Biomass Production and Chemistry |
General Description |
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Biomass measurements near Toolik Lake, Alaska were first made in 1982. Since then additional measurements have been made, including harvesting several times through the growing season. The harvests have included several different tundra types (heath, wet sedge, acidic and non acidic mesic tussock, shrub), both treated and untreated plots, woody stem biomass, and across several different sites. Per cent carbon nitrogen and phosphorus were also measured for several of the harvests. |
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Table 1 lists the biomass harvests. It contains the following information for each harvest: date, site and treatment. |
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Below is a description of the general method. Exceptions and modifications for a particular harvest are noted in the documentation for that harvest. |
Method |
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Field: Samples are obtained by collecting all aboveground biomass and belowground stems and rhizomes in 20 x 20 cm quadrats, located randomly along line transects within the site. Normally, 4 or 5 quadrats are collected along each of 4 transects at each site or treatment. Aboveground biomass is considered "within" the quadrat if it is associated with a meristem that is within the quadrat. Details are given in Shaver and Chapin (Ecological Monographs, 61(1), 1991, pg. 1.) |
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Lab: Each quadrat is first sorted into species and then into tissue type. Depending on the harvest, tissue types can be broad categories, i.e. above and below, or more detailed, i.e. inflorescences, new growth, old growth, etc. The separated samples are dried for several days at approximately 65 ºC and then weighed. The dry weight for each quadrat, species and tissue type is recorded. Finally the samples from all quadrats in a transect are combined according to tissue type. Samples are then returned to Woods Hole for nutrient analysis. |
Table 1: Biomass Harvests 1982-Present |
| Date | Site | Treatment |
| -------------------- | ------------------------------- | ---------------------------------- |
| 01-Jun-1982 | Atigun Wet Sedge | Control |
| Toolik Heath | Control | |
| Toolik Shrub | Control | |
| 1981 Toolik Tussock | Control | |
| 31-Jul-1982 | Atigun Wet Sedge | Control |
| Toolik Heath | Control | |
| 1981 Toolik Tussock | Control | |
| 01-Sep-1982 | Atigun Wet Sedge | Control |
| 1981 Toolik Tussock | Control | |
| 21-May-1983 | 1981 Toolik Tussock | Control |
| Greenhouse | ||
| Greenhouse Nitrogen Phosphorus | ||
| Nitrogen Phosphorus | ||
| Shade | ||
| 14-Jun-1983 | 1981 Toolik Tussock | Control |
| Nitrogen Phosphorus | ||
| 03-Jul-1983 | 1981 Toolik Tussock | Control |
| Nitrogen Phosphorus | ||
| 30-Jul-1983 | 1981 Toolik Tussock | Control |
| Greenhouse | ||
| Greenhouse Nitrogen Phosphorus | ||
| Nitrogen Phosphorus | ||
| Shade | ||
| 23-Aug-1983 | 1981 Toolik Tussock | Control |
| Nitrogen Phosphorus | ||
| 26-Jul-1984 | 1981 Toolik Tussock | Control |
| Nitrogen Phosphorus | ||
| 31-Jul-1988 | Sag Willow (1) | Control |
| Sag Wet Sedge (2) | Control | |
| Sag Foot Slope (3) | Control | |
| Sag Hill Slope (4) | Control | |
| Sag Heath (5) | Control | |
| Sag Tussock (6) | Control | |
| 21-Jul-1989 | 1981 Toolik Tussock | Control |
| Greenhouse | ||
| Greenhouse Nitrogen Phosphorus | ||
| Nitrogen Phosphorus | ||
| Shade | ||
| 27-Jun-1992 | LTER Acidic Tussock 15N | Control |
| 10-Aug-1992 | LTER Acidic Tussock 15N | Control |
| 04-Jul-1993 | LTER Acidic Tussock 15N | Control |
| 031-Jul-1994 | LTER Wet Sedge | Control |
| Greenhouse | ||
| Greenhouse Nitrogen Phosphorus | ||
| Nitrogen | ||
| Nitrogen Phosphorus | ||
| Phosphorus | ||
| Shade | ||
| 31-Jul-1995 | 1981 Toolik Tussock | Control |
| Nitrogen Phosphorus | ||
| 31-Jul-1996 | LTER Health | Control |
| Nitrogen | ||
| Nitrogen Phosphorus | ||
| Phosphorus | ||
| Shade | ||
| 31-Jul-1999 | LTER Non Acidic Tussock | Control |
| LTER Moist Acidic Tussock | Control Small Fenced | |
| Control Unfenced | ||
| Nitrogen Phosphorus Small Fenced | ||
| Nitrogen Phosphorus Unfenced | ||
| 30-Jul-2000 | 1981 Toolik Tussock | Control |
| Nitrogen Phosphorus | ||
| 031-Jul-2001 | LTER Wet Sedge | Control |
| Greenhouse | ||
| Greenhouse Nitrogen Phosphorus | ||
| Nitrogen | ||
| Nitrogen Phosphorus | ||
| Phosphorus | ||
| 031-Jul-2001 | LTER Acidic and NonAcidic Moist Tussock Tundra | Control |
| Greenhouse | ||
| Greenhouse Nitrogen Phosphorus | ||
| Nitrogen | ||
| Nitrogen Phosphorus | ||
| Phosphorus | ||
| 30-Jul-2002 | LTER Moist Acidic Tussock | Control |
| Nitrogen Phosphorus | ||
| Control Small Fenced | ||
| Nitrogen Phosphorus Small Fenced | ||
| Nitrogen Phosphorus Unfenced |