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Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is a powerful tool for investigating the biochemical fingerprint of plants, but its applicability to tundra plant leaves has yet to be addressed. The present study aimed to apply ATR-FTIR measurement to characterize tundra plant leaves and to discriminate these among plant species with different growth forms. The ATR-FTIR spectra in the fingerprint region (1800–800 cm−1) of live and dead leaves from 14 tundra plant species of shrubs, forbs, graminoids, and mosses showed a variability in overall appearance among plant species and a degree of similarity between live and dead leaves of the same plant species. Four highest peaks were found at 1637–1575 cm−1, 1452–1406 cm−1, 1325–1313 cm−1, and 1058–1022 cm−1 in these spectra and are attributed to chemical features of lignin, cellulose, and/or oxalate. Principal component analyses showed that leaves of Oxyria digyna and other forbs had distinctive spectral characteristics attributable to the content of oxalate and other putative compounds and that contents of lignin relative to cellulose were generally greater in shrubs than in graminoids and mosses. These results demonstrated that ATR-FTIR spectroscopy is useful for future applications in polar biology and ecology, for example the description of functional traits of arctic plants and decomposition processes by microbes. [ABSTRACT FROM AUTHOR]

Moss tundra that accumulates a thick peat layer is one of the most important ecosystems in the High Arctic, Svalbard. The importance of this ecosystem for carbon sequestration was estimated from the apparent rates of carbon accumulation based on the 14 C age and amount of peat in the active layer. The study site at Stuphallet, Brøgger Peninsula, northwestern Svalbard was covered with a thick peat layer dominated by moss species such as Calliergon richardsonii , Paludella squarrosa , Tomenthypnum nitens , and Warnstorfia exannulata . The average thickness of the active layer (brown moss and peat) was approximately 28 cm in 1 August 2011. The calibrated (cal) age of peat from the bottom of the active layer (20–30 cm below the peatland surface) ranged from 81 to 701 cal yr BP (median value of 2σ range). Based on the total carbon (4.5–9.2 kg C m −2 ), the apparent rate of carbon accumulation in the active layer was 9.0–19.2 (g C m −2 yr −1 ), which is similar to or greater than the net ecosystem production or net primary production reported for other vegetation types in this area. Our data suggest that moss tundra plays an important role in carbon sequestration in this area. [ABSTRACT FROM AUTHOR]

We used observational and experimental analyses to investigate the photosynthetic activity and water relationships of five lichen species attached to different substrates in a glacier foreland in the High Arctic, Ny-Ålesund, Svalbard (79°N) during the snow-free season in 2009 and 2010. After the rains ceased, lichens and their attached substrates quickly dried, whereas photosynthetic activity in the lichens decreased gradually. The in situ photosynthetic activity was estimated based on the relative electron transportation rate (rETR) in four fruticose lichens: Cetrariella delisei , Flavocetraria nivalis , Cladonia arbuscula ssp . mitis , and Cladonia pleurota . The rETR approached zero around noon, although the crustose lichen Ochrolechia frigida grown on biological soil crust (BSC) could acquire water from the BSC and retain its WC to perform positive photosynthesis. The light-rETR relationship curves of the five well-watered lichens were characterized into two types: shade-adapted with photoinhibition for the fruticose lichens, and light-adapted with no photoinhibition for O. frigida . The maximum rETR was expected to occur when they could acquire water from the surrounding air or from substrates during the desiccation period. Our results suggest that different species of Arctic lichens have different water availabilities due to their substrates and/or morphological characteristics, which affect their photosynthetic active periods during the summer. [ABSTRACT FROM AUTHOR]

Abstract: Mosses are a dominant component of high-arctic terrestrial ecosystems, yet little is known regarding the abundance and diversity of fungi associated with these abundant plants. We investigated vertical patterns of abundance and diversity of fungi and their relationship with chemical properties within profiles of Hylocomium splendens and Racomitrium lanuginosum collected in the Oobloyah Bay area on Ellesmere Island, Canada. The moss profiles were divided into 6 (H. splendens) and 5 (R. lanuginosum) layers according to the color and texture, and hyphal length, fungal assemblages, and contents of organic chemical components (acid-unhydrolyzable residues, total carbohydrates, extractives) and nutrients (N, P, K, Ca, Mg) were measured. Total hyphal length was greatest at the middle layers of H. splendens and at the deepest layers of R. lanuginosum and was significantly affected by moss species and nutrient contents. A total of 18 and 19 fungal taxa was isolated from the profiles of H. splendens and R. lanuginosum, respectively, with 11 taxa being common to both moss species. Moss species significantly affected the species distribution of fungi. Individual fungal taxa showed patterns of vertical distribution within the moss profiles. The contents of acid-unhydrolyzable residues and nutrients increased and the content of total carbohydrates decreased down the profile, which was attributable to the ability of fungi to decompose carbohydrates selectively and to immobilize nutrients in decomposed moss residues. [Copyright &y& Elsevier]

