• Sherri L. Johnson - Principal Investigator
  US Forest Service ;Pacific NW Research Station ;3200 SW Jefferson Way, Corvallis, OR, 97331, USA
  Phone: 541-758-7771
  Email: sherri.johnson2@usda.gov, sherri.johnson@oregonstate.edu
  URL: https://www.fs.fed.us/research/people/profile.php?alias=sherrijohnson
• Julia A. Jones - Principal Investigator
  Oregon State University;Department of Geosciences; Wilkinson Hall 104, Corvallis, OR, 97331-5506, USA
  Phone: (541) 737-1224
  Email: Julia.Jones@oregonstate.edu, geojulia@comcast.net
  URL: http://ceoas.oregonstate.edu/profile/jones/
  ORCID: http://orcid.org/0000-0001-9429-8925
• Matthew G Betts - Principal Investigator
  Department of Forest Ecosystems and Society; 201E Richardson Hall; College of Forestry; Oregon State University, Corvallis, OR, 97331
  Phone: (541) 737-3841
  Email: matt.betts@oregonstate.edu
  URL: http://www.fsl.orst.edu/flel/index.htm
• Michael P. Nelson - Principal Investigator
  Department of Forest Ecosystems and Society; 201K Richarson Hall; College of Forestry; Oregon State University, Corvallis, OR, 97331
  Phone: 541-737-9221
  Email: mpnelson@oregonstate.edu
  URL: http://www.michaelpnelson.com
  ORCID: http://orcid.org/0000-0001-6917-4752
• David Bell - Principal Investigator
  Email: david.bell@usda.gov, david.bell@oregonstate.edu
  URL: https://lemma.forestry.oregonstate.edu/about/david-bell

• The H.J. Andrews Experimental Forest is a living laboratory that provides unparalleled opportunities for the study of forest and stream ecosystems in the central Cascade Range of Oregon. Since 1980, as a part of the National Science Foundation Long Term Ecological Research (NSF-LTER) program, the Andrews Experimental Forest has become a leader in the analysis of forest and stream ecosystem dynamics.
• Long-term field experiments and measurement programs have focused on climate dynamics, streamflow, water quality, and vegetation succession. Currently researchers are working to develop concepts and tools needed to predict effects of natural disturbance, land use, and climate change on ecosystem structure, function, and species composition.
• The Andrews Experimental Forest is administered cooperatively by the USDA Forest Service Pacific Northwest Research Station, Oregon State University and the Willamette National Forest. Funding for the research program comes from the National Science Foundation (NSF), US Forest Service Pacific Northwest Research Station, Oregon State University, and other sources.

Data were provided by the HJ Andrews Experimental Forest research program, funded by the National Science Foundation's Long-Term Ecological Research Program (DEB 2025755), US Forest Service Pacific Northwest Research Station, and Oregon State University. National Science Foundation: DEB1440409

• Long-Term Ecological Research
  The Andrews Forest is situated in the western Cascade Range of Oregon, and covers the entire 15,800-acre (6400-ha) drainage basin of Lookout Creek. Elevation ranges from 1350 to 5340 feet (410 to 1630 m). Broadly representative of the rugged mountainous landscape of the Pacific Northwest, the Andrews Forest contains excellent examples of the region's conifer forests and associated wildlife and stream ecosystems. These forests are among the tallest and most productive in the world, with tree heights of often greater than 250 ft (75 m). Streams are steep, cold and clean, providing habitat for numerous aquatic organisms.

• Sample collection, preparation, and storage:
• FBOM was collected from stream beds with a hand vacuum pump into a 2 L collecting jar. The intake line was fitted with a 1 mm stainless steel screen, allowing benthic material to be wet-sieved during sampling. Samples were transferred to polystyrene jars (500 ml) and stored during field sampling in an insulated chest with stream water and ice. In the laboratory, a slurry was prepared by decanting excess stream water from the jars and mixing, keeping FBOM suspended while subsampling. Subsamples were dispensed using 1, 3, or 5 ml plastic syringes with enlarged openings. All laboratory analyses involving slurry began immediately upon return from FBOM collection which took 8-12 hours.

