Northward shift in faunal diversity is a general pattern of evolution of the phanerozoic marine biota

The analysis of two global databases on spatio-temporal distribution of fossil marine animal genera (Sepkoski's compendium and The Paleobiology Database) has revealed the presence of the latitudinal diversity gradient (LDG) in the marine realm throughout the Phanerozoic. Within each time interval, LDG is characterized by two parameters: the latitudinal position of peak diversity and the steepness of monotonous decline of diversity with increasing distance from the zone of the highest diversity. During the Phanerozoic, peak diversity has drifted gradually from the tropics and subtropics of the Southern hemisphere into northern midlatitudes. The shift in peak diversity is not likely to be an artifact of incompleteness of the fossil record or uneven sampling of different regions. The shift proceeded in a stepwise manner, with periods of relatively fast changes separated by longer periods of little or no change. The latitudinal shift in peak diversity was probably due to a combination of several causes: tectonic (northward shift in the latitudinal distribution of continental shelf area), climatic (as demonstrated by the fact that peak diversity tended to occur near equator during the cold epochs and in midlatitudes during the warm epochs), and historical ("evolutionary inertia" of local faunas).     

Relationship between the alpha diversity of communities and the appearance rates of new genera in the evolution of phanerozoic marine biota

The influence of the alpha diversity of communities on the appearance rates of new species may be either positive (due to coevolution and niche construction) or negative (due to community saturation). The development of global paleontological databases allows the extrapolation of the analysis of these effects to past geological epochs. To assess the effect of alpha diversity on the rates of generic formation in the evolution of the Phanerozoic marine biota, the correlation of the parameters D (mean generic diversity of paleontological collections containing representatives of a large taxon) and B (relative rate of the appearance of new genera in the given large taxon) was analyzed. The majority of large taxa, and the Phanerozoic biota in general, characteristically show predominance of periods of positive correlation (synchronous changes) of B and D, separated by shorter periods of negative correlation (opposite phase changes). These can be interpreted as periods of positive and negative influence of alpha diversity on diversification, although positive correlation can be generated by other factors, including taphonomic ones. Apparently, in the evolution of the Phanerozoic marine biota, the coevolution and “niche construction” played a more significant role than the effect of “saturation” of communities.     

近5.4亿年以来生物多样性的变化

简要介绍了地质年代表的划分以及地球历史中的重要类群的起源时间;重点介绍了5.4亿年以来有关生物多样性变化的研究。生命发展史表明人类需要保护生物多样性来维持自己的生存。     

Ecology and evolution of mammalian biodiversity

Mammals have incredible biological diversity, showing extreme flexibility in eco-morphology, physiology, life history and behaviour across their evolutionary history. Undoubtedly, mammals play an important role in ecosystems by providing essential services such as regulating insect populations, seed dispersal and pollination and act as indicators of general ecosystem health. However, the macroecological and macroevolutionary processes underpinning past and present biodiversity patterns are only beginning to be explored on a global scale. It is also particularly important, in the face of the global extinction crisis, to understand these processes in order to be able to use this knowledge to prevent future biodiversity loss and loss of ecosystem services. Unfortunately, efforts to understand mammalian biodiversity have been hampered by a lack of data. New data compilations on current species' distributions, ecologies and evolutionary histories now allow an integrated approach to understand this biodiversity. We review and synthesize these new studies, exploring the past and present ecology and evolution of mammalian biodiversity, and use these findings to speculate about the mammals of our future.     

Economic growth and biodiversity

I argue that there is no fundamental conflict between economic growth and biodiversity. Humans can maintain and produce biological diversity just as we can maintain and produce other goods. Efforts to preserve and enhance biodiversity add to the size and growth of the economy. We are losing biodiversity because of human preferences and human inefficiencies, not because of economic growth. Inefficiency occurs when our actions do not reflect our real preferences, and is mainly due to failures of social coordination. To alleviate the problem of biodiversity loss we should address these failures.     

Antarctic marine biodiversity and deep-sea hydrothermal vents

The diversity of many marine benthic groups is unlike that of most other taxa. Rather than declining from the tropics to the poles, much of the benthos shows high diversity in the Southern Ocean. Moreover, many species are unique to the Antarctic region. Recent work has shown that this is also true of the communities of Antarctic deep-sea hydrothermal vents. Vent ecosystems have been documented from many sites across the globe, associated with the thermally and chemically variable habitats found around these, typically high temperature, streams that are rich in reduced compounds and polymetallic sulphides. The animal communities of the East Scotia Ridge vent ecosystems are very different to those elsewhere, though the microbiota, which form the basis of vent food webs, show less differentiation. Much of the biological significance of deep-sea hydrothermal vents lies in their biodiversity, the diverse biochemistry of their bacteria, the remarkable symbioses among many of the marine animals and these bacteria, and the prospects that investigations of these systems hold for understanding the conditions that may have led to the first appearance of life. The discovery of diverse and unusual Antarctic hydrothermal vent ecosystems provides opportunities for new understanding in these fields. Moreover, the Antarctic vents south of 60°S benefit from automatic conservation under the Convention on the Conservation of Antarctic Marine Living Resources and the Antarctic Treaty. Other deep-sea hydrothermal vents located in international waters are not protected and may be threatened by growing interests in deep-sea mining.     

