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Conditions of Use

The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, educational, government, recreational, or other not-for-profit professional purposes. The Data User is permitted to produce and distribute derived works from this dataset provided that they are released under the same license terms as those accompanying this Data Set. Any other uses for the Data Set or its derived products will require explicit permission from the dataset owner.
2 ) Redistribution. The data are provided for use by the Data User. The metadata and this license must accompany all copies made and be available to all users of this Data Set. The Data User will not redistribute the original Data Set beyond this collaboration sphere.
3 ) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly cite the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier. For example:

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 

4 ) Acknowledgement. The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed significantly to its content. Acknowledgements should identify the supporting party, the party that received the support, and any identifying information such as grant numbers. For example:

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.

5 ) Notification. The Data User will notify the Data Set Contact when any derivative work or publication based on or derived from the Data Set is distributed. The Data User will provide the data contact with two reprints of any publications resulting from use of the Data Set and will provide copies, or on-line access to, any derived digital products. Notification will include an explanation of how the Data Set was used to produce the derived work.
6 ) Collaboration. The Data Set has been released in the spirit of open scientific collaboration. Data Users are thus strongly encouraged to consider consultation, collaboration and/or co-authorship with the Data Set Creator.

By accepting this Data Set, the Data User agrees to abide by the terms of this agreement. The Data Owner shall have the right to terminate this agreement immediately by written notice upon the Data User's breach of, or non-compliance with, any of its terms. The Data User may be held responsible for any misuse that is caused or encouraged by the Data User's failure to abide by the terms of this agreement.

Disclaimer

While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data, Dataset via LTER Data Poral
Dataset ID:2005gsimHydrlysN.03
Dataset Title:Pool size and 15N atom % of nydrolyzable N in natural and enriched soils in Imnavait watershed
Investigator 1: 
First Name:Gus
Last Name:Shaver
Organization:Ecosystems Center
Address line 2:Marine Biological Lab
Address line 3:
City:Woods Hole
State:MA
Zip Code:2543
Country:USA
Investigator 2: 
First Name:Yuriko
Last Name:Yano
Organization:Ecosystems Center
Address line 2:Marine Biological Lab
City:Woods Hole
State:MA
Zip Code:2543
Country:USA
Investigator 3: 
First Name:Anne
Last Name:Giblin
Organization:
Address line 2:
City:
State:
Zip Code:
Country:
Investigator 4: 
First Name:Ed
Last Name:Rastteter
Investigator 5: 
First Name:Jim
Last Name:Laundre
Investigator 6: 
First Name:Christie
Last Name:Haupert
Associate Investigators:
Keywords:hydrolyzable ammonium, hydrolyzable amino sugars, hydrolyzable amino acids, inorganic nutrients, organic matter
Abstract:Hydrolyzable N pool size and 15N atom % of natural and enriched soils collected from Imnavait watershed in summer of 2005.
For questions about the Metadata and data contact the Investigators.
For information about this web site 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.10181&urlTail=terrest/bulk/data/2005gsimHydrlysN.csv
Data File Name 2005gsimHydrlysN.dat
Beginning Date 7/16/2005
End Date 7/20/2005
Number of Data Records 120
Other Files to Reference
Availability Status 1
Quality Control Information
Maintenance Description
Log of Changes: Updated Metadata sheet
Version 2: Updated units to current standards. Missing values changed to #N/A. Updated metadata form to newer version (without site sheet). Fixed discrepency with header variable names. CH 24 Jan 2013 Updated to newer metadata with site sheet. CH March 2013.
Version 3: Checked keywords against the LTER network preferred list and replaced non-preferred terms. Jim L 27Jan14
 
RESEARCH LOCATION:                                            
Location Name Imnaviat watershed- eastern slope Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One  
Geographic Description Eastern slope of Imnavait watershed. ~1km south of main weir, ~4 km south of Dalton Hwy. Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description  
Location Bounding Box                                            
West Bounding Coordinate                                            
East Bounding Coordinate                                            
North Bounding Coordinate                                            
South Bounding Coordinate                                            
OR if single point location                                            
Latitude 68.6081 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Longitude -149.3078 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Elevation In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters In Meters  
Link to Google Map View on Google Map                                          
                                             
