Impact of 21st century climate change on the Baltic Sea fish community and fisheries

The Baltic Sea is a large brackish semienclosed sea whose species-poor fish community supports important commercial and recreational fisheries. Both the fish species and the fisheries are strongly affected by climate variations. These climatic effects and the underlying mechanisms are briefly reviewed. We then use recent regional – scale climate – ocean modelling results to consider how climate change during this century will affect the fish community of the Baltic and fisheries management. Expected climate changes in northern Europe will likely affect both the temperature and salinity of the Baltic, causing it to become warmer and fresher. As an estuarine ecosystem with large horizontal and vertical salinity gradients, biodiversity will be particularly sensitive to changes in salinity which can be expected as a consequence of altered precipitation patterns. Marine-tolerant species will be disadvantaged and their distributions will partially contract from the Baltic Sea; habitats of freshwater species will likely expand. Although some new species can be expected to immigrate because of an expected increase in sea temperature, only a few of these species will be able to successfully colonize the Baltic because of its low salinity. Fishing fleets which presently target marine species (e.g. cod, herring, sprat, plaice, sole) in the Baltic will likely have to relocate to more marine areas or switch to other species which tolerate decreasing salinities. Fishery management thresholds that trigger reductions in fishing quotas or fishery closures to conserve local populations (e.g. cod, salmon) will have to be reassessed as the ecological basis on which existing thresholds have been established changes, and new thresholds will have to be developed for immigrant species. The Baltic situation illustrates some of the uncertainties and complexities associated with forecasting how fish populations, communities and industries dependent on an estuarine ecosystem might respond to future climate change.     

Low nekton abundance in the western Bering Sea according to trawl survey data and model estimates

Complex trawl surveys were conducted in the upper epipelagic zone of the western Bering Sea and adjacent Pacific waters in the summer and fall seasons of 2002–2006. The abundance of small nekton (micronekton) was estimated using two independent methods: traditional trawling and a mathematical model of selective feeding by fish. According to the trawl data, total micronekton density varied from 1 to 158 (average 40) mg/m³ on the northwestern Bering Sea shelf and from 6 to 151 (37) mg/m³ in deep-water areas of the southwestern Bering Sea and adjacent Pacific waters. According to model calculations, micronekton density was higher—72–193 (141) mg/m³ on the shelf and 78–507 (228) mg/m³ in the deep-water part of the studied area. Both trawl and model data showed that small nekton on the northwestern shelf mostly consisted of larval and juvenile walleye pollock, as well as small fish species, such as capelin and Pacific sand lance. In the deepwater areas, mesopelagic fish and squid (northern lampfish, northern smoothtongue, and boreopacific gonate squid), which migrate to the surface at night, juvenile Atka mackerel, and shortarm gonate squid dominated among micronekton. The advantages and disadvantages of both the trawl and model methods for calculating the abundance of small fish and squid were considered. Comparison of abundance estimates for mass fish species, obtained through trawl and model methods, enabled us to analyze trawl catchability coefficients and propose a more differentiated division of micronekton into size classes than had been done earlier. A function that characterizes the dependence of the catchability coefficient (CC) on body length was offered for juvenile Atka mackerel. This equation can be also used for evaluation of CC for other fishes that have similar size and behavior.     

21世纪初农业生态系统健康研究方向

农业生态系统健康是指农业生态系统免受发生“失调综合症”,处理胁迫的状态和满足持续生产农产品的能力,目前,农业生态系统健康研究范围主要涉及农业生态系统健康评价方法,土壤质量和水质与农业生态系统健康的联系,农业生态系统健康与人类健康的关系,害虫生态管理对农业生态系统健康的贡献,杂草综合管理在农业生态系统健康中的作用,从生态病理学到农业生态系统健康,线虫群落作为农业生态系统健康指示生物的研究,转基因作物对农业生态系统健康的生态影响评价,农业投入政策对农业生态系统健康的影响,景观生态学在农业生态系统健康评价中的应用,农业生态系统健康与绿色食品开发等,首先论述了农业生态系统健康研究的现状,介绍了农业生态系统健康研究实例-土壤健康的生物指标,最后提出了今后农业生态系统健康的研究方向,为保障农产品安全和增进人类健康提供依据。     

The winter abundance and distribution of birds in western peter the Great Bay in the Sea of Japan

The data on the abundance and distribution of sea birds and waterfowl at the coast of southern Primorye and distribution diagrams of the sea ducks along the surveyed coast in winter season are given. The dependence of the presence of the birds in certain coastal areas on the winter ice condition was revealed.     

The diversity,abundance and fate of ice algae and phytoplankton in the Bering Sea

Despite being an essential part of the marine food web during periods of ice cover, sea ice algae have not been studied in any detail in the Bering Sea. In this study, we investigated the diversity, abundance and ultimate fate of ice algae in the Bering Sea using sea ice, water and sub-ice sediment trap samples collected during two spring periods in 2008 and 2009: ice growth (March–mid-April) and ice melt (mid-April–May). The total ice algal species inventory included 68 species, dominated by typical Arctic ice algal diatom taxa. Only three species were determined from the water samples; we interpret the strong overlap in species as seeding of algal cells from the sea ice. Algal abundances in the ice exceeded 10⁷ cells l^?1 in the bottom 2-cm layer and were on average three orders of magnitude higher than in the water column. The vertical flux of algal cells beneath the ice during the period of ice melt (>10⁸ cells m^?2 day^?1) exceeded export during the ice growth period by one order of magnitude; the vertical flux during both periods can only be sustained by the release of algae from the ice. Differences in the relative species proportions of algae among sample types indicated that the fate of the released ice algae was species specific, with some taxa contributing to seeding in the water column, while other taxa were preferentially exported.     