Contrasting patterns in species boundaries and evolution of anemonefishes (Amphiprioninae, Pomacentridae) in the centre of marine biodiversity

Many species of coral reef fishes are distinguished by their colour patterns, but genetic studies have shown these are not always good predictors of genetic isolation and species boundaries. The genus Amphiprion comprises several species that have very similar colouration. Additionally, morphological characters are so variable, that sibling species can show a considerable overlap, making it difficult to differentiate them. In this study, we investigated the species boundaries between the sibling species pair A. ocellaris and A. percula (Subgenus Actinicola) and three closely related species of the subgenus Phalerebus (A. akallopisos, A. perideraion, A. sandaracinos) by phylogenetic analysis of mitochondrial cytochrome b and control region sequences. These two subgenera show strong differences in their patterns of species boundaries. Within the A. ocellaris/A. percula complex, five clades were found representing different geographic regions. Two major divergences both with genetic distances of 4-7% in cty b and 17-19% in the d-loop region indicate the presence of three instead of two deep evolutionary lineages. The species of the subgenus Phalerebus show three monophyletic clades, independent of the geographical location of origin, but concordant to the morphological species classification. The genetic distances between the Phalerebus species were 2-5% in cty b and 10-12% in the control region.     

Highly diverse, poorly studied and uniquely threatened by climate change: an assessment of marine biodiversity on South Georgia's continental shelf

We attempt to quantify how significant the polar archipelago of South Georgia is as a source of regional and global marine biodiversity. We evaluate numbers of rare, endemic and range-edge species and how the faunal structure of South Georgia may respond to some of the fastest warming waters on the planet. Biodiversity data was collated from a comprehensive review of reports, papers and databases, collectively representing over 125 years of polar exploration. Classification of each specimen was recorded to species level and fully geo-referenced by depth, latitude and longitude. This information was integrated with physical data layers (e.g. temperature, salinity and flow) providing a visualisation of South Georgia's biogeography across spatial, temporal and taxonomic scales, placing it in the wider context of the Southern Hemisphere. This study marks the first attempt to map the biogeography of an archipelago south of the Polar Front. Through it we identify the South Georgian shelf as the most speciose region of the Southern Ocean recorded to date. Marine biodiversity was recorded as rich across taxonomic levels with 17,732 records yielding 1,445 species from 436 families, 51 classes and 22 phyla. Most species recorded were rare, with 35% recorded only once and 86% recorded <10 times. Its marine fauna is marked by the cumulative dominance of endemic and range-edge species, potentially at their thermal tolerance limits. Consequently, our data suggests the ecological implications of environmental change to the South Georgian marine ecosystem could be severe. If sea temperatures continue to rise, we suggest that changes will include depth profile shifts of some fauna towards cooler Antarctic Winter Water (90-150 m), the loss of some range-edge species from regional waters, and the wholesale extinction at a global scale of some of South Georgia's endemic species.     

Predicted levels of future ocean acidification and temperature rise could alter community structure and biodiversity in marine benthic communities

A mesocosm experiment was conducted to quantify the effects of reduced pH and elevated temperature on an intact marine invertebrate community. Standardised faunal communities, collected from the extreme low intertidal zone using artificial substrate units, were exposed to one of eight nominal treatments (four pH levels: 8.0, 7.7, 7.3 and 6.7, crossed with two temperature levels: 12 and 16°C). After 60 days exposure communities showed significant changes in structure and lower diversity in response to reduced pH. The response to temperature was more complex. At higher pH levels (8.0 and 7.7) elevated temperature treatments contained higher species abundances and diversity than the lower temperature treatments. In contrast, at lower pH levels (7.3 and 6.7), elevated temperature treatments had lower species abundances and diversity than lower temperature treatments. The species losses responsible for these changes in community structure and diversity were not randomly distributed across the different phyla examined. Molluscs showed the greatest reduction in abundance and diversity in response to low pH and elevated temperature, whilst annelid abundance and diversity was mostly unaffected by low pH and was higher at the elevated temperature. The arthropod response was between these two extremes with moderately reduced abundance and diversity at low pH and elevated temperature. Nematode abundance increased in response to low pH and elevated temperature, probably due to the reduction of ecological constraints, such as predation and competition, caused by a decrease in macrofaunal abundance. This community‐based mesocosm study supports previous suggestions, based on observations of direct physiological impacts, that ocean acidification induced changes in marine biodiversity will be driven by differential vulnerability within and between different taxonomical groups. This study also illustrates the importance of considering indirect effects that occur within multispecies assemblages when attempting to predict the consequences of ocean acidification and global warming on marine communities.     

