Filtration and growth rate of Lake Mead Quagga Mussels (Dreissena bugensis) in laboratory studies and analyses of bioaccumulation
by Link, Carolyn Louise, M.S., UNIVERSITY OF NEVADA, LAS VEGAS, 2010, 106 pages; 1479079

Abstract:

In January of 2007, Quagga Mussels (Dreissena bugensis) were identified in Lake Mead, Nevada. An aquatic invasive species, these mussels can significantly alter ecosystems. This study sought to quantify three ecological traits of the species through a series of laboratory experiments and analyses, providing information both for comparison with Dreissena in other locations, as well as for limnologic management decisions. Filtration rate of quagga mussels was quantified using algal strains and natural seston. Two strains of green algae, Nannochloris and Scenedesmus were used to determine mussel filtration rates with a spectrophotometer. Quagga filtration rates of collected Lake Mead seston were determined with a turbidity meter. All clearance rate studies included both a large and small mussel size class, with maximum filtration rates for small mussels from 1167 mL/g dry mussel/hr for algae, and 496 mL/g dry mussel/hr for large mussels filtering algae. Ecologically related to the clearance rate, the growth rate of quagga mussels was also quantified during a 32 day trial in Lake Mead (Lake) water and also in lake water supplemented with the above mentioned algae strains, illustrating potentially higher growth rates than currently occur in Lake Mead could be possible depending on lake algae levels. Mussel growth was 0.35 day-1 in natural seston, and 1.42 day -1 in supplemented lake water. Implications of mussel growth and filtration led to the study of quagga mussels’ potential for concentration of trace elements of concern in the tissue, and feces and pseudofeces of mussels. The contaminant levels in these biological samples were compared to sediment samples from both Boulder Beach at Lake Mead and from the Las Vegas Wash, a potential source of contaminants that flows into Lake Mead. All samples were processed via EPA Method 3050B and elemental analysis was completed with ICP-OES. While a large spectrum of elements were investigated, elements of concern in which statistically higher levels were observed in mussel tissue or pseudofeces and feces over sediment from the adjacent location included arsenic, molybdenum, lead, and selenium. Based on the results, it can be concluded that quagga mussels filter more when smaller in size and still growing, and they filter more when exposed to lower quality foods, and could potentially grow and expand their population impact if lake parameters change. Contaminant data illustrated that for selenium and arsenic bioaccumulation is appearing in mussel tissue, while for lead and molybdenum bioaccumulation is occurring in mussel excretions, potentially leading to changes in benthic composition. Future research studying assimilation, particle filtration, and the impact of seasonal and climate changes on filtration and concentration rates would be valuable for determining the mass balance impact of this species on aquatic environments in the Southwest.

 
AdvisersCharalambos Papelis; Kumud Acharya
SchoolUNIVERSITY OF NEVADA, LAS VEGAS
SourceMAI/ 48-06, p. , Aug 2010
Source TypeThesis
SubjectsEcology; Water resources management; Limnology
Publication Number1479079
Adobe PDF Access the complete dissertation:
 

» Find an electronic copy at your library.
  Use the link below to access a full citation record of this graduate work:
  http://gateway.proquest.com/openurl%3furl_ver=Z39.88-2004%26res_dat=xri:pqdiss%26rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation%26rft_dat=xri:pqdiss:1479079
  If your library subscribes to the ProQuest Dissertations & Theses (PQDT) database, you may be entitled to a free electronic version of this graduate work. If not, you will have the option to purchase one, and access a 24 page preview for free (if available).

About ProQuest Dissertations & Theses
With over 2.3 million records, the ProQuest Dissertations & Theses (PQDT) database is the most comprehensive collection of dissertations and theses in the world. It is the database of record for graduate research.

The database includes citations of graduate works ranging from the first U.S. dissertation, accepted in 1861, to those accepted as recently as last semester. Of the 2.3 million graduate works included in the database, ProQuest offers more than 1.9 million in full text formats. Of those, over 860,000 are available in PDF format. More than 60,000 dissertations and theses are added to the database each year.

If you have questions, please feel free to visit the ProQuest Web site - http://www.proquest.com - or call ProQuest Hotline Customer Support at 1-800-521-3042.