• Because of significant perturbation (e.g., suction, sieving, mixing, and preparing slurries) of FBOM during sampling and subsampling, we performed laboratory analyses described in the following sections to measure potential activity rates. These rates do not reflect in-stream FBOM activity rates, but rather give us a relative sense of the variability of rates among treatments and over time.
• Denitrification potential was determined as NO emission by anaerobically incubating FBOM supplemented with glucose and NaNO (Martin et al., 1988). Duplicate 5-ml slurry samples in 25-ml Erlenmeyer flasks were capped with rubber stoppers and purged for 3 min with argon at a rate of at least 120 cc /min. In the middle of the purge, the flasks were shaken gently to ensure removal of air bubbles. The flasks were allowed to incubate for 1 h at 24 degrees C, and then 2 ml of sterile solution of 1 mM glucose and 1 mM NaNO were injected through the stopper, and 2 ml of headspace gas were withdrawn with the syringe. Flasks were allowed to incubate for another hour at 24 degrees C. At zero and 2 h time, 0.5 ml of headspace gas was removed from the flasks and assayed for NO in a gas chromatograph equipped with an electron capture detector. All gas chromatographs had stainless steel columns packed with Poropak-Q, either 50/80 or 80/100 mesh (Water Associates, Inc., Medford, MA).
• To determine respiration rates, duplicate 5-ml subsamples were placed in 25-ml Erlenmeyer flasks, and then capped with rubber stoppers. After incubating for 1 h at 24 degrees C, 0.5 ml of headspace gas was analyzed for CO in a gas chromatograph fitted with a thermal conductivity conductor. After incubating for an additional 2 h under the same conditions, a second headspace gas sample (0.5 ml) was collected and analyzed.
• Putative acetylene reduction rates were determined by the acetylene reduction method (Weaver and Danso, 1994). Samples were prepared in the same way as for denitrification potential, except that the headspace gas contained 1.5% O2, 12.5% acetylene, and 86% argon. After 24 h of incubation, 0.5 ml of headspace gas was removed and analyzed for ethylene in a gas chromatograph fitted with a flame ionization detector. A control was analyzed for ethylene production in the absence of acetylene.
• For mineralizable nitrogen measurements, the microbial conversion of organic N to inorganic N in the form of NH-N was measured by the "anaerobic" incubation method (Koeney, 1982). Duplicate 10-ml sediment subsamples were added to 50-ml screw-topped test tubes, which then were completely filled with deionized water (53 ml), capped, and incubated at 40 degrees C for 7 d. After incubation, subsamples were transferred to 25-ml Erlenmeyer flasks, and 53 ml of 4 M KCl and 0.4 ml of 10 M NaOH were added to each. The flasks were shaken for 1 h, and then analyzed with a selective ion electrode (Corning ammonium electrode, Medford, MA). Extractable ammonium concentrations were measured by adding 50 ml of 2 M KCl to duplicate 10-ml subsamples in 250-ml Erlenmeyer flasks. The flasks were capped, shaken while incubating for 1 h in the presence of 0.4 ml 10 M NaOH, and analyzed with a selective ion electrode to determine KCl-extractable ammonium concentration. Net mineralization was calculated as mineralizable N ( extractable ammonium to account for ammonium present prior to incubation.
• Phosphatase activity was determined according to the spectrophotometric assay of Tabatabai and Bremner (1969) as modified by Zou et al. (1992) One ml of 50 mM p-nitrophenyl phosphate substrate was added to duplicate 1-ml subsamples containing suspended FBOM. The tubes were shaken and then placed, along with duplicate controls with no phosphatase substrate addition, in a 30 degrees C water bath for 1 h. After incubation, 1 ml of 50 mM Sigma 104 phosphatase substrate was added to the controls; reactions were stopped immediately with the addition of 2 ml 0.5 M NaOH and 0.5 ml 0.5 M CaCl. The assay mixtures were centrifuged for 5 min at 500 x g. A 0.2-ml subsample of the supernatant was diluted with 1.8 ml deionized water, and the optical density was measured at 410 nm. A standard curve was prepared from 0.02 to 1.00 ?mol ml-1 p-nitrophenol. Enzyme activity was expressed as ?mol p-nitrophenol released gdw h. The B-glucosidase activity assay required the same general procedure as was used for phosphatase activity, except that the substrate was 1 ml 10 mM p-nitrophenyl ?-D glucopyranoside, the incubation period was 2 h, and 2 ml 0.1 M tris[hydroxymethyl]aminomethane at pH 12.0, instead of 0.5 M NaOH, were added to terminate the reaction.
• Total C and N were determined by dry combustion with a Carlo-Erba NA 1500 Series II high-temperature combustion furnace on oven-dried subsamples ground to pass through a 250-mm sieve.

• FBOM samples were collected from 14 first-order streams flowing through forest in three successional age classes: three Douglas-fir (Pseudotsuga menziesii) stands approximately 10 years old (10YS), five 30 year old Douglas-fir stands (30YS) and six old-growth forest (OG) dominated by Douglas-fir and western hemlock (Tsuga heterophylla) in the H.J. Andrews Experimental Forest, in the Western Cascade Mountains of Oregon. Riparian vegetation of the 8 young stands was dominated by herbaceous plants (10YS) or deciduous trees (30YS), primarily alder (Alnus rubra) and maple (Acer macrophyllum, A. circinatum). No riparian vegetation buffers were left on harvested stands and all stands had been replanted with Douglas-fir seedlings. Streams at high (1220-1280 m) and low elevations (580-800 m) were selected. An effort was made to keep similar stand age x elevation plots on the same slope and aspect. FBOM was also collected at the settling basins at the bottom of HJA Water Sheds 1, 2, 3, 9 and 10.
• Sampling frequency: seasonal

• Streams were sampled for FBOM on 8 occasions: August 9, October 14, October 28, November 4, November 18 and December 9, 1995, and April 6 and May 12, 1996. As a way of integrating FBOM characteristics from small watersheds over larger spatial scales and longer time periods, sediments were also collected from the settling basins of 5 HJA experimental small watersheds.

• Andrews Experimental Forest (HJA)
  W -122.26172200, E -122.10084700, N 44.28196400, S 44.19770400
  Altitude: 1631 to 1631 meter

Object name: HS00501.csv

Records: 120

Attributes: 17

Temporal coverage: 1995-08-09 to 1996-05-12

File size: 9290 byte

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