海洋生物多样性保护优先区域的确定

为了有效利用资源和资金,合理保护海洋生物多样性,海洋生物多样性保护优先区域的确定成为目前保护生物学领域的热点之一.本文首先探讨了生物多样性保护优先区域的定义和内涵,认为海洋生物多样性保护优先区域是指生物多样性丰富、物种特有化程度高、珍稀濒危物种分布集中、具有重要生态功能和过程的海洋区域.其次对保护优先区域确定的内容和方法进行了总结,主要包括单元区划、指标体系的构建及保护优先区域评估3个方面.继而根据我国海洋生物多样性现状提出保护优先区域确定的基本思路,即在海洋生物地理分区的基础上,根据物种和生境的生物多样性指标确定保护优先区域.最后针对存在问题提出建议,包括运用生物地理学方法进行单元区划、基于物种和生态系统的方法构建生物学指标以及信息网络数据库的构建等.     

Genome evolution and biodiversity in teleost fish

Teleost fish, which roughly make up half of the extant vertebrate species, exhibit an amazing level of biodiversity affecting their morphology, ecology and behaviour as well as many other aspects of their biology. This huge variability makes fish extremely attractive for the study of many biological questions, particularly of those related to evolution. New insights gained from different teleost species and sequencing projects have recently revealed several peculiar features of fish genomes that might have played a role in fish evolution and speciation. There is now substantial evidence that a round of tetraploidization/rediploidization has taken place during the early evolution of the ray-finned fish lineage, and that hundreds of duplicate pairs generated by this event have been maintained over hundreds of millions of years of evolution. Differential loss or subfunction partitioning of such gene duplicates might have been involved in the generation of fish variability. In contrast to mammalian genomes, teleost genomes also contain multiple families of active transposable elements, which might have played a role in speciation by affecting hybrid sterility and viability. Finally, the amazing diversity of sex determination systems and the plasticity of sex chromosomes observed in teleost might have been involved in both pre- and postmating reproductive isolation. Comparison of data generated by current and future genome projects as well as complementary studies in other species will allow one to approach the molecular and evolutionary mechanisms underlying genome diversity in fish, and will certainly significantly contribute to our understanding of gene evolution and function in humans and other vertebrates.     

