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| Jonathan instructing me on testing for nitrates. |
IMES
Saturday, November 16, 2013
Project in the lab- Seaira
This week I collected water samples from the northern Indian River Lagoon, and Mosquito Lagoon to test nutrient content in the lab. With this project I plan on comparing my findings to optimum water conditions for healthy seagrass communities. Using my collected samples I tested for salinity, turbidity, nitrates, and dissolved phosphates.To test for salinity I used the refractometer; using a pipette I was able to first calibrate it with DI water, and then put a sample of water on the slide to view the saline levels in ppt (parts per thousand). I tested the turbidity using the AquaFlour hand held Turbidimeter, remembering to continually re-suspend my sample, and clean off the outside of the sample vile. Finally I tested for dissolved phosphates, and nitrates using the HACH DR 1890 Colorimeter.Testing for dissolved phosphates was a breeze, after filtering my water sample, it was the same process we used on the boat and only took a few moments. Testing for nitrates was much more involved, it not only took 15 minutes to calibrate but it also required mixing in Ammonia Salicylate and Cyanurate reagent powders. Unfortunately a very interesting testing procedure turned into some less than exciting results, but there are still three more sample sites to test so we will see how the rest of the lagoon fairs.
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Yay Seaira! Did you find very little traces of nitrates? If so, why do think that is? Where will you collect for your optimum water condition?
ReplyDeleteI found very minimal amounts of nitrates, lower than suggested levels for estuaries which I will describe during my presentation. My hypothesis on why the nitrate levels were so low is because prior to sampling we had very little recent rainfall, which can streamline the nutrient runoff from agricultural and fecal material sources. The high saline levels that I got from the sites also suggests some water evaporation in the small lagoon segment because of the lack of rain. As for the optimum water levels I can do this one of two ways A.) Based on current research conducted by the St. John's Water Management District I can view their data and estimate which location is in best health consistently, and sample there. Or B.) Base my interpretations of the nutrient levels on the "natural" levels described by researchers. I have found suggested optimal levels for estuaries provided by researchers of the Indian River Lagoon. An example would be normal levels of dissolved phosphates for marine environments is said to be 0.005 - .20mg/L.
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