Regional distribution and temporal trends of some contaminants in the water of the Baltic Sea

During a cruise on board RV Gauss in May/June 1988, joint investigations into organochlorine compounds, dissolved trace metals, petroleum hydrocarbons and basic hydrography were carried out at representative stations of the Baltic Monitoring Programme (BMP). The aim of the cruise was to study distribution patterns and — using previous data — to establish temporal trends if at all discernible.Each group of contaminants investigated showed specific characteristics, with differences even between compounds within the same group. The differences are due to:

蒙古南戈壁中洛霍考夫阶(泥盆系)牙形刺的首次发现

蒙古南戈壁新金斯特(Shine Jinst)地区Ulaan-Shand 剖面的查干安普拉格(Tsagaanbulag)组以前曾划归志留系(文洛克统至普里多利统). 但在Tsagaanbulag组及其上部的阿曼采尔(Amansair)组发现了非常重要的牙形刺, 包括Lanea omoalpha, Amydrotaxis johnsoni, “Ozarkodina” planililingua, Pedavis sp., 清楚地指明这两个组应当归下泥盆统中洛霍考夫阶. 中洛霍考夫阶的海相地层在中国和蒙古国广泛分布. 志留系文洛克统和洛德罗统下部的海相地层在蒙古是否存在是值得注意的问题.     

Nickeloan pyrite from Prangenhaus quarry, Niederberg area, Germany—A short communication

The mineral chemistry of two nickeloan pyrite samples from the Prangenhaus quarry, Wülfrath, is presented. Sample PRH 5: main zone=4.32-9.7 wt% Ni (0.089-0.202 atoms per formula unit (a.p.f.u.)), 0.21-1.31 wt% Co (0.004-0.027 a.p.f.u.); rim zone=11.76-22.38 wt% Ni (0.244-0.466 a.p.f.u. ), 1.35-8.16 wt% Co (0.028-0.168 a.p.f.u.). Sample PRH 6: 6.75-11.33 wt% Ni (0.139-0.234 a.p.f.u.), 0.86-2.46 wt% Co (0.018-0.051 a.p.f.u.). Estimated Fe/Ni and Fe/Co ratios of the hydrothermal fluids forming the nickeloan pyrite point to very local fluctuations in the chemistry of the ore forming fluids in the Prangenhaus quarry. The presence of nickeloan pyrite indicates formation temperatures below 137 °C, which is in accordance with earlier findings of formation temperatures for sphalerite (60-130 °C) in the Niederberg area.     

Organic carbon fluxes from the upper Yangtze basin: an example of the Longchuanjiang River,China

To investigate the effects of anthropogenic activity, namely, land use change and reservoir construction, on particulate organic carbon (POC) transport, we collected monthly water samples during September 2007 to August 2009 from the Longchuanjiang River to understand seasonal variations in the concentrations of organic carbon species and their sources and the yield of organic and inorganic carbon from the catchment in the Upper Yangtze basin. The contents of riverine POC, total organic carbon and total suspended sediment (TSS) changed synchronously with water discharge, whereas the contents of dissolved organic carbon had a small variation. The POC concentration in the suspended sediment decreased non‐linearly with increasing TSS concentration. Higher molar C/N ratio of particulate organic matter (average 77) revealed that POC was dominated by terrestrially derived organic matter in the high flows and urban wastewaters in the low flows. The TSS transported by this river was 2.7 × 10⁵ t/yr in 2008. The specific fluxes of total organic carbon and dissolved inorganic carbon (DIC) were 5.6 and 6 t/km²/yr, respectively, with more than 90% in the high flow period. A high carbon yield in the catchment of the upper Yangtze was due to human‐induced land use alterations and urban wastes. Consistent with most rivers in the monsoon climate regions, the dissolved organic carbon–POC ratio of the export flux was low (0.41). Twenty‐two percent (0.9 t/km²/yr) of POC out of 4 t/km²/yr was from autochthonous production and 78% (3.1 t/km²/yr) from allochthonous production. The annual sediment load and hence the organic carbon flux have been affected by environmental alterations of physical, chemical and hydrological conditions in the past 50 years, demonstrating the impacts of human disturbances on the global and local carbon cycling. Finally, we addressed that organic carbon flux should be reassessed using adequate samples (i.e. at least two times in low‐flow month, four times in high‐flow month and one time per day during the flood period), daily water discharge and sediment loads and appropriate estimate method. Copyright © 2011 John Wiley & Sons, Ltd.     

