Assessing the regional carbon sink with its forming processes- a case study of Liaoning province, China.

Assessing the regional carbon sink sets the basis of regional carbon management, which involves many measures but has large uncertainties. Carbon sink assessment scheme based on its forming processes (CSF) is a recently proposed measure but repeatly calculates emission from water erosion and ignored human inducing carbon inputs. Therefore, we revised the CSF by calculating the direct outputs from land surface and adding human returned carbon (HC) to the input. The revised CSF thus involved gross primary productivity (GPP), ecosystem respiration (ER), carbon removal from cropland (CRC), emission from reactive carbon (ERC), emission from water erosion (Ewat), and HC, which can be obtained from public data sources. Then the revised CSF was applied to the Liaoning province of China. The estimated carbon input of Liaoning province during 2000-2014 was 114.77 ± 8.41 TgC yr-1, while the carbon output was 110.48 ± 8.38 TgC yr-1. The difference between input and output induced a carbon sink of 4.30 ± 2.20 TgC yr-1, accounting for 3.75% of total carbon input. The carbon sink spatially decreased from northeast to southwest, which was highly correlated with that of GPP. However, though its forming fluxes significantly increased from 2000 to 2014, the carbon sink showed a decreasing trend. In addition, the revised scheme only needed published and public data, which made it serve as an alternative approach for regional carbon budget assessment.

The possible reduction pathways of 2,4,6-trinitrotoluene (TNT) by sulfide under simulated anaerobic conditions.

To predict the final fate of 2,4,6-trinitrotoluene (TNT) and its intermediates in an anaerobic fermentative solution containing reduced sulfur species and to provide a basis for the adoption of remediation methods, we investigated the pathways of TNT (TNT(0) = 50 mg/L) reduction by Na(2)S at 30 ± 1 °C in an acetic acid-sodium bicarbonate buffer. Liquid chromatography/mass spectrometry (LC/MS) was used to identify TNT metabolites at different reaction times. The law of growth and decline of TNT and its metabolites was determined with time. The LC/MS result, combined with the physicochemical characteristics of related products and information from the literature, indicated possible TNT conversion pathways. Sulfide can initiate both nitroreduction and denitration of TNT simultaneously. Nitroreduction led to the accumulation of primary intermediates 4-hydroxylaminodinitrotoluene and 4-aminodinitrotoluene, whereas denitration resulted in the production of unidentified substances with molecular weight less than that of TNT. Also, polyreaction between the above intermediates formed many unidentified substances. Humification was concluded to be the best choice for remediation of TNT-contaminated soil and water due to the formation of intermediates with stable, intact aromatic systems. However, the denitration pathway of TNT offered the possibility of mineralization.

[Recognition of landscape characteristic scale based on two-dimension wavelet analysis].

Three wavelet bases, i. e., Haar, Daubechies, and Symlet, were chosen to analyze the validity of two-dimension wavelet analysis in recognizing the characteristic scales of the urban, peri-urban, and rural landscapes of Shenyang. Owing to the transform scale of two-dimension wavelet must be the integer power of 2, some characteristic scales cannot be accurately recognized. Therefore, the pixel resolution of images was resampled to 3, 3.5, 4, and 4.5 m to densify the scale in analysis. It was shown that two-dimension wavelet analysis worked effectively in checking characteristic scale. Haar, Daubechies, and Symle were the optimal wavelet bases to the peri-urban landscape, urban landscape, and rural landscape, respectively. Both Haar basis and Symlet basis played good roles in recognizing the fine characteristic scale of rural landscape and in detecting the boundary of peri-urban landscape. Daubechies basis and Symlet basis could be also used to detect the boundary of urban landscape and rural landscape, respectively.