These data are from two remote field campaigns in the Noatak National Preserve. Various thermokarst features and their receiving streams were sampled and characterized. A suite of water chemistry (nutrients, major anions and cations, total suspended sediment) and benthic variables (particulate carbon, nitrogen and phosphorus, and chlorophyll-a) were measured at 6 major sites (2 in 2010 and 4 in 2011). There were additional sites sampled for water chemistry above and below thermokarst features in 2011.
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We measured total suspended sediment (TSS) in the Reference and Impacted reach using standard methods (USGS method I-3765). For each sample, a known volume of stream water was filtered in the field through a pre-dried (105°C) and pre-weighed 47-mm diameter glass fiber filter (GF/F) and re-dried and re-weighed. TSS was calculated as the difference in filter mass before and after filtration divided by the volume filtered (mg L-1). Turbidity sensors (DTS-12 from FTS Environmental, Victoria, BC, Canada) were installed in conjunction with automated ISCO samplers (Teledyne ISCO, Lincoln, NE, USA) to collect 5-minute turbidity measurements in the Reference and Impacted reaches for the 2010 season only.
A WTW handheld meter was used to measure pH, Specific Conductance, Temperature &amp;amp;amp;amp;amp;amp; Dissolved Oxygen.
Water samples for chemical analyses were collected as grab water samples. All water samples were filtered through pre-combusted (450°C) 25-mm diameter GF/Fs with a nominal pore size of 0.07 um, with the exception of the water designated for base cation analyses, which were filtered with nylon syringe filters with a pore size of 0.45um. Separate samples were taken for each analyte. Samples for soluble reactive ortho-phosphate (SRP or PO43--P), nitrate (NO3--N), and ammonium (NH4+-N) were frozen; samples for DOC (dissolved organic carbon), TDN (total dissolved nitrogen), TDP (total dissolved phosphorus); and base cations (calcium, Ca2+; magnesium, Mg2+; potassium, K+; and sodium, Na+); micronutrients and metals (aluminum, Al; iron, Fe; manganese, Mn; boron, B; copper, Cu; zinc, Zn; sulfur, S; strontium, Sr; lead, Pb; nickel, Ni; chromium, Cr; and cadmium, Cd) were acidified with 100ul 6N hydrochloric acid for every 50-mL of sample; and anions (chloride, Cl- and sulfate, SO42--S) and alkalinity samples were refrigerated. Samples were shipped back to the University of Vermont in Burlington, Vermont; the Ecosystems Center in Woods Hole, Massachusetts; or the University of Michigan for analysis within six to nine months. LTER Streams Protocols were followed.
Arctic LTER Streams Protocol
annual data is updated into new file
v1. October 2014: metadata added, file contains water chemistry data - JL