Marine Worms

Lecture notes 

Worms...the deep sea worm snail Neopelina galatheae is the oldest living creature with fossils proving they existed exactly in the same form 500 million years ago....Nematode sea worms are the most numerous of all sea or land animals with an estimated population of 40 septillion. The convoluta worm feeds only once in its life feeding off a special algae and is sustained by starches made through photosynthesis by the algae it swallowed.

Phylum Platyhelminthes...flatworms...3 layers, organs, no anus. They are the only worm like creature without an anus, use cilia on the bottom to glide along the surface and have muscle contraction in the body walls. These animals are worm like...tapeworms, planaria flukes and marine flatworms. There is a free-living flat worm that lives in the book lungs of a horseshoe crab, a tapeworm in the digestive system of the whiting fish some live on the beards or threads of mussels and one lives on the sandy beaches in France...bright green!

Christmas tree worm spawning video

Phylum Nemertea...ribbon worms...900 species..most marine. Like flatworm but has one way digestive system and circulatory system . Usually very highly colored and found burrowing in sand and mud on the shore or in crevices of rocks. Some can swim and most capture their prey. The most distinctive feature is a proboscis, a long fleshy tube to entangle prey . Though common, some are nocturnal and not usually seen, and others are found under rocks at low tide. They are very elastic. They are of little economical or ecological importance.

Phylum Nematoda or round worms usually found in sediments , especially rich organic matter. Many can even live nicely in tissues of other organisms. The actual number is debatable 10-15,000 but maybe more like 1/2 million.

Phylum Annelida segmented worms 13,000 species mainly the Polychaetes make up the marine annelids. (6,000 species) They have short extensions or parapodia with stiff sharp bristles or setae often with gills on them for respiration. The life cycle includes a trochophore larval feeding stage...like other groups of invertebrates. They include sandworms, bloodworms, fanworms or featherduster worms, palolo worms and a variety of tube dwelling worms. These can make tubes from mucus, protein, mudgrains, bits of seaweed, shell fragments etc.. Feeding methods relate to the locomotion and many are either suspension feeders/deposit feeders or just plain carnivores.

Sand Worms   Worm cases

LOPHOPHORATES

Three phyla of marine animals, Ectoprocta, formally Bryozoa, Brachiopdoa and Phoronida, are characterized by a lophophore, a circular or U-shaped ridge around the mouth bearing either one or two rows of ciliated, hollow tentacles. Because of this unusual feature, they are thought to be related to one another. The coelomic cavity of them lie within the lophophore and its tentacles and the anus is always elsewhere. The lophophore functions in these animals as a food collection organ and as a surface for gas exchange. They are attached to the substratum or move slowly, using the cilia of the lophophore to capture the plankton on which they feed.

Phylum Phoronida resemble common tube worms seen on dock pilings. Look like polychaete worms. They secrete a chitinous tube within which it lives out its life and they also extend tentacles to feed and quickly withdraw them when disturbed but that's where the resemblance to the tube worm ends. There is no straight tube within a tube but a U-shaped gut within a sac. Only 10 species are known ranging in length from a few mm to 30 cm. Some lie buried in sand and others attach to rocks signally or in groups.

Phylum Ectoprocta (Bryozoa) look like tiny short versions of the phoronoids ..small .5mm and colonial and called moss animals. The new name, ectoprocta refers to the location of the anus (proct) which is external to the lophophore. 4000 species include marine and freshwater forms..only non-marine lophophores. Most live in shallow water but some live at 18,000 feet.

Individuals secrete a tiny chitinous or limestone chamber, ZOECIUM, attached to other members of the colony and to rocks. Individuals communicate chemically through pores between chambers.

Bryozoans- Moss animals or sea mats..sedimentary or bottom dwelling. They live attached to the substratum, either on rocks or empty shells, or on tree roots, weeds or where ever they can hold on to. They are almost all marine, found from the shore downwards in all parts of the world, they are colonial, meaning individuals are termed zooids live together in a common mass. Their taxonomy depends on the sizes shape, and organization of the colonies. The arrangement of the zooids on the colonies is also highly variable. Some are important as pests as they can foul up piers, pilings, buoys and ship hulls.

PHYLUM BRACHIOPODA or lampshells

Bottom dwelling clamlike organism that are permanently attached to the substrate and possess a complex lophophore, which consists of two spiral ciliated tentacles resembling arms.

The LOPHOPHORE is a circular or U-shaped ridge around the mouth bearing either one or two rows of ciliated, hollow tentacles.

The lamp shells resemble clams because they have two shells but these shells are hinged so that one shell covers the top and the other its bottom side (dorsal and ventral whereas the clam its the left and right side. Many species attach to rocks or sand by stalks that protrude from within the shell, a contractile muscle called the PEDUNCLE, while others become cemented by shell secretions to the substratum. These shells feed on particles suspended in the water, the cilia creating water currents sweeping food particles onto the lophophore which lies within the shell (as opposed to others that are outside). There are only 300 species of brachiopods existing today but more than 30,000 species are known as fossils with the genus Lingula having fossil records back to 500 million years.

Reading with Questions

. Tube Worms

1. Where was the giant tube worm found?

2. How do pogonophorans feed?

3. Where do bacteria get their energy?

4. How are shrimp around the vents different than the normal shrimp near the surface?

5. How hot is the water running out the vents?  _______What about water about a foot away from the vent?

6. What is the most prevalent chemical dissolved in vent water?

7. How many bacteria are in an ounce of  tissue?

8. How do tube worms reproduce?

9. What happens when the vents stop flowing?

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