Spatial and temporal prokaryotic variability in the northern Adriatic Sea

The prokaryotic community, both in terms of abundance and activity (exoenzymatic hydrolysis of proteins, polysaccharides and phosphorylated molecules and leucine uptake), was investigated seasonally for a 3‐year period (2004–2006) in the Gulf of Venice (northern Adriatic Sea). By focusing on spatial and temporal variability, the prokaryote dynamics showed significant variations on a horizontal and seasonal scale, but no substantial differences were observed among years. The basin‐scale variability was mainly influenced by allochthonous inputs from the Po river and the Venice Lagoon, which were the main source of nutrients, acting as a ‘bottom up’ control on prokaryotes. On a seasonal scale, all the microbial parameters (except the polysaccharide degradation) showed significant variations following the temperature fluctuations. The annual rate of change was very low for all the chemical, physical and biological parameters and only the abundance and phosphatase activity of the prokaryotes differed significantly among years.     

Relationship between heavy metal accumulation and genetic variability decrease in the intertidal crab Pachygrapsus marmoratus (Decapoda; Grapsidae)

The “genetic erosion” hypothesis posits that heavy metal stress is related to a loss of genetic diversity at the population level. The genetic diversity of natural populations can, however, be affected by natural processes as well as by human impact. We studied the relationship between heavy metal bioaccumulation and genetic variability in the intertidal crab Pachygrapsus marmoratus. Tissue samples were collected from 40 individuals inhabiting four polluted and four unpolluted sites along the Tuscan coast (Mediterranean basin), and were examined for four heavy metals (arsenic, As, cadmium, Cd, lead, Pb, and copper, Cu). We also assessed the genetic variability of 235 crabs from the same localities using six microsatellite loci.Our results show that the bioaccumulation levels of these individuals accurately reflect the levels of pollution in their immediate environment, and that heavy metals accumulate more in the hepatopancreas than in the gills. Moreover, populations from polluted sites have significantly less genetic variability, measured as mean standardized d², and a significantly lower percentage of unrelated individuals, than populations from unpolluted sites. This evidence supports the “genetic erosion” hypothesis for metal heavy exposure in natural environments.     

A large encrusting clionaid sponge in the Eastern Mediterranean Sea

An excavating sponge, which covers extensive areas of limestone rock, has been found at several locations of the Eastern Mediterranean Sea. This zooxanthellate clionaid, brown with yellow oscula, may have an extension of several square meters under the β-form, similar to what has been described in coral reef areas. It has been observed at 3–30 m depth, generally in clear water in the Ionian Sea, Crete, Cyprus and Lebanon. The gross morphology and the spicule characters are described from all the collected specimens. The spicule complement, with variable tylostyles and rare, sometimes absent, thin spirasters, is compared with that of Cliona parenzani Corriero & Scalera-Liaci 1997 from the Apulian coast (Ionian Sea, Mediterranean Sea), and of several Caribbean and Indo-Pacific clionaid species, which display the same morphology and rather similar spicule characters. The sponge is tentatively identified as C. parenzani , although there are some differences with the type specimens in the highly variable spiculation, suggesting that it may represent a species complex similar to what is known for other species in the Caribbean and Indo-Pacific areas. Although the sponge appears to be closely related to large brown spreading clionaids from tropical areas and was previously practically overlooked in the Eastern Mediterranean, it does not appear to be a recent introduction. It is suggested that it could be a survivor in the warmer area of the Mediterranean of an ancient thermophilous fauna, which did not survive in the colder Western Basin during glacial episodes of the Pleistocene.     

渤海东部晚第四纪环境演变及潮流沙席沉积

通过对渤海东部CD5孔岩性、生物以及年代学的地层分析,晚第四纪以来划分出2个陆相和2个海相层,两次海侵的时间段分别为39～22和9kaBP至今。CD5钻孔附近渤海潮流三角洲大约在3600～2400aBP以来开始快速沉积,形成了4·8m厚的潮流沙席,结合渤海中东部10多个钻孔资料,总结了潮流沙席的环境演变过程,自全新世海侵以来可以大致分为9～8、8～3·6～2·4、3·6～2·4kaBP以来3个阶段,而目前正处于相对稳定状态。     

Sensitivity of wave model predictions to wind fields in the Western Mediterranean sea

