Lake water samples were collected at specific depths with a five-liter Niskin bottle during normal LTER limnological sampling. Sub-samples were decanted into three-1 L Nalgene bottles (2-light and 1-amber), two-500 mL amber Nalgene bottles, three-150 mL borosilicate glass bottles, two-20 mL scintillation vials, and one-30 mL serum vial. One-100 mL sub-sample was taken from the one-liter amber Nalgene bottle. The sample was filtered through a combusted (475 degrees C for 4 hours) Whatman 25 mm GF/F filter using a bell jar apparatus. The filtrate was collected in a 125 mL acid washed Nalgene bottle and stored at -20 degrees C until analysis.