深海微生物高压适应与生物地球化学循环

深海是典型的高压环境,嗜压微生物是深海生态系统中的重要类群.随着深海采样技术的发展及高压微生物特殊培养设备的开发,已从深海环境中分离到一系列嗜压微生物,包括一些常压环境不能生长的严格嗜压菌.对这些嗜压菌的研究,不仅对微生物适应极端高压环境的机制有一定了解,而且发现了一些特殊的代谢产物.研究微生物高压嗜压机理,还有助于探索地球生命的温度压力极限及生命起源和演化等科学问题.从深海嗜压微生物多样性、深海微生物高压环境适应机理及深海微生物在生物地球化学循环中的作用等方面对嗜压微生物的研究进展进行综述.     

低温微生物及其酶类的研究概况

广泛分布在地球寒冷生境 ,如南北两极、高山、深海以及冰川中的低温微生物 ,不但为研究低温生态系统、生命起源与进化以及生物适冷机制提供了丰富的材料 ,同时在生物工程方面也具有潜在的巨大开发价值。国内外越来越多的科研人员对低温微生物及其产物的研究表现出了浓厚的兴趣。关于细胞膜和低温酶的研究 ,是目前微生物适冷机制研究中的 2个热点。就低温微生物的研究现状和适冷机制以及低温酶类的研究进行了综述。     

深海真菌多样性及其代谢产物生物活性的研究进展

深海环境复杂多样,深海微生物逐渐进化以适应其生存环境。真菌作为深海环境中的重要微生物类群,是开发海洋生物的新兴资源。综述了近年来深海真菌的物种多样性、活性代谢产物的多样性及其生物学功能等的研究进展,并对未来深海真菌的应用进行了展望。     

深海微生物资源研究开发技术进展

深海微生物由于生存环境的特殊性而具有各种与陆地和浅海微生物不同的功能,这些特殊功能具有重要的应用价值,是争夺激烈的深海热点资源之一。近年来,不断有新的研究技术和方法得到应用,推动了深海微生物资源的获取、研究和开发。对深海微生物菌株和基因资源研究开发方面的技术发展以及工作策略进行了综述与讨论。     

深海热液区微生物矿化过程的功能群和分子机制

深海热液区富含铁、锌、铜等含金属矿物(硫化物、氧化物、碳酸盐等)和无机小分子气体(H_2S、H_2、CO_2、CH_4等),具有独特的生态系统。微生物是深海热液生态系统的主要生产者和重要组成,并以控制矿化和诱导矿化两种途径参与了深海热液区的生物地球化学循环。在深海热液区存在着不同类型的微生物参与了生物矿化过程,如硫氧化菌、金属氧化菌、硫还原菌和金属还原菌等。本文详述了这些微生物参与的生物矿化现象、菌群多样性和矿化过程的分子机制,并对研究微生物矿化的研究工作进行了展望。     

海底万米也有原始生态系统

日本海洋研究开发机构的一个研究小组报告说,在世界最深的马里亚纳海沟,水深1.09万m的海底泥沙中,原始微生物非常活跃,这表明那里存在适合贫营养环境的生态系统。研究小组开发出能够抗超深海水压的观测装置,向马     

