Spatial association between northern fur seal (Callorhinus ursinus) and potential prey distribution during the wintering period in the northern Sea of Japan

Elucidating the response of marine predators to oceanographic features helps in understanding their foraging strategies and the cause of their spatial overlap and interference with fishery activities. Northern fur seal is a highly pelagic species during the wintering period. In recent years, fur seals have consistently been found distributed near the coast of southwest Hokkaido, Japan. Because interference by fur seals with coastal fishery activities has become a serious concern, an understanding is sought as to why fur seals come ashore in this area. We conducted ship‐based observations and estimated fur seal density. To elucidate the spatial and seasonal association of fur seal distribution and ocean environments, we constructed statistical models to describe how potential prey distribution and oceanographic features influenced the fur seal spatial distribution during the wintering period. Fur seal distribution corresponded markedly to potential prey distribution, and they tended to aggregate along the narrow continental shelf that is the main geographic feature of this area, which is 2000 m deep and approximately 10 km from the coast. Walleye pollock [Gadus chαlcogrαmmα (Theragra chαlcogrαmmα)] and arabesque greenling (Pleurogrammus azonus), which are one of the main prey for fur seals, move to the shallow area to spawn on the continental shelf seasonally, so potential prey abundance could be higher in coastal areas than offshore. Moreover, the absence of a mesopelagic biotic community may be one of the main factors in the coastal distribution of the fur seal.     

综合研究以生态修复为指导思想的水土保持技术路线探讨

生态修复的理论和实践证明,我国大多数地区都具有一定的生态修复自然条件和潜力。水土流失防治的指导思想要从注重工程建设向充分依靠生态系统的自我修复能力、积极开展流域治理的思路上转变,流域治理的总体布局、措施配置等要更加尊重自然规律,减少对自然生态系统的负面干扰,以人与自然和谐相处的理念认识自然、改造自然和利用自然。在防治标准、评价指标体系、不同类型区的关键技术措施等方面,还需强有力的技术支持。     

不同脂肪源对施氏鲟幼鱼血清生化指标的影响

在饲料蛋白质水平和能量水平均能满足生长需要的基础上,以不同的油脂(添加水平均为6%)配制成6种试验饲料,投喂施氏鲟幼鱼7周,分析脂肪源对幼鱼血清胆固醇(TC)、甘油三酯(TG)和高密度脂蛋白(HDL-C)的含量和谷丙转氨酶活性(GPT)等生化指标的影响。结果显示:猪油组、葵花籽油组和氧化鱼油组幼鱼的TG和TC都高于鱼油组、混合油组,而其HDL-C、TC含量显著低于鱼油组、混合油组。表明猪油、葵花籽油和氧化鱼油都不利于鲟鱼的脂肪代谢;而鱼油能够调节和平衡鱼体内的脂肪代谢,降低体脂和肝脂的含量,有利于施氏鲟的健康生长。这与不同油脂具有不同的脂肪酸种类和比例有关。     

基于SSSL的水稻重要性状QTL的鉴定及稳定性分析

【目的】单片段代换系（SSSL）是通过高代回交和分子标记辅助选择构建的，只含有来自供体亲本的一个染色体片段，遗传背景与受体亲本相同的品系。本研究的目的是利用SSSL检测不同环境条件下水稻重要性状的QTL。【方法】以32个SSSL为材料，随机区组试验设计，在2～4个季节中对水稻22个重要性状的QTL进行分析。【结果】共鉴定出59个QTL，分布于第1、2、3、4、6、7、8、10和11号染色体上。其中的18个QTL能够在2次以上重复检出，稳定性较好的QTL占检出QTL的30.5%，大多数农艺性状的QTL效应较小、稳定性较差。不同的性状，QTL稳定性不同，千粒重、粒长、谷粒长宽比、抽穗天数等性状的QTL较稳定。稳定性好的QTL，不仅具有较大的加性效应，而且受环境影响较小。【结论】利用单片段代换系可以有效地对水稻重要性状的QTL进行多年多季的稳定性分析。水稻大多数重要农艺性状QTL的不稳定性，反映了水稻生长发育过程的可塑性，可能是通过栽培措施使水稻品种获得高产优质的重要遗传基础。     

Effect of Tillage Systems and Axle Load on Undisturbed Soil Hydraulic Properties

The effects of tillage treatment and axle load resulting from wheeled traffic on tilled soil (0 to 20 cm) were evaluated by measuring the changes in soil physical properties (bulk density and infiltration rate) and by measuring the impact on water retention in comparison with controlled plots. Data obtained from the experimental plots showed that infiltration rate was strongly affected by tillage treatments in 0‐ to 20‐cm depths. Dry bulk density was affected in 0‐ to 20‐cm depths by tillage treatments and axle load. Tillage system changed the ability of the soils to hold moisture and decreased the plant‐available water capacity.     

养猪废水深度治理技术研究进展

对国内外养猪废水的深度治理技术进行了分析,首先对养猪废水水质进行了分析,并与排放限值要求进行了对比。其次,系统地总结了养猪废水的治理技术,并对各种技术的治理效果及治理成本进行了分析,提出了畜禽养殖废水治理工艺的设计思路。最后,分析了我国生猪养殖污染治理面临的困境,提出了小规模分散式养殖污染治理的发展方向,以期为我国畜禽养殖污染的治理提供科学依据。     

不同品系杜洛克后代商品猪胴体性状的比较分析

为研究不同品系杜洛克作为终端父本对其后代商品猪胴体性状的影响,选取214和108头分别由美系和加系杜洛克公猪配种、出生时间相近(±2 d)和体重相近(35±5 kg)的后代三元商品猪进行育肥饲养,结束饲养后开展屠宰试验,测定背膘厚度、眼肌厚度、瘦肉率和肋骨数.结果显示:加系杜洛克商品后代的背膘厚度、眼肌厚度显著(P<0...     

