Influences of a <i>Cladophora</i> Bloom on the Diets of <i>Amblema Plicata </i>and <i>Elliptio Dilatata</i> in the Upper Green River, Kentucky

<p>Freshwater mussels are the most imperiled group of freshwater invertebrates globally. Recent research suggests a better understanding of mussel feeding ecology may facilitate and improve conservation efforts. The use of stable isotopes is becoming an increasingly common method to study aquatic food webs. Carbon (C) and nitrogen (N) are two of the most frequently employed elements in food web studies. Differences in natural abundance of¹³C/¹²C can indicate which food sources are the basal sources of carbon incorporated into a consumer’s tissue, while the ratio of ¹⁵N /¹⁴N provides a method of assessing trophic position within a food web. Attached macroalgae, including the genus <em>Cladophora</em>, may be the dominant primary producers in running water systems. <em>Cladophora</em>, however, has not yet been indicated as a prominent assimilated food source for freshwater mussels. The overall purpose of this study was to assess if the diet of two common Green River mussel species, <em>Amblema plicata</em> (Say) and <em>Elliptio dilatata</em> (Rafinesque) were influenced by the seasonal change in availability of <em>Cladophora</em> during a summer-autumn rapid growth period. Two specific questions were asked: 1) Are the assimilated diets different between control and treatment areas, and 2) are the assimilated diets influenced by differing <em>Cladophora</em> levels across the study period? A mesocosm approach was employed in order to manipulate <em>Cladophora</em> levels within a treatment area. Seventy-two mussels, 36 each species, were sampled across four months,twice between control (= reach-scale, heavy <em>Cladophora</em> cover) and treatment (= localscale removal of <em>Cladophora</em>) areas. The freeware program, IsoSource, a concentration weighted linear mixing model, was used to determine the potential contribution of potential food sources to the diet of both mussel species. IsoSource revealed that <em>Cladophora</em> was the primary assimilated food source for both species across the study period. Although assimilated diets were not different between control and treatment areas, diets were, however, influenced by <em>Cladophora</em> availability across time. The results of this study indicate that, during bloom conditions,<em> Cladophora</em> is the primary carbon source for both <em>A. plicata</em> and <em>E. dilatata</em> and may form the base of food webs in the upper Green River.</p>

Name thesis:degree_name

Master of Science

Discipline thesis:degree_discipline

Department of Biology

Year

2012

Author dc:creator

• Yates, Jennifer Maria

Contributors dc:contributor

• Dr. Scott Grubbs (Director), Dr. Albert Meier, Dr. Michael Collyer

• stable isotope analysis
• feeding ecology
• aquatic food webs
• freshwater mussels
• Aquaculture and Fisheries
• Biology

Repository record dc:identifier

https://digitalcommons.wku.edu/theses/1221

OAI identifier oai:identifier

oai:digitalcommons.wku.edu:theses-2224