers<br />
in the aquatic trophic food web,<br />
zooplankton.<br />
Plankton participate in the largest migration on the planet which<br />
happens under the cover of darkness every single night<br />
Zoo (animal) plankton<br />
Many zooplankton, or animal<br />
plankton, are grazers, filtering the<br />
planktonic soup of phytoplankton<br />
and other floating organic material.<br />
These animals participate in the<br />
largest migration on the planet which<br />
happens under the cover of darkness<br />
every single day. At night trillions of<br />
tiny plankton move from the deep<br />
scattered layer well over 300m deep<br />
towards the surface to feed. Come<br />
early morning hours, they then dive<br />
down to escape hungry mouths from<br />
above. So even though plankton<br />
are considered wanders, living a<br />
life adrift in the open ocean, they<br />
actually make an amazing vertical<br />
movement every single day.<br />
The richness of our seas is directly<br />
related to abundance and diversity<br />
of these drifting plants and animals.<br />
They not only provide the base of a<br />
rich web of life in the oceans, they<br />
are even preyed upon by the largest<br />
Inset Photo credit: Richard Murphy, PhD @Ocean Futures Society<br />
www.dive-pacific.com 17