0000000000026007
AUTHOR
Pekka Vanhala
Effects of heavy metals on soil microflora
Elevated concentrations of heavy metals are known to cause disturbances in all living organisms. A reduction in the activity of forest microbes, expressed as decreased carbon and nitrogen mineralisation, may result in a slower rate of litter decomposition and slower nutrient cycling in the whole ecosystem (Baath 1989). In areas severely polluted by heavy metals, this can be seen as an accumulation of undecomposed litter on the forest floor. Thus, in addition to the direct toxicity of heavy metals, the trees may suffer from nutrient deficiency resulting from the decrease in the mineralisation of nutrients from the litter. Heavy metals can also retard litter decomposition processes in less po…
Priming effect increases with depth in a boreal forest soil
Abstract Climate warming increases labile carbon (C) inputs to soil through increased photosynthesis and C allocation belowground. This could counterintuitively lead to losses of soil C via priming effects (PE): the stimulation of soil organic matter (SOM) decomposition caused by labile C addition. Systematic quantification of PEs in different ecosystems is needed. We measured PEs of free-living soil microbes in different layers of a boreal forest soil, and found that the relative magnitude of the PE increased with soil depth. The relationship between relative PE and the added glucose amount also depended on the soil layer. Our results indicate that the decomposition of SOM in deeper soil l…