Do bacteria-sized marine eukaryotes consume significant bacterial production?

Up to 60 percent of the total marine primary production (or about one-fourth of the total global carbon dioxide fixation) passes through the free-living bacterioplankton. Grazing by bacteriovores is probably the predominant fate of the bacteria, although data are scarce. Evidence is presented that previously uncharacterized, small eukaryotes that are able to pass even 0.6-micrometer filters may be responsible for a large fraction (more than 50 percent) of the total grazing in coastal waters. These organisms have not yet been observed microscopically.     

滨海新区填海造陆的地形地貌环境演变影响分析

填海造陆对海岸环境的影响主要体现在改变海岸线长度与形态及直接吹填沙导致近海海底地形地貌变化[1],这些变化影响着海岸带规划管理和可持续发展,具有重要的理论和现实意义。本文利用滨海新区遥感影像及其海图资料,对该区域近30年海岸线变迁、围填海演变及海底地形信息进行了提取,并对其具体进程和驱动因素进行了研究。研究表明：30年间,滨海新区海岸线变迁是向海洋推进,且推进的趋势越来越明显,岸线长度增长趋势愈发明显,变迁面积较大。针对填海造陆引起围堤基底冲刷问题,笔者提出了可供参考的解决方案。     

江苏海涂土壤的形成与开发

本文阐明了江苏海涂土壤有盐分平衡、积盐和脱盐的地带,并分析了这三个盐分地带与潮间带沉积规律以及地面景观之间的关系。此外,论述了海涂土壤的治理与开发应因地而异。淤长海岸海涂士壤的开发要以综合农业为目标,建立优质商品棉生产基地,走农林牧渔全面发展的道路。治理上特别要解决排水问题,可考虑动力排水方法。     

Biological consequences of the 1975 el nino

The weak El Ni?o event of 1975 had a clearly defined effect on the biological productivity of the southeastern tropical Pacific. During February and March 1975, warm (27 degrees C) water of low salinity (33.5 parts per thousand) and low nutrient content extended south across the equator east of the Galápagos Islands, replacing the nutrient-rich water normally supplied by equatorial upwelling. Equatorial primary production was less than 0.2 gram of carbon per square meter per day, one-fifth of the normal value. At the maximum development of the 1975 event, the coastal region of Peru continued to have strong nearshore upwelling with primary production values greater than 2.5 grams of carbon per square meter per day, although the zone of high production was confined to a 250-kilometer-wide band, one-half its normal width. The biological effects of the 1975 event were short-lived; in April and May 1975 the equatorial region had begun to reestablish its normal levels of primary production.     

Strong top-down control in southern California kelp forest ecosystems

Global-scale changes in anthropogenic nutrient input into marine ecosystems via terrestrial runoff, coupled with widespread predator removal via fishing, have created greater urgency for understanding the relative role of top-down versus bottom-up control of food web dynamics. Yet recent large-scale studies of community regulation in marine ecosystems have shown dramatically different results that leave this issue largely unresolved. We combined a multiyear, large-scale data set of species abundances for 46 species in kelp forests from the California Channel Islands with satellite-derived primary production and found that top-down control explains 7- to 10-fold more of the variance in abundance of bottom and mid-trophic levels than does bottom-up control. This top-down control was propagated via a variety of species-level direct and indirect responses to predator abundance. Management of top-down influences such as fishing may be more important in coastal marine ecosystems, particularly in kelp forest systems, than is commonly thought.     

中国海岸带研究II——海岸带生态环境问题及其解决途径

海岸带生态环境问题是目前海洋环境科学研究的热点问题之一。从近海富营养化、石油污染、生物资源破坏、生活垃圾和固体废弃物污染以及海水入侵等方面概括总结了我国海岸带的主要生态环境问题并给出了海岸带生态修复的方法和海岸带可持续发展对策。同时指出,可持续发展是解决我国海岸带生态环境问题的必由之路,加快制定并完善一整套海岸带可持续发展对策是今后努力的重要方向。     

