Patterns in diversity and community structure of epipelagic copepods from the Brazil–Malvinas Confluence area, south-western Atlantic

Diversity and structure of epipelagic copepod communities were investigated using 70 zooplankton samples collected from the top 50 m of the Brazil–Malvinas Confluence area between 35° and 55°S. Biogeographic patterns were investigated using multivariate analysis. Biodiversity patterns were examined using different univariate indexes. Representatives of 35 species of copepods from 23 genera and 13 families were found. Two zones were delimited based on their copepod composition, one in the subtropical waters of the Brazil current, and the other in the subantarctic waters of the Malvinas current. Both environments displayed contrasting patterns of biodiversity depending upon which element is measured (regional species richness as well as mean point species richness were significantly higher in the subtropical group of stations, whereas taxonomic distinctness was significantly higher in the subantarctic community). Based on these contrasting results, we suggest the use of both kind of indexes when defining priority areas for conservation.     

内蒙古达斡尔族群体9个X-STR位点的遗传多态性及法医学应用价值评估

目的研究内蒙古达斡尔族群体9个X-STR位点(DXS6789、DXS101、DXS8378、DXS7132、DXS7133、DXS7423、DXS6804、DXS6799、HPRTB)的多态性分布及法医学应用价值。方法抽取内蒙古达斡尔族87名健康无关个体静脉血,提取DNA,经PCR扩增、变性聚丙烯酰胺凝胶电泳及银染显色技术进行等位基因分型;采用SPSS13.0软件计算各位点基因型频率和等位基因频率,并检验等位基因分布差异有无统计学意义;Genepop软件进行Hardy-Weinberg平衡检验;Fstat软件计算基因多态性、固定指数并检验固定指数偏离平衡的程度;Powerstats软件计算各种法医学应用指标。结果获得内蒙古达斡尔族群体9个X-STR位点等位基因频率分布的数据;进一步检验获得9个X-STR位点中DXS7133位点的多态性和分化程度较低;DXS7423和DXS7132位点在不同民族中基因分布差异无统计学意义。结论9个X-STR位点中,DXS6789、DXS101、DXS8378、DXS7132、DXS7423、DXS6804、DXS6799、HPRTB 8个位点有较高的遗传多态性和个体识别率,在个体识别和女孩的亲权鉴定中有较高应用价值,对疾病相关研究有实际意义。     

Seasonality of picophytoplankton chlorophyll a and biomass in the central Cantabrian Sea, southern Bay of Biscay

Seasonal changes in the abundance and biomass of cyanobacteria (Synechococcus and Prochlorococcus) and picoeukaryotes were studied by flow cytometry in the upper layers of the central Cantabrian Sea continental shelf, from April 2002 to April 2006. The study area displayed the typical hydrographic conditions of temperate coastal zones. A marked seasonality of the relative contribution of prokaryotes and eukaryotes was found. While cyanobacteria were generally more abundant for most of the year (up to 2.4 10⁵ cells mL^− 1), picoeukaryotes dominated the community (up to 10⁴ cells mL^− 1) from February to May. The disappearance of Prochlorococcus from spring through summer is likely related to shifts in the prevailing current regime. The maximum total abundance of picophytoplankton was consistently found in late summer–early autumn. Mean photic-layer picoplanktonic chlorophyll a ranged from 0.06 to 0.53 µg L^− 1 with a relatively high mean contribution to total values (33 ± 2% SE), showing maxima around autumn and minima in spring. Biomass (range 0.58–40.16 mg C m^− 3) was generally dominated by picoeukaryotes (mean ± SE, 4.28 ± 0.27 mg C m^− 3) with an average contribution of cyanobacteria of 30 ± 2%. Different seasonality of pigment and biomass values resulted in a clear temporal pattern of picophytoplanktonic carbon to chlorophyll a ratio, which ranged from 10 (winter) to 140 (summer). This study highlights the important contribution of picoplanktonic chlorophyll a and carbon biomass in this coastal ecosystem.     

CO2 air–sea disequilibrium and preformed alkalinity in the Pacific and Indian oceans calculated from subsurface layer data

This work estimates new regionalized empirical parameterizations for preformed alkalinity (A_T^o) and the CO₂ air–sea disequilibrium (?C_dis). Both are key terms for the computation of anthropogenic CO₂ in the back-calculation methods. Data from the subsurface layer (75–180 m depth range) covering an area from North to South and from 19°E to 67.5°W (Pacific and Indian oceans) were taken from GLODAP (The Global Ocean Data Analysis Project) database. The subsurface layer is proved as a reliable reference for representing the main characteristics of the different water masses of the oceans. Besides, handing data from the two ocean basins altogether makes the new parameterizations of A_T^o and ?C_dis to be more globally consistent. Nevertheless, each ocean basin, at least in some regions, has different oceanographic characteristics based on its proper dynamical processes and water masses formation. In order to maintain each ocean basin ‘identity’ the whole domain was divided in six different regions (two of them sharing waters from Pacific and Indian oceans) and parameterizations in each region for both terms were obtained. Previously, data were transformed into a grid of 4°lat. × 5°lon. and the results obtained from the parameterizations were visualized and compare with pCO₂ climatologies. From the comparisons with previous ?C_dis estimations good results are obtained showing the reliability and robustness of the new regionalized empiric parameterizations.     

