Arctic LTER Database

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Shaver, G. 1989. Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska. Arctic LTER, Marine Biological Lab, Woods Hole, Ma 02543. 1989gsttbm http://ecosystems.mbl.edu/arc/terrest/biomass/index.shtml 

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Data sets were provided by the Arctic LTER. This material is based upon work supported by the National Science Foundation under Grants #DEB-981022, 9211775, 8702328; #OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529; #BSR 9019055, 8806635, 8507493.

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Dataset URLs:	METADATA: HTML, Rich Text, XML(EML compliant) DATA: Comma Delimited, Excel file with Metadata and data
Dataset ID:	89_96bometa
Dataset Title:	Epilithic respiration, photosynthesis, chlorophyll a and nutrients from light/dark benthic metabolism chamber experiments, Arctic LTER 1989-1996.
Investigator 1:
First Name:	William (Breck)
Last Name:	Bowden
Address line 1:	304 Aiken Center
Address line 2:	Rubenstein School of Environment and Natural Resources
Address line 3:
City:	Burlington
State:	Vermont
Zip Code:	05405
Country:	USA
Associate Investigators:	Jacques Finlay, Bruce Peterson, Jane Tucker
Keywords:	metabolism, benthic, stream, epilithon, respiration, photosynthesis, chlorophyll a, nutrients, Kuparuk River, control, fertilized, primary production
Abstract:	Epilithic respiration, photosynthesis, chlorophyll a and nutrients from light/dark benthic metabolism chamber experiments. Samples were collected from stations within the CONTROL, +P, and +NP zones of the Kuparuk River during the +P and +NP experiments run during 1989 - 1996.
Contact:	Arctic LTER Information Manager The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole, MA 02543 Phone (508) 289 7496 Email: arc_im@mbl.edu Online URL: http://ecosystems.mbl.edu/ARC/
DATA FILE INFORMATION:
Data File URL	http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-arc.1284&urlTail=streams/primprod/data/89_96bometa.dat
Data File Name	89_96bometa
Beginning Date	5/1/1989
End Date	9/1/1996
Number of Data Records	995
Other Files to Reference
Availability Status	Type 1
Quality Control Information
Maintenance Description
Log of Changes:	data files compiled. Metadata updated. 8Feb10 EBS
	Version 3: Update LTERNET Data Access server proxy link for Excel and comma delimited data files. Changed from knb to das in url.

RESEARCH LOCATION:	Site 1	Site 2
Geographic Description	Kuparuk River just above 1989 +P dripper location (CONTROL, about +0.4k), just above the 1989 +NP drippers (+P, about +1.7k), and at +2k (+NP2K) and +4k (+NP4k) below the 1989 +NP drippers.
Location Bounding Box
West Bounding Coordinate
East Bounding Coordinate
North Bounding Coordinate
South Bounding Coordinate
OR if single point location
Latitude
Longitude
Elevation

