Access Type

Open Access Dissertation

Date of Award

January 2018

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Biological Sciences

First Advisor

Donna R. Kashian

Abstract

Quagga mussels (Dreissena rostriformis bugensis) originate from brackish waters of the Ponto-Caspian area and are nuisance invasive species in North American and European freshwaters. Their invasion has caused major economic and ecological damages in the Laurentian Great Lakes. Through selective filter feeding, quagga mussels have promoted the growth of cyanobacteria. Harmful cyanobacteria blooms have the potential to produce toxins, which can be toxic to humans and wildlife. Although quagga mussels can increase the prevalence of cyanobacteria blooms, it is unknown how they are physiologically affected by cyanobacteria and understanding these dynamics can be useful in the management of this invasive species. To evaluate the effects of cyanobacteria on quagga mussels, I evaluated reproduction, early development, and physiological and cellular stress in several laboratory studies. Sperm motility was assessed using a novel optical bioassay to record sperm movement and measure distance, velocity, and acceleration of individual sperm cells in the presence of eleven cyanobacteria cultures and the purified cyanotoxin, microcystin. Sperm motility was reduced in the presence of four cyanobacteria cultures, but was unaffected by microcystin. Next, I evaluated spawning success by inducing quagga mussels to spawn using serotonin and exposing them to thirteen cyanobacteria cultures and found one culture of Aphanizomenon flos-aquae hinders gamete release. I then combined quagga mussel sperm and eggs in cyanobacteria solution to determine if cyanobacteria would prevent successful fertilization and found six cultures reduced fertilization rates compared to the control. To determine how cyanobacteria influence the sensitive larval veliger stage of dreissenid mussels, I collected veligers off shore from the Detroit River, MI, USA and observed mortality in the presence of five concentrations of eleven cyanobacteria cultures and microcystin. In a series of bioassays, I then determined a dose response curve for each cyanobacteria culture and microcystin and found that veligers experience high mortality rates when exposed to environmentally relevant concentrations of cyanobacteria and cyanotoxins. Results from these experiments can be used to create management techniques that target invasive quagga mussels at their most sensitive life history stages. Finally, I explored how the brackish origins of quagga mussels impact their metabolism and oxidative stress response in freshwater systems by comparing them to another freshwater invasive bivalve, the Asian clam (Corbicula fluminea) when exposed to cyanobacteria and microcystin stressors. My results support previous work that brackish to freshwater invasion can act as a context dependent form of stress and result in higher respiration and filtration rates and altered oxidative stress response. The findings from these studies can be used to predict invasive species distribution and range expansion and can lead to more effective control of nuisance populations.

Download

Share

COinS