Analysis of common water sampling techniques used to assess lake trophic state
Sat, 12/05/2015 - 00:21
Abstract: Volunteer lake management programs (VLMPs) across the country employ different surface water sampling techniques to establish long-term trends in nutrient availability and trophic state. The three most common techniques are a surface grab (SG), 2m integrated tube sampler (IT), and a discrete sampler, such as a Van Dorn or Kemmerer bottle deployed to a depth of 1.5m (DD). These various sampling techniques vary not only in depth, but also in cost and ease of use. The objectives of my study are to 1) determine if there is a statistical difference in chlorophyll-a (chl-a) and total phosphorus (TP) concentration obtained between the three different sampling techniques, 2) determine if the treatment effect (sampling device) varies over time, 3) determine which method has the least amount of variability, and 4) determine if sampling technique ultimately influences trophic state classification. The study was conducted on Upper St. Regis Lake, Paul Smiths, New York. I collected 10 samples from the lake using the three different techniques during the months of June – August, 2015. I found a significant difference in chlorophyll-a concentration between sampling techniques during June and July, and during the month of July for TP. The three sampling techniques yielded similar variability for chlorophyll-a but significantly different variability for TP. Ultimately, the trophic status rating for Upper St. Regis was not effected by sampling technique. My study suggests that VLMP should utilize a SG or IT rather than a costly DD sampler.
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Major: Environmental Sciences