Yonghui Lin

Removal of Crystal Violet from aqueous solution using powdered mycelial biomass of Ceriporia lacerata P2

A biosorbent prepared from powdered mycelial biomass of Ceriporia lacerata (CLB), a basidiomycetous fungus, was applied for the uptake of Crystal Violet from aqueous solution. A batch adsorption experiment was used for the biosorption process, involving effect of experimental factors and biosorption kinetics and equilibrium. Biosorption process showed that the removal of Crystal Violet by CLB was effective over wide pH range, and meanwhile was independent on ionic strength. Biosorption capacities of CLB increased with the initial dye concentration increasing, due to an increase in the driving force of the concentration gradient. The adsorbed Crystal Violet amount per unit biomass weight decreased with increasing biosorbent dosage, due to the splitting effect of flux (concentration gradient) between sorbate and biosorbent. A maximum sorption capacity of 239.25 mg/g was observed. Biosorption kinetics was found to be best represented by the pseudo second-order kinetic model. The equilibrium adsorption data was well described by the Koble-Corrigan model. FT-IR (Fourier Transform Infrared Spetroscopy) spectrum showed the presence of O-H, COOH, C=O, C-N, C-H, -NH2 and P-OH in the surface of CLB as functional groups. This study showed CLB can effectively remove CV from dye wastewater.

Responses of litter decomposition to temperature along a chronosequence of tropical montane rainforest in a microcosm experiment

We conducted a microcosm experiment for studying the decomposition of Altingia obovata leaf litter by the decomposer community at 20 and 30°C from three forest stands (namely a 35-year-old secondary forest, a 47-year-old secondary forest, and a primary forest) of a tropical montane rainforest. Our results showed that rank-order of the litter decomposition among the three forest stands was not parallel to the stand age. At 20°C, the mass loss of A. obovata leaf litter from the primary forest was higher than those from the two secondary forests, of which the younger stand showed higher mass loss than did the older one. However, there were no differences in mass loss among these three stands at 30°C. The mass loss for the two secondary forest stands, but not for the primary forest stand, increased significantly from 20 to 30°C. The level of lignin decomposition among the three stands at 20°C corresponded to their forest stand age, i.e., the primary forest > the 47-year-old secondary forest > the 35-year-old secondary forest. A rise of 10°C in temperature significantly increased lignin decomposition for the two secondary forests, while the reverse was true for the primary forest. Carbohydrate decomposition was positively related to the temperature but not to the stand age. The different responses of litter decomposition to the forest stand age and temperature might be due to the differences in the microbial activities among the three forest stands.

What determines the number of dominant species in forests

In this work, the difference in number of dominant species in a community on global scale and successional trajectories was analyzed based on the published data. We explained the reasons of these differences using a resource availability hypothesis, proposed in this work, that the distribution of available resource determined the pattern of community dominance. The results showed that on global scale the number of dominant species of community varied across latitudinal forest zone, namely from single-species dominance in boreal and temperate forest to multi-species codominance, even no dominant species in tropical forest. This was consistent with the pattern of resource distribution on global scale. Similarly, in successional trajectories, the number of dominant species gradually radiated from single-species dominance to multi-species codominance, even no dominant species in tropical forest. The changing available resources in trajectories were responsible for this difference. By contrary, a community was often dominated by single species in temperate or boreal forest. This was determined by the low available resource, especially low available water and temperature. In boreal forest, low temperature greatly reduced availability of water and nutrient, which were responsible for the single-species dominance. In addition, the conclusion that high available resources sustained low dominance of community might be deduced, based on the fact that the dominance of community declined with the increasing of species diversity. To sum up, the richer the available resources were, the lower the dominance of community was, and vice versa. The hypothesis that the resource availability controlled the dominance of community could well elucidate the difference of community dominance on global and community scale.