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Published byDwayne Dale Thomas Modified over 9 years ago
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Temperature and DO Temperature A measure of heat Dissolved Oxygen (DO) The concentration of oxygen (gas) which is dissolved in water. Both are important individually and to one another
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Why is Temperature Important? Most aquatic organisms are poikilothermic (“cold-blooded”), which means they don’t internally regulate their core body temperature. The rate of many chemical reactions increases at higher temperatures. Oxygen solubility
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Temperature - Units Fahrenheit (°F), Celsius (°C), Kelvin (K) Celsius (°C) used for most science (SI unit) –a.k.a. centigrade, where “centi-” = hundredth Water Freezes at 0°C = 32°F = 273.15 K Water Boils at 100°C = 212°F = 373.15 K 0°C 32°F 100°C 212°F
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Temperature - Units Conversion Factors (°F – 32) 1.8 °F = (°C x 1.8) + 32 °C =
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Temperature – Q 10 Rule General rule which predicts: Growth rates of cold-blooded aquatic organisms and many biochemical reaction rates will double for every 10°C (18°F) temperature increase within their "preferred" range.
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Temp – Biological Effects Growth Rate Temperature (Celsius) 010203040 50 Lethal Optimum
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Temperature Standards Temperature All waters64°F (17.8°C) Salmon spawning, egg incubation, and fry emergence 55°F (12.8°C) Bull Trout50°F (10°C) Columbia River (to RM 309)68°F (20°C) Willamette River (to RM 50)68°F (20°C) Rolling 7-day average of maximum daily temperatures
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Temperature – Deep Cr (Clack) 20.9 21.3 20.9 20.2 20.9 19.4 20.5 21.0 7-day max AVG = 20.6°C
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Temperature – Causes Loss of riparian shading Warm water inputs –Retention ponds –Municipal or industrial wastewater –Stormwater runoff Groundwater inputs Weather –Air temperature, cloud cover, day length Turbidity
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Dissolved Oxygen O 2 gas dissolved in water Required by nearly all aquatic life O2O2 CO 2 Atmosphere21 %0.035 % Water 0 % 20 %
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DO – Solubility Inverse, non-linear relationship to temperature Decreases with decreasing barometric pressure –Weather, elevation High salinity reduces solubility
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DO – Solubility
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DO – Units Concentration: mg/L = µg/mL = ppm (parts per million) Percent Saturation: DO % Sat. = Measured DO (mg/L) Solubility (mg/L)
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DO – Sources Photosynthesis –Influenced by sunshine, temperature, water velocity Atmospheric Re-aeration –Turbulent mixing Water velocity and depth Oxygen deficit Inflow of oxygenated water
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DO – Sinks Respiration –Greatest source of DO loss in summer Biochemical Oxygen Demand (BOD) –Decomposition of organic wastes –Standard measure is 5-day BOD = BOD 5 Nitrification (NBOD) –NH 3 + O 2 = NO 3
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DO – Diel Fluctuations Dissolved Oxygen Time of Day AM PM
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DO – Standards Salmonid Spawning thru Fry Emergence Water Quality Standard> 11 mg/L Intergravel Standard> 6 mg/L unlessIntergravel DO > 8 mg/L> 9 mg/L orNatural conditions> 95% sat. Cold-water Aquatic Resources> 8 mg/L Natural conditions> 90% sat. Cool-water Aquatic Resources> 6.5 mg/L Warm-water Aquatic Resources> 5.5 mg/L
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DO and Temp Data Quality AccuracyPrecision Temperature+ 0.5°C+ 1.0°C Dissolved Oxygen + 0.3 mg/L+ 0.5 mg/L
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Measuring DO and Temp Measure Immediately - In Field Measure Both at Same Time Recording Time is Crucial Sample Collection –Below surface ~ 4 inches (or ½ way to bottom of shallow stream) –Cap DO bottle underwater
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