The polar willow ( Salix polaris), predominant in the late successional stage in deglaciated areas of Ny-Ålesund, Svalbard, is rarely found in the early stage, when purple saxifrage ( Saxifraga oppositifolia) dominates. To elucidate the pattern and the mechanism of successional change from the Saxifraga stage to the Salix stage, we examined the distribution pattern, size structure and habitat conditions of a colonizing Salix population in the seral stage where Salix was invading Saxifraga-dominated sites. The present distribution pattern and aerial photographs taken in the past suggest that Salix colonization at this site commenced within the last 70 years. We found 115 Salix individuals (22 male, 13 female and 80 unknown) in a 30 m × 30 m quadrat on the seral stage. Although the largest individual had a size of 2000 cm (length × maximum width), the majority (84%) of individuals were smaller than 100 cm. The seedling size distribution, as inferred from the leaf scar number, indicated that annual recruitment was slight. Of the individuals observed about 75% had colonized bare ground; only four individuals grew within Saxifraga colonies. No significant difference was found in soil characteristics (water content, and carbon and nitrogen concentrations) between the seral stage and the earlier stage prior to colonization by Salix. These results suggest that difficulties in seed production, germination and/or seedling establishment of Salix, rather than soil formation by preceding species ( Saxifraga), limits the early-stage colonization by Salix. [ABSTRACT FROM AUTHOR]

•We examined the photosynthetic characteristics and net primary production of biological soil crusts to evaluate their contribution to the carbon cycle in the High Arctic glacier foreland. •Biological soil crust samples were collected from a deglaciated area in Ny-Ålesund, Svalbard, Norway. Net photosynthetic rates ( Pn) and dark respiration rates ( R) of biological soil crusts were determined using CO2 gas exchange rates. We examined the effects of moisture conditions, temperature and photon flux density on Pn and R, and estimated the net primary production by a model based on the relationships between abiotic factors and Pn and R. •The maximum Pn value occurred at 50% of the maximum water-holding capacity. Pn decreased with increasing temperature and dropped below zero at high temperatures ( c. > 13°C). The estimated net primary production of the biological soil crust was greater than the net primary production of other vegetation when based on ground surface area, during the early stage of primary succession. Model simulation showed that the net primary production of the biological soil crust decreased with increasing temperature. •These results suggest that biological soil crust productivity plays an important role in the carbon cycle during the early stage of succession of the High Arctic glacier foreland, and is susceptible to temperature increases from global warming. [ABSTRACT FROM AUTHOR]

Raised beach deposits are widespread on the north-western coast of Spitsbergen, Svalbard. To elucidate the importance of these deposits in an ecosystem carbon cycle, we measured the concentrations of organic carbon and adenosine 5-triphosphate (ATP; an index of living microbial biomass) in a raised beach deposit found under terrestrial vegetation in Ny-Ålesund. A shell in the deposit found at a depth of ca. 20 cm below the ground surface had a (not calibrated) 14C age of 11080 ± 140 yr BP, whereas soil organic carbon in the same deposit showed an older 14C age (22380 ± 90 yr BP). Organic carbon concentration in the layer of 20–40 cm belowground was about 1–2%, which was comparable to those in shallower mineral soil layers. Results of ATP analyses suggested that low but non-negligible amounts of microorganisms existed in the deposit. The proportion of biomass carbon to soil organic carbon tended to decrease with increasing depth, suggesting that organic carbon in the deep layer was less available to microorganisms than that in the shallow layers. [ABSTRACT FROM AUTHOR]

The hypotheses that carbon and nitrogen availability limit microbial activity, and that the key factors limiting microbes vary along the successional gradient were tested in a High Arctic glacier foreland. We examined the responses of the respiration rate and the phospholipid fatty acid content to the addition of carbon and/or nitrogen. Soil samples were collected from the early stage and late stage of primary succession in the foreland of a glacier near Ny-Ålesund, Svalbard. The addition of both carbon (glucose) and nitrogen (ammonium nitrate) engendered an increase in the microbial respiration rate in the early stage of succession. In contrast, the addition of either carbon or nitrogen did not increase the microbial respiration rate. In the late stage of succession the addition of carbon alone, as well as the addition of both carbon and nitrogen, increased the microbial respiration rate. However, neither the addition of carbon nor the addition of nitrogen affected the total phospholipid fatty acid content (an index of microbial biomass) for any soil within 15 days of incubation at 10°C. An increase in the respiration rate was therefore attributed to changes in the physiological activities of the microbial community, such as enzymatic activity. Our study suggests that microbial respiration was limited by the low availability of both carbon and nitrogen in the early stage of succession. Thereafter, nitrogen limitation is mitigated. [ABSTRACT FROM AUTHOR]