Interannual variation in spring biomass and gut content composition of copepods in the Kuroshio current, 1971–89

We examined the effects of climate factors on interannual variations of copepod biomass and gut content composition in early spring in the Kuroshio and the slope water off the Pacific coast of central Japan from 1971 to 1989. The biomass trends were different for large (prosomal length ≥ 1 mm) and small (prosomal length < 1 mm) copepods in both waters. Peaks in biomass of large copepods decreased in magnitude, and the biomass of small copepods was low around 1980. For the large copepods in the Kuroshio, 3-year running mean biomass was related to the Kuroshio meander index. The yearly mean biomass was related to diatom abundance in the gut which, in turn, was related to wind speed and temperature. The 3-year running mean biomass of large copepods in the slope water was positively related to solar radiation in March. The biomass of small copepods in both waters was negatively related to solar radiation in February, and years with high biomass of small copepods corresponded with not only the years with high abundance of larger foods (diatoms and micro-sized foods) in copepod guts, but also with the years with high abundance of the nano-sized foods. We hypothesize that nutrient supply to upper layers regulates interannual variation of biomass of large copepods in the Kuroshio. Thus, climate influences both size composition and biomass of copepods in and near the Kuroshio in early spring.     

雪灾干扰下林窗对木荷幼苗更新的影响

林窗干扰是维持森林生态系统的重要驱动力之一,对种子萌发、幼苗等自然更新过程、森林物种组成和动态、森林生物多样性的维持具有重要作用。本研究以2008年雪灾干扰后的浙江江郎山木荷林为研究对象,对木荷林窗大小结构、幼苗更新、生长等进行调查研究,结果表明:扩展林窗以50 100 m2的林窗个数最多(占总数的45.45%),各等级林窗中以50 100 m2的林窗占总面积比例最大(占总面积的30.31%)。林窗中木荷幼苗的平均高度和地径较对照林分分别高1.44 cm和0.61 mm,幼树在林窗中的平均高度和地径则比对照林分中分别高45.37 cm和5.00 mm且差异显著;林窗大小对木荷幼苗、幼树的高度和地径生长影响显著,中林窗中幼苗的高度和地径均高于小林窗和大林窗中的幼苗且差异均显著(F=4.893,P=0.007;F=5.203,P=0.004;n=357);幼树的地径在不同大小林窗中差异显著(F=3.569,P=0.037;n=43)。林窗幼苗的更新密度随着林窗面积的增大而增大,在林窗面积达到76 m2时,更新密度达到最大值,而后随着林窗面积的增大下降;中林窗和小林窗中更新苗木以低矮植株(1级、2级)为主,面积100 m2大林窗中,木荷幼苗生长较快。与他人研究的森林天然林窗相比,雪灾干扰后改变了林窗的大小分布结构和面积,50 100 m2的林窗比例较大,一定程度上更利于幼苗更新,具有相对较大的林窗幼苗更新密度;不论林窗大小,林窗内的更新幼苗都比林内多,郁闭度较大的林内或大面积的空地上都不利于更新幼苗的生长。因此,从受灾木荷林窗大小结构、幼苗更新、生长等来看,中林窗是幼苗适宜更新的面积,为木荷灾后恢复与重建提供了科学依据。     

我国几种重要松毛虫基因组大小测定

本研究采用流式细胞术,以公鸡(Gallus domesticus)血红细胞DNA含量为标准,测定了我国南方几种重要松毛虫的基因组大小(或称C-值)。结果显示,马尾松毛虫(Dendrolimus punctatus)的基因组大小为563.36±7.26 Mb,其雌、雄2C DNA含量分别为1.175 6±0.016 4和1.128 6±0.013 4 pg;思茅松毛虫(Dendrolimus kikuchii)的基因组大小为719.30±9.70 Mb,其雌、雄2C DNA含量分别为1.449 2±0.021 2和1.442 8±0.018 4 pg;云南松毛虫(Dendrolimus houi)的基因组大小为586.82±8.94 Mb,其雌、雄2C DNA含量分别为1.244±0.018 2和1.156±0.018 4 pg。统计分析结果发现,思茅松毛虫基因组显著大于云南松毛虫和马尾松毛虫基因组,后两者的基因组也存在显著差异,但绝对值相差较小。3种松毛虫雌雄虫的基因组大小之间也存在显著的差异,雌虫基因组大于雄虫。几种松毛虫基因组大小的测定,为进一步比较其分子差异、构建基因组文库和基因组学研究奠定了基础。     