山东省东·中·西部开发区土地集约利用地域差异的实证研究——以山东招远、新泰、陵县经济开发区为例

以山东招远、新泰、陵县共3个典型经济开发区土地集约利用情况为主要对象,结合2010年山东省开展的开发区土地集约利用成果更新数据,运用统计分析法、空间分析法,研究山东省东部半岛、中部山区、西部平原开发区土地集约利用的地域差异以及影响因素。结果表明,山东省东部沿海的开发区土地集约利用程度较高,中部山区开发区其次,西部平原的开发区得分则略低。主要原因是地质特点不同,土地供应利用存在差异;经济发展水平、产业特点不同导致用地效益出现差距。     

基于模糊聚类分析的田间精确管理分区研究

【目的】以海涂围垦区盐碱土为研究对象，将从SPOT遥感影像提取出的NDVI数据和盐碱地土壤生产力的主要限制因子盐分数据及部分养分数据作为变量进行精确农业管理分区研究。【方法】模糊c均值聚类方法被用来进行分类分区，并引入了模糊聚类指数和归一化分类熵两种分区效果评价指标，对分区结果进行比较和评价。【结果】本研究区，最佳的分区数目为3个。对处于每一子区内土样的化学特性和实测棉花产量数据进行方差分析，发现其均值在所定义的每个管理分区内都存在着统计意义上的显著差异性，其中子区3具有最高的肥力水平和作物产量，而子区1最低。【结论】利用所选取的变量，模糊c均值聚类算法可以较好地进行管理分区划分。分区结果不但可以指导采样，而且可用于实施变量投入和精确施肥推荐，为样区土壤管理提供科学的决策依据。     

中国滨海盐沼湿地碳收支与碳循环过程研究进展

滨海盐沼湿地由于其较高的初级生产力和较缓慢的有机质降解速率而成为缓解全球变暖的有效蓝色碳汇,近年来引起全球范围内的热切关注。我国滨海盐沼湿地分布较广,国内学者对滨海盐沼湿地碳循环及碳收支研究取得了一定进展,深入研究滨海盐沼湿地碳循环有助于对全球碳循环及全球变化的理解,并为利用滨海湿地进行碳的增汇减排提供科学依据。主要从我国滨海盐沼湿地碳循环主要观测方法、碳收支与碳循环过程及特点、碳库的组成与影响因素、气态碳的输入输出、潮汐作用对其碳收支的影响这5个方面出发,对国内的滨海盐沼湿地碳循环与碳收支的研究进展进行了归纳总结,并对今后的研究方向给出如下建议:(1)加强滨海盐沼湿地土壤碳库在深度上和广度上的研究;(2)标准化滨海盐沼湿地碳储量、碳通量的量化方法和观测技术;(3)在研究尺度上要宏观、微观并重,同时加强长期原位监测湿地碳通量的变化与室内模拟研究;(4)量化在潮汐影响下滨海盐沼湿地碳与邻近生态系统之间的横向交换通量。只有对我国滨海盐沼湿地碳库收支进行更准确的评估和长期的碳库动态变化监测,方可进一步认识我国盐沼湿地对全球气候变化的影响及其反馈作用,这对于预测全球变化及制定湿地碳储备功能的提升策略具有重要的意义。     

Deep magma body beneath the summit and rift zones of kilauea volcano, hawaii

A magnitude 7.2 earthquake in 1975 caused the south flank of Kilauea Volcano, Hawaii, to move seaward in response to slippage along a deep fault. Since then, a large part of the volcano's edifice has been adjusting to this perturbation. The summit of Kilauea extended at a rate of 0.26 meter per year until 1983, the south flank uplifted more than 0.5 meter, and the axes of both the volcano's rift zones extended and subsided; the summit continues to subside. These ground-surface motions have been remarkably steady and much more widespread than those caused by either recurrent inflation and deflation of the summit magma chamber or the episodic propagation of dikes into the rift zones. Kilauea's magmatic system is, therefore, probably deeper and more extensive than previously thought; the summit and both rift zones may be underlain by a thick, near vertical dike-like magma system at a depth of 3 to 9 kilometers.     

