Estimation of the annual primary production of the lichen Cetrariella delisei in a glacier foreland in the High Arctic, Ny-�lesund, Svalbard

2006 ◽  
Vol 25 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Masaki Uchida ◽  
Takayuki Nakatsubo ◽  
Hiroshi Kanda ◽  
Hiroshi Koizumi
Polar Biology ◽  
2015 ◽  
Vol 39 (3) ◽  
pp. 543-552 ◽  
Author(s):  
T. Riis ◽  
K. S. Christoffersen ◽  
A. Baattrup-Pedersen

Polar Science ◽  
2014 ◽  
Vol 8 (4) ◽  
pp. 397-412 ◽  
Author(s):  
Takeshi Inoue ◽  
Sakae Kudoh ◽  
Masaki Uchida ◽  
Yukiko Tanabe ◽  
Masakane Inoue ◽  
...  

2010 ◽  
Vol 7 (1) ◽  
pp. 1101-1129 ◽  
Author(s):  
T. Tagesson ◽  
M. Mastepanov ◽  
M. P. Tamstorf ◽  
L. Eklundh ◽  
P. Schubert ◽  
...  

Abstract. Arctic wetlands play a key role in the terrestrial carbon cycle. Recent studies have shown a greening trend and indicated an increase in CO2 uptake in boreal and sub- to low-arctic areas. Our aim was to combine satellite-based normalized difference vegetation index (NDVI) with ground-based flux measurements of CO2 to investigate a possible greening trend and potential changes in gross primary production (GPP) between 1992 and 2008 in a high arctic fen area. The study took place in Rylekaerene in the Zackenberg Research Area (74°28' N 20°34' W), located in the National park of North Eastern Greenland. We estimated the light use efficiency (ε) for the dominant vegetation types from field measured fractions of photosynthetic active radiation (FAPAR) and ground-based flux measurements of GPP. Measured FAPAR were correlated to satellite-based NDVI. The FAPAR-NDVI relationship in combination with ε was applied to satellite data to model GPP 1992–2008. The model was evaluated against field measured GPP. The model was a useful tool for up-scaling GPP and all basic requirements for the model were well met, e.g., FAPAR was well correlated to NDVI and modeled GPP was well correlated to field measurements. The studied high arctic fen area has experienced a strong increase in GPP between 1992 and 2008. The area has during this period also experienced a substantial increase in local air temperature. Consequently, the observed greening trend is most likely due to ongoing climatic change possibly in combination with CO2 fertilization, due to increasing atmospheric concentrations of CO2.


2002 ◽  
Vol 80 (11) ◽  
pp. 1193-1202 ◽  
Author(s):  
Hiroyuki Muraoka ◽  
Masaki Uchida ◽  
Masako Mishio ◽  
Takayuki Nakatsubo ◽  
Hiroshi Kanda ◽  
...  

Photosynthetic characteristics and their leaf-age dependence were examined to estimate ecophysiological effects on net primary production (NPP) of a polar willow (Salix polaris), a dominant dwarf shrub species in a polar semi-desert area of Ny-Ålesund, Svalbard. Leaves of S. polaris emerged just after snowmelt in early July in 2000; flowers were initiated within 1 week, and fruits in late July. Light-saturated rate of photosynthesis and stomatal conductance to water vapor increased rapidly to their maximum values within 1 week after leaf emergence and then decreased gradually. Depending on the leaf age, photosynthetic rates saturated at photosynthetically active photon flux density (PPFD) of 200–400 µmol·m–2·s–1, which is the light level usually available in the natural habitat. Optimum leaf temperature of photosynthesis ranged from 10 to 18°C, while air temperature in the habitat ranged from 8 to 20°C. These light and temperature responses of photosynthesis of S. polaris would be suitable for efficient carbon gain in the natural habitat characterized by highly variable light and temperature conditions. Using the photosynthetic and respiratory characteristics, biomass distribution, and meteorological data, NPP of S. polaris in the current year was estimated to be 26.1 g C·m–2. A model simulation of rising temperature conditions predicted a reduction of NPP because of a large increase in respiration. It was suggested that temperature condition and leaf phenological aspects strongly influence the carbon fixation by plants in the high arctic area studied.Key words: arctic semi-desert, climate change, net ecosystem production (NEP), net primary production (NPP), Salix polaris, photosynthesis.


2020 ◽  
Vol 151 (2-3) ◽  
pp. 187-201
Author(s):  
Louis J. Skovsholt ◽  
Ada Pastor ◽  
Catherine L. Docherty ◽  
Alexander M. Milner ◽  
Tenna Riis

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