Trophodynamic control by clupeid predators on recruitment success in Baltic cod?   总被引：5，自引：3，他引：5  

Koster  Friedrich W.; Mollmann  Christian 《ICES Journal of Marine Science》2000,57(2):310-323

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Eastern Baltic cod (Gadus morhua callarias) stock dynamics: extending the analytical assessment back to the mid-1940s     

Eero  Margit; Koster  Friedrich W.; Plikshs  Maris; Thurow  Fritz 《ICES Journal of Marine Science》2007,64(6):1257-1271

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Arsenic in seawater and brown algae of the Baltic and the North Sea     

Markus Stoeppler  Mechthild Burow  Friedrich Backhaus  Winfried Schramm  Hans Wolfgang Nürnberg   《Marine Chemistry》1986,18(2-4)

A long-term study within the pilot environmental specimen bank programme of the Federal Republic of Germany on arsenic levels in coastal and open seawater and their reflection in the brown seaweed (Fucus vesiculosus) has been performed. Dissolved arsenic was on average 0.76 (range 0.45–1.11) μgl⁻¹ for 17 sampling stations in the Baltic Sea, whereas contents of dissolved arsenic are somewhat higher in shallow waters of the coastal zone of the North Sea. Total arsenic levels in algae ranged up to 40 mg kg⁻¹ (dry weight) and showed for the four locations studied obvious seasonal variations for comparatively nonpolluted or nondisturbed locations only. However, probably due to biological influences, the results obtained so far indicate that composite samples integrating a one year period are supposed to be the best strategy for future environmental specimen banking. Using a new efficient speciation technique the percentage of chemically stable organoarsenic compounds in the investigated algae has been found to be 95% of the total arsenic content and thus somewhat lower than in teleost fish. For comparison, typical data for a few other algae species from the Baltic and the Mediterranean Sea are also shown.  相似文献   

Accessory minerals in igneous and metamorphic rocks     

Igor Broska  Friedrich Finger  Daniel Harlov 《Mineralogy and Petrology》2011,102(1-4):1-2

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Holocene aeolian dynamics in the European sand‐belt as indicated by geochronological data     

Johann Friedrich Tolksdorf  Knut Kaiser 《Boreas: An International Journal of Quaternary Research》2012,41(3):408-421

Aeolian sands are widespread in the European sand‐belt. While there is a consensus about the timing of increased aeolian activity and, in contrast, of surface stabilization during the Lateglacial, knowledge about Holocene aeolian dynamics is still very sparse. It is generally assumed that aeolian processes have been closely connected to human activities since at least the Neolithic period. A compilation of 189 luminescence dates from aeolian sands of Holