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answers to Annelida questions!
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 Bamboo
Worms - Received from Silva in Ucluelet, B.C.
Q:
Thanks for answering my limpet question! Here's another one:
about marine worms.
Every few months there is a huge drift of what I think are
worm tubes washed up on Long Beach. The tubes are empty, translucent,
segmented, and only a few millimetres in diameter. Locally
they are called "bamboo worms" What I'm curious about
is: are they worm tubes? If yes, why do they wash up in huge
drifts every few months? Are the worms shedding their tubes
or do they die off?
A: Yes, what you found on
the beach are Spiochaetopterus costarum (commonly known
as the Bamboo worm) tubes. Bamboo worms are members of a family
of polychaete worms called Chaetopteridae and are found in rocky
subtidal habitats. All chaetopterids have translucent tubes and
usually occur in large aggregations. Spiochaetopterus costarum is
distinctive because of its segmented tube. Since tubes of bamboo
worms are found on the surface of the substratum, any disturbance,
especially storms, can easily dislodge pieces of the tube or
the entire tube. The tubes you see washed up on the beach are
not shed by the worms, but the empty tubes do not indicate a
dead worm either. Often when there is a disturbance, bamboo worms
will contract so that their bodies are located near the bottom
of the tube, leaving the empty top part of the tube to be broken
off and washed away, or eaten by a predator. They can build new
tubes if their old one is damaged. It should be noted that the
common name of "bamboo worm" is often applied to members
of the family Maldanidae, which are actually quite different
from chaetopterids. These have tubes with thick walls made of
mud and fine sand grains, and are not translucent and thin-walled
like those of chaetopterids.
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Polycheate
Worm Reproductive Phenomenon - Received from Robert
Lewis in Winnipeg
Q: My name is Rob Lewis
and I'm a second year bio major at the University of Winnipeg.
I (and three other universities) are having trouble identifying
an animal. One of my professors said that you folks would be
the people to ask. I'm not sure if I'm emailing the right person
about this but I'm sure you could let me know who to deal with
at the station.
Well, here's the situation, a friend of mine is a professional underwater cinematographer.
He was filming during a night dive somewhere in central America(I don't excactly
recall where) when out of the darkness came these thin, roughly fifteen foot
worms. The worms swam in a cork-screw fashion towards the divers. When they
got to close to the light they literally exploded into a green silty substance.
Any pieces of the initial organism still intact continued to swim about. Ian
(my friend) managed to attain about five minutes of high quality footage of
the animals.
In the past three years Ian has been trying to identify these creatures without
any luck. If you or any of your colleagues would be interested in trying to
identify the animals I would be more than happy to mail a copy of the tape
to you. Please let me know. Thanks.
A. Most likely, the event
that your friend Ian observed and filmed was a reproductive frenzy
of
polychaete worms. We have a related phenomenon here on the BC coast each summer.
A few species of polychaetes belonging to the genus Nereis will swarm
on certain summer nights. Both males and females swim near the surface and
their segments break up dispersing gametes that will fertilize and develop
as plankton in the sea. The spawning of Nereis pelagica is especially
spectucular, as they can form swarms of thousands of worms. Nereis brandti also
spawns at the surface, and they are so big (up to approximately 3 cm in diameter
and 60 cm long) that they look like a mink swimming in the water from a distance.
Your
observed event probably involved sexually mature worms of both
sexes swarming (they generally
are attracted toward the moon, -- your friend's dive lights probably
substituted for that). The posterior portion of each worm was
probably an "epitoke", a gamete-filled sequence of
segments, that suddenly breaks apart releasing the gametes in
the thick of the frenzy of worms. The anterior portion of the
animal probably then swam offto return to the coral reef.
In
the South Pacific there is a similar event where "Palolo" worms
swarm precisely on the 7th night after the first full moon following
the autumnal
equinox. The Palolo worms are reported to be 40cm or more, and
they are actually only the epitoke portion (the head end remains
down in the coral reef). You might check the textbook by Pears,
Pearse, Buchsbaum, and Buchsbaum LIVING INVERTEBRATES, 1987 edition
or later. On page 413 and 414 of this edition, there are pictures
of the worms.
Answered by David Denning,
BioMedia Associate and Tara Macdonald, polychaetologist.
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Nereis
virens (Polychaeta) - Received from Tyler in Lake
George, New York.
Q: I am currently doing some research on Nereis virens with the assistance
of Dr. Carl Merrill and Dr. Tom Trott, both with Suffolk University. I am attempting
to determine what particle size in the substrate will be most advantageous
to worm growth and health in mariculture. If you could give me any info or
links to info on this polychaete it would be greatly appreciated.
