Date of Award

2022

Degree Name

Environmental Science

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Scott Simonton, Committee Chairperson

Second Advisor

Dr. Mindy Yeager-Armstead

Third Advisor

Mandee Wilson M.S.

Abstract

Standard toxicity testing organisms are utilized for regulatory purposes and often ecological risk assessments. Ephemeroptera taxa have been reported to be more sensitive to aquatic contaminants than the standard toxicity testing organisms currently used in determining effects on aquatic ecosystems. Establishing methods for culturing native Ephemeroptera taxa will provide a more sensitive test organism to determine the toxicity of contaminants and will be more representative of the responses of native taxa. Additionally, it will provide a test organism at the most sensitive life stages. The objective of this research is to develop methods for culturing and testing of native Ephemeroptera in the laboratory. Two different experiments were conducted to try to establish culturing and testing methods: temperature fluctuation effects on egg development and preliminary high sulfate toxicity tests on eggs and nymphs. Eggs were collected from native Ephemeroptera via oviposition or dissection and exposed to various temperature and high sulfate toxicity treatments during incubation. During the temperature test the eggs would either be put in a constant temperature or moved from a low (10℃) to a high temperature (20℃ or 24℃). Incubation duration, hatch rate and hatch length were evaluated to see if incubation temperature manipulation can be utilized to provide consistently available juvenile Ephemeroptera for toxicity testing. The results showed no significant difference between the temperature treatments and egg development, which shows the low storage method can be utilized and will allow for less frequent field collections and more testing year-round due to increased holding time for eggs. In the preliminary high sulfate toxicity test, both eggs and nymphs were exposed to a simulated mine effluent representing exposure to elevated conductivity in mining influenced Appalachian streams. Endpoints evaluated were hatch rate, hatch duration, incubation period, survival and growth of juveniles exposed to elevated conductivity post-hatch. Multiple taxa were evaluated including Ephemeridae (Hexagenia sp.), Heptageniidae (Epeorus sp.) and Baetidae (Acentrella sp. and Baetis sp.). The significant difference between the natural water control, the reconstituted water control and all treatment groups was hypothesized to originate from the natural conditions being optimal for genus-specific survival. These mechanisms of greater development and survival in the natural water have not been confirmed but are under further investigation.

Subject(s)

Mayflies – Larvae – Research – Appalachian Region.

Mayflies – Research – Appalachian Region.

Toxicity testing – in vitro – Appalachian Region.

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