The Changing Seasonality of Arctic Stream Systems (CSASN) did extensive arctic stream research from 2010 to 2012. Specifically, 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 determine how these influences will shift under seasonal conditions that are likely to be substantially different in the future. Throughout the project, samples were collected from Benthic Rock Scrubs and Fine Benthic Organic Matter (FBOM).
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The entire surface of rocks fitting into an area of 546cm^2 ( +/- 18cm) (363 cm2 ( +/- 18cm) in 1996) were scrubbed with a brass brush.
The slurry was brought to a volume of 1 L.The samples were returned to the lab
where they were filtered through a GF/C or GF/F glass fiber filter.
Fine Benthic Organic Matter (FBOM):
A container with a known bottom diameter was placed in the stream. The entire benthic layer was then disturbed to release all the FBOM. The depth of the water was then recorded so that overall sample volume could be calculated. A sample was taken from this known volume of water which contained FBOM material.
For Chl a:
The filters were then placed in 10 ml of 90% buffered acetone and extracted in the dark for 24 hours. The samples
were then read on a Turner 111 (1990-1991) and Turner 450 (1992-1997), TurnerDesigns 10AU (1998-2010) Fluorometers.
Beginning in 2004, samples were analyzed for for chlorophyll a. After taking an initial fluorescence reading the sample was acidified with 100uL of 0.3N HCl and the sample was read again after waiting approximately 90 seconds. To calculate chlorophyll a concentration the second value is subtracted from the first value. The two different values represent total chlorophyll concentration and phaeophytin pigment concentration, by subtracting the phaeophytin from total chlorophyll, chlorophyll a is determined.
Reference Citations: R.G. Wetzel and G.E. Likens. 1979. Limnological Methods. Saunders. Philadelphia.
Notes: In 2004 several adjustments were made to the protocol from 2003. Extraction took place at approximately 4C using chilled acetone. A multipoint curve was analyzed using a chl a stock std. A Turner Designs solid standard could then be utilized as a check. GF/F 25mm filters were used. Additionally, chl a was corrected for pheophytin following EPA 445 and data is reported in corrected chl a. For more information please reference the chlorophyll protocol available on the Arctic LTER website.
Particulate Carbon and Nitrogen (PC or PN):
The PE2400 CHN uses a combustion method to convert the sample elements to the simple gases (CO2, H2O, and N2). The sample is first oxidized in a pure oxygen environment; the resulting gases are then controlled to exact conditions of pressure, temperature, and volume. Finally, the product gases are separated. Then, under steady-state conditions, the gases are measured as a function of thermal conductivity. A known standard is first analyzed to calibrate the analyzer in micrograms. The calibration factor is then used to determine unknowns. All quantitation is performed on a weight percent basis, using a gravimetric technique. The systems uses a steady state, wave front chromatographic approach to separate the measured gases. This approach involves separating a continuous homogenized mixture of gases through a chromatographic column. As the gases elute, each gas separates as a steady state step, with each subsequent gas added to the previous one. Consequently, each step becomes the reference for the subsequent signal.
Particulate Phosphorus (PP):
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.
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