TAXONOMIC COVERAGE:
Taxonomic Protocols
Organisms studied
Methods:	Photosynthesis and respiration were estimated from changes in oxygen within closed chambers during separate light and dark incubations (Bott et al., 1978; Pennak & LaVelle, 1979; King, 1982; Duff et al., 1984). Rocks with epilithon were placed in sealed Plexiglas chambers filled with river water. Dissolved oxygen decreased in the dark due to respiration alone and normally increased in the light due to the net effect of photosynthesis and respiration. Photosynthesis was estimated as the sum of dissolved oxygen changes in the light and dark incubations. The chambers were constructed from a 25 cm length of stock cast acrylic tubing (21.590 cm O.D by 0.635 cm wall). A piston, constructed from a 5 cm length of stock cast acrylic tubing (20.320 cm O.D. by 0.635 cm wall), was used to isolate the interior of the chamber from the atmosphere. The piston fit snugly, but not tightly, into the chamber. Oxygen leaks into the chamber were limited to the minute area between the piston and chamber and the long diffusion path, through water, along the piston edge. A BOD port on the top of the piston accepted a stirred, BOD probe from an Orbisphere Model 2714 oxygen meter. Water was recirculated in the chamber with an external, submersible pump. Water samples were removed for analysis by displacing the piston with the sample tube open. When not in use, the sample tube was pinched closed and the BOD port was stoppered with a #1 rubber stopper. Rocks were collected at random locations within pools or riffles at each site. Surface rocks with a "typical" development of epilithon, based on visual inspection of the site, were selected for study. We rejected rocks with heavy moss growth and favored rocks of a uniform size and shape, that would fit neatly in the chamber bottom. We found that 3 to 4 rocks of a modal shape and size would essentially cover the chamber bottom in a single layer, at a surface density similar to that found in the river. Water for the incubations was collected in carboys. Rocks were collected from the river and placed in coolers, without water, to keep them cool and moist. We found that if the rocks were kept submerged in water in the coolers, delicate epilithic material was dislodged during transport from the field to the lab. Without water, we were able to transport the rocks and epilithon, and place them in the chambers with the epilithon essentially intact, even with flocculent pool epilithon. The time from collection and transport to installation in a chamber was generally 1-2 h. At the lab, rocks were carefully lowered into an open chamber previously filled with fresh river water. The piston was inserted into the chamber and all bubbles were removed via the open BOD port. The piston was pushed into the chamber as far as practical, to minimize the headspace volume and so maximize the change in dissolved oxygen concentration per unit time. The entire chamber and pump were submerged in a recirculating water bath to maintain constant water temperatures near those found in the Kuparuk River. Toolik Lake was used as a source of cooling water. Each chamber could be illuminated by four, fluorescent, plant and aquarium bulbs that together provided about 190 uE m-2 sec-1 of energy at the chamber surface. The lights, water bath, and chambers were operated under a thick, rubberized tarp to enable dark incubations. In a typical experiment, four chambers were run simultaneously. After rocks were in place and chambers were sealed and submerged, we started with dark incubations. Dissolved oxygen and chamber temperature were measured at three time points, until the dissolved oxygen had been reduced by 3 to 4 mg O2/L or approximately 4 h had elapsed. After the third time point, we turned on the lights and measured dissolved oxygen at two additional time points, until the dissolved oxygen returned to the initial reading or approximately 4 h had elapsed in the light (8 h from the beginning of the experiment). Typically dissolved oxygen decreased linearly in the dark and increased linearly in the light. If non-linearity was encountered (e.g. supersaturation in the light), only the first two data points in a sequence were used in the calculations. Water samples were taken at the beginning and end of each experiment to monitor N dynamics in the chambers. At the end of each experiment, rocks were removed from each chamber and the epilithic material was scrubbed from the rocks with a wire brush, into a known volume of clean water (usually 2 or 5 L), mixed vigorously, and replicate volumes (usually 5 or 10 ml) were removed by pipette and filtered onto 25 mm, Whatman, GF/F filter papers. Each filter paper was placed in 10 ml of 90% acetone/10% water in a polyethylene, screw-cap, centrifuge tube and extracted in the dark for 24 to 48 h. Chlorophyll a in the acetone/water extract was estimated by fluorometry (Greenberg et al. 1985). The amount of epilithic chlorophyll a originally on the rocks in each chamber was calculated from this concentration plus the total and sub-sampled volumes. Epilithic chlorophyll a, photosynthesis, and respiration expressed on a per chamber basis, were converted to an areal basis by multiplying each variable by the area of the chamber bottom (0.0324 m2). Essentially, this assumes that the cobble density in the chamber is similar to that in the river and that only the top layer of cobble is important for the variables measured. More complicated methods could be used to ascertain rock surface area per unit area of stream bed (e.g. Naiman, 1983; Murphy, 1984). However, this method was quick, unbiased, and is probably not in error by more than a factor of two (i.e. misrepresented the true rock surface area by 1/2 to 2 times) as long as the chambers were loaded with similar cobble sizes, shapes, and densities. Ammonium was measured in headspace water by a manual, phenol-hypochlorite method in which ammonium was measured as an indophenol dye at 640 nm (Grasshoff & Johannsen, 1972). Nitrite was measured as a diazo dye at 540 nm (Bendschneider & Robinson, 1952). Nitrite was typically at or below detection limits. Nitrate was converted to nitrite using a manual, mossy cadmium reduction method (MacKereth et al., 1978; Jones, 1984; Elliot & Porter, 1971). Notes: A manuscript based on these data has been published: Bowden, W.B., B.J. Peterson, J.C. Finlay, and J. Tucker. 