Life began in the ocean billions
of years ago. Most of the life forms which currently
occupy the earth had their start as single-celled organisms,
forced into evolution by an ever-changing environment.
Even now, species are disappearing and appearing without
our knowledge.
There two types of aquatic
biome, the marine regions, and the freshwater regions.
The marine regions
The marine regions are divided
between coral reefs, estuaries, and oceans.
Oceans represent the largest and most diverse of the ecosystems;
salt water evaporates and turns to rain which falls on the land
regions, while most of the oxygen in our atmosphere is generated
by algae. Algae is also responsible for the absorption of
large amounts of carbon dioxide from our atmosphere.
The ocean connect to the land
via what is called the inter-tidal zone. Because of
rising and falling tides, coastal areas are constantly changing,
with various animals and marine plants living at the bottom, and
on the seashore. Rocky coastal areas are host to fewer
species due to the fact that only the highest of tides will
reach the top of the cliffs.
In the warm shallow waters
which line the continents and surrounding islands lie barriers
called coral reefs. Coral is a living organism consisting
of animal and algae tissues. Corals feed like plants through the
process of photosynthesis, and like animals, they also use their
tentacles to catch micro-organisms. The coral reef is also
host to other species such as starfish, octopi, and other
mollusks.
Out in the open ocean is
what is called the pelagic zone, which is host to many
species of fish and marine mammals, plankton ,and some floating
seaweed. the area underneath the pelagic zone is called the
benthic zone, or deep-sea, and is host to silt, sand, and
slowly decomposing organisms. This area is very cold due
to its depth, which is untouched by the light of the sun. There
are few plants at this level, and the animals include mostly
bottom feeding organisms such as starfish, anemones, sponges,
amongst others, as well as various micro-organisms.
The deepest part of the ocean
is called the abyssal zone. it is host to many species of
invertebrates and fish including such oddities as the
coelacanth, a prehistoric fish once thought extinct and found in
the depths of the Indian Ocean, and other fish that glow in the
dark via a process called photoluminescence.
The abyssal zone is very cold, and highly pressurized. Its
floor features vents formed by spreading tectonic plates which
release hydrogen sulfide and
other minerals which are consumed by the bacteria which are then
consumed by other micro-organisms, which are in turn, consumed
by the fish, and so on.
