Effects of Crude Oil Contamination on Soil Physical and Chemical Properties in Momoge Wetland of China

Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary.

Responses of Phytolith in Guinea Grass(Leymus chinensis) Leaves to Simulated Warming,Nitrogen Deposition and Elevated CO_2 Concentration in Songnen Grassland,Northeast China

Deposited in plant cells and their intercellular space,phytoliths,a special form of silica,could be used to determine information on plant structure and physiology especially their size and content.With the hypothesis that phytolith in plant would change under variable climate and environment,the dominant plant species in Songnen grassland,guinea grass(Leymus chinensis),was treated by an open-top chamber(OTC) to elevate CO2 concentration,infrared heaters,and artificial nitrogen(N) addition for three years from 2006–2008.Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on.We found that the responses to elevated CO2 are complicated,and warming is positive while N addition is negative to the deposition of phytoliths in L.chinensis leaves.Especially,warming could reduce the negative impact of N addition on phytolith in L.chinensis.The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes.The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration,warming,and N addition,and could become some new indicators for environmental changes.In conclusion,different phytolith types have various responses to simulated warming,N addition and elevated CO2 concentration.

Alternative Fuzzy Cluster Segmentation of Remote Sensing Images Based on Adaptive Genetic Algorithm

Remote sensing image segmentation is the basis of image understanding and analysis. However,the precision and the speed of segmentation can not meet the need of image analysis,due to strong uncertainty and rich texture details of remote sensing images. We proposed a new segmentation method based on Adaptive Genetic Algorithm(AGA) and Alternative Fuzzy C-Means(AFCM) . Segmentation thresholds were identified by AGA. Then the image was segmented by AFCM. The results indicate that the precision and the speed of segmentation have been greatly increased,and the accuracy of threshold selection is much higher compared with traditional Otsu and Fuzzy C-Means(FCM) segmentation methods. The segmentation results also show that multi-thresholds segmentation has been achieved by combining AGA with AFCM.

Patterns and causes of geographic variation in bat echolocation pulses

Evolutionary biologists have a long-standing interest in how acoustic signals in animals vary geographically,because divergent ecology and sensory perception play an important role in speciation.Geographic comparisons are valuable in determining the factors that influence divergence of acoustic signals.Bats are social mammals and they depend mainly on echolocation pulses to locate prey,to navigate and to communicate.Mounting evidence shows that geographic variation of bat echolocation pulses is common,with a mean 5-10 kHz differences in peak frequency,and a high level of individual variation may be nested in this geographical variation.However,understanding the geographic variation of echolocation pulses in bats is very difficult,because of differences in sample and statistical analysis techniques as well as the variety of factors shaping the vocal geographic evolution.Geographic differences in echolocation pulses of bats generally lack latitudinal,longitudinal and elevational patterns,and little is known about vocal dialects.Evidence is accumulating to support the fact that geographic variation in echolocation pulses of bats may be caused by genetic drift,cultural drift,ecological selection,sexual selection and social selection.Future studies could relate geographic differences in echolocation pulses to social adaptation,vocal learning strategies and patterns of dispersal.In addition,new statistical techniques and acoustic playback experiments may help to illustrate the causes and consequences of the geographic evolution of echolocation pulse in bats.

Response to seasonal change of insect resources in Changbai Mountain temperate forests by Greater Horseshoe bats

Knowing how bats select different habitats in response to environmental changes provides a framework for anticipating the likely consequences of changes in climate or vegetation. In this study we assessed the presence of greater horseshoe bats (Rhinolophus ferrumequinum) and their foraging behavior. This study depicts an effective approach for seasonal responses of habitat selection by Chiroptera.

Growth and Carbon Metabolism Responses to Flooding Timing and Frequency in Three Marsh Plants in Sanjiang Plain

Flooding timing and frequency may have different effects on the growth and carbon metabolism of plants in wetlands. We tested this hypothesis using three marsh plants in Sanjiang Plain, which were growing in different flooding timing and frequency environments for 24 days. The three marsh plants in different elevations along a water-level gradient, high-elevation species Calamagrostis angustifolia, mid-elevation species Carex limosa and low-elevation species Carex lasiocarpa. Our experiment included 6 kinds of treatments: control, longer flooding timing, medial flooding timing and frequency(2 treatments), and higher flooding frequency(2 treatments). Longer flooding timing and higher flooding frequency treatments led to similar reductions in biomass accumulation and relative growth rate of Calamagrostis angustifolia, whereas growth of Carex limosa was not affected by either flooding timing or frequency. However, biomass accumulation and relative growth rate of Carex lasiocarpa was only reduced by the higher flooding frequency. Starch and soluble sugar contents of Calamagrostis angustifolia were negatively affected by flooding frequency. On Carex limosa, higher flooding frequency resulted in higher starch content, but longer flooding timing led to accumulated starch content in Carex lasiocarpa. Soluble sugar contents of Carex lasiocarpa and Carex li mosa were not affected by either flooding timing or flooding frequency. These results indicated that growth responses of the three marsh plants to flooding timing and frequency was closely related to the different physiology of carbohydrate metabolism.