CT扫描分析秸秆隔层孔隙特征及其对土壤水入渗的影响

为阐明不同物理形态玉米秸秆建立的隔层对盐碱土壤灌溉水入渗特征的影响机制,该文采用室内模拟试验方法,在距地表40～45 cm处均匀铺设同一隔层厚度(5 cm)段状秸秆(SL)、颗粒状秸秆(SK)与粉末状秸秆(SF),以不埋设秸秆隔层为对照(CK),并利用CT扫描和图像处理技术,定量分析不同形态秸秆隔层内部孔隙度、孔隙大小分布、连通度等孔隙参数及其与灌溉水入渗特征之间的关系。结果表明:与CK处理相比,不同物理形态的玉米秸秆隔层均显著提高了40～45 cm隔层处总孔隙度,其中以SF处理最高,分别较CK、SL与SK处理显著提高了29.25、12.09与12.61个百分点(P 0.05),但SL与SK处理间差异不显著。SF处理在灌溉水入渗各阶段均显著增加了孔隙直径≤1 mm的孔隙度(P 0.05),入渗开始前、结束后分别较SL与SK处理提高了19.18、17.25和9.45、9.41个百分点,从而增大了封闭气体体积,导致灌溉水入渗速率较慢,而SL处理在灌溉水入渗开始前孔隙直径1 mm孔隙度较SK处理提高了1.04个百分点,但在入渗结束后SK处理孔隙直径1 mm孔隙度较SL处理显著提高,这种 1 mm大孔隙的变化导致SK处理出现湿润锋通过秸秆隔层耗时长于SL处理,而湿润锋通过隔层后至土柱底部耗时短于SL处理的现象。相关性分析结果表明:湿润锋通过秸秆隔层用时与入渗开始前、结束后隔层处总孔隙度、≤1 mm直径孔隙度均呈极显著正相关,与入渗前 1 mm直径孔隙度呈极显著负相关(P 0.01),而在入渗结束后这种大孔隙的作用减弱,但≤1 mm孔隙度的阻渗作用依旧显著,孔隙连通度对灌溉水入渗速率的影响较总孔隙度小。可见,不同形态玉米秸秆隔层均影响灌溉水入渗过程,CT扫描技术可作为定量研究秸秆隔层内部孔隙结构及其对灌溉水入渗影响机制的手段,该结果可为筛选和建立盐碱土壤最佳灌溉淋盐效果的物理形态秸秆隔层提供参考。     

中国城市水土流失的现状、对策及研究展望——以广东省深圳市为例

[目的]总结城市水土流失的概念、危害、成因、特点和防治对策,分析城市水土保持工作存在的问题和未来研究方向,旨在为中国城市水土流失治理及研究工作提供参考依据。[方法]根据多年的研究工作经验和文献资料,综合分析国内外城市水土流失及水土保持研究的成果。[结果](1)城市水土流失的概念蕴涵自然和人为两种动力,水和土两个流失主体,城市和周边及地表与地下两类分布空间;(2)城市水土流失危害主要包括管道淤积、风沙扬尘、水源污染、资源衰退、环境破坏等多方面;(3)城市水土流失防治对策主要包括法律、机制、宣传、监管、兼治和科研等6个方面。[结论]人们对城市水土流失的认识尚存不足,城市水土保持理论、技术及法规体系有待完善。城市水土流失及城市水土保持工作应从理论研究、应用优化以及经验推广等方面深入开展。     

Long-term culture of Atlantic salmon (Salmo salar L.) in submerged cages during winter affects behaviour, growth and condition

In the search for alternative farming methods, we investigated whether large salmon submerged below 10 m in winter conditions behaved normally and performed as well as control fish held in standard surface cages. On average, 2345 salmon of ~ 3.5 kg were kept in each of six 2000 m³ sea-cages for 6 weeks; three of which were submerged to 10–24 m depth and three acted as surface controls (0–14 m). Behaviour during both day and night was studied with echo-sounders, and underwater video cameras fitted with infra-red lamps. A sub-sample of fish from each cage was weighed, measured and assessed for fin and snout condition prior to and after the experimental period. In addition, the vertebral column of 50 fish from the control and submerged treatments were dissected and X-rayed to assess vertebral deformities. The submerged salmon seemed unable to re-fill any gas into the swim bladder, as a linear decrease in echo reflection to < 5% of pre-submergence levels after 22 days of submergence indicated loss of almost all gas from the physostomous swim bladders and negatively buoyant fish. Around day 22, submerged salmon swam at night time with a distinct ‘tail-down, head-up’ tilt (26°) compared to the horizontal swimming position of control fish (− 3°). Average swimming speed (body length per second) of submerged salmon were 1.3–1.4 times faster (day: 0.77 ± 0.02; night: 0.46 ± 0.02, (mean ± SE)) than control fish (day: 0.54 ± 0.01; night: 0.37 ± 0.02) both during day and night. Almost no mortality was seen, and the submerged salmon maintained similar diurnal vertical migrations as the surface fish, indicating that deep submergence did not exhaust the fish. However, submerged fish fed less efficiently, resulting in lower growth and reduced feed utilization. Fins and snouts of the submerged fish had small, but significantly more erosion than the control fish. Vertebrae in the tail region were significantly compressed in the submerged fish compared to control fish. This could be an early symptom of development of vertebral deformities. The results suggest that continuous submergence below 10 m for longer than 2 weeks reduces the welfare and performance of Atlantic salmon.