The effects of heavy metals on the asexual reproduction of the annelid Aeolosoma headleyi Beddard (1888)

Chronic bioassays were conducted on the annelid Aeolosoma headleyi Beddard (l888) to determine the effects of heavy metals on asexual reproduction. Bioassays were conducted with the chloride and sulfate salts of zinc, copper, cadmium, cobalt, and nickel. Additionally, chromium, as potassium dichromate, was tested. Of these metals, only two, zinc chloride and copper sulfate, significantly stimulated reproduction at or below 0.01 ppm of the metal. All metals inhibited reproduction at high concentrations and none, except the two above, had any significant effect on reproduction at the sublethal concentrations tested. Hydrogen ion concentrations between 6 and 10 units had no effect on reproduction. The effects of the metals were not due to pH or osmotic effects. Subsequent studies were conducted with zinc chloride to determine its effect on zooid scissiparity. As zinc concentrations increase, the time for first zooid scissiparity decreased. Second bud formation was inhibited by zinc levels greater than 0.1 ppm. Normally the worm exhibits paratomy (release of zooid with a developed cephalic region). Above 7.0 ppm zinc, the worms also exhibit architomy where the cephalic region is not developed prior to scissiparity.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Zoology

Department dc:contributor.department

Zoology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1975

Author dc:creator

• Newman, James Preston

Chair dc:contributor.committeechair

• Buikema, Arthur L. Jr.

Committee members dc:contributor.committeemember

• Cairns, John Jr.
• Holt, Perry C.

• heavy metals
• asexual reproduction

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-06022010-020200

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42839