深海微生物的研究进展*

从生态学的角度介绍了深海微生物的营养来源、生物多样性及相关研究方法并展望深海微生物资源的开发前景。     

土壤生态系统微生物多样性-稳定性关系的思考

自20世纪50年代以来,生物多样性与生态系统稳定性的关系一直是生态学中重点讨论的理论问题之一.在当今人类活动对自然生态系统产生重大影响的情况下,全面理解生态系统多样性与稳定性的关系,有助于我们更好地应对环境变化和生物多样性丧失等生态问题.在陆地生态系统中,关注重点多集中在地上植物生态系统;而对地下生态系统,尤其是对微生物多样性与系统稳定性关系的研究尚重视不够.事实上,土壤微生物作为生命元素循环的驱动者,主导和参与地下生态系统中一系列重要生态过程,对土壤能否正常有序地执行各项生态功能至关重要.对土壤微生物多样性的研究,能使我们明确土壤中微生物对各种环境条件(包括自然和人为因素)变化的响应机制,更好地维持土壤生态系统的稳定性及其生态服务功能.本文在介绍土壤微生物多样性概念、研究方法、地下生态系统稳定性的基础上,重点讨论了土壤微生物多样性对土壤生态系统稳定性的影响,对多样性-稳定性关系在土壤微生物生态学中的应用进行了较为深入和全面的思考.作者提出,土壤微生物系统是一个动态变化的自组织系统,通过遗传来维持其组成和结构的相对稳定性,通过变异而适应外界干扰,共同构成土壤微生物系统的抵抗力(resistance)和恢复力(resilience),维护土壤生态系统的稳定性.今后土壤微生物多样性-稳定性关系的研究,需要注重地上与地下生态系统的结合与统一,借鉴宏观生态学理论来构建微生物生态学的理论框架,建立微生物多样性-稳定性关系的机理模型,从定性描述向定量表征方向发展.     

深海微生物的研究进展

从生态学的角度介绍了深海微生物的营养来源、生物多样性及相关研究方法并展望深海微生物资源的开发前景。     

中国大洋生物基因资源研究开发战略研讨会闭幕

近日,由中国大洋矿产资源研究开发协会办公室组织的“2005中国大洋生物基因资源研究开发战略研讨会”在福建厦门召开。此次会议旨在加强我国大洋领域生物基因资源的研究和开发力度,了解国际相关研究领域的进展和趋势,推动我国深海生命科学研究的发展,促进我国深海生物及其基因资源的产业化。     

Novel use of burrow casting as a research tool in deep-sea ecology

Although the deep sea is the largest ecosystem on Earth, its infaunal ecology remains poorly understood because of the logistical challenges. Here we report the morphology of relatively large burrows obtained by in situ burrow casting at a hydrocarbon-seep site and a non-seep site at water depths of 1173 and 1455 m, respectively. Deep and complex burrows are abundant at both sites, indicating that the burrows introduce oxygen-rich sea water into the deep reducing substrate, thereby influencing benthic metabolism and nutrient fluxes, and providing an oxic microhabitat for small organisms. Burrow castings reveal that the solemyid bivalve Acharax johnsoni mines sulphide from the sediment, as documented for related shallow-water species. To our knowledge, this is the first study to examine in situ burrow morphology in the deep sea by means of burrow casting, providing detailed information on burrow structure which will aid the interpretation of seabed processes in the deep sea.     

深海氨氧化古菌的环境适应基础及生态功能

氨氧化古菌是地球上丰度最高的微生物类群之一,驱动氮循环。尤其在深海,其相对丰度可达原核生物的20%-40%。然而,纯培养的缺乏严重阻碍了我们全面认知深海氨氧化古菌的生理特性和生态贡献。本文系统性地分析了深海环境特征与微生物适应性之间的关系,聚焦深海氨氧化古菌的潜在生存策略和代谢偏好。这些信息将有助于我们设计适用于深海氨氧化古菌的培养技术。此外,从系统发育和生理特性来看,深海氨氧化古菌与土壤或表层海洋来源的氨氧化古菌有显著区别,提示我们需要根据其特性重新估算全球海洋氮通量。     

