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LBA-ECO CD-04 Soil Respiration, km 83 Tower Site, Tapajos National Forest, Brazil
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Revision date: September 7, 2011

Summary:

This data set reports on the flux of carbon dioxide from logged forest soils near the eddy flux tower at the km 83 site, Para, Brazil. The automated soil respiration measurements were collected using 15 chambers, installed August 2001 in primary forest. Data were collected between December 19, 2001 and March 1, 2002. There is one comma-delimited data file with this data set.


Figure 1. Automated collection chamber

Data Citation:

Cite this data set as follows:

Goulden, M.L., H.R. da Rocha, S.D. Miller and H.C. de Freitas. 2011. LBA-ECO CD-04 Soil Respiration, km 83 Tower Site, Tapajos National Forest, Brazil. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. http://dx.doi.org/10.3334/ORNLDAAC/1039

Implementation of the LBA Data and Publication Policy by Data Users:

The LBA Data and Publication Policy [http://daac.ornl.gov/LBA/lba_data_policy.html] is in effect for a period of five (5) years from the date of archiving and should be followed by data users who have obtained LBA data sets from the ORNL DAAC. Users who download LBA data in the five years after data have been archived must contact the investigators who collected the data, per provisions 6 and 7 in the Policy.

This data set was archived in September of 2011. Users who download the data between September 2011 and August 2016 must comply with the LBA Data and Publication Policy.

Data users should use the Investigator contact information in this document to communicate with the data provider. Alternatively, the LBA Web Site [http://lba.inpa.gov.br/lba/] in Brazil will have current contact information.

Data users should use the Data Set Citation and other applicable references provided in this document to acknowledge use of the data.

Table of Contents:

1. Data Set Overview:

Project: LBA (Large-Scale Biosphere-Atmosphere Experiment in the Amazon)

Activity: LBA-ECO

LBA Science Component: Carbon Dynamics

Team ID: CD-04 (Goulden / Rocha)

The investigators were Goulden, Dr. Michael L.; Menton, Mary Catherine; Miller, Dr. Scott D.; Rocha, Prof. Humberto Ribeiro da; Freitas, Helber Custodio de; Figuera, Michela and Sousa, Cleilim Albert Dias de . You may contact Miller, Dr. Scott D. (smiller@albany.edu ) and Goulden, Dr. Michael L. (mgoulden@uci.edu)

LBA Data Set Inventory ID: CD04_Soil_Respiration

Automated soil respiration measurements were collected using 15 chambers near the eddy flux tower at km 83, Tapajos National Forest, Para, Brazil. Chambers were installed August 2001 in primary forest. Selective logging occurred between September and December of 2001. After logging, 5 chambers were moved to a gap formed by the logging. Data were collected between December 19, 2001 and March 1, 2002.

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2. Data Characteristics:

Data are presented in one comma-delimited ASCII file:

CD04_TNF_KM83_Soil_Respiration.csv

ColumnHeading Units/formatDesription
1Day_of_study Sampling point in decimal day. Noon on January 1 2001 equals 1.5
2Vegetation Location of the chamber: intact forest or gap, at day 410 chambers 11- 15 were moved from intact forest to a gap
3Chamber Chamber ID
4CO2_Fluxmicromol m-2 s-1Flux of carbon dioxide in micromoles per meter squared per second (umol m-2 s-1), positive values represent net flux from the soil surface to the atmosphere while negative values represent net uptake of CO2 by the soil
5T_chamber_airdegrees CTemperature of the air inside the chamber in degrees Celsius
 
Missing data are represented by -999

Example data records:

Day_of_study,Vegetation,Chamber,CO2_Flux,T_chamber_air

353.0049,forest,1,1.6,23.9
353.0132,forest,2,1.8,24.0
353.0215,forest,3,1.8,23.7
353.0299,forest,4,1.1,24.2
353.0382,forest,5,2.0,23.5
353.0465,forest,6,1.9,23.0
353.0549,forest,7,2.2,22.6
353.0632,forest,8,2.7,22.3
...

Site boundaries: (All latitude and longitude given in decimal degrees)

Site (Region) Westernmost Longitude Easternmost Longitude Northernmost Latitude Southernmost Latitude Geodetic Datum
Para Western (Santarem) - km 83 Logged Forest Tower (Para Western (Santarem)) -54.9707- 54.9707- 3.017 - 3.017 World Geodetic System, 1984 (WGS-84)

Time period:

Platform/Sensor/Parameters measured include:

3. Data Application and Derivation:

Soil CO2 efflux is the sum of litter decomposition, soil organic matter decomposition, and root respiration. It can account for up to 30 percent of ecosystem respiration in tropical forests. This data set is a valuable tool to determine the diurnal, seasonal, and interannual controls on CO2 efflux from the soil surface in the Tapajos National Forest.

4. Quality Assessment:

Fluxes were not calculated for periods with obvious sampling problems (e.g. abnormally high or low initial CO2 mixing ratios, extremely non-linear fluxes, etc.) Fluxes deemed good visually were fitted with a linear least squares regression to the linear part of the curve for each individual chamber closure. Efflux of CO2 from the soil was calculated as the slope of the linear fit (ppmv/min) converted to molar volume divided by the collar area and multiplied by the system volume (chamber volume and tubing volume). The short closure times for the fluxes allow for the least amount of buildup of CO2 in the chamber headspace while still allowing for a flux calculation based on 10 to 20 concentration measurements.

5. Data Acquisition Materials and Methods:

Automated soil respiration measurements were collected near the eddy flux tower at km 83, Tapajos National Forest, Para, Brazil. Selective logging occurred between September and December of 2001. After logging, 5 chambers were moved to a gap formed by the logging.

Aluminum chambers were used to measure the efflux of CO2 from the soil to the atmosphere following the procedures of Goulden and Crill (1997). Fifteen chambers were set up to measure trace gas exchange between the soil and atmosphere about 8 times a day. Each chamber was sampled for 12 min although the CO2 flux was measured within the first 4 minutes. Chambers were pushed closed over an area of 1,866 cm2 by a pneumatic cylinder onto an anchor/frame that was set about 2 cm into the soil and extended an average of 4 cm above the soil surface. Closed chambers were sealed to the frame by fitting into a water-filled trough that was replenished as needed. They enclosed an average volume of 38,100 cm3. Headspace air was pulled through an infrared gas analyzer (LI-6262, LiCor Inc., Lincoln, Nebraska, USA) in absolute mode at a flow rate of 300 ml m-1 (MKS Instruments, Andover, MA). Air was circulated through the chambers at 1,000 ml min-1. Chambers were intentionally leaky to ensure no pressure gradient when the chambers were closed. All tubing and connectors were selected to minimize water vapor, and CO2 absorption and permeability.

The data were recorded and the system managed with a CR10X datalogger (Campbell Scientific, Logan UT). The chamber temperature, IRGA sample cell pressure, and raw CO2 were sampled every 3 seconds and averaged every 12 seconds. The solenoids used for chamber selection, chamber closure and calibration were controlled with four 16-channel control modules. The set point for the mass flow controller was provided by a 4 channel analog output module. The signals from the thermocouples in each chamber were multiplexed.

 

6. Data Access:

This data is available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Data Archive Center:

Contact for Data Center Access Information:
E-mail: uso@daac.ornl.gov
Telephone: +1 (865) 241-3952

7. References:

Goulden M.L. and P.M. Crill. 1997. Automated measurements of CO2 exchange at the moss surface of a black spruce forest. Tree Physiology 17:537-542.

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