1992. Epilithic chlorophyll a, photosynthesis, and respiration in control and fertilized reaches of a tundra stream. Hydrobiologia 240: 121-131. The variable EXPT refers to assignments in Bowden and Finlay's field notebooks for these experiments. The variable CHAMID refers to chamber identification numbers assigned by Bowden, Finlay or Tucker during the various experiment (EXPT) runs. The variable APHOTO refers to photosynthesis change per unit total chlorophyll a, i.e. the ASSIMILATION COEFFICIENT. The variables INITNH4, INITNO2, and INITNO23 refer to the initial concentrations of ammonium, nitrite, and nitrite+nitrate in the chambers. RATENH4, RATENO2, and RATENO23 refer to the rate of change of these nutrient concentrations within the chambers during the incubations. Calculations: Variable Formula CCHLA, PHAEO, and TOTAL Method: Filtration through a Whatman GF/C filter followed by extraction in 90% acetone WITHOUT grinding. Extraction for at least 24h in dark. Read on Turner 111 fluorometer. Working equation: (meter reading x 100) ug CHLa/ml acetone = ::::::::::::::- (% filter) (window) where, meter reading = fluorometer reading from Turner 111 100 = a factor required to correct for the ammeter %filter = filter used to attenuate light to instrument range window = used to attenuate light This is converted to CHLa per unit stream bottom area, as follows: (total mls of scrubbate) (mls acetone used) mg CHLa/m2 = :::::::::::::::::::::::::- (mls filtered)(mls acetone expected)(m2 chamber area) total mls = scrubate volume, either 2000 or 5000 mls mls acetone = volume used to extract, always 10 ml in 1989 mls filtered = aliquot of total mls, usually 2 or 5 mls mls acetone expected = should be 10 mls, thus the ratio of mls acetone used and that expected shoud be 1. chamber area = constant = 0.0324 m2 for 1989 piston chambers NOTE: This calculation is a revision from the original method and supersedes any earlier descriptions. WBB 8 May 1997. NOTE: Standard Methods (Section 10200H, 1989, 17th Edition) reports that fluorometric determination of phaeopigments when calculating chlorophyll a is not recommended when chlorphyll b is present. Acidification of the sample produces phaeophytin b which fluoresces at the same wavelength as phaeophytin a. This will cause the overestimation of phaeophytin a concentrations and an underestimations of active chlorophyll a. Although phaeophytin a concentrations were estimated (PHAEO) these data are unreliable and should not be used in any calculations of chlorophyll. Corrected chlorophyll a (CCHLA), which depends on PHAEO, should not be used. TOTAL chlorophyll a is the variable that has been used in the calculations of respiration, gross photosynthesis, and net photosynthesis per unit chlorophyll a. Total chlorophyll a has been used in all calculations in metabolism files from 1989 - 1992. RESP, PHOTO, and NET These variables were calculated from the change in oxygen during incubations of 1 to several hours in either light or dark conditions. RESP = (final DO - initial DO)/(incubation time) in DARK NET = (final DO - initial DO)/(incubation time) in LIGHT PHOTO = NET + RESP = LIGHT + DARK where DO is the dissolved oxygen content in mgO2/liter. Note that the absolute values of RESP and DARK are used in the PHOTO equation. INITNH4, INITNO2, and INITNO23 Calculated from standard curves of absorbance versus known concentrations of standard solutions. concentration (ugN/liter) = [(m) * (absorbance)] + b RATENH4, RATENO2, and RATENO23 Calculated from changes in nutrient content within chambers from the beginning to the end of the incubation. rate = (final [N] - initial [N])/(incubation time) where [N] is the nutrient concentration. Reference Citations: Bendschneider, K. & R.J. Robinson, 1952. A new spectrophotometric method for the determination on nitrite in sea water. J. Mar. Res. 11: 87-96. Bott, T.L., J.R. Brock, C.E. Cushing, S.V. Gregory, D. King & R.C. Petersen, 1978. A comparison of methods for measuring primary productivity and community respiration in streams. Hydrobiologia 60: 3-12. Duff, J.H,, K.C. Stanley & R.J. Avanzino, 1984. The use of photosynthesis-respiration chambers to measure nitrogen flux in epilithic algal communities. Verh. Internat. Verein. Limnol. 22: 1436-1443. Elliot, R.J. & A.G. Porter, 1971. A rapid cadmium reduction methods for the determination of nitrate in bacon and curry lines. Analyst 96: 522-527. Grasshoff, K. & J. Johannsen, 1972. A new sensitive and direct method for the automatic determination of ammonia in seawater. J. Cons. Int. Explor. Mer. 34: 516-521. Greenberg, A.E., R.R. Trussell & L.S. Clesceri (Eds.), 1985. Standard methods for the examination of water and wastewater, 16th edition. American Public Health Association, Washington. Jones, M.N., 1984. Nitrate reduction by shaking with cadmium. Water Res. 18(5): 643-646. King, D.K., 1982. Community metabolism and autotrophic-heterotrophic relationships of woodland stream riffle sections. Ph.D. Thesis. Michigan State University, East Lansing. 356 pp. MacKereth, F.J.H., J.Heron & T.F. Talberg, 1978. Nitrate. In: MacKereth, F.J.H., J. Heron & T.F. Talberg (Eds.), Water analysis: some revised methods for limnologists, Freshwater Biological Association, Windermere, U.K.: 72-73. Murphy, M.L., 1984. Primary production and grazing in freshwater and intertidal reaches of a coastal stream, southeast Alaska. Limnol. Oceanogr. 29(4): 805-815. Naiman, R.J., 1983. The annual pattern and spatial distribution of aquatic oxygen metabolism in boreal forest watersheds. Ecol. Monogr. 53: 73-94. Pennak, R.W. & J.W. Lavelle, 1979. In situ measurements of net primary production in a Colorado mountain stream. Hydrobiologia 66: 227-235. Sampling Description. None