Additions to Mexican freshwater copepods with the description of the female Leptodiaptomus mexicanus (Marsh)

A survey on 10 temporary and permanent water-bodies, located at more than 2000 m above the sea level in the central part of Mexico resulted in the presence of 17 cyclopoid and five calanoid copepods. From the total taxa found, seven are new to the country: Leptodiaptomus assiniboiaensis (Anderson), Microcyclops dubitabilis Kiefer, Ectocyclops rubescens Brady, Eucyplops cf. bondi Kiefer, Eucyclops cf. prionophorus Kiefer, Eucyclops pseudoensifer Dussart, and Eucyclops cf. solitarius. The female of Leptodiaptomus mexicanus, a species known only from a single male found near Mexico City in 1929, is here described for the first time. Copepod fauna for each of the systems was highly diverse, with up to 12 species co-occurring in temporary ponds. This study revealed a mixture of north and south American taxa in the area.     

Surface CO2 measurements in the English Channel and Southern Bight of North Sea using voluntary observing ships

Ships of opportunity have been used to investigate ocean–atmosphere CO₂ fluxes in the English Channel and Southern Bight of the North Sea. Continuous underway measurements of the fugacity of seawater carbon dioxide (fCO₂^sw), chlorophyll, temperature and salinity have been performed along 26 transects during the spring and autumn periods. The spatial fCO₂^sw distribution along the Channel and Southern Bight is modulated by the photosynthetic activity, temperature changes and water mixing between inputs from the North Atlantic Ocean and riverine discharges. The seasonal variability of fCO₂^sw is assessed and discussed in terms of the biology and temperature effects, these having similar impacts. The variation of fCO₂^sw shows similar interannual patterns, with lower values in spring. The annual average of air–sea CO₂ fluxes places the English Channel as neutral area of CO₂ uptake. The spring and autumn data allow differentiating between distal and proximal continental areas. The Southern Bight shows a tendency towards net CO₂ uptake on the distal continental shelf, whereas the Scheldt and Thames Plumes show a CO₂ source behaviour on the proximal continental shelves.     

Vulnerability of Coastal Resort Cities to Mean Sea Level Rise in the Mexican Caribbean

We evaluated the potential economic impacts of increasing sea level rise (SLR) along the Mexican Caribbean where there are major gaps in our understanding of the mechanisms controlling flooding duration and frequency associated to future ecological and economic impacts. We determined the negative economic impact of SLR on infrastructure in the largest urban centers (Cancun, Isla Mujeres, Playa del Carmen, Puerto Morelos and Cozumel) in the state of Quintana Roo (Mexico) that are considered the largest tourism “hot spots” (resort cities) in the country. The tourism industry in this coastal area injects >8 billion dollars year^?1 to the Mexican economy. Our conservative economic assessment regarding the impact of SLR, under a 1?m scenario for all coastal cities is $330 million USD. Further projections for worst scenarios (SLR >2 m) show a non-linear trend where the cost of inaction can reach up to $1.4 billion USD (2?m SLR scenario) and $2.3 billion USD (3?m SLR scenario). This potential loss of infrastructure, as construction cost, is staggering and represents a robust baseline to start evaluating with more detail future impacts of climate variability and change on the Mexican Caribbean coastline.     

PB位相相干态的振幅平方压缩特性

研究了ＰＢ位相相干态的振幅平方压缩特性。结果表明，对于ｓ〉４的ＰＢ位相相干态均可存在振幅平方压缩特性，并给出了振幅平方压缩条件。     

ALTERATION IN CONTRACTILE RESPONSE TO NORADRENALINE,5-HYDROXYTRYPTAMINE, SARAFOTOXIN 6c, AND ANGIOTENSINⅡ IN RAT MESENTERIC ARTERY DURING ORGAN CULTURE

Theresistanceinindividualvascularbedsdeter minesthelocaldistributionofbloodflowtoandwithindifferentorgans.Thecontractilestateofanarteryiscontrolledbymediatorsreleasedlocallyfromnerveterminalsandendothelialcells ,andbycirculatinghormones .Thesemediatorsgiverisetoeffectsthroughtheirreceptors .Mediatorscanaffectvascularsmoothmuscleei therdirectly ,byactingonthesmoothmusclecellsthemselves ,orindirectly ,byactingonendothelialcellsoronnerveterminals ,especiallythoseofthesympatheticnervoussystem .Som…     

Assessment of Vulnerability and Integrated Management of Coastal Dunes in Veracruz,Mexico

Dune systems are essential to the ecological balance and sediment inputs of coastal environments and they provide numerous environmental services; however, their existence is threatened by natural and human stressors that contribute to their degradation. Future impacts are expected to be greater because of global climate change in association with further rises in sea level. Beaches and dune systems occupy large areas along the coastline of the state of Veracruz on the Gulf of Mexico. The aim of this study is to establish the intrinsic vulnerability of nine dune fields in Veracruz to current and future impacts and to assess their integrated management status. These dune–beach systems are more vulnerable to the effects of economic activities and land use change than to those induced by natural forces. Results show that six of these dune systems have medium vulnerability and an ecological conservation policy should be adopted; the other three, with high or very high vulnerability, are candidates for a restoration policy.