Ancient Lake Ohrid: biodiversity and evolution

Worldwide ancient lakes have been a major focal point of geological, biological, and ecological research, and key concepts in, for example, evolutionary biology are partly based on ancient lake studies. Ancient lakes can be found on most continents and climate zones with most actual or putative ancient lakes in Europe being restricted to the Balkan Region. The arguably most outstanding of them is the oligotrophic and karstic Lake Ohrid, a steep-sided graben of rift formation origin situated in the central Balkans. Here, an attempt is made to summarize current knowledge of the geological, limnological, and faunal history of Lake Ohrid. Additionally, existing data on biodiversity and endemism in Lake Ohrid are updated and evaluated, and patterns and processes of speciation are reviewed in the context of the Ohrid watershed, including its sister lake, Lake Prespa. Whereas the geological history of the Ohrid Graben is relatively well studied, there is little knowledge about the limnological and biotic history of the actual lake (e.g., the age of the extant lake or from where the lake first received its water, along with its first biota). Most workers agree on a time frame of origin for Lake Ohrid of 2–5 million years ago (Mya). However, until now, the exact limnological origin and the origin of faunal or floral elements of Lake Ohrid remain uncertain. Two largely contrasting opinions either favour the theory of de novo formation of Lake Ohrid in a dry polje with a spring or river hydrography or a palaeogeographical connection of Lake Ohrid to brackish waters on the Balkan Peninsula. Whereas neither theory can be rejected at this point, the data summarized in the current review support the de novo hypothesis. An assessment of the fauna and flora of Lake Ohrid confirms that the lake harbours an incredible endemic biodiversity. Despite the fact that some biotic groups are poorly studied or not studied at all, approximately 1,200 native species are known from the lake, including 586 animals, and at least 212 species are endemic, including 182 animals. The adjusted rate of endemicity is estimated at 36% for all taxa and 34% for Animalia. In terms of endemic biodiversity, Lake Ohrid is with these 212 known endemic species and a surface area of 358 km² probably the most diverse lake in the world, taking surface area into account. Preliminary phylogeographical analyses of endemic Lake Ohrid taxa indicate that the vast majority of respective sister taxa occurs in the Balkans and that therefore the most recent common ancestors of Ohrid- and non-Ohrid species likely resided in the region when Lake Ohrid came into existence. These data also indicate that there is relatively little faunal exchange and overlap between Lake Ohrid and its sister lake, Lake Prespa, despite the fact that the latter lake is a major water supplier for Lake Ohrid. Studies on selected species flocks and scatters, mostly in molluscs, point towards the assumption that only few lineages originally colonized Lake Ohrid from the Balkans and that the majority of endemic species seen today probably started to evolve within the lake during the early Pleistocene. Within the Ohrid watershed, endemism occurs at different spatial and taxonomic scales, ranging from species endemic to certain parts of Lake Ohrid to species endemic to the whole watershed and from subspecies to genus level and possibly beyond. Modes of speciation in the Ohrid watershed are largely affected by its degree of isolation. Observational evidence points towards both allopatric (peripatric) and parapatric speciation. Though sympatric speciation within a habitat is conceivable, so far there are no known examples. Today, the lake suffers from increasing anthropogenic pressure and a “creeping biodiversity crisis”. Some endemic species presumably have already gone extinct, and there are also indications of invasive species penetrating Lake Ohrid. The comparatively small size of Lake Ohrid and the extremely small range of many endemic species, together with increasing human pressure make its fauna particularly vulnerable. It is thus hoped that this review will encourage future research on the ecology and evolutionary biology of the lake’s taxa, the knowledge of which would ultimately help protecting this unique European biodiversity hot spot. Guest editors: T. Wilke, R. V?in?l? & F. Riedel Patterns and Processes of Speciation in Ancient Lakes: Proceedings of the Fourth Symposium on Speciation in Ancient Lakes, Berlin, Germany, September 4–8, 2006     

Convergent evolution of modularity in metabolic networks through different community structures

ABSTRACT: BACKGROUND: It has been reported that the modularity of metabolic networks of bacteria is closely relatedto the variability of their living habitats. However, given the dependency of the modularityscore on the community structure, it remains unknown whether organisms achieve certainmodularity via similar or different community structures. RESULTS: In this work, we studied the relationship between similarities in modularity scores andsimilarities in community structures of the metabolic networks of 1021 species. Bothsimilarities are then compared against the genetic distances. We revisited the associationbetween modularity and variability of the microbial living environments and extended theanalysis to other aspects of their life style such as temperature and oxygen requirements. Wealso tested both topological and biological intuition of the community structures identifiedand investigated the extent of their conservation with respect to the taxomony. CONCLUSIONS: We find that similar modularities are realized by different community structures. We findthat such convergent evolution of modularity is closely associated with the number of(distinct) enzymes in the organism's metabolome, a consequence of different life styles ofthe species. We find that the order of modularity is the same as the order of the number ofthe enzymes under the classification based on the temperature preference but not on theoxygen requirement. Besides, inspection of modularity-based communities reveals thatthese communities are graph-theoretically meaningful yet not reflective of specificbiological functions. From an evolutionary perspective, we find that the communitystructures are conserved only at the level of kingdoms. Our results call for moreinvestigation into the interplay between evolution and modularity: how evolution shapesmodularity, and how modularity affects evolution (mainly in terms of fitness andevolvability). Further, our results call for exploring new measures of modularity andnetwork communities that better correspond to functional categorizations.     

Safeguarding marine life: conservation of biodiversity and ecosystems

Reviews in Fish Biology and Fisheries - Marine ecosystems and their associated biodiversity sustain life on Earth and hold intrinsic value. Critical marine ecosystem services include maintenance of...     

