The distributions of cyanobacterial bioactive and odorous metabolites were investigated in the fifth largest lake in China in the fishing season 2012. The highest microcystins (MCs) concentration in water reached 3.4 lg L -1. A high b-ionone concentration reached 35.6 ng L -1 in water. Mean MCs concentration in muscle was highest in omnivorous Carassius auratus (20.9 ng g -1 dry weight), followed by phytoplanktivorous Hypophthalmichthys molitrix (7.4 ng g -1 DW) and carnivorous Coilia ectenes (3.0 ng g -1 DW). The maximum off-flavor concentrations kept 9.5 lg kg -1 wet weight for geosmin (C. auratus), 5.5 lg kg -1 WW for b-cyclocitral (C. ectenes) and 25.5 lg kg -1 WW for b-ionone (C. ectenes). Positive correlation was found between the offflavor and fat contents in C. ectenes. To be different with MCs, b-cyclocitral content was highest in fore-gut contents (87.6 lg kg -1 WW) in H. molitrix. It should not be reliable to predict odorous compounds level in fish muscle by only measuring the off-flavor in lake water only.
The seasonal variations of taste and odor (T&O) compounds in western Lake Chaohu were evaluated from July to December 2013. High values were detected in particulate fractions, with peak values 28.25 ng/L for geosmin (GEO), 45.18 ng/L for dimethyltrisulfide (DMTS), 714.77 ng/L for β-cyclocitral, 11.23 ng/L for β-ionone in surface water, and 14.21 ng/L for GEO, 103.68 ng/L for DMTS, 11.97 ng/L for β-ionone in overlying water, all exceeding their odor thresholds. The maximum off-flavor concentrations in sediment ranged from 2010.76 ng/kg for GEO to 1.7 ng/kg for β-ionone. Positive correlations could be found not only between Anabaena and particulate GEO (r = 0.813, p < 0.01), but also between Microcystis and total β-cyclocitral (r = 0.652, p < 0.01) or β-ionone (r = 0.560, p < 0.01) in surface water. TP, TN, PO4-P, Chl-a and organic matter contributed significantly to the variations of T&O compounds in water or sediment. The cause of the variations of T&O compounds was the accumulation and degradation of cyanobacteria in water rather than nutrient-rich sediment.
As a basic agricultural parameter in the formation, transformation, and consumption of surface water resources, soil moisture has a very important influence on the vegetation growth, agricultural production, and healthy operation of regional ecosystems. The Aksu river basin is a typical semi-arid agricultural area which seasonally suffers from water shortage. Due to the lack of knowledge on soil moisture change, the water management and decision-making processes have been a difficult issue for local government. Therefore, soil moisture monitoring by remote sensing became a reasonable way to schedule crop irrigation and evaluate the irrigation efficiency. Compared to in situ measurements, the use of remote sensing for the monitoring of soil water content is convenient and can be repetitively applied over a large area. To verify the applicability of the typical drought index to the rapid acquisition of soil moisture in arid and semi-arid regions, this study simulated, compared, and validated the effectiveness of soil moisture inversion. GF-1 WFV images, Landsat 8 OLI images, and the measured soil moisture data were used to determine the Perpendicular Drought Index (PDI), the Modified Perpendicular Drought Index (MPDI), and the Vegetation Adjusted Perpendicular Drought Index (VAPDI). First, the determination coefficients of the correlation analyses on the PDI, MPDI, VAPDI, and measured soil moisture in the 0–10, 10–20, and 20–30 cm depth layers based on the GF-1 WFV and Landsat 8 OLI images were good. Notably, in the 0–10 cm depth layers, the average determination coefficient was 0.68; all models met the accuracy requirements of soil moisture inversion. Both indicated that the drought indices based on the Near Infrared (NIR)-Red spectral space derived from the optical remote sensing images are more sensitive to soil moisture near the surface layer; however, the accuracy of retrieving the soil moisture in deep layers was slightly lower in the study area. Second, in areas of vegetation coverage, MPDI and VAPDI had a higher inversion accuracy than PDI. To a certain extent, they overcame the influence of mixed pixels on the soil moisture spectral information. VAPDI modified by Perpendicular Vegetation Index (PVI) was not susceptible to vegetation saturation and, thus, had a higher inversion accuracy, which makes it performs better than MPDI’s in vegetated areas. Third, the spatial heterogeneity of the soil moisture retrieved by the GF-1 WFV and Landsat 8 OLI image were similar. However, the GF-1 WFV images were more sensitive to changes in the soil moisture, which reflected the actual soil moisture level covered by different vegetation. These results provide a practical reference for the dynamic monitoring of surface soil moisture, obtaining agricultural information and agricultural condition parameters in arid and semi-arid regions.
By means of field investigation, this paper found the factors that restricting the development of Qinhuangdao port logistics low carbonization. The factors are: the planning layout port is not reasonable; related policies and regulations of low carbon lag; port infrastructure is weak and low carbon logistics technology level need to be improved; the lack of talented person for port of low carbon logistics. This paper put forward the measures and suggestions on Qinhuangdao port logistics low carbonization: striving to optimize the layout; enhancement of infrastructure capacity; the introduction of technology to reduce emissions, improvement of the level of low carbon development; enhancement of port operation management and operation ability; improvement of low carbon consciousness of port industry practitioners; government and industry play an active role in Qinhuangdao port logistics low carbonization.
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