Astrobiology of life on Earth

Astrobiology is mistakenly regarded by some as a field confined to studies of life beyond Earth. Here, we consider life on Earth through an astrobiological lens. Whereas classical studies of microbiology historically focused on various anthropocentric sub-fields (such as fermented foods or commensals and pathogens of crop plants, livestock and humans), addressing key biological questions via astrobiological approaches can further our understanding of all life on Earth. We highlight potential implications of this approach through the articles in this Environmental Microbiology special issue ‘Ecophysiology of Extremophiles’. They report on the microbiology of places/processes including low-temperature environments and chemically diverse saline- and hypersaline habitats; aspects of sulphur metabolism in hypersaline lakes, dysoxic marine waters, and thermal acidic springs; biology of extremophile viruses; the survival of terrestrial extremophiles on the surface of Mars; biological soils crusts and rock-associated microbes of deserts; subsurface and deep biosphere, including a salticle formed within Triassic halite; and interactions of microbes with igneous and sedimentary rocks. These studies, some of which we highlight here, contribute to our understanding of the spatiotemporal reach of Earth'sfunctional biosphere, and the tenacity of terrestrial life. Their findings will help set the stage for future work focused on the constraints for life, and how organisms adapt and evolve to circumvent these constraints.     

极地和深海环境中低温噬菌体研究进展

极地和深海是地球上较为独特的生态系统,生活在其中的生物由于长期处于低温、寡营养和黑暗封闭的环境中,大多缺乏基本的光合作用,而被认为是研究生命进化和地球环境演化等问题的＂活化石＂。在这样的极端环境中,低温噬菌体的丰度却很高,越来越多的证据表明它们在维持这类环境的生态平衡和调控生物地球化学循环等方面扮演着非常重要的角色。对极地与深海中低温噬菌体的研究进行简要综述。     

A synthesis of genetic connectivity in deep‐sea fauna and implications for marine reserve design

With anthropogenic impacts rapidly advancing into deeper waters, there is growing interest in establishing deep‐sea marine protected areas (MPAs) or reserves. Reserve design depends on estimates of connectivity and scales of dispersal for the taxa of interest. Deep‐sea taxa are hypothesized to disperse greater distances than shallow‐water taxa, which implies that reserves would need to be larger in size and networks could be more widely spaced; however, this paradigm has not been tested. We compiled population genetic studies of deep‐sea fauna and estimated dispersal distances for 51 studies using a method based on isolation‐by‐distance slopes. Estimates of dispersal distance ranged from 0.24 km to 2028 km with a geometric mean of 33.2 km and differed in relation to taxonomic and life‐history factors as well as several study parameters. Dispersal distances were generally greater for fishes than invertebrates with the Mollusca being the least dispersive sampled phylum. Species that are pelagic as adults were more dispersive than those with sessile or sedentary lifestyles. Benthic species from soft‐substrate habitats were generally less dispersive than species from hard substrate, demersal or pelagic habitats. As expected, species with pelagic and/or feeding (planktotrophic) larvae were more dispersive than other larval types. Many of these comparisons were confounded by taxonomic or other life‐history differences (e.g. fishes being more dispersive than invertebrates) making any simple interpretation difficult. Our results provide the first rough estimate of the range of dispersal distances in the deep sea and allow comparisons to shallow‐water assemblages. Overall, dispersal distances were greater for deeper taxa, although the differences were not large (0.3–0.6 orders of magnitude between means), and imbalanced sampling of shallow and deep taxa complicates any simple interpretation. Our analyses suggest the scales of dispersal and connectivity for reserve design in the deep sea might be comparable to or slightly larger than those in shallow water. Deep‐sea reserve design will need to consider the enormous variety of taxa, life histories, hydrodynamics, spatial configuration of habitats and patterns of species distributions. The many caveats of our analyses provide a strong impetus for substantial future efforts to assess connectivity of deep‐sea species from a variety of habitats, taxonomic groups and depth zones.     

Evidence for Permo-Triassic colonization of the deep sea by isopods

The deep sea is one of the largest ecosystems on Earth and is home to a highly diverse fauna, with polychaetes, molluscs and peracarid crustaceans as dominant groups. A number of studies have proposed that this fauna did not survive the anoxic events that occurred during the Mesozoic Era. Accordingly, the modern fauna is thought to be relatively young, perhaps having colonized the deep sea after the Eocene/Oligocene boundary. To test this hypothesis, we performed phylogenetic analyses of nuclear ribosomal 18S and 28S and mitochondrial cytochrome oxidase I and 16S sequences from isopod crustaceans. Using a molecular clock calibrated with multiple isopod fossils, we estimated the timing of deep-sea colonization events by isopods. Our results show that some groups have an ancient origin in the deep sea, with the earliest estimated dates spanning 232–314 Myr ago. Therefore, anoxic events at the Permian–Triassic boundary and during the Mesozoic did not cause the extinction of all the deep-sea fauna; some species may have gone extinct while others survived and proliferated. The monophyly of the ‘munnopsid radiation’ within the isopods suggests that the ancestors of this group evolved in the deep sea and did not move to shallow-water refugia during anoxic events.     

