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Abstract:Boreal mire landscapes are rich in soil carbon and significantly contribute to the carbon input of aquatic ecosystems. They are composed of different mesoscale ecohydrological subunits, whose individual contributions to the water and carbon export of mire catchments are not well understood. The spring snowmelt period is the major hydrological event in the annual water cycle of the boreal regions and strongly influences the carbon flux between the terrestrial and aquatic systems. The aim of this study was (1) to provide a conceptual understanding of the spatial and temporal dynamics of the surface water chemistry along a swamp forest-fen-bog gradient during the snowmelt period, (2) to quantify the exported dissolved organic carbon (DOC) content in the runoff and (3) to identify the ecohydrological landscape unit that contributes most to DOC export during the snowmelt period in a heterogeneous mire complex in Northwest Russia. The highest DOC concentrations were detected in the swamp forest, and the lowest concentrations were observed at the treeless bog by the end of the snowmelt period (swamp forest: 37-43 mg l À1 , bog: 13-17 mg l À1 ). During the spring snowmelt period, a significant amount (~1.7 g C m À2 ) of DOC was transferred by the~74 mm of runoff from the catchment into the river. Variability in the thawing periods led to differences in the relative contributions of each ecohydrological zone to the carbon export measured at a stream channel draining the studied part of the mire complex. An increased understanding of the variation in DOC concentrations and contributions from the mesoscale ecohydrological subunits to carbon export can help to predict the potential regional loss of DOC based on land cover type under climate change.

Introduction Wheat straw is an underutilized energy resource for animals: it is indigestible and has a low protein content. Most methods for improving the digestibility are not cost effective or have potential health and environmental hazards. This paper focuses on using a biological pre-treatment with Pleurotus spp, lignin degrading white-rot fungi, to improve wheat straw from low to high available energy feed. Pleurotus spp. are able to degrade the lignin in a selective way (Kerem & Hadar, 1993) thus making cellulose available for ruminants. Pleurotus spp. are widely cultivated worldwide to produce oyster mushrooms and have a high protein content, are free from cholesterol and are rich in carbohydrates, fibre, vitamins and minerals (Kues & Liu, 2000). Pleurotus spp. also have a medicinal potential. The aims of this study were to investigate the ability of different Pleurotus spp. to increase the protein content, degrade lignin and improve digestibility of the wheat straw. Production of edible mushrooms was also considered. Material and methods Five Pleurotus spp. were screened for their ability to increase the protein content, degrade lignin and improve digestibility of wheat straw. Four of the Pleurotus strains used came from local resources (P. ostreatus: P. ost x TW, P. ost x TG, Po x K; P. florida) and 1 commercial strain of P. pulmonarius was purchased (Mycelia, Ghent, Belgium). Wheat grain was infected to inoculate straw. Straw was chopped into lengths of 3-5 cm and soaked in water for 20 mins and left to drain. Culture bags were each filled with 1 kg of soaked straw and a microelement solution was added (Per bag: ZnSO 4 .7H 2 O: 0.017 mg, MgSO 4 .7H 2 O: 0.32 mg and CuSO 4 : 0.025 mg). Bags were autoclaved sterilised and inoculated by adding 60 g of colonised grain. Bags were sealed and incubated for 19 or 42 days in total, in duplicate. Those which were incubated for 42 days in total were incubated for 19 days for colonisation at 22 °C, 65% relative humidity, 1 day cold shock at 10 °C and 22 days fruiting at 24 °C, 75% relative humidity with a 10 hours per day light cycle (470-700 nm). In the final stage pinholes were made in bags to support air exchange and this allowed emergence and proper development of fruit bodies. The other set of bags were incubated for 19 days as above. For each treatment, 2 bags without fungal inoculation were used as controls. Crude protein, and lignin content were determined (Halliday 1985), while the Modified Faeces Liquor technique (Omed et al. 1989) was used for digestibility estimation. The statistical analysis was performed using SPSS 14.2. Results During the experiment all strains produced fruit bodies, but not all fruiting bodies reached the point of harvest at the experiment end. Increases in digestibility and crude protein were highly significant (p=0.000), especially after 42 days incubation but lignin decreases were not (p=0.386) (Tables 1-3). Table 1 Relative increase compared to control, *statistically different from the control (p<0.01)) Strain Digestibility ...