Kenneth Fortino edited MethodsLab.tex  about 8 years ago

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\subsection{Lab Procedures} \subsection{Sediment Oxygen Demand Experiment}  Sediments and pond water for the experiment were collected from Lancer Park Pond Sediment samples were collected from near the littoral zone (approximately 10 m from shore) on May 29, 2014, using an Ekman dredge. Two dredge samples were collected from a depth of 0.4 m and another 2 dredge samples were collected from a depth of 1 m. The sediments from each location were combined and sieved through a 250 µm mesh net to remove macroinvertebrates and CPOM. The CPOM retained by the nets dried at 50\textsuperscript{o} C and ashed at 550\textsuperscript{o} C for 4 h to determine AFDM. Pond water was collected from at a depth of 0.5m on June 9, 2014 by submerging 1 L plastic bottles.  Once back at the lab, the 1m and 0.4m sieved sediment slurry was combined and allowed to settle overnight. Overlaying water could then be siphoned off. 10ml sediment samples were taken and placed into pre-weighed crucibles, dried, and then ashed at 550 degrees Celcius.   The contents of the 1 Liter bottles were rinsed through a 1mm sieve and visible macroinvertebrates were removed. All retained materials were placed into pre-weighed paper bags. The bags were then placed in a drier at 50 degrees Celcius. Once dry, the CPOM was weighed and ashed at 550 degrees Celcius to determine ash free dry mass (AFDM). The AFDM was used to determine the amount of CPOM, in this case leaf disks, needed to add to the BOD bottles.