Eigenschaften und Bildung aufweitbarer (quellbarer) Dreischicht-Tonminerale in Böden aus Sedimenten

Contributions to Mineralogy and Petrology - Mineralogische, chemische und kolloidchemische Untersuchungen an den Tonfraktionen von Böden aus Sedimenten haben gezeigt,     

Environmental responses of jellyfish polyps as drivers of medusa populations off the coast of Namibia

Jellyfish populations in the southeastern Atlantic off the coast of Namibia have increased subsequent to the decline of small pelagic fisheries at the end of the 1960s, although the environment there has also become warmer and the waters off Walvis Bay have become richer in zooplankton in recent years. Laboratory experiments were conducted with the scyphozoan jellyfish Chrysaora fulgida to investigate the effects of food density (0, 30, 70, 100 or 150 Artemia nauplii 200 ml^?1), feeding frequency (once daily or once every third day) and water temperature (12, 16 or 20 °C) on the asexual reproduction, growth and development of polyps. The results of a generalised linear mixed-effects model reveal that all variables impacted asexual reproduction, with greater polyp production attained at higher food concentrations, increased feeding frequencies and increased temperatures. The most common mode of asexual reproduction was by lateral budding. These laboratory results suggest that polyps of C. fulgida may have proliferated off Namibia in recent times, which would contribute to increased numbers of jellyfish there.     

Numerical studies of the Kelvin-Hemholtz instability in a coronal jet

Kelvin-Hemholtz(K-H)instability in a coronal EUV jet is studied via 2.5D MHD numerical simulations.The jet results from magnetic reconnection due to the interaction of the newly emerging magnetic field and the pre-existing magnetic field in the corona.Our results show that the Alfv e′n Mach number along the jet is about 5–14 just before the instability occurs,and it is even higher than 14 at some local areas.During the K-H instability process,several vortex-like plasma blobs with high temperature and high density appear along the jet,and magnetic fields have also been rolled up and the magnetic configuration including anti-parallel magnetic fields forms,which leads to magnetic reconnection at many X-points and current sheet fragments inside the vortex-like blob.After magnetic islands appear inside the main current sheet,the total kinetic energy of the reconnection outflows decreases,and cannot support the formation of the vortex-like blob along the jet any longer,then the K-H instability eventually disappears.We also present the results about how the guide field and flux emerging speed affect the K-H instability.We find that a strong guide field inhibits shock formation in the reconnecting upward outflow regions but helps secondary magnetic islands appear earlier in the main current sheet,and then apparently suppresses the K-H instability.As the speed of the emerging magnetic field decreases,the K-H instability appears later,the highest temperature inside the vortex blob gets lower and the vortex structure gets smaller.     

The relationship of the Cocos and Carnegie ridges: age constraints from paleogeographic reconstructions

Paleogeographic restorations for the oceanic crust formed by the Cocos-Nacza spreading center and its precursors were performed to reconstruct the history and ages of the submarine aseismic ridges in the Eastern Pacific Basin, the Carnegie, Coiba, Cocos, and Malpelo ridges. The bipartition of the Carnegie ridge reflects the shift from a precursor to the presently active Cocos-Nazca spreading center. The Cocos ridge is partly composed of products from the Galápagos hotspot but may also contain material from a second center of volcanic activity which is located approximately 600 km NE of Galápagos. The Malpelo ridge is a product of this second hotspot center, whereas the Coiba ridge probably formed at the Galápagos hotspot. The geometric relationship of the Cocos and Carnegie ridges indicates symmetric spreading and a constant northward shift of the presently active Cocos-Nazca spreading center.     

Improved representation of topographic effects by a vertical adaptive grid in Vector-Ocean-Model (VOM). Part II: Simulations in unstructured adaptive grids

A static adaptive grid approximates the topography and defines the vertical resolution in Vector-Ocean-Model (VOM). The adaptation to topography creates unstructured grids, which are organised in a one-dimensional vector by column-wise storage of only wet cells. The model’s name reflects this data structure. The intention of VOM is better resolving flow and stratification near topographic boundaries in Z-coordinates. This is the second part of a publication that describes the generation of adaptive grids (part I), and simulations with VOM in unstructured grids (this part). Adaptive grids generated for a synthetic topography in part I include shelf, continental slope, and ocean. Three of those grids are here utilised in upwelling simulations. Under the same forcing increased vertical resolution at seabed and slopes yields a significant increase in flow energy as compared to coarser grids. Results allow explaining the surface intensification of a continental slope jet by vertical displacements of water masses in the seabed Ekman layer. Results in unstructured grids are almost identical to reference simulations in equidistant grids where the respective smallest grid size of unstructured grids was used. Negative effects of grids on predicted flow and stratification are absent also over particularly rough topography, as demonstrated by using vertical velocity as most sensitive indicator. In a further simulation an overflow governed by the advection of water mass properties is presented to demonstrate the conservation properties of the model. After 5 months of simulation the predicted domain average temperature deviated by 10⁻⁸ from the initial temperature field. Compared to equidistant grids the advection/diffusion scheme looses about one order of magnitude in accuracy when used in an unstructured grid. The results of VOM, being defined in Z-coordinates, are void of coordinate transformation errors. In an arbitrary topography unforced zero-flow remains quiescent in a stratification that only varies in the vertical. VOM due to its depth-independent vertical resolution appears particularly suitable for simulations of ocean-shelf exchange.