 
TAXONOMIC COVERAGE:
Organisms studied
 
Methods:Soil sampling and extraction
Four randomly-located soil cores (diameter range: 5-6cm) were collected from each 15N addition plot after 2 yr (16 and 20 Jul 2005). At each collection, cores were taken to the maximum possible depth, defined as either the full core length (40 cm), the bottom of the seasonally thawed “active layer”, or to a rock (at Crest only). Upon collection, the length of the core was measured and the core was separated in the field into the following layers by cutting with a knife on a clean plastic sheet:
(1) Green Layer, the surface live moss-detritus-plant layer including lichens, graminoid foliage < 2 cm above the ground, and groundcover species (e.g., Vaccinium vitis-idaea, Empetrum nigrum, forbs).
(2) 2nd layer or 1st Organic Layer, the upper ~10 cm of organic soil beneath Green layer

Within 12 hrs of collection, soil samples were weighed, homogenized, and live roots and rocks hand-picked. Subsamples were dried at 50 ºC to determine moisture content. Subsamples of the 1st Organic Layer was chemically fractionated by acid hydrolysis. To obtain natural 15N abundance for these fractions, three additional soil cores were collected from outside of the plots at six topolocations (CR, MS-WT, MS_NWT, FS_WT, FS_NWT, and R), processed as described above, then composited by the topolocations (total number of subsamples =6). All soils were kept frozen until analysis.

Pool size and d15N signature of hydrolyzable-N pools
The pool size and % 15N atom excess (determined as a difference in atom% between natural abundance soil and 15N added soil) were determined by chemically fractionating soil N into three hydrolysable labile-N pools; hydrolysable NH4+ (HNH4+), amino acids (HAA), and amino sugars (HAS).

Soils were thawed and five replicates (2–10 g) of ground samples were hydrolyzed in hot 6 N HCl for 12 h under reflux according
to Mulvaney and Khan (2001). The hydrolysates were neutralized with NaOH (Mulvaney and Khan 2001). Hydrolysable NH4+ was determined by a hypochlorite-alkaline phenol method. To determine d15N in this pool, aliquots (~10 mmol-N) of the hydrolysates were diffused in a 450-mL Mason jar with MgO at 50 °C for 6 hr onto an acid trap according to Mulvaney and Khan (2001), but replacing their “wet” acid trap (a beaker containing 5 mL of 4% H3BO3) with a “dry” acid trap (an acidified GF/D filter disc encapsulated in Teflon tape) so that N on the trap could be directly analyzed for d15N by isotope ratio mass spectrometry.

Concentration and d15N of hydrolysable amino sugar and amino acid were determined by a sequential diffusion of the neutralized hydrolysates. For concentration, the hydrolysate was diffused for 8 hrs into a wet acid trap, then re-diffused with a new wet acid trap for 6 hrs after converting amino acids to NH4+ by a ninhydrin reaction under an acidic condition (Mulvaney and Khan 2001). Both first (HAS) and second (HAA) acid traps were analyzed for NH4+concentration as for hydrolysable ammonium.

To determine d15N of the HAS and HAA pools, aliquots of the hydrolysate (~10 mmol-N) were sequentially diffused with dry acid traps in place of wet traps. Because total soil N is a sum of hydrolysable-labile N (HNH4+, HAS, and HAA) and non-hydrolysable-labile N (non-HLN), pool sizes and d15N signatures of non-HLN fraction was calculated by mass balance of known N pools (total soil N, HNH4+, HAS, and HAA).


** Mulvaney, R. L., and S. A. Khan. 2001. Diffusion methods to determine different forms of nitrogen in soil hydrolysates. Soil Science Society of America Journal 65: 1284-1292.

Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
15NLevel 15N level (natural abundance vs. enriched) text        
Type Type text        
Topo Topolocation at which 15N treatment plots were established and soilcores collected. The 15N treatment plots are located along the hillslope (CR=crest; MS= mid-slope; FS=foot-slope; R=riparian wetsedge) text        
WT Whether the tundra has watertrack or not. WT = watertrack tussock; NWT= non-watertrack tussock; "na" = non tussock tundra. text        
Plot Location of the soil cores collection. Enriched samples were collected from within the 15N addtion plots (A, B, C, ...L), whereas natural abundance samples were collected from outside of those plots either near the plots. "nearAB" = near plots A and B, "nearCE" near plots C and E, ...etc) text        
N_umol_g N concentration determined for 15N-addition plots (micro mol of N per gram of dry soil) number micromolePerGram     #N/A=Missing or Not Measured
15NApct 15N Atom% (15N mass% of total N) number percent      
pctAE %15N atom excess (difference between 15N Atom% of enriched soil and natural-abundance soil). "na" = not applicable for natural abundance soils. number percent     #N/A=Missing or Not Measured
pctNpool percent pool size of total bulk N number percent      

Please contact arc_im@mbl.edu with questions, comments, or for technical assistance regarding this web site.