NOTICE -- The LBA-ECO Project website is no longer being supported.  This archive is a snapshot, as it existed in 2013, of the LBA-ECO website, maintained by NASA Goddard Space Flight Center, and now archived at the ORNL DAAC.  Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC.
banner
banner banner banner banner banner banner
banner banner banner banner banner banner banner
home aboutlibrarynews archivecontacts banner

spacer
banner
Investigations
Overview
Abstracts & Profiles
Publications
Research Sites
Meetings
Synthesis Groups
LBA-HYDROMET
LBA-Air-ECO
Logistics
Overview
Field Support
Travel
Visa
Shipping
Data
  Overview
Find LBA Data
Investigator Checklist
Process & Policy
Documentation & Archive
Training & Education
  Overview
Activities Summary
T&E Goals
Student Opportunities
  Folha Amazônica
 
spacer

Investigation:

ND-02 (Davidson / Stone / Markewitz / Carvalho / Sa / Vieira / Moutinho / Figueiredo)

LBA Dataset ID:

ND02_SOIL_GASES_REE

Originator(s):

1. DAVIDSON, E.A.
2. DE CARVALHO, C.J.R.
      3. FIGUEIREDO, R.D.O.

Point(s) of Contact:

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Dataset Abstract:

Changes in precipitation in the Amazon Basin resulting from regional deforestation, global warming, and El Nino events may affect emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and nitric oxide (NO) from soils. Changes in soil emissions of radiatively important gases could have feedback implications for regional and global climate. Here we report results of a multi-year a large-scale (1 ha) throughfall exclusion experiment, conducted in a mature evergreen forest near Santarem, Brazil.

Beginning Date:

1999-12-09

Ending Date:

2002-06-14

Metadata Last Updated on:

2012-09-14

Data Status:

Archived

Access Constraints:

PUBLIC

Data Center URL:

http://daac.ornl.gov/

Distribution Contact(s):

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Access Instructions:

PUBLIC

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

LBA-ECO ND-02 Soil Gas and Water Content, Rainfall Exclusion, Tapajos National Forest:  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1117

Documentation/Other Supporting Documents:

LBA-ECO ND-02 Soil Gas and Water Content, Rainfall Exclusion, Tapajos National Forest:  http://daac.ornl.gov/LBA/guides/ND02_Soil_Gases_REE.html

Citation Information - Other Details:

Davidson, E.A., C.J.R. de Carvalho, R.O. Figueiredo. 2012.LBA-ECO ND-02 Soil Gas and Water Content, Rainfall Exclusion, Tapajos National Forest: 1999-2002. 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/1117

Keywords - Theme:

Parameter Topic Term Source Sensor
CARBON DIOXIDE BIOSPHERE SOILS FIELD SURVEY GAS CHROMATOGRAPHS
NITROUS OXIDE BIOSPHERE SOILS FIELD SURVEY GAS CHROMATOGRAPHS
SOIL MOISTURE/WATER CONTENT BIOSPHERE SOILS FIELD SURVEY TIME DOMAIN REFLECTOMETER

Uncontrolled Theme Keyword(s):  GAS FLUX, SOIL GASES, TROPICAL FORESTS

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
Pará Western (Santarém) km 67 Seca-Floresta Site -2.75000 -2.75000 -55.00000 -55.00000

Related Publication(s):

Davidson, E.A., F.Y. Ishida, D.C. Nepstad. 2004. Effects of an experimental drought on soil emissions of carbon dioxide, methane, nitrous oxide, and nitric oxide in a moist tropical forest. Global Change Biology 10:718-730. doi:10.1111/j.1365-2486.2004.00762.x

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data are available in one ASCII comma separated file titled: REE_soil_gases_1999-2002.csv



The data are organized as follows:





File name:,REE_soil_gases_1999_2002.csv

File date:,2-Jul-12

Associated LME file: ND02_Soil_Gases_REE





Column,Column_heading,Units/format,Explanation

1,Depth ,cm,Sampling depth from soil surface

2,Pit number,,Pit identifcation

3,Treatment,,Plot treatment either rainfall exclusion or control

4,Date,YYYMMDD,Sampling date

5,VWC,cm3 H2O per cm3 soil,Soil volumetric water content reported in cubic centimeters of water per cubic centimeter of soil

6,conc_CO2,% ,Concentration of carbon dioxide reported in percent

7,conc_N2O ,ppm ,Concentration of nitrous oxide reported in parts per million



,missing data represented by -9999



Sample data:

