The main focus of the experiment is to determine the importance of climate controls (temperature and moisture), the effects of nutrient availability, and the source of carbon and reducing power for methanogensis in the tundra system. To obtain this type of information methane and carbon dioxide emissions were monitored in control, greenhouse, and nitrogen and phosphorus fertilized plots of three different plant ecosystems; 1. Wet Sedge Tundra 2. Tussock Tundra 3. Heath Tundra The treatments were started at the Toolik site in 1989, In 1991 the fertilized plots received 10 g N per m^2 in the form of ammonium nitrate and 5 g of P per m^2 in the form of phosphoric anhydride.

This data set was obtained by the collaboration of three projects. The LTER Arctic Tundra (NSF), The Global Change and the Carbon Balance of Arctic Ecosystems (P.I.-Shaver and others, NFS), and the main project, Controls on Radiatively Active Trace Gases in Tundra and Taiga Ecosystems (P.I.s J.Schimel and K. Nadelhoffer, EPA)
The schematic below shows the SITE, ECOSYSTEM, # of BLOCKS within each ecosystem, the TREATMENTS (CT=Control;GH=Green House;NP=Nitrogen and Phosphorus additions) and the # OF CHAMBERS PER TREATMENT.
ALL CHAMBER BASES WERE PUT IN AT THE BEGINNING OF THE SEASON OF 1992 WITH
THE EXCEPTION OF 1 CHAMBER BASE PER EACH BLOCK AT THE HEATH SITE.
The deployment dates of the chamber bases are given for each ECOSYSTEM
ECOSYSTEM
TREATMENTS W/IN # OF CHAMBERS/ DATE CHAMBER
SITE ECOSYSTEM # OF BLOCKS EACH BLOCK BLOCK BASES DEPLOYED
|- 4 ::::: CT::::::::: 4-(T;IT)*
| TUSSOCK
|:TUSSOCK:::|- 4 ::::: GH::::::::: 2-(T;IT)* 16 JUNE 92'
| |
| |- 4 ::::: NP::::::::: 2-(T;IT)*
| :-
| subtotal 32
|
T | |- 2 ::::: CT::::::::: 3
O | | WET SEDGE
O :-|- WET SEDGE::|- 2 ::::: GH::::::::: 2 16 JUNE '92
L | |
I | |- 2 ::::: NP::::::::: 3
K | :-
| subtotal 16
|
| |- 3 ::::: CT::::::::: 2
| | HEATH
|: HEATH:::-|- 2 ::::: GH::::::::: 2 19 JUNE 92'
| only one new
|- 3 ::::: NP::::::::: 2 chamber per block
:-
subtotal 16
===
TOTAL 64
*In the TUSSOCK ECOSYSTEM T= Chamber bases around tussocks- odd chamber #'s and
IT= Chamber bases around intertussocks- even chamber #'s.

Notes: Calculated by using only T0 and T1 time samples except where these values were bad/odd.

CALCULATIONS
Variable Formula
CH4_C MG|M2|DAY: (CH4FLUX*0.012*1440)
CO2_C G|M2|DAY: (CO2FLUX*0.000012*1440)