Taxonomic composition and abundance of macrozoobenthos in the Rybinsk Reservoir at the beginning of the 21st century

The structure of macrozoobenthos has been studied in the deep-water part of the Rybinsk Reservoir. A total of 73 species of bottom macroinvertebrates have been recorded, the majority of which are mollusks, oligochaetes, and chironomids. The macrozoobenthos on gray silts of channel parts of the reservoir was the richest in taxonomic composition and quantitative abundance. The maximum number of species has been recorded in the former mouth of the Mologa River, and the highest abundance of macrozoobenthos has been recorded near the village of Breitovo in June. Most of the macrozoobenthos is made up of oligochaetes and chironomid larvae; midge larvae dominate by biomass. Compared to the end of the 20th century, changes in the taxonomic composition and in dominating species of macrozoobenthos are observed.     

Gap junction channel structure in the early 21st century: facts and fantasies

Gap junction channels connect the cytoplasms of adjacent cells through the end-to-end docking of single-membrane structures called connexons, formed by a ring of six connexin monomers. Each monomer contains four transmembrane alpha-helices, for a total of 24 alpha-helices in a connexon. The fundamental structure of the connexon pore is probably similar in unpaired connexons and junctional channels, and for channels formed by different connexin isoforms. Nevertheless, variability in results from structurally focused mutagenesis and electrophysiological studies raise uncertainty about the specific assignments of the transmembrane helices. Mapping of human mutations onto a suggested C(alpha) model predicts that mutations that disrupt helix-helix packing impair channel function. An experimentally determined structure at atomic resolution will be essential to confirm and resolve these concepts.     

Thermodynamics,biochemistry and microscopy for the 21st century

The aim of biology is the study of the properties of cells in living intact animals. Many steps of research procedures in biochemistry change the entropy, and therefore, the free energy of the chemical reactions from those in vivo. Sections prepared for histology, histochemistry, electron microscopy and immunocytochemistry, yield limited information about the original cells in life, although their problems have been documented. Approaches to the biological and histological difficulties are suggested.     

Pavlov and psychophysiology in the 21st century]

Psychophysiology, physiological psychology (Sechenov), human physiology of higher nervous activity (Pavlov) is an interdisciplinary field, which appeared at the interface between psychology and neurosciences for exploration of the brain mechanisms of mental functions. The fundamental complementation of subjective and objective, psychological and neurobiological approaches as the facets of investigation of the basically whole process made it possible to fill with a specific content and clearly differentiate the forms of human psyche such as emotion, consciousness, personality, character, and creativity.     

21世纪医患关系的伦理学评判

随着医疗技术的迅猛发展,医疗水平不断提高,为人们带来福音的同时,使得医患关系的矛盾尤为凸显。21世纪的医患矛盾已经不仅仅是医生和患者之间的矛盾与冲突,而是两大社会群体之间的问题。在法律还无法规范的前提下,医学伦理学的评判标准可以为新时期医患关系提出更根本的指引与解释。     

The need for a more effective biological nomenclature for the 21st century

HAWKSWORTH, D. L., 1992. The need for a more effective biological nomenclature for the 21st century. The procedures of biological nomenclature are now under immense pressure to change. Users are frustrated by the instability of names and lack of consensus, and increasingly undertake work previously the province of taxonomists; data are presented to show they tend to ignore unwelcome changes. Taxonomists themselves are deflected from both systematic and phylogenetic investigations, and documenting the world's biodiversity, by nomenclatural matters. A survey of 60 U.K. botanical taxonomists revealed that about half spent 10–75% of their research time on nomenclatural matters; extrapolated to the U.K. as a whole, botanical nomenclature could occupy up to 52 full-time posts at a cost of £ 1.3 million. Further, an analysis of 15 monographs of fungal genera showed that overall 85% of the names investigated were not accepted. The major problems to confront relate to concepts of priority, effective and valid publication, illegitimacy, types, ambiregnal organisms and the decision-making bodies. While most of these issues have been overcome by bacteriologists, only now are those concerned with botanical and zoological nomenclature starting to tackle them in earnest. A more effective biological nomenclature could be produced by extending the concept of lists of nomenclaturally protected names. This would resolve questions of effective and valid publication, priority, and application. Such lists would primarily assist taxonomists by dealing with much of the nomenclatural ‘noise’ of the past. Registration procedures are needed to complement such lists for names introduced in the future. The need for standard names and classifications fixed for limited periods is increasingly being met by specialist user groups and also concerns some taxonomists, but is best handled outside formal systems by appropriate specialist bodies. Increased harmonization of the Codes is possible when facing common problems and essential to resolve the difficulties posed by ambiregnal organisms. The image of taxonomy is adversely affected by unsatisfactory nomenclatural systems. Taxonomists should be responsible and refrain from changing names only for nomenclatural reasons while these matters are in discussion. Users and taxonomists need to work with nomenclaturalists to improve the effectiveness of biological nomenclature, if they are to ensure that it will fulfil both their requirements in the 21st century. The prospects for systematics are bleak if it fails to consummate the dual responsibilities of scientific endeavour and user requirements