Pyrogenic carbon, also called black carbon (BC), is an important component in the global carbon cycle. BC produced by biomass burning or fossil fuel combustion is transported to oceans by the atmosphere or rivers. However, environmental dynamics (i.e., major sources and sinks) of BC in marine environments have not been well-documented. In this study, dissolved BC (DBC) collected from surface wa...

Many of the world's northern peatlands are underlain by rapidly thawing permafrost. Because plant production in these peatlands is often nitrogen (N)-limited, a release of N stored in permafrost may stimulate net primary production or change species composition if it is plant-available. In this study, we aimed to quantify plant-available N in thawing permafrost soils of subarctic peatlands. We ...

1. A fundamental trade-off among vascular plants between traits inferring rapid resource acquisition and those leading to conservation of resources has now been accepted broadly, but is based on empirical data with a strong bias toward leaf traits. Here we test whether interspecific variation in traits of different plant organs obeys this same trade-off and whether within-plant trade-offs are c...

We developed a mobile remote sensing measurement facility for spectral and anisotropic reflectance measurements. We measured reflection properties (BRF) of over 100 samples from most common land cover types in boreal and subarctic regions. This extensive data set serves as a unique reference opportunity for developing in-5 terpretation algorithms for remotely sensed materials as well as for mod...

High-latitude ecotonal populations at the species margins may exhibit altered patterns of genetic diversity, resulting from more or less recent founder events and from bottleneck effects in response to climate oscillations. Patterns of genetic diversity were investigated in nine populations of the conifer black spruce (Picea mariana [Mill.] BSP.) in northwestern Québec, Canada, using seed-dispe...

Methylocapsa palsarum NE2T is an aerobic, mildly acidophilic, obligate methanotroph. Similar to other Methylocapsa species, it possesses only a particulate methane monooxygenase and is capable of atmospheric nitrogen fixation. The genome sequence of this typical inhabitant of subarctic wetlands and soils also contains genes indicative of aerobic anoxygenic photosynthesis.

Densification of the shrub layer has been reported in many subarctic regions, raising questions about the implication for large herbivores and their resources. Shrubs can tolerate browsing and their level of tolerance could be affected by browsing and soils productivity, eventually modifying resource availability for the caribou. Our objective was to assess the compensatory growth potential of ...

Both heliophysical and anthropogenic (wastewater) effects on zooplankton biomass and abundance of the Imandra Lake (the largest subarctic lake at Kola Peninsula, Russia) were investigated during the 1990 - 2003 period. We used different indexes of solar activity (sunspot numbers and UV- radiation values) as heliophysical factors. Information about UV- radiation values was derived from satellite...

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The tundra-taiga interface, or forest-tundra (lesotundra in Russian, and toundra forestière in French), corresponds to the subarctic zone where the closed boreal forest gradually becomes less dense and progressively breaks down into tree islands towards the treeless, Arctic tundra (1). The interface does not form a sharp limit of tree growth in the landscape but is instead a north-south transit...