Tuesday 21 May
Freshwater bryozoan (Lophopus crystallinus)
What’s the World’s Favourite Species?Find out here.
Freshwater bryozoan fact file
- Find out more
- Print factsheet
Freshwater bryozoan description
There are 11 described species of freshwater bryozoa in the UK; this bryozoan is the only member of the family Lophopodidae to be found here (3). Bryozoans are a group of small aquatic animals that live as colonies. The colony is comprised of zooids, or individual animals, that each contain a set of internal organs and a crown of tentacles, surrounding the mouth, which is used to gather food (2). The gelatinous colonies (4) of L. crystallinus form cream-coloured globular patches that grow to about 1cm in diameter. When L. crystallinus is submerged, the horseshoe-shaped crowns of tentacles of the component zooids are visible with the use of a hand-lens (2).
- Diameter: up to 1 cm (2)
Freshwater bryozoan biology
Bryozoans can reproduce either sexually, in which a free-swimming stage results, or asexually either through 'budding' or by the production of a dormant 'statoblast' stage. These statoblasts are packages of cells, in which there is stored food, surrounded by a tough layer. They can survive freezing and drying-out, and can persist for many years (6). L. crystallinus produces distinctive lemon-shaped statoblasts, which may allow the species to disperse over quite long distances (2). These statoblasts are approximately 1mm long and 0.5mm wide and range in colour from dark to light brown (2).Top
Freshwater bryozoan range
The freshwater bryozoan is found in various countries in Europe, but its precise status is presently unclear, although it is classified as Rare in the British Red Data Book (1). Since 1970 it has only been recorded from 5 sites in Norfolk, Oxfordshire, Humberside and Lancashire (3). Following recent work commissioned by Action for Invertebrates and further work conducted by Reading University, two sites are currently known, Barton Blow Wells in north Lincolnshire, and Chil Brook in Oxfordshire (5). Elsewhere, it also occurs in the Middle East, and America, where it is rare (4).Top
Freshwater bryozoan habitat
This species grows on the underside of various substrate types such as plants, rock, wood, plastic, glass, and shells in freshwater lakes, ponds, ditches and rivers (2).Top
Freshwater bryozoan status
Classified as Rare in Great Britain (2).Top
Freshwater bryozoan threats
Water abstraction and eutrophication are thought to have affected this species, along with over-zealous tidying of waterways (3). Habitat loss and increased boat traffic are also likely to have played a part in the decline (4).Top
Freshwater bryozoan conservation
This bryozoan is a priority species under the UK Biodiversity Action Plan; the Species Action Plan aims to maintain all populations of the freshwater bryozoan and assist an increase in the species' range by 2010, perhaps using artificial substrata to aid research and monitoring (3). One of the sites that supports this species is designated a Site of Special Scientific Interest (SSSI), and therefore receives a degree of protection (4).Top
Information authenticated by Dr Beth Okamura and Samantha Hill of Reading University:
- Of asexual reproduction: reproduction that does not involve the formation of sex cells ('gametes'). In many species, asexual reproduction can occur by fission (or in plants 'vegetative reproduction'); part of the organism breaks away and develops into a separate individual. Some animals, including vertebrates can develop from unfertilised eggs, this process, known as parthenogenesis gives rise to offspring that are genetically identical to the parent
- Type of asexual reproduction (reproduction that does not involve the formation of sex cells), in which new individuals develop from the parent organism, forming a swelling similar in appearance to a bud. The 'bud' slowly separates from the parent as it grows.
- A group of organisms living together, individuals in the group are not physiologically connected and may not be related, such as a colony of birds. Another meaning refers to organisms, such as bryozoans, which are composed of numerous genetically identical modules (also referred to as zooids or 'individuals'), which are produced by budding and remain physiologically connected.
- Nutrient enrichment of aquatic or terrestrial ecosystems.
- National Biodiversity Network Species Dictionary (September 2002) http://www.nhm.ac.uk/nbn/
- S. Hill & Dr B. Okamura (2003) Reading University. Pers. Comm.
- UK Biodiversity. Species Action Plan. (September 2002): http://www.ukbap.org.uk
- Bratton, J. H. (Ed) (1991) British Red Data Books: 2 Invertebrates other than insects. JNCC, Peterborough.
- Buck, D. (2003) The Environment Agency. Pers. Comm.
- Allaby, M. (1991) The Concise Oxford Dictionary of Zoology. Oxford University Press, Oxford.
Play the Team WILD game
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.