The Changing Seasonality of Arctic Stream Systems (CSASN) was active from 2010 to 2012. The CSASN goal was to quantify the relative influences of through flow, lateral inputs, and hyporheic regeneration on the seasonal fluxes C, N, and P in an arctic river network, and to determine how these influences might shift under seasonal conditions that are likely to be substantially different in the future. During the project, well and mini-piezometer samples were collected from various depths near stream channels and analyzed for a variety of nutrients.
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Water samples were collected at designated stations along various stream channels. Water was filtered through a 25mm GF/F filter in the field. Particulates were analyzed which remained on the filter. Dissolved nutrients were analyzed with the filtered water.
Many of the methods used for analyte analysis resembled the sampling protocol for LTER streams. The link to this protocol can be found below in the Sampling or Lab protocols section.
Ammonium was analyzed using the Salicylate method at the University of Vermont. Reference to this type of method can be found with the USGS. Method ID: I-2522-90.
Nitrate and Nitrate were analyzed using the cadmium reduction method to convert all nitrate to nitrite. Nitrite was then reacted with sulfanilamide and N-(1-naphthyl)-ethylenediamine dihydrochloride to form a colored azo dye. The formation of the color dye is proportional to the concentration of both nitrate and nitrite in the water sample. More detailed information about this method can be found on the EPA method for nitrate-nitrite: 353.4
Soluble Reactive Phosphorus:
Parsons et al. 1984. It involves the reaction of phosphorus with molybdate, ascorbic acid, and trivalent antimony. The molybdic acids are reduced to a blue-colored complex which is then read for absorbance on a UV spectrophotometer. A 1 cm cell is used in the spectrophotometer. Parsons, T.R., Maita, Y., Lalli, C.M., 1984. A manual of chemical and biological methods for seawater analysis. Pergamon Press, New York. pp. 173.
Total Dissolved Phosphorus:
Samples were digested in an autoclave with potassium persulfate. Samples were then analyzed for phosphorus using the ascorbic acid molybdate method on a UV-Vis spectrophotometer. More detailed information about this method can be found on the EPA method for Phosphorus: 365.1.
Soluble reactive phosphorus was commonly run with a standard curve with standards much higher in concentration. This lead to blank samples having higher than normal average concentrations. Therefore, if blanks were high, the average blank value concentration was subtracted from the sample concentration during the QAQC process.
Particulate samples were collected by filtering water through an ashed GF/F filter and drying for 24 hours at 60oC. The samples were then shipped to the UVM for further analysis. Particulate matter collected on a glass fiber filter is ignited at low temperature to destroy organic matter. The ignited filter is heated with dilute HCl, which extracts the phosphorus and converts it to ortho-phosphate. The phosphorus is then analyzed by a version of the reactive phosphorus method.
Total Organic Carbon and Total Dissolved Nitrogen:
A Shimadzu TOC-L was used for analysis of TDN and DOC.
The TOC-L uses carrier gas, which is used to supply oxygen at 150mL/min to the combustion tube filled with oxidation catalyst. This tube is heated to 680 degrees C and samples are burned in the combustion tube to form carbon dioxide. The carrier gas, containing the carbon dioxide created from the combustion, flows into a dehumidifier, where it is cooled and dehydrated. The gas then goes through a halogen scrubber before it reaches the cell of a non-dispersive infrared NDIR gas analyzer. This analyzer detects the carbon dioxide, and the analog detection signal of the NDIR forms a peak. The area of this peak is measured by a data processor, and the peak’s area is proportional to the concentration of the TC in the sample. To detect TN, the sample also goes through a combustion tube at 720 degrees C. The sample decomposes at this temperature to become nitrogen monoxide. The carrier gas carries the nitrogen monoxide to a dehumidifier, where it is dehydrated. Then it enters a chemiluminescence gas analyzer, where the nitrogen monoxide is detected. The detection signal from the analyzer generates a peak which are proportional to the concentration of the TN in the sample. Refer to the LTER streams protocol for more detailed information about this protocol.
Conductivity was analyzed with a handheld instrument in the field.
Arctic LTER Streams Protocol, updated 2010 by EBS
No more updates. Project completed in 2012.
Organized and Prepared by J. Benes: Nov. 2013
Version 2: File path reset, key words updated (JD.Dec2013)
Version 3: Checked keywords against the LTER network preferred list and replaced non-preferred terms. Jim L 15Jan14