Date of Award


Document Type


Degree Name

Master of Science (MS)

First Advisor

Catherine C. O'Reilly


Turbidity is an important measure of drinking water quality. However, there is difficulty ascertaining sources of turbidity due to the resources needed to monitor streams and can be puzzling when there are diel cycles within a stream despite no changes in water level. Six Mile Creek, located in Mclean County, Illinois, is a small agricultural stream in the Evergreen Lake watershed that exhibits diel turbidity cycle changes of 10 NTUs. We hypothesized that turbidity is being caused by increased bioactivity in the stream at night. To understand the potential for bioactivity to influence diel turbidity cycles we deployed a hydrophone in Six Mile Creek to record frequency over time. We then analyzed the recorded acoustics in R using the packages SeeWave, tuner, soundecology, tidyverse, and code that was provided by Camille Desjonquères, to obtain acoustic indices and compared the day and night cycle indices against each other. We also chose to record different dates including those for moon cycles changes of new and full moons. When analyzing the acoustic complexity, we found an increase in the average from day cycles (from 9:00 to 16:59) to night cycles (from 22:00 to 04:59). In acoustic diversity we found a difference of over 100% from day to night cycles (an increase from 0.342094 to 1.06686).Results showed that there is a difference between day and night cycles for acoustic indices that were measured and show an increase in the amount of biodiversity and complexity at night. This supports the hypothesis that diel turbidity increases are caused by increased bioactivity at night in the stream. KEYWORDS: acoustic indices, diel turbidity, ecoacoustics, sound ecology, soundscape


Imported from Hong_ilstu_0092N_12404.pdf


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