Depth ,Pit number,Treatment,Date,VWC,conc_CO2,conc_N2O

10,1,exclusion,19991209,-9999,0.74,0.7

25,1,exclusion,19991209,-9999,1.49,1.29

30,1,exclusion,19991209,0.337,-9999,-9999

50,1,exclusion,19991209,0.217,1.96,1.85

100,1,exclusion,19991209,0.212,1.96,0.54

200,1,exclusion,19991209,0.247,2.65,0.7

300,1,exclusion,19991209,0.201,2.81,0.68

400,1,exclusion,19991209,0.245,-9999,-9999

500,1,exclusion,19991209,0.273,-9999,-9999

600,1,exclusion,19991209,0.329,-9999,-9999

700,1,exclusion,19991209,0.348,4.28,0.58

800,1,exclusion,19991209,0.256,-9999,-9999

900,1,exclusion,19991209,0.239,-9999,-9999

1000,1,exclusion,19991209,0.313,-9999,-9999

1100,1,exclusion,19991209,0.391,10.23,0.84

10,2,exclusion,19991209,-9999,1.46,1.35

25,2,exclusion,19991209,-9999,0.82,1.41

30,2,exclusion,19991209,0.364,-9999,-9999

50,2,exclusion,19991209,0.268,0.35,2.75

100,2,exclusion,19991209,0.285,3.03,1.74

Data Application and Derivation:

Stratified measurements of soil gas concentrations can be used to understand the effect of drought and seasonality on carbon and nitrogen budgets as well as greenhouse gas emissions from mature tropical forests.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

Duplicate syringe samples were analyzed for gas concentrations from each gas sampling tube at each depth in each soil pit. All chromatographs were visually inspected to determine good peak separation. Standard curves were repeated approximately every two hours to adjust for potential instrument drift.

Process Description:

Data Acquisition Materials and Methods:

The Tapajos National Forest, located in east-central Amazonia, receives 600 to 3000 mm of rain each year, with a mean of 2000 mm, most of which falls during the wet season from January to June. The forest is situated on a terrace

of tertiary sediments capped by the Belterra Clay Formation (Clapperton, 1993). The Oxisol soil (Haplustox) is acidic (pH 4 to 5), is dominated by kaolinite clay minerals (60 to 80% clay), and is free of hardpan or iron oxide concretions in the upper 12 m; the water table is more than 100 m deep. The forest has emergent trees up to 55 m in height, with a continuous canopy at approximately 30 m (Nepstad et al., 2002).



Two 1 ha plots were identified from an initial survey of 20 ha of forest. A 1.5 m deep trench was excavated around the perimeter of the treatment plot to reduce the potential for lateral movement of soil water from the surrounding forest into the plot. A similar trench was excavated around the control plot to avoid the confounding of treatment and trenching effects.



Plastic PAR-transmitting greenhouse panels were installed in the understory of the exclusion plot only for the duration of the rainy season. The panels were

installed such that small gaps were left around tree stems to allow in nutrient-rich stemflow. In all, about half of the annual rainfall was diverted from the exclusion plot. While they were in place, panels were flipped on their sides every two days to return any accumulated litter to the forest floor beneath.



Volumetric soil water content was measured to 11 m depth in each of the soil

shafts using time domain reflectrometry (TDR). The rods of each sensor were imbedded at one end in an epoxy resin head. Each sensor was installed at the end

of a 1.5 m auger hole drilled horizontally into the wall of the shaft (the rods pushed into the intact soil) to avoid shaft effects on soil moisture; the holes were then backfilled with soil. Each of the six shafts (three per plot) have duplicate vertical sensors at the soil surface and duplicate horizontal sensors in opposite walls at 50, 100, 200, 300 cm, and at 100 cm intervals to 1100 cm

depth. The dielectric constant of the TDR probes was measured with a cable tester, and VWC was estimated from the calibration equation developed in a similar Belterra clay formation, in eastern Amazonia (Jipp et al., 1998). The mean VWC was calculated from the duplicate TDR probes at each depth in each shaft.



Soil gas sampling

Stainless steel gas sampling tubes (3 mm diameter) were installed into the walls of each of the six soil shafts at depths of 10, 25, 50, 100, 200, 300, 700, and 1100 cm, following the methodology of Davidson and Trumbore,(1995). The tubes were placed into 1.5 m long horizontal auger holes that were then backfilled. Duplicate gas samples of 20 mL were withdrawn from each tube through a septum and fitting on the exposed end in the soil pit using a nylon syringe. The N2O and CH4 concentrations were analyzed by ECD and FID gas chromatography, as described above for syringe samples. The CO2 concentrations in the soil profiles were sufficiently high that quantification could be achieved with the ECD.

References:

Clapperton C (1993) Quaternary Geology of South America.

Elsevier Science, New York



Davidson EA, Trumbore SE (1995) Gas diffusivity and production of CO2 in deep soils of the eastern Amazon. Tellus, 47B, 550--565



Jipp P, Nepstad DC, Cassel K et al. (1998) Deep soil moisture storage and transpiration in forests and pastures of seasonally-dry Amazonia. Climatic Change, 39, 395--412



Nepstad DC, Moutinho PRdS, Dias-Filho MB et al. (2002) The effects of rainfall exclusion on canopy processes and biogeochemistry of an Amazon forest. Journal of Geophysical Research, 107, 8085, doi:10.1029/2001JD000360.

Skip navigation linksHOME | ABOUT | LIBRARY | NEWS ARCHIVE | CONTACTS | INVESTIGATIONS | LOGISTICS | DATA |TRAINING & EDUCATION

NASA logo
ORNL DAAC
Get Acrobat Reader