Current and future patterns of global marine mammal biodiversity

Quantifying the spatial distribution of taxa is an important prerequisite for the preservation of biodiversity, and can provide a baseline against which to measure the impacts of climate change. Here we analyse patterns of marine mammal species richness based on predictions of global distributional ranges for 115 species, including all extant pinnipeds and cetaceans. We used an environmental suitability model specifically designed to address the paucity of distributional data for many marine mammal species. We generated richness patterns by overlaying predicted distributions for all species; these were then validated against sightings data from dedicated long-term surveys in the Eastern Tropical Pacific, the Northeast Atlantic and the Southern Ocean. Model outputs correlated well with empirically observed patterns of biodiversity in all three survey regions. Marine mammal richness was predicted to be highest in temperate waters of both hemispheres with distinct hotspots around New Zealand, Japan, Baja California, the Galapagos Islands, the Southeast Pacific, and the Southern Ocean. We then applied our model to explore potential changes in biodiversity under future perturbations of environmental conditions. Forward projections of biodiversity using an intermediate Intergovernmental Panel for Climate Change (IPCC) temperature scenario predicted that projected ocean warming and changes in sea ice cover until 2050 may have moderate effects on the spatial patterns of marine mammal richness. Increases in cetacean richness were predicted above 40° latitude in both hemispheres, while decreases in both pinniped and cetacean richness were expected at lower latitudes. Our results show how species distribution models can be applied to explore broad patterns of marine biodiversity worldwide for taxa for which limited distributional data are available.     

The biodiversity of macrofaunal organisms in marine sediments

Marine sediments cover most of the ocean bottom, and the organisms that reside in these sediments therefore constitute the largest faunal assemblage on Earth in areal coverage. The biomass in these sediments is dominated by macrofauna, a grouping of invertebrate polychaetes, molluscs, crustaceans and other phyla based on size. Globally, only a small portion of marine habitats have been sampled for macrofauna, but sampled areas have led to global estimates of macrofaunal species number ranging from 500,000 to 10,000,000. Most of these species are undescribed, and global syntheses of patterns of individual taxa and biodiversity are few and based on limited samples. The significance of biodiversity in marine sediments to ecosystem processes is poorly understood, but individual species and functional groups are known to carry out activities that have global importance. Macrofaunal activity impacts global carbon, nitrogen and sulphur cycling, transport, burial and metabolism of pollutants, secondary production including commercial species, and transport of sediments. Documented extinctions of marine macrofauna are few, but the ramifications of species loss through habitat shrinkage and undocumented extinctions are unknown. Limited data suggest there is substantial functional redundancy in macrofauna within trophic groups but whether this redundancy is sufficient to allow species loss without significantly altering ecosystem processes is unknown. Sorely needed are experiments that test specific hypotheses on biodiversity, redundancy, and ecosystem processes as they relate to marine macrofauna.     

中国海物种多样性研究进展

中国海的生物多样性研究是中国科学院青岛海洋生物研究室1950年成立后开始大规模系统进行的.经过半个多世纪的努力,迄今已有千篇论文和约200部专著出版.主要专著《中国动物志》“无脊椎动物”已出版47卷,其中27卷为海洋生物,5年计划编写中17卷;《中国动物志》“脊椎动物”鱼类11卷,哺乳类1卷;《中国海藻志》8卷,待出版4卷,编写中3卷.另外,《海洋科学集刊》已出版的50卷中有22卷是海洋生物的专刊;另有《西沙群岛生物考察专辑》6卷.其中有代表性的著作《中国海洋生物种类与分布》(黄宗国,1994)集成国内外文献,记载物种20,278种(内有化石种及异名应除去).2008年出版的《中国海洋生物名录》(刘瑞玉主编)记录22,629现生种,比1994年相同门类多5,118种,仅次于澳大利亚和日本,居世界第三位.主要进展是取得了中国海翔实可靠的物种鉴定、编目和分布数据.此外还参加了国际“物种2000”计划项目,交出的“中国生物名录”比2008年名录显著增多.全部物种正进行“世界海洋物种登录,”(WoRMS),可供与世界不同海域和生境的种类多样性作比较研究.完成国家标准《海洋生物分类代码》(国家质量技术监督局1999发布)的修订,纠正了种名和分类系统的错误,增补了物种,保证了作为国家标准的高水平,待付印.完成全国濒危物种评估,负责编写《中国物种红色名录》1、3、2卷海洋无脊椎动物部分;结果发现濒危物种显著增多.1997-2000年“专属经济区大陆架环境资源调查”的结果进一步显示陆架海域生物多样性和主要资源衰退,还提出了应采取的措施.中国参加了国际重大项目“海洋生物普查计划”,进行了浮游动物普查,提交了中国国家汇总报告——中国海生物多样性研究,交PLoS ONE出版.全面加强了多样性和濒危种的保护,全国已建立国家级海洋自然保护区33个,特别保护区21个.论文在肯定中国海生物多样性研究进展和成绩的同时,指出了存在的主要不足是调查采集和研究的生境主要在陆架浅海,深海大洋特殊生境刚刚起步;多样性调查缺少全国统一计划行动,缺全面的多样性“背景值”资料.而监测、采集、研究不够;评估、保护亟待加强.文终提出了几点涉及学科发展和多样性监测、评估、保护的关键性建议.