Great Bend Region Spring 2012 Sampling Blitz

Volunteers sampled 206 stream sites on Friday, April 13th between 3 and 5 p.m.  Results of their efforts are presented below.

Temperature - Samplers measured temperature in the field directly from the stream at the time of sample collection. Temperature is an important parameter as it is the regulator for aquatic communities - all plankton, bug, and fish species have a preferred temperature. Temperature also controls the amount of dissolved oxygen present in the water - cooler temperature waters hold more dissolved oxygen. Finally, temperature controls the rate at which chemical reactions occur, such as the conversion of nitrate-nitrogen to ammonia-nitrogen. Higher temperatures are shown in darker colors. Several factors affect temperature including riparian buffers or shading, watershed inputs, and surrounding land uses. Temperatures typically measured higher than those measured during previous spring sampling events – measuring nearly as high in headwater streams as those temperatures measured during the most recent fall sampling blitz. Highest temperatures were measured in the headwater streams and in the Wabash River.

pH - Samplers measured pH from water samples at the staging location. Water pH is a measure of the amount of hydrogen ion available in the water. Water pH determines the solubility and biological availability of chemicals, including nutrients such as nitrogen and phosphorus, and metals, like copper or lead. Typical pH levels in streams measure between 6.5 and 8.5. pH levels are indicative of the geological materials in the drainage area. Additionally, the amount of photosynthesis occurring in the stream can affect pH levels. Higher pH levels are shown in darker colors, while lower pH levels are displayed in lighter colors. pH levels below 6 are of concern for biotic communities. Further observation is necessary in those tributaries where low pH levels were measured.

Transparency - Samplers measured water transparency using transparency tubes. Water transparency in streams reflects the distance downstream that you can see through the water. Tubes measured 114 centimeters, so any values greater than 114 centimeters exceed our ability to detect a change in water transparency. Low numbers (10 cm) indicate poor transparency while those in the 70 centimeter (2 foot) range indicate good transparency. Lower transparencies were typically measured in small headwater streams throughout the Region of the Great Bend of the Wabash River.

Nitrate/Nitrite - Nitrate-nitrogen and nitrite-nitrogen, like orthophosphate, represent the available nitrogen in an aquatic system. Nitrogen is also available in the atmosphere and can move from the air into the water by nitrogen-fixers. Nitrogen can readily convert between different forms, especially nitrate and nitrite. Conversion to and from ammonia also occurs when dissolved oxygen is available in the system. Nitrate and nitrite concentrations are displayed below with darker colors representing higher concentrations. Nitrate-nitrogen concentrations measuring higher than 2 ppm can inhibit aquatic communities. Concentrations higher than 10 ppm violate the state water quality standards. As previously observed, nitrate concentrations measured much higher during the Spring sampling than those measured during the Fall sampling events.

E. coli - E. coli is an indicator organism used to monitor pathogen concentrations with surface waters. E. coli is present in the intestines of all warm-blooded mammals and can survive and reproduce outside of the body. Untreated sewage, combined sewer overflows, polluted discharges, input from animals, and source populations can all contribute E. coli to surface waters. In Indiana, concentrations measuring greater than 235 colonies/100 mL are deemed non-supporting of their designated use. Those watersheds which do not meet water quality standards are shown in darker colors.

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