中国南方小麦优质高效生产的若干问题

文章分析了当前我国南方麦区小麦生产存在的问题和解决这些问题的可能方法。近二十年来 ,中国南方麦区小麦生产的发展落后于北方麦区 ,主要原因是育成的小麦新品种和北方麦区相比 ,表现为品质差、产量低和抗病性丧失快。本文批驳了南方麦区可以不种小麦的观点 ,指出在农业结构调整中 ,小麦生产仍然是重要的内容。南方小麦的品质差的主要原因不是气候因素 ,而是没有与南方生态条件相适应的优质品种。文中提出了培育南方麦区优质小麦品种的策略。本文指出 ,根据南方麦区的气候和生态特点 ,认真研究适应南方麦区的优质高产抗病小麦新品种和高效栽培的方法 ,是使南方小麦生产走出困境的途径     

海-陆交互作用与海岸带碳中和农业驱动

海岸带既是生态脆弱区也是低碳农业发展“前哨”。推动和发展碳中和农业符合时代所需,也符合绿色、可持续发展理念。基于此,本文阐述了在海岸带区域发展碳中和农业的相关问题和重要性。首先,本文阐释了海陆交互作用以及海岸带碳中和农业发展理念;然后,分析了海岸带碳中和农业驱动中的碳中和农业生物、人工光合作用与农业驱动以及该理念的工程化应用问题;最后,深入剖析了如何识别海岸带农业核心碳汇,包括原位监测、同位素标记与统计学分析方法,并在此基础上提出了农业碳汇增强技术,为后续海岸带碳中和农业的构建、发展和实践提供参考,同时对促进脆弱的海岸带生态系统的保护和绿色低碳农业的发展具有重要意义。     

辽南沿海牡蛎科Ostreidae种类的调查及其增养殖前景研究

经过调查，确定辽南地区沿海分布有６种牡蛎，其中猫爪牡蛎Ｃｒａｓｓｏｓｔｒｅａ Ｐｅｓｔｉｇｇｒｉｓ Ｈａｎｌｅｙ在辽宁省为首次记录。对各种牡蛎的分布情况作了简要描述，并对其生产状况和增养殖前景进行了研究，提出今后主要增养殖的种类和途径。     

中国文化产业发展的空间不均衡性分析

我国文化产业处在产业发展的初级阶段,且呈现空间不均衡现状。文化产业产能的空间不均衡,与社会经济发展水平正相关,呈现东多西少;城乡文化产品消费不均衡,在经济不发达省份表现更为明显;一般文化消费品与高端文化消费品的空间分布不均衡,东部沿海省份人均高端文化产品丰富,而普适文化产品匮乏;现阶段各地对文化产业发展的扶植力度和重视程度不一。文化产业产能与供给的空间分布不均衡主要符合我国产业等级分布的一般特征,是马斯洛需求理论的生动体现,主要由各区域文化产业发展扶植力度差异和受重视程度差异所造成。     

Expanding oxygen-minimum zones in the tropical oceans

Oxygen-poor waters occupy large volumes of the intermediate-depth eastern tropical oceans. Oxygen-poor conditions have far-reaching impacts on ecosystems because important mobile macroorganisms avoid or cannot survive in hypoxic zones. Climate models predict declines in oceanic dissolved oxygen produced by global warming. We constructed 50-year time series of dissolved-oxygen concentration for select tropical oceanic regions by augmenting a historical database with recent measurements. These time series reveal vertical expansion of the intermediate-depth low-oxygen zones in the eastern tropical Atlantic and the equatorial Pacific during the past 50 years. The oxygen decrease in the 300- to 700-m layer is 0.09 to 0.34 micromoles per kilogram per year. Reduced oxygen levels may have dramatic consequences for ecosystems and coastal economies.     

