THE BENTHIC LIFESTYLE

Classification by Location - The Benthic Zone

The Benthic Zone, (God bless it) is the division of the ocean that lies peacefully at the bottom. I bet you don't think the bottom is very interesting. But it turns out that a lot of really cool stuff tends to sink. Depending on how deep it sinks, it could end up in the intertidal littoral zone, the bathyal zone, the abyssal zone or the hadal zone. The littoral zone is subdivided into the inner and outer sublittoral zones. But that may be a little more information than you were looking for. (The supralittoral zone - the splash zone above the high intertidal is not part of the ocean bottom because it is not really at the bottom.) The inner sublittoral zone is ocean bottom near shore and the outer sublittoral zone is ocean floor out to the edge of the continental shelf. The bathyal zone covers the seabed on the slopes and down to great depths. That is where the abyssal zone begins. The hadal zone is the deepest seabed of all. It is found on the trench walls and floors.

What do they eat? Mostly phytoplankton and zooplankton. Sometimes algae and kelp. Early forms of sponges, mollusks, or crustaceans eat anything small and soft that's sitting on the rock or gets in their way and anything organic that floats by that they can get their "tubie" tentacles on. (Heed this advice when planing to take your favorite marshmallow to the beach.)

What do they do? They sink; they don't swim; they don't float; they stick to rocks; they also filter feed or scavenge; sometimes they move (often they move very slowly or remain stationary), but mostly they just stick to the bottom because, after all, they are benthic. Benthic organisms are sinkers. Plankton are FLOATERS and nekton are SWIMMERS!

Many familiar and unfamiliar animals inhabit the benthic zone. The most diverse habitat is that of the littoral zone.

Crabs

Crabs (Crustacea) are littoral zone inhabitants. The come in many forms and colors. This enables them to exploit the diverse habitats that exist along the sea coast. Most typical crabs are oval, rectangular or triangular with a front pair of legs ending in pincers and have four pairs of legs for walking. Male fiddleer crabs have a distinctive, large claw on the right front leg. Hermit crabs are readily identified by their habit of occupying snail shells to protect their vulnerable bodies.

Urchins and Sand Dollars

Two other common inhabitants of the littoral zone are the urchin and the sand dollar. The skeletons of the sea urchins (Echinoidea), which are shaped like doorknobs, and those of sand dollars which are pancake-shaped, are frequently washed up on the beach. (However, sometimes actual doorknobs and pancakes wash up on the beach, so don't make assumptions.) In life, seaurchins are covered with moveable spines and vary widely in color form, black and brown to white, green, red and purple. The closely related sand dollars have shorter and more numerous spines and a distinctive, starlike pattern on the back. In life, their coloration varies from dark to light brown, but their dried skeletons, like those of urchins, are chalky grey.

WHAT DO URCHINS DO?

Sea Stars and Brittle Stars

Among the best known of all marine invertebrates, the sea stars (Stelleroidea) are chractererized by their five-armed shape. They come in brown, green, red and orange. (On sale today at Macy's!) Sun stars, (a kind of sea star) are larger with up to fourteen arms. Fragile, fast moving brittle stars have long arms and a central disk. The arms of the Caribbean basket star branch repeatedly.

Limpets and Abalones

Both of these snail species have flattened shells, often pierced with holes that are used by the animal to strain water from its gills. Limpets sometimes have beaded, streaked or ribbed shells. Abalones have disk shaped shells with the exterior often covered by marine growth. The iridescent interior of the shell is used in jewelry.

Barnacles

The white barnacles seen at low tide covering rocks and pilings of the seacoast are sedentary crustaceans. The secrete tiny shells composed of many interlocking plates which often have a trap door opening at the top that can be closed for protection. In the Leaf Barnacle the plates are reduced and the body extended on a long stalk.

Sea Cucumbers and Polychaete Worms

These brilliantly colored flower-like Sea Cucumbers (Holothuroidea) have feeding tentacles and gills that give them their unusual appearance. They are sometimes white or brown, but often they are red or purple. These showy mucus-covered tufts surround the animals' mouth, and trap floating micro-organisms. The Ragged Sea Hare is also covered in mucus-covered filaments.

Wormlike Animals

A variety of wormlike animals of different sizes and shapes live on or in the ocean floor. Some, like the paddle worm, clam worm (Errantia) and stick-skin sea cucumber have protruding legs or spines, others like the nemerteans (Anopla), Limulus Leech (Tricladida) and Silky Sea Cucumber have smooth, flattened or rounded bodies while still others like the scale worms are covered with protective plates. Fire worms (also Errantia) can inflict a paiful sting and should not be handled.

Sponges and Corals

Sponges are large and colorful animals (Demospongiae) that are frequently found in tropical seas where they live in communities. These communities support other life. Red, purple, and blue sponges intermingle with yellow, brown and green corals (Anthozoa). Certain sponges and corals can sting severely and should not be handled. (Be especially cautious of scraping yourself on coral while snorling in shallow water.)

Sea Anemones

Among the most visually appealing of the invertebrates, the sea anemones (Anthozoa) are immediately recognizable by their unique form. They consist of a tube with a mouth at the top surrounded by unbranched tentacles. While many anemones live attached to a solid object, burrowing anemones excavate a hole in the ocean floor fromwhich their feeding tentacles extend. Certain corals have a shape similar to anemones.

Oysters, Mussels and Clams

In this group are many of those bivalve mollusks (Bivalvia) well known to both shell collectors and sea food eaters alike. Oysters, mussels and razor clams are enjoyed by many diners. There are some unusual bivalves like the piddocks with bulging bodies and tiny valves, the jingle shells with fragile transparent valves and the destructive shipworm whose valve is modified for burrowing through wood.

Periwinkles and Other Snails

Snails (Gastropda) are known for the spiral shell into which they can withdraw when not moving on their broad, muscular foot. The shape of a shail's shell ranges from high and conical to low and compressed. Many snail shells including the Northern Moon snail are rounded with low spires. Still others have higher or pointed spires such as the Chink Snail. Peculiar to this group are the Common Purple Sea Snail, which hangs suspened from the water's surface by a bubble net and wrom snails with their elongated spiral tubes.

Chitons

Chitons (Polyplacophora) are flattened mollusks most often found tightly clamped to a rock. The eight shells running down a chiton's back are held in place by a girdle that completely obscures the shell in some species. Chitons vary widely in color from black, brown, red, and green to vivid pink, aquamarine and violet.

  Foraminifera

SONNET TO FORAMINIFERA by David Samas Intricate lime spiral, old as stone, Spinning sections, delicate in curl, Sealed in glass, most ancient watery bone, What tiny tentacles did you unfurl. Whose trilibitic shape is in this shell; What colour graced its prehistoric youth; In what deep chasm did your live form dwel; And when you thought, what did you think of truth? Ambiguous and chalky, crumbling form, Grainy sand, your camouflage of rock, Hidden- flowing in a wild sea storm- Then die, persist, defy old nature's clock. And though it dies and from the waves it falls, They rise again, up mighty Dover's walls.

OOOOOOOOOOOOO, FORAMINIFERA PICTURES

OOOOOOOOOOOOOOOOO, OTHER PICTURES - AND INFO.

THIS IS A COOL LINK WITH A LOT OF PICTURES-ONLY IT'S IN FRENCH

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