微波真空冷冻干燥时怀山药的微CT孔道分布

局部温度过高的问题限制了微波真空冷冻干燥（microwave freeze drying,MFD）技术在果蔬干燥中的广泛应用。发展传热传质理论是解决MFD局部温度过高问题的根本途径。数值模拟是研究传热传质机理的重要方法,并有望解决MFD中局部温度过高的问题。利用详细的孔径和孔隙分布建立结构模型对数值模拟至关重要。该研究以怀山药为样品,利用微CT（X-ray micro-computed tomography）技术分析不同干燥仓压力（100、200、300 Pa）和微波加载量（0.5、1.0、1.5、2.0 W/g）时孔隙和孔隙分布的变化。结果表明,干燥仓内的低压环境更倾向于形成小孔隙,干燥仓内压力的变化对外层的孔隙大小和分布无明显影响,但对内层的孔隙大小和分布有明显影响。微波加载量对内、外层的孔隙大小和分布均有显著影响。研究结果将为解决MFD中局部温度过高问题的数值计算研究提供试验支持。     

不同粒级煤矸石风化物总有机碳含量比较

对抚顺西露天矿煤矸石山表层煤矸石风化母岩进行多点取样,把风化物筛分成＞2mm、2mm ～0．05mm和＜0．25mm 3个粒级,分析测定了矸石山表层母岩及其风化物不同粒级中总有机碳含量,比较了表层矸石不同粒级风化物总有机碳的含量差异。结果表明：矸石山表层风化物总有机碳在53．1～84．7g＆#183;kg -1之间,母岩总有机碳在4．5～23．6g＆#183;kg -1之间。页岩风化物＜0．05mm粒级总有机碳含量最高,均值为118．4mg ＆#183; kg -1;燃后矸石风化物在＜0．05mm 粒级中有机碳含量次之,均值为108．8 mg ＆#183; kg -1。随着风化物颗粒减小,表层矸石风化物总有机碳含量有逐渐升高的趋势。     

积温和放养规格对网箱养殖罗非鱼的影响

利用大秋房水库网箱养罗罗非鱼的６年生产记录，以放养规格以及每天大于１５℃、大于２０℃的积温和天数作为自变量、以个体增肉倍数、饵料系数作为变量，进行一元和二无回归分析。结果发现：每天大于１５℃的积温和天数与增肉倍数相关最显著；第天大于１５℃的天数和放养规格与饵料系数相关也较显著。     

山东近海魁蚶生长的研究

研究了山东近海魁蚶的渔获年龄组成，体重与壳长的关系，一般生长型、生长速度和生长加速度，指出最小捕捞年龄，壳长和体重分别为３龄、７０－８０ｍｍ和１１０－１５０ｇ并提出筏式养殖蚶应加强３龄前的管理。     

