The lethal and sublethal effects of aldicarb on the estuarine grass shrimp, Palaemonetes pugio

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dc.contributor.authorDvorak-Grantz, Andrea Lynnen
dc.contributor.committeechairBuikema, Arthur L. Jr.en
dc.contributor.committeememberFell, Richard D.en
dc.contributor.committeememberLauth, John R.en
dc.contributor.committeememberTurner, Bruce J.en
dc.contributor.departmentBiologyen
dc.date.accessioned2014-03-14T21:50:09Zen
dc.date.adate2008-11-18en
dc.date.available2014-03-14T21:50:09Zen
dc.date.issued1996-11-05en
dc.date.rdate2008-11-18en
dc.date.sdate2008-11-18en
dc.description.abstractEstuaries, an important facet of coastal regions, are highly productive natural systems, frequently acting as drainage basins for various pollutants such as agricultural runoff. The estuarine grass shrimp, Palaemonetes pugio, has been shown to be a sensitive indicator of pesticide exposure. In this study, emphasis was placed on the quantification of the lethal and sublethal effects of aldicarb on three different life stages of P. pugio. Acute 96-h toxicity tests were conducted with newly hatched larvae, 22-d old larvae and adult grass shrimp to determine lethal toxicant ranges. LC₅₀ values were 85.0 ug/L for newly hatched larvae, 70.7 ug/L for 22-d old larvae and 125.4 ug/L for adults. The impact of aldicarb on specific neurological functions in the grass shrimp was examined using an acetylcholinesterase assay. Acetylcholinesterase (AChE) activity was reduced in the larvae after exposure to acute concentrations of aldicarb. Mean whole-body AChE activity for the newly hatched and 22-d larvae was significantly lower from the controls (P=0.009). Conversely, mean whole body AChE activity in the adult shrimp was not significantly different from the controls at any concentration (P=0.401), although there was a trend towards reduced activity at 50 and 100 ug/L exposures. A behavioral study was conducted to examine the ability of adult grass shrimp to detect and avoid aldicarb-treated seawater. Behavioral responses were measured in a modified steep gradient chamber. A partition divided the chamber, creating three distinct areas: 1) seawater 2) aldicarb-treated seawater and 3) mixing. There were significant differences between the control and exposed adult shrimp in the amount of time spent in the mixing area (P<0.05). Aldicarb exposed shrimp spent, on the average, 20% more time in the mixing area than the controls. Additionally, exposed shrimp spent significantly more time facing downstream, away from the toxicant source (P<0.05). Exposed shrimp displayed increasing hyperactivity and attempted to jump out of the chamber.en
dc.description.degreeMaster of Scienceen
dc.format.extentix, 61 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-11182008-063315en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11182008-063315/en
dc.identifier.urihttp://hdl.handle.net/10919/45852en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1996.D867.pdfen
dc.relation.isformatofOCLC# 36436534en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectPalaemonetes pugioen
dc.subjectbehavioren
dc.subjectacetylcholinesteraseen
dc.subjectgrass shrimpen
dc.subjectaldicarben
dc.subjecttoxicityen
dc.subject.lccLD5655.V855 1996.D867en
dc.titleThe lethal and sublethal effects of aldicarb on the estuarine grass shrimp, Palaemonetes pugioen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineBiologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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