The paper compares the wave hindcast in the Western Mediterranean sea using the reanalysis wind fields from HIPOCAS and ERA-40 from ECMWF for November 2001. The study has concentrated on the Mediterranean coast of Spain where there are known difficulties with the wind and wave modelling. Two winter storms have been compared. The main differences between the significant wave heights using the ERA-40 reanalysis (ECMWF) and HIPOCAS reanalysis winds were observed to increase when moving southwards in the geographical domain at the offshore locations. Systematic negative biases of Hs were obtained with the ERA-40 data at all the coastal locations analyzed, whereas positive biases are typical for the HIPOCAS reanalysis. For offshore and coastal locations when using the ERA-40 data the Hs biases increased moving to South, while this pattern was not so clear for the HIPOCAS data. The inconsistencies in the comparisons of modelled waves against measurements seem to be associated with the quality of the wind fields.     

近50 a中国东部和西部湖区水量空间变化趋势

基于近代湖泊水量(水位、水深和面积)记录,对近50 a中国东部和西部湖区水量的空间变化趋势进行半定量研究.结果表明:整体上看,20世纪80年代以前,东部湖区水量呈现波动变化而西部湖区水量基本趋于减少;80年代以后东部和西部湖区水量均表现为不同程度的增加.其中,20世纪50年代,东部和西部湖区水量状况基本相似,均保持高湖面特征.20世纪60年代,东部湖区水量有所减少但幅度不明显,而西部湖区以中高水量为主.20世纪70年代,不同区域湖泊基本都保持中湖面特征.20世纪80年代,东部湖区水量呈增加趋势而西部湖区水量相对70年代略有减少.20世纪90年代,东部和西部湖区水量均表现为增加趋势.进一步研究发现,最近50 a来中国不同区域湖泊水量发生变化除了气候因素的驱动外,人类活动的影响也是不可忽视的.     

藏东怒江板块结合带郭庆复式花岗岩体特征及其成因

根据作者在“三江”地区进行１∶２０万洛隆幅区域地质调查工作中收集的资料,对产出于怒江板块结合带东侧的郭庆复式花岗岩体进行了解体,将岩体划分为燕山早期的黑云母二长花岗岩,燕山晚期的黑云母石英正长岩、黑云母花岗闪长岩三种岩石类型。通过对它们的地质学、岩石学、岩石地球化学特征的研究表明,这三种侵入岩分属陆壳改造Ｓ型花岗岩和壳幔同熔Ⅰ型中酸性岩。燕山早期花岗岩形成于同碰撞造山期,燕山晚期黑云母石英正长岩形成于板块碰撞后的抬升阶段,燕山晚期黑云母花岗闪长岩形成于造山晚期构造环境,是区内板块构造不同演化阶段的产物。郭庆复式岩体的形成与三江地区板块构造演化密切相关     

长江口崇明东滩潮间带甲烷(CH4)排放及其季节变化

2004年5月至2005年4月在长江口崇明东滩湿地采用原位静态箱法对甲烷(CH₄)排放通量进行了现场测定。结果表明,崇明东滩潮间带(CM)是大气CH₄的排放源,且CH₄排放具有明显的季节变化规律,中潮滩(CM-2)7月CH₄排放最多,其通量为9.27 mg/(m²·h),在次年4月排放最少,只有0.03 mg/(m²·h)。低潮滩(CM-3)在春季5月CH₄排放最多,通量为0.09 mg/(m²·h);冬季2月CH₄通量值最低,只有0.002 mg/(m²·h),中、低潮滩CH₄年平均排放通量分别为2.06 mg/(m²·h)和0.04 mg/(m²·h)。     

中国东部季风区夏季雨型的划分及其环流成因分析

在总结前人关于中国夏季雨型划分的研究成果及其存在的主要问题的基础上 ,对中国夏季雨型的划分进行了新的尝试。根据东部季风区夏季 ( 6～ 8月 )降水的客观气候规律及业务预报应用需要 ,利用经验正交分解、主成分分析、奇异值分解、聚类分析等数理统计方法 ,结合经验分析 ,对中国东部季风区 1 880年以来 1 2 0多年夏季降水进行了客观分型 ,将中国东部季风区夏季降水划分为两类四型 ,并进一步分析了各类雨型的大气环流成因。