Data Table

Variable Name	Variable Description	Units	Measurement Scale	Code Information	Number Type	DateTime Format	Missing Value Code	Missing Value Code Explanation
SITE	LTER site code		nominal
D/D	distance from 1983 P dripper	kilometer	ratio		real
DATE date ddmmyy	date		datetime			dd-mmm-yy
LOCATION location (CONTROL, +P, +NP)	control, +P, or +NP		nominal
SUBSITE typically POOL or RIFFLE n	Pool or Riffle		nominal
Cover	Epilithic cover - epilithon, schistidium, or hygrohypnum		nominal
EXPT	experiment number		nominal
CHAMID	chamber id		nominal
TOTAL total chlorophyll a	Chlorophyll a	milligramsPerSquareMeter	ratio		real
RESP	respiration	milligramPerMeterSquarePerHour	ratio		real
PHOTO	photosynthesis	milligramPerMeterSquarePerHour	ratio		real
NET	Light	milligramPerMeterSquarePerHour	ratio		real
Temp	water temperature	celsius	interval		real
INITNH4	initial chamber NH4	microgramPerLiter	ratio		real
INITNO2	Initial chamber NO2	microgramPerLiter	ratio		real
INITNO23	Inititial chamber NO2+NO3	microgramPerLiter	ratio		real
RATENH4	change in NH4	microgramPerLiterPerHour	ratio		real
RATENO2	change in NO2	microgramPerLiterPerHour	ratio		real
RATENO23	change in NO2+NO3	microgramPerLiterPerHour	ratio		real
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