2003年安徽省小麦赤霉病的发生特点·防治对策与建议

20 0 3年安徽省小麦扬花灌浆期间频频降雨 ,4月份降水量淮北中北部地区偏多 8成～ 1.5倍 ,其他地区偏多 1～ 6成 ;月雨日沿淮淮北地区 10～ 16d ,淮河以南地区 17～ 2 1d ,显著偏多 ;全省大部分地区土壤墒情处于过湿状态 ,渍涝面积大。而赤霉病子囊孢子成熟度和释放高峰期又与小麦扬花期正好吻合 ,加上冬春季的低温冻害又降低了一些品种的抵抗力 ,导致小麦赤霉病发病时间早 ,持续时间长 ,发病范围广 ,危害程度大 ,造成损失重。小麦赤霉病打破了南北界限 ,沿江、江淮地区病情严重 ,淮北部分地区病穗率高达 5 0 %以上 ,严重度大多达到 3～ 4级 ,为历史所罕见 ,一般减产 3 0 %以上 ,严重的超过 5 0 % ,沿淮、淮南麦区部分田块损失更大。小麦赤霉病对人、畜健康和生命安全危害大 ,应引起高度重视。在防治对策上积极采取以农业防治为基础 ,结合选用抗病品种 ,关键时期进行药剂保护的综合防治策略 ;培育与利用抗病品种是控制小麦赤霉病 ,保证小麦高产、稳产、优质经济有效和安全的根本办法。建议 :尽快建立和完善专用小麦等农产品品质及安全检测体系 ,同国际接轨 ,制定赤霉病DON毒素的检测标准 ;进一步加强小麦赤霉病等病虫害的流行预测预报和防治工作 ,在品种布局上考虑高产优质的同时 ,一定要增强品种的抗性     

种鸡蛋孵化后期死亡原因分析

在邯郸地区采集了不同规模种鸡孵化场的终死鸡胚,并详细进行了流行病学调查和实验室检验,得出鸡白痢沙门氏菌是导致种鸡蛋在孵化后期死亡的主要原因。     

Impact craters on venus: initial analysis from magellan

Magellan radar images of 15 percent of the planet show 135 craters of probable impact origin. Craters more than 15 km across tend to contain central peaks, multiple central peaks, and peak rings. Many craters smaller than 15 km exhibit multiple floors or appear in clusters; these phenomena are attributed to atmospheric breakup of incoming meteoroids. Additionally, the atmosphere appears to have prevented the formation of primary impact craters smaller than about 3 km and produced a deficiency in the number of craters smaller than about 25 km across. Ejecta is found at greater distances than that predicted by simple ballistic emplacement, and the distal ends of some ejecta deposits are lobate. These characteristics may represent surface flows of material initially entrained in the atmosphere. Many craters are surrounded by zones of low radar albedo whose origin may have been deformation of the surface by the shock or pressure wave associated with the incoming meteoroid. Craters are absent from several large areas such as a 5 million square kilometer region around Sappho Patera, where the most likely explanation for the dearth of craters is volcanic resurfacing. There is apparently a spectrum of surface ages on Venus ranging approximately from 0 to 800 million years, and therefore Venus must be a geologically active planet.     

Paleogeographic reconstructions of coastal aegean archaeological sites

Many studies have been made of ancient Greek topography, some of the more recent ones based on modern techniques. However, most still ignore the subsurface dimension of coastal and other environments and hence fail to fully explain coastal and alluvial-colluvial processes, rates of change of geomorphology, and the effects of coastal change on humans. In this article subsurface geological analyses have been used to elucidate paleogeographic coastal settings of major archaeological sites around the Aegean Sea. Similar approaches could be applied in the Middle and Far East and elsewhere in the Mediterranean.     

天津设施农业发展思路与对策研究

根据天津设施农业生产发展现状和天津发展都市型农业的总体部署,围绕蔬菜、花卉、食用菌和果品等园艺产业,科学规划设施农业发展空间,重点打造环城、滨海服务型设施农业发展区和郊区平原生产型设施农业发展区,因地制宜建设蓟县山区生态型设施农业共三个发展区.实施"4412"工程.用现代农业技术和装备武装农业.实施功能提升战略、科技支撑战略、组织带动战略、园区引领战略、经营模式创新战略和市场营销战略,努力实现设施农业环境控制自动化、主要生产过程机械化、生产管理规范化、生产技术标准化、经营管理企业化、目标产品品牌化.