C ∕ N ratio, stable isotope (δ13C, δ15N), and n-alkane patterns of brown mosses along hydrological gradients of low-centred polygons of the Siberian Arctic

• Published in: Biogeosciences
• Main Authors: Zibulski, Romy, Wesener, Felix, Wilkes, Heinz, Plessen, Birgit, Pestryakova, Luidmila A., Herzschuh, Ulrike
• Format: Text
• Language: English
• Published: 2018
• Subjects: Arctic; Taymyr; lena river; Taymyr Peninsula; Siberia
• Online Access: https://doi.org/10.5194/bg-14-1617-2017; https://www.biogeosciences.net/14/1617/2017/

Mosses are a major component of the arctic vegetation, particularly in wetlands. We present C ∕ N atomic ratio, δ 13 C and δ 15 N data of 400 brown-moss samples belonging to 10 species that were collected along hydrological gradients within polygonal mires located on the southern Taymyr Peninsula and the Lena River delta in northern Siberia. Additionally, n -alkane patterns of six of these species (16 samples) were investigated. The aim of the study is to see whether the inter- and intraspecific differences in C ∕ N, isotopic compositions and n -alkanes are indicative of habitat, particularly with respect to water level. Overall, we find high variability in all investigated parameters for two different moisture-related groups of moss species. The C ∕ N ratios range between 11 and 53 (median: 32) and show large variations at the intraspecific level. However, species preferring a dry habitat (xero-mesophilic mosses) show higher C ∕ N ratios than those preferring a wet habitat (meso-hygrophilic mosses). The δ 13 C values range between −37.0 and −22.5 ‰ (median = −27.8 ‰). The δ 15 N values range between −6.6 and +1.7 ‰ (median = −2.2 ‰). We find differences in δ 13 C and δ 15 N compositions between both habitat types. For some species of the meso-hygrophilic group, we suggest that a relationship between the individual habitat water level and isotopic composition can be inferred as a function of microbial symbiosis. The n -alkane distribution also shows differences primarily between xero-mesophilic and meso-hygrophilic mosses, i.e. having a dominance of n -alkanes with long ( n -C 29 , n -C 31 ) and intermediate ( n -C 25 ) chain lengths, respectively. Overall, our results reveal that C ∕ N ratios, isotopic signals and n -alkanes of studied brown-moss taxa from polygonal wetlands are characteristic of their habitat.