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BRYOZOANS
Bits and Bobs
Helen C. Dyer
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Navigation
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This website:
In developing my website on bryozoans, I wanted to
avoid mirroring (repeating) the same information that can be found at many EXCELLENT
bryozoan websites. [However, even with the best intentions there will be some
redundancy (there are only so many ways to describe what a bryozoan is!)]. Instead, I decided to provide you with
some very basic information, then provide you with links to other sites for a more in depth look
at bryozoans. You will find links on: bryozoans (Excellent sites), Literature searches on
bryozoans (Speaking from Experience), Using
the SEM (Close-up look at bryozoans), Taxonomic Classification Schemes
(Identification of Bryozoans), My Research,
My Curriculum Vitae, Other Interests [My Favorite Links to
museums, etc), and a Link to other
personal bits and bobs. My hope is that you will find this website useful.
I have tried to be as accurate as possible at all times, however, there is so
much current research being accomplished that information may become out of date
rapidly. Bryozoans are fascinating creatures and whether you are serious about studying
them or just curious about them, the fact that you are here is a great start!
Cheers, Helen
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So what exactly is a Bryozoan and why should anyone care?
Bryozoans are sessile (mostly), colonial organisms that form an external calcareous skeleton, such that they are often mistaken for corals . They are found in both marine and freshwater systems throughout the world. Bryozoans can be found from tidal areas to benthic (sea floor), streams and rivers, and from the Arctic to the Tropics. They attach themselves to all sorts of substrates; they can be found on rocks, shells, seaweed (and other plants), other organisms, free drifting and interstitially.
Bryozoans belong to the phylum bryozoa and along with phylum brachiopoda and phylum phoronida are assigned to the superphylum Lophophorata or Lophotrochozoa (depending on which research line you follow). Although the organisms are morphologically different, their assignment to a superphylum is based upon the common character of a U-shaped lophophore . The superphylum of lophophorata has been found to have embryonic developmental characteristics of both the deuterostomes and the protostomes, which has led to some debate as to their phylogenetic relationship with other invertebrates. Recent DNA studies have indicated that the lophophorates are indeed protostomes, however, this determination is still subject to further research.
Bryozoans first appeared in the fossil record in the Ordovician period, the only modern phylum to appear after the Cambrian. There are approximately 5000 extant bryozoan species comprising three Classes, with about 16000 known extinct bryozoans comprising two classes. Bryozoans are composed of a polymorphic, microscopic animal (the zooid) that secretes a calcareous macroscopic skeleton (the zooecium) in which it resides. Bryozoan forms may be encrusting, dendroid, fenestrate, foliaceous, or solid/massive. The framework of the skeleton varies in shape and size depending upon the class and in some instances there can be variation of the growth form and size within species, due to environmental conditions. Because of these variations, identification of bryozoans can be challenging (especially fossil forms). Bryozoan Glossary of Terms
Bryozoans are invertebrates, and like corals, sponges and other invertebrate organisms are sensitive to changes in salinity, temperature, turbidity, pH, and other environmental conditions (pollution). When tide pools and coral reefs are heavily polluted or damaged by other human interactions, invertebrates are the first organisms affected, due to their lack of (or limited) locomotive abilities and their limited environmental niche (what they eat and the environmental conditions they can tolerate). Bryozoans are important organisms for a number of reasons (not just the fact that they are fascinating to study); they are documented fouling organisms (found on piers, pilings, and ships); they are a food source for other marine organisms such as nudibranchs, Chitons, gastropods, sea spiders, sea urchins, angel fish and puffers (to name a few); they have possible medical use in the form of anti-cancer properties (Bryostatin); and as a colony it has been suggested that they can filter up to 48,000 gallons of seawater a day (this depends upon the size and number of colonies within a given area). Reference List
Bryozoan images © Wim van Egmond/ Micropolitan Museum:
http://www.microscopy-uk.org.uk/micropolitan/index.html
I have tried to ensure the accuracy of all of the information provided in this website. All pictures are either the sole property of this website or being used with the written permission of the owner or their representative. No part of this website may be reproduced without the expressed written permission of the administrator.
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Page Last Updated January 2005