感受季节的变化

稻子熟了，沉甸甸地垂着头，风一吹，刷刷地响。秧田里，青青的禾苗已经探出了头。

Community Structure and Seasonal Variation of Soil Arthropods in the Forest-Steppe Ecotone of the Mountainous Region in Northern Hebei,China

Soil fauna have been receiving more and more attention because they play an important role in nutrient cycling.However,there is a lack of information on soil arthropods in the forest-steppe ecotone in the mountainous region of northern Hebei,which makes it difficult to meet the need of protecting biodiversity in this area.Soil arthropod communities were investigated in the forest-steppe ecotone in northern Hebei province to provide basic information on changes in mountain soil fertility,which could promote the development of soil arthropod communities in mountain ecotones.From the preliminary identification,a total of 7994 individual soil arthropods were collected,which belonged to 25 groups,6 classes and 24 orders.Acarina,Hymenoptera and Collembola were the dominant groups in the ecotone.The number of Acarina was higher than Collembola,and this phenomenon was obviously different from other areas in the same climate zone.The increased abundance of rare groups in the Forest zone with the richer vegetation,higher arthropod abundance and more substantial litter depth,could be interpreted as a reaction to the suitable soil environment and food supply.And these rare groups were sensitive to environmental changes,which could be regarded as biotic indicators for evaluating soil quality.The analysis of community diversity showed that the abundance index (d),the Shannon-Wiener index (H'),the evenness index (J) and the density-group index (DG) were significantly higher in the forest zone,lower in the forest-steppe zone,and lowest in the meadow-steppe zone.Seasonal variations in community composition correlated with changes in average air temperature and precipitation in this ecotone.Groups and individuals of soil arthropod communities in the three zones were present in greater numbers in the middle of the rainy season than in the early or late periods of the rainy season as a whole.At the same time,seasonal changes in soil arthropod communities from different plots were also influenced by habitat condition.

Seasonal Changes of Reproductive Activity and Biochemical Composition of Pen Shell Atrina pectinata Linnaeus,1767 in Bohai Sea,China

Seasonal variations in the biochemical composition and the reproductive cycle of pen shell Atrina pectinata in Bohai Sea were investigated from May 2013 to April 2014. Histological analysis indicated that the reproductive cycle of A. pectinata can be divided into two phases, inactive stage and gametogenesis, which were equally and significantly influenced by seawater temperature and food availability. Gametogenesis began in late autumn(October), and completed in June and July. Spawning took place in August, coinciding with the highest water temperature and the richest phytoplankton. The significantly high glycogen content in adductor muscles sustained throughout the late active and ripeness stages, but plummeted during spawning and inactive stages. The protein content in female gonads exhibited a synchronous increase along with oocyte diameter and lipid content, suggesting that the female gonads could accumulate protein and lipid for vitelline in A. pectinata. Furthermore, the RNA/DNA ratio was found to be a useful index to indicate the level of gonad maturation in both males and females. The findings of the present study provided a foundation for the fishery resource administration and the aquaculture development of this species.

Seasonal variation of the surface North Equatorial Countercurrent (NECC) in the western Pacific Ocean

The North Equatorial Countercurrent(NECC) is an important zonal fl ow in the upper circulation of the tropical Pacifi c Ocean, which plays a vital role in the heat budget of the western Pacifi c warm pool. Using satellite-derived data of ocean surface currents and sea surface heights(SSHs) from 1992 to 2011, the seasonal variation of the surface NECC in the western tropical Pacifi c Ocean was investigated. It was found that the intensity(INT) and axis position(Y_(CM)) of the surface NECC exhibit strikingly different seasonal fl uctuations in the upstream(128°–136°E) and downstream(145°–160°E) regions. Of the two regions, the seasonal cycle of the upstream NECC shows the greater interannual variability. Its INT and Y CM are greatly infl uenced by variations of the Mindanao Eddy, Mindanao Dome(MD), and equatorial Rossby waves to its south. Both INT and YC M also show semiannual signals induced by the combined effects of equatorial Rossby waves from the Central Pacifi c and local wind forcing in the western Pacifi c Ocean. In the downstream region, the variability of the NECC is affected by SSH anomalies in the MD and the central equatorial Pacifi c Ocean. Those in the MD region are especially important in modulating the Y CM of the downstream NECC. In addition to the SSH-related geostrophic fl ow, zonal Ekman fl ow driven by meridional wind stress also plays a role, having considerable impact on INT variability of the surface NECC. The contrasting features of the variability of the NECC in the upstream and downstream regions refl ect the high complexity of regional ocean dynamics.

日语中和“雨”有关的表达方式

日本是一个多雨的国家,因此日语中和雨有关的词汇以及表达方式极其丰富,说明日本人对自然一直抱有亲近感。本文拟就日语中和“雨”有关的表达方式做一个总结。

Seasonal variations of carboxylic acids and their contributions to the rainwater acidity: A case study of Guiyang and Shangzhong,China

Low molecule weight carboxylic acids are ubiquitous and important chemical constituents in the troposphere.Seven carboxylic acids in the rainwater of Guiyang and Shangzhong were simultaneously determined by ion chromatography from April 2006 to April 2007.Formic, acetic and oxalic acids were found to be the predominant carboxylic acids.Their volume weighted average concentration (VWA) in the rainwater of Guiyang were 14.24 μmol/L, 9.35 μmol/L and 2.79 μmol/L, respectively;as compared to 4.95 μmol/L, 1.35 μmol/L and 2.31 μmol/L in the rainwater of Shangzhong.In Shangzhong it is witnessed that the concentra-tions of these acids were higher in the summer than in the winter and direct emissions from vegetations or soils may account for the main provenance of the acids.This is, however, not the case in Guiyang, where the concentrations of the carboxylic acids were higher during the non-growing season than during the growing season.The relatively weak scavenging affected by scarce and little rainwater as well as the particles accompanied with the rainfall may have some effect on the carboxylic acids during the wintertime in Guiyang.Carboxylic acids in the rainwater of Guiyang were estimated to account for 18.7% to the free acidity, where formic, acetic and oxalic acids accounted for 7.9%, 4.7%, 6.1%, respectively.In Shangzhong, the 3 primary carboxylic acids represented 58.1% to the free acidity where formic, acetic and oxalic acids represented 25.1%, 7.5%, 25.5%, respectively.Carboxylic anions accounted for 6.6% (1.7%–19.2%) to the total anions in the rainwater of Guiyang.Carboxylic anions repre-sented 13.2% (0.5%–92.2%) to the total anions in the rainwater of Shangzhong.These results indicated that carboxylic acids were the important contributors to the rainwater acidity, especially in remote regions.

Study of Influence of Terrain and Climatic Factors on Groundwater-Level Fluctuation in a Minor River Basin Using GIS

Terrain environment parameters play a vital role in controlling groundwater movement:its recharge and discharge me-chanisms.Many earlier studies have been conducted relating terrain parameters and groundwater condition using conventional me-thods and remote sensing techniques.This study,however,endeavors to spatially visualize the degree of fluctuation in the ground-water level of Ongur,a minor river basin in different terrain units under different seasons(monsoon and summer) for three histori-cal periods of time using Geographic Information System(GIS) raster analysis.