CENTENNIAL HONORS COLLEGE
Western Illinois University
Undergraduate Research Day 2016
PosterPresentation
TheRelationshipofNutrientsandDissolvedOxygenConcentrationstoStreamflowina
TributarytoSpringLake
GraceIftner
FacultyMentor:SteveBennett
Geology
TheconcentrationsofthenutrientsphosphateandnitrateinastreamthatisatributarytoSpringLake
weremeasuredduringthisresearchproject.Specificconductance,pH,temperature,dissolvedoxygen,
andtotaldissolvedsolidswerealsomeasured.Measurementsofunfilteredsampleswereconductedin
the field using a TDS/conductivity/temperature meter, pH meter, and parameter-specific colorimeters
ortestkits.Thesamplelocationisnexttoacowpastureandhasabedofalgaerestingonthewater
surface.Previousresearchatthislocationshowedthatnitrateconcentrationsincreasedandphosphate
concentrationsdecreasedafterrain,howeverthisresearchhasshownotherwise.Theresultsfromthis
researchshowedaspikeinphosphateconcentrationsandadeclineinnitrateconcentrationsafterlarge
rain events. The average concentrations for nitrate and phosphate were 4.2 mg/L and 0.46mg/L,
respectively.Afteralargeraineventthatresultedinafloodwarning,thenitratedecreasedto1.8mg/L
and the phosphate increased to 2.52mg/L. The average concentration for dissolved oxygen was
10.9mg/L,butdecreasedto7.8mg/Lafterthesamerainevent.Therunofffromthesurroundingareas
may have washed the phosphates into the stream and the rain may have diluted the nitrate
concentrations.Itwassuspectedthatthealgaeconsumedthenitratebetweenrainevents,causingthe
decreasing levels after a rain. However this research does not support this hypothesis. By comparing
data from when algae was present to data from when it was absent, it appears the loss of algae
stabilizedtheconcentrationofdissolvedoxygen.