Download Nutrition of a Sea Anemone

Nutrition of a Sea Anemone
Sea anemones live throughout the world's oceans,
from poles to equator, and from the deepest
trenches to the shores, as do fishes. But no one
kind of either lives in all places. Of nearly 1000
species of sea anemones, only 10 are host to
anemone fishes. Because the 28 species of clown
fishes live only with these 10 species of sea
anemones, they are found in the same places.
These anemones, and their anemone fishes, exist only in shallow water. That is
because within the cells of an anemone's tentacles and oral disc live microscopic,
single-celled, golden-brown algae (dinoflagellates) called zooxanthellae. Like all
plants, they require sunlight for photosynthesis, a process in which solar energy
is used to make sugars from carbon and water.
Some of these sugars fuel the algae's metabolism,
but most of them "leak" to the anemone, providing
energy to it. Therefore, the anemones that are
host to clown fishes must live in sunny places. So
these anemones live at depths of no more than
about 50 m, generally in clear water.
Nutrition:
The internal anatomy of anemones is simple. There is a gastrovascular cavity
(which functions as a stomach) with a single opening to the outside which
functions as both a mouth and an anus: waste and undigested matter is excreted
through the mouth/anus, which can be described as an incomplete gut.
Captured prey or other food particles are typically moved by the tentacles to
the mouth and the food is taken into the gastrovascular cavity through the
mouth. Digestion occurs within the gastrovascular cavity, and any undigestible
portions of the food are later ejected through the mouth/anus.
Anemones of some species are capable of absorbing nutrients directly from
seawater through their thin tissues, and that may be another source of nutrition
for these animals as well.