Climate change considerations are fundamental to management of deep‐sea resource extraction

Climate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to affect most deep‐ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep‐sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep‐seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full‐cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth‐System Model projections of climate‐change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep‐seabed mining. Models that combine climate‐induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep‐seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral‐related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep‐ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.     

Retention of ice-associated amphipods: possible consequences for an ice-free Arctic Ocean

Recent studies predict that the Arctic Ocean will have ice-free summers within the next 30 years. This poses a significant challenge for the marine organisms associated with the Arctic sea ice, such as marine mammals and, not least, the ice-associated crustaceans generally considered to spend their entire life on the underside of the Arctic sea ice. Based upon unique samples collected within the Arctic Ocean during the polar night, we provide a new conceptual understanding of an intimate connection between these under-ice crustaceans and the deep Arctic Ocean currents. We suggest that downwards vertical migrations, followed by polewards transport in deep ocean currents, are an adaptive trait of ice fauna that both increases survival during ice-free periods of the year and enables re-colonization of sea ice when they ascend within the Arctic Ocean. From an evolutionary perspective, this may have been an adaptation allowing success in a seasonally ice-covered Arctic. Our findings may ultimately change the perception of ice fauna as a biota imminently threatened by the predicted disappearance of perennial sea ice.     

Signal transduction in cells of the immune system in microgravity

Life on Earth developed in the presence and under the constant influence of gravity. Gravity has been present during the entire evolution, from the first organic molecule to mammals and humans. Modern research revealed clearly that gravity is important, probably indispensable for the function of living systems, from unicellular organisms to men. Thus, gravity research is no more or less a fundamental question about the conditions of life on Earth. Since the first space missions and supported thereafter by a multitude of space and ground-based experiments, it is well known that immune cell function is severely suppressed in microgravity, which renders the cells of the immune system an ideal model organism to investigate the influence of gravity on the cellular and molecular level. Here we review the current knowledge about the question, if and how cellular signal transduction depends on the existence of gravity, with special focus on cells of the immune system. Since immune cell function is fundamental to keep the organism under imnological surveillance during the defence against pathogens, to investigate the effects and possible molecular mechanisms of altered gravity is indispensable for long-term space flights to Earth Moon or Mars. Thus, understanding the impact of gravity on cellular functions on Earth will provide not only important informations about the development of life on Earth, but also for therapeutic and preventive strategies to cope successfully with medical problems during space exploration.     

Prebiotic materials from on and off the early Earth

One of the greatest puzzles of all time is how did life arise? It has been universally presumed that life arose in a soup rich in carbon compounds, but from where did these organic molecules come? In this article, I will review proposed terrestrial sources of prebiotic organic molecules, such as Miller-Urey synthesis (including how they would depend on the oxidation state of the atmosphere) and hydrothermal vents and also input from space. While the former is perhaps better known and more commonly taught in school, we now know that comet and asteroid dust deliver tons of organics to the Earth every day, therefore this flux of reduced carbon from space probably also played a role in making the Earth habitable. We will compare and contrast the types and abundances of organics from on and off the Earth given standard assumptions. Perhaps each process provided specific compounds (amino acids, sugars, amphiphiles) that were directly related to the origin or early evolution of life. In any case, whether planetary, nebular or interstellar, we will consider how one might attempt to distinguish between abiotic organic molecules from actual signs of life as part of a robotic search for life in the Solar System.