采样设计对估计矛尾虾虎鱼体长-体质量关系参数b的影响

鱼类体长-体重关系参数估计的准确与否影响进一步的渔业资源评估和管理。不同采样设计获得的生物学数据,对鱼类体长-体重关系参数b估计可能会有一定的影响。本文基于2013-2014年在黄河口水域调查获得的矛尾虾虎鱼(Chaemrichthys stigmatias)体长、体重数据,采用计算机模拟重抽样方法,选取相对估计误差和相对偏差两个指标,比较了不同采样设计对估计矛尾虾虎鱼体长-体重关系参数b的影响。结果表明,增加样本量可有效提高其体长-体重关系参数b的估计精度。不同季节数据对参数估计精度具有不同影响,应用多季节调查采样数据估计参数精度往往优于单季节采样。夏季数据对矛尾虾虎鱼体长-体重关系参数估计尤为重要。方案9(夏-冬季方案)在样本量达到540尾时,相对估计误差REE为2.08%,相对偏差RB的绝对值为0.71%,在相同样本量下该设计方案表现最好。在估计黄河口矛尾虾虎鱼等鱼类体长-体重关系参数时,应保证获得一定样本量的对参数估计具有较大影响的季节的生物学数据。     

A scheme for soil classification of paddy fields in Japan with special reference to mineral paddy soils

Introduction

Paddy (irrigated) rice is the most important single crop in Japan. Nearly half of the total arable lands covering approximately 6.5 million hectares, are devoted to the growing of the rice plant. It is grown mainly on the alluvial plains which are intensively cultivated, and are the most productive soils of the country. Since the idea of modern pedology was introduced into Japan, some work has been done by some Japanese investigators to classify paddy soils on the basis of their morphological characteristics. A brief historical review on the soil survey work in Japan has been given by Kamoshita⁸⁾. In 1936 Kawamura described methods of soil survey in Korea through a careful study of the work developed by Stremme and his colleagues in Danzig. In those days Kamoshita⁹⁾,¹⁰⁾ devised a scheme of paddy soil classification by applying the concept of the wet soil types (mineralische Nassböden) proposed by Stremme, and he established five predominant soil types as follows: Bog soils (Moorböden), Half-bog soils (anmoorige Böden), Meadow soils (Wiesenböden), Gray lowland soils (graue Auenböden), and Brown lowland soils (braune Auenböden). The names in parentheses represent the wet soil types proposed by Stremme. These soil types are subdivided into soil kinds (Bodenarten) on the basis of differences in texture, rusty mottling, and humus content. The soil kinds were used as both categorical and cartographical units for detailed soil surveys.     

Separation and characterization of the constituents of compost and soil humic acids by two-dimensional electrophoresis

To investigate the chemical heterogeneity of humic acids (HAs), we applied two-dimensional (2-D) electrophoresis to HAs from a compost and two types of soils. In this method, HAs are first separated by isoelectric focusing (IEF) and then separated by polyacrylamide gel electrophoresis (PAGE). IEF and PAGE were carried out in the presence of 7?M urea. Upon 2-D electrophoresis of HAs, dark-colored substances were spread out across the gel mainly in the isoelectric point (pI) range of 3.0–4.5. Green fluorescence was observed in the smaller molecular size region of the gel, especially in the pI range of 3.0–4.5, and the most intense fluorescence was found at the moving front. The gels were divided into 36 sections, and then HA constituents were extracted from the individual sections and recovered by precipitation with acid. The distribution of organic carbon (C) among the gel sections coincided with that of the dark-colored substances on the gel. The total C recoveries were only 43–50%, suggesting that a considerable amount of HA constituents was lost during the extraction from the gels and purification. High-performance size-exclusion chromatography confirmed that the constituents of HAs were separated based on their molecular sizes by PAGE. The measurement of diffuse reflectance infrared Fourier transform (DRIFT) spectra indicated that the chemical properties of the HA constituents differed depending on the position on the gels and were affected by the molecular size rather than the pI. The fractions of the compost HA were characterized by higher proportions of aliphatic, proteinous and polysaccharide moieties and by the presence of lignin-derived structures. For the soil HAs, the fractions were characterized by a high proportion of the carboxyl group and a low proportion of aliphatic moieties. The proportion of proteinous and polysaccharide moieties in the fractions of soil HAs decreased with decreasing molecular size. The chemical properties of the green fluorescent substances remained unclear, since there was not enough of the substances to measure the DRIFT spectra. The present study showed that 2-D electrophoresis in the presence of concentrated urea offers an effective method for fractionating and isolating the constituents of HAs.