The Bathypelagic Zone
zone extends down
from 1000m to 4000m, which is getting pretty deep. The only
light is from bioluminescent organisms, and
the only food is what trickles down from above, or from eating
other animals. Although the water pressure at this depth is
considerable, there are many different representatives of the
normal marine groups: fish, molluscs, jellies, and crustaceans.
Sperm whales can dive down into this zone when hunting giant
squid. At these depths and below, most animals are either black
or red in colour. Because only the faintest blue/green light
penetrates this deep, and most bioluminescence is blue in colour,
red is not reflected and looks black. Pretty tricky.
The animals shown above
is one of the best known deep sea molluscs: the vampire squid.
The picture on the right is a defensive posture of this animal.
It completely inverts its tentacles, with their obvious webbing,
up over the rest of the body. The sharp spines on the underside
of the tentacles deter any potential enemies, as well as being
very useful for grasping and holding onto prey. Vampire squid
tend to drop down on unsuspecting victims from above and drape
them in the net formed by their tentacles.
The snake dragonfish is another highly specialized fish found in the deep sea. Like
the viperfish and dragonfish, this animal has large eyes, sharp
teeth, a wide mouth, a glowing lure, and other light organs along
the belly and near the eye. They live in the upper portion of
the bathypelagic, around 1200m, and may migrate up to hunt (hence
the ventral light organs for counter-illumination).
The angler fish is also
a pretty famous deep water animal. There are many kinds with
different looks, but all have a huge gaping mouth and a lure
which is lit in deep sea species. Anglers have teeth in their
throats to prevent prey from escaping. In these fish, the male
has become a tiny parasite that attaches to and lives on the
female, near her genitals. The range of these animals is from
the surface down to the darkest depths.
This odd-looking specimen
is a crustacean called an amphipod. Note that their body is red
and transparent for camouflage. Swarms of these small animals
scavenge whatever they can find in the deep ocean, and make up
an important food source for other animals of the deep. Larger
Although not technically
a pelagic (open ocean) animal, the slimestar does live in the
bathyl depths, on the slopes and plains of the sea bottom. Echinoderms
are very successful in the deep sea, some burrowing along the
bottom sifting through the mud and sand for organic debris, and
some flying above it in the abyssal zone (yes, flying). Slime
stars, like other sea stars, can get quite big. This one is around
Back to the Mesopelagic Zone
Back to the Abyssopelagic Zone
Back to the Deep Sea Page
to marine biodiversity index