A: Nereis
virens inhabits
muddy sand areas of the littoral and sublittoral zones in both
marine and estuarine habitats. This species is found throughout
the temperate regions of the northern hemisphere. N. virens lives
in both sandy and gravelly sediment types, and has been kept
experimentally in sand sediment sieved between 500 and 1000
mm using Endecott sieves and then washed with running sea water.
This species does not appear to do well in muddy sediment,
at least under laboratory conditions.
References:
Bass, N.R. and A.E. Brafield.
1972. The life-cycle of the polychaete Nereis virens.
Journal of the Marine Biological Association of the U.K. 52:
701-726.
McLeese, D.W., C.D. Metcalfe
and D.S. Pezzack. 1980. Uptake of PCBs from sediment by Nereis
virens and Crangon septemspinosa. Archives of Environmental
Contamination and Toxicology. 9: 507-518.
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Clam
worms? - Received from Jessica in Duncan, B.C.
Q. : what is a clam worm? could you please tell me what it is. Thanks
Jessica
A:This
was a tough one! It points out the difficulty that we can sometimes have with
so-called "common names" for
animals and plants. A common name in one area may not be the same anywhere
else! In this case, the name "Clam Worm" does not appear in any of
our local field guides to marine animals, and nobody that we contacted could
say for sure what it might be, but we do have a couple of guesses.
You might be talking about the Shipworm, Bankia setacea.. This animal
is not really a worm at all, but is actually a related to a clam! (so perhaps
some people might call it a "clamworm") It burrows through wood by
rocking its rough shells and carving out a smooth channel. A piece of wood
that has been floating at sea for a long time may sometimes contain the burrows
from these animals, and sometimes live animals inside. The burrows are about
the thickness of a pencil, and have material inside that looks like it was
made out of clamshell.
Another possibility for your mystery animal might be the worm, Nereis vexillosa.
This is a large worm, up to 15 cm in length, and can be bluish or greenish
in colour. It is often seen in quiet bays, especially at night, as it is attracted
to the lights around docks. It burrows into muddy and sandy areas, often around
mussel beds and in areas where there are likely to be clams. These worms may
be referred to as "clam worms" by some people.
A common name for an animal is essentially a name that has been made up without
regard for accuracy or duplication. A "scientific name" is a two
part name that has been agreed upon by scientists all over the world. Only
one animal in the whole world can have this two part name, which enables scientists
from all over the place, who may speak different languages, to communicate
with each other. It helps to avoid confusion! A scientific name is written
in Latin, and is printed in italics - genus first, then species. For example,
your genus and species is Homo sapiens.
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Worm
feeding - Received from Emily in Indiana.
Q: How are earthworms and amphitrites alike regarding what they eat but very
different in how they obtain their food? Why have the amphitrite evolved its
particular way of getting food?
A: This
is quite an interesting question, and needs some background first
for those who may be unfamiliar with the genus of worms known
as Amphitrite. The common earthworm (for example, the
genus Lumbricus) and the worms in the genus Amphitrite are
both in the Phylum Annelida (segmented worms). However, they
are in different classes - earthworms are in the class Oligochaeta,
while Amphitrite are in the class Polychaeta. To put this in
perspective, they are as distantly related as a bird is to a
mammal.
Both of these worms are deposit feeders. They take sediment or dirt into their
mouths, and digest the organic material found in this sediment. Where they
differ is in where they live, and how they obtain the sediment to eat.
Amphitrite are in the family Terebellidae, and live in soft sediment on the
ocean floor. They are selective deposit feeders. Special head stuctures extend
over the ocean substrate, and move back and forth. Deposit material sticks
onto mucous found on these structures, and is conveyed back to the mouth where
it is eaten. The worm does not have to leave it's burrow to feed. Earthworms
crawl through the soil, eating sediments or dirt directly. The pharynx acts
like a pump, drawing material into the mouth.
We are not aware of any speculation as to why the Terebellid worms have evolved
the selective deposit method of obtaining food. It is possible that on the
ocean floor, organic debris is located primarily on the surface, so these worms
concentrate their food gathering activity only on the top layer of the substrate.
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Mysterious
calcified clusters - Recieved from Greg in Malvern,
PA
Q: When diving on a wreck
in the bay behind Atlantic City, New Jersey, the sunken ship
was covered with calciferous clusters of small white tubules
(~0.2 - 2.0 mm dia and 1 - 10 cm in length). What are these
stuctures? Are these the exoskeleton of Teredo navalis ?
A: Teredo
navalis is actually
a mollusc specialized for boring into wood. Although they line
their borrows with calcium carbonate (it's not really an exoskeleton),
these linings are in the wood, and usually flake off when the
animal dies and the borrow is exposed to sea water. If the
ship's hull was metal, it definitely wasn't T. navalis.
What you are seeing is likely the result of tube-dwelling worms
which excrete a tough calcified tube for protection. There
are many different types out there. I suggest you look up a
local intertidal field guide at a library or bookstore to see
exactly which species it is.
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