Cs-137 in fungal sporocarps in relation to vegetation in a bog, pine swamp and forest along a transect

• In this study, we estimated the relative importance of vegetation and fungi for radiocesium uptake and biological retention in adjacent bog, pine swamp, and forest. The measurements for Cs-137 activity concentration in sporocarps (i.e. fruitbodies of fungi) and vegetation along a bog to forest transect were combined with complementary published data to calculate estimates. Aboveground vegetation comprised 17.7% of the total fallout-derived radiocesium in the system in bog, 16.5% in pine swamp, and 40.6% in forest. In fungal sporocarps grown along a gradient, Cs-137 activity comprised <0.001% of the total radiocesium for peat bog, <0.02% for pine swamp, and 0.11% for forest. Total Cs-137 activity in sporocarps increased along the gradient due to increased production of sporocarps in the presence of trees from 0.006 (bog), 0.097 (pine swamp) and 0.67 (forest) g dwt m(-2). Based on calculation of the total vegetation biomass and through relationships between fungal biomass in sporocarps and as mycelia in soil, the total Cs-137 activity located in fungi was estimated as 0.1% in bog, 2% in pine swamp, and 11% in forest. An analysis of the time-dependency of Cs-137 in the sporocarps in forest between 1990 and 2011 suggested an ecological half-life for Cs-137 between 8 and 13 years. Although fungi comprised a relatively small fraction of the total radiocesium in the systems, its activity decreased slowly with time, and ecological residence time for Cs-137 in sporocarps of fungi was long, suggesting they will continue to contribute to the accumulation and cycling of this radionuclide in forest. (C) 2012 Elsevier Ltd. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Mikrobiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Microbiology (hsv//eng)

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