Stable isotope composition of plants and peat from Arctic mire and geothermal area in Iceland

• Published in: Polish polar research Vol. 29; no. 4; pp. 365 - 376
• Main Authors: Skrzypek, G, Paul, D, Wojtun, B
• Format: Journal Article
• Language: English
• Published: 01.01.2008
• ISSN: 0138-0338

Stable hydrogen, carbon, nitrogen, and oxygen isotope compositions and elements ratios are presented for peat and plant samples (liverworts, mosses, sedge, willow, grass) from two contrasting ecosystems in Iceland: Arctic mire at the northwest coast (Drangajoekull) and a geothermal area (Kerlingarfjoell). In a peat core from the Arctic mire excellent correlation between different pairs of elements H-C, H-N and C-N were observed. These strong linear correlations (R super(2) between 0.98 and 1.00, p < 0.01) suggest that the elements ratios are nearly constant along the peat core profile and are close to the initial values in the peat-forming plants. The delta super(13)C values of mosses collected from climatically different locations correlate with average air temperature at the sampling place (-1.6ppt per degree C). The 8D and delta super(18)O values of plants are dependent on the isotopic composition of water sources, whereas the delta super(15)N value of plants is dependent on the nitrogen sources (decay of organic matter, amino acid assimilation, fixation of atmospheric nitrogen). The negative delta super(15)N values of plants in the range from -1.72 to -5.49ppt at Kerlingarfjoell suggest the uptake of nitrogen of organic origin released during bacterial decay. In contrast, the positive delta super(15)N close to 0ppt at Drangajoekull may have resulted primarily from atmospheric nitrogen fixation. The major goal of this study was to confirm that the original elements ratios, as well as the stable isotopic compositions ( delta D, delta super(13)C and delta super(15)N) of peat-forming plants are well preserved in a peat formed in cold regions. Therefore, stable isotope composition of peat may potentially be used in palaeoenvironmental reconstruction of Arctic environments.