Common bivalve larvae from New Zealand: Leptonacea

The late stage larvae of three erycinid bivalves (Mollusca: Pelecypoda: Leptonacea) taken from the brood chamber of the adult are described (Kellia cycladiformis, Lasaea rubra hinemoa, and L. maoria), and the provisionally identified late stage larva of the erycinid Arthritica bijurca taken from the plankton is described. Also, the D‐shaped larvae of the erycinid bivalves Kellia cycladiformis, Borniola reniformis, Arlhritica crassijormis, and A. bifurca taken from the parent brood chamber are described. The seasonal occurrence of each late stage larva in the plankton at the Bay of Islands (35° 15'S, 174° 10'E), Wellington Harbour (41° 16'S, 174° 51'E), and Raumati Beach (40° 56'S, 174° 58'E), New Zealand is described. Aspects of the reproductive cycles of Lasaea rubra hinemoa and Arthritica bifurca are presented.     

福建省兴化湾、九龙江河口和东山湾潮间带沉积物岩心碘研究

用碱熔法处理样品,水沥取,用分光光度法测量了采集自福建省兴化湾、九龙江河口和东山湾3个海湾潮间带沉积物岩心的碘分布。兴化湾、九龙江河口和东山湾3岩心中的碘含量分别为2.5~43.7,17.3~39.6和11.3~29.1 mg/kg。3个沉积物岩心中的碘含量稍高于福建省的土壤的碘含量,与我国海域的沉积物碘含量在同一水平,但明显低于文献报道的开阔海域沉积物的碘含量。兴化湾和东山湾沉积物中的碘与有机碳含量有较好的相关性;在九龙江河口采集的岩心中的碘与有机物碳含量的相关性较差。推测海洋源的沉积物碘与有机碳含量相关性较好,而陆源沉积物的碘与有机碳含量相关性较差。     

Chemical analyses of campbell Island fresh waters

Ten samples of freshwater from Campbell Island were analysed for their main ionic constituents. All show a preponderance of sodium and chloride derived from sea water. Potassium, calcium, and magnesium gave slightly higher concentrations than would be expected if derived solely from sea water. It is con‐eluded that the excess potassium is derived from the underlying rocks and soil, and the excess calcium and magnesium from the sea by fractionation into salt particles.     

末次盛冰期末期以来南海北部陆坡的陆源物质输入及其控制因素

通过对南海北部陆坡KNG5孔沉积物粒度、粘土矿物和14C年龄的综合分析, 探讨了南海北部陆坡的沉积物来源及其控制因素。物源分析表明, KNG5孔17.5-12.5ka BP的沉积物主要来源于珠江, 12.5ka BP 时粘土矿物组合突然发生改变, 并且自12.5ka BP以后, 高岭石含量总体稳定, 说明12.5ka BP时海平面已上升到相当的高度, 并且可能当时南海的现代环流系统已开始形成, 西行的广东沿岸流导致向外扩散的珠江物质减少, 由于受北太平洋深层水(NPDW)和黑潮(KC)南海分支的作用, 台湾成为此时沉积物的主要贡献者。KNG5孔17.5-11ka BP时期的粘土矿物和粒度变化主要受控于海平面和洋流系统的变化。全新世早期(11.0-8ka BP)平均粒径达到最细和1-2.2m 粒级含量达到最高值可能是强盛的夏季风作用的结果。全新世中晚期(8—0ka BP) 1-2.2?m组分含量的减少是8ka BP以来东亚夏季风减弱的具体体现, 1-2.2m 粒级含量指示的东亚夏季风变化能和北半球其它季风指标能很好地对应起来, 说明这次季风减弱是北半球各个季风系统的共同现象。     

Sulphate reduction in the sediment of the Venice canals (Italy)

The sulphur cycle in the sediment of the Venice canal network was investigated by considering the sulphate reduction rate (SRR) and the distribution of sulphur compounds, in both pore water and sediment. Sulphate reduction (SR) is the main process in the metabolism of the organic matter supplied to the network by untreated urban effluents. Although it might account for the decomposition of only a limited percentage of the total organic-C inputs, the estimated rates are among the highest observed in coastal sediments. Measured rates range from 0.26 to 0.99 micromolcm(-3)d(-1), while mean annual values, estimated by a diagenetic model, vary from 0.16 to 0.43 micromolcm(-3)d(-1). The speciation of S in the sediment reveals that pyrite-S is the most abundant component of the total reduced S pool, whereas acid volatile sulphides and elemental sulphur together account for less than 45%. A preliminary budget indicates that the rate of burial of solid-phase S is small compared to the S produced by SR (from 10 to 25%). A large amount of reduced S is then lost from the canal deposits to be re-oxidised at the sediment-water interface or in the overlying water column.     

Expression of heat shock protein 70 in a permanent cell line (EPC) exposed to sediment extracts from the North Sea and the Baltic Sea

Heat shock proteins 70 (hsp70) are known to be induced by a great variety of chemical stressors. The effects of different environmental contaminants, which were identified in sediments of the North Sea and the Baltic Sea as main contaminants or as contaminants of special toxicological interest, on the extent of expression of hsp70 in a permanent cell line Epithelioma papulosum cyprini (EPC) were investigated. Concentrations of the single contaminants leading to elevated hsp70 levels were compared to the respective concentrations of these contaminants encountered in the sediment extracts thus allowing an assessment of their contribution to the toxicity of these sediments. Analysis of hsp70 was performed using western blotting techniques with subsequent comparative quantification by densitometry. Eleven of thirteen contaminants have shown a dose-dependent increase in hsp70 levels. An expression of hsp70 was observed in most cases between 0.1 and 10 microg/mL test solution. Some of the investigated stressors led to extremely high hsp70 contents even at low concentrations. However, in most cases contaminant concentrations in sediments were too low to cause an effect. For this reason, effects of the tested sediments are attributed to other contaminants or rather to mixtures of stressors.     

Iron and phosphorus effects on the growth of Cryptomonas sp. (Cryptophyceae) and their availability in sediments from the Pearl River Estuary, China

Based on lab-culture experiments analyzing limitation and combination of iron and phosphorus on the growth of Cryptomonas sp. (Cryptophyceae), and the study of accumulation and release of Fe-bound P in sediment cores collected from the marine region of the Pearl River Estuary, China, reasons for the high frequency of phytoplankton bloom therein are discussed. Results show that the combined effect of Fe and P can obviously accelerate algal development, and the optimum culture conditions maintaining maximum growth rate are 0.05 μM Fe and 50 μM P. Cellular contents of Fe and P is consistent and the P:Fe molar ratio is 159:1. The optimum range of the P:Fe molar ratio in culture experiments for cell incubation is 500–1400. The vertical trends of total Fe and total P variations in sediments are parallel. Fe-bound P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34–80% of exchangeable P and 4–23% of exchangeable Fe are concurrently released from the surficial sediments. This is a possible way by which nutrients are made available to phytoplankton. These factors might be responsible for a high frequency of harmful algal blooms in the Pearl River Estuary.     

湖南城步火成岩锆石SHRIMP U-Pb年龄及其对江南造山带新元古代构造演化的约束

目前对新元古代中期江南造山带构造演化及钦杭结合带南西段构造性质存在不同认识。本文对湘西南城步地区新元古代火山岩和花岗岩进行了锆石SHRIMPU-Pb年龄测定并厘定其构造环境,从而为区域构造演化提供了约束。城步新元古代花岗岩侵入于云场里组变质火山-沉积地层中。云场里组变质火山岩与花岗岩的锆石SHRIMPU-Pb年龄分别为828±10Ma和805.7±9.2Ma。构造环境的地球化学判别图解表明花岗岩形成于岛弧环境;区域地质背景指示云场里组可能形成于活动陆缘弧前盆地。以城步火山岩和花岗岩研究为基础,结合区域地质资料,提出新元古代中期江南造山带西段构造演化过程:872～835Ma期间为陆缘盆地;835～820Ma期间俯冲造山,江南造山带形成基性—超基性岩和早阶段岛弧花岗闪长岩,东侧的城步地区为弧前盆地;820～810Ma期间江南造山带发生弧-陆碰撞;810～800Ma期间江南造山带进入后碰撞环境并形成晚阶段强过铝(黑云母)花岗岩,东侧城步地区因华南洋洋壳俯冲而形成新的岛弧;800Ma后华南进入伸展裂陷盆地演化阶段。上述认识揭示出扬子陆块东南缘的连续岛弧增生过程,同时为钦杭结合带南西段雪峰期"残留洋盆"属性提供了新证据。     

青藏高原拉萨地块新生代超钾质岩与南北向地堑成因关系

青藏高原拉萨地块广泛分布有新生代超钾质岩,岩石地球化学和Sr-Nd-Pb同位素特征表明这些超钾质岩来源于与古俯冲环境有着密切联系的含金云母的富集地幔源区,它们主要喷发于25~10 Ma。同时在拉萨地块分布有多条南北向地堑(裂谷),且它们的切割深度可能到达下地壳的深部甚至岩石圈地幔,它们主要形成于23~8 Ma。拉萨地块大多数超钾质岩沿着新生代的南北向地堑(裂谷)分布,并且它们在形成时代和空间分布上存在着明显的耦合性,结合沿着印度-雅鲁藏布江缝合带分布的中新世埃达克质岩,笔者认为这些超钾质岩很可能与中新世早期北向俯冲的印度岩石圈沿着印度-雅鲁藏布江缝合带附近发生断离,以及由此而引起拉萨地块东西向伸展构造活动产生的南北向地堑(裂谷)系统有关。     

甲烷水合物在人工毛细管沉积物柱中的形成和分解

天然气水合物在海底的形成与沉积物性质密切相关,沉积物的粒度、孔隙度、矿物组成等都可以影响到水合物的成核生长。通过拉曼测试和显微镜下观察人工毛细管模拟沉积物中CH4水合物的形成和分解过程,实验发现无论是在气液界面还是在溶有过饱和CH4的流体内,水合物都能够成核形成,但水合物更容易在气液和固液界面成核,并迅速生长;水合物在较大粒径石英砂(39~53μm)形成的孔隙内的成核机会比在粘土粒级的砂粒孔隙中的机会更大;水合物晶体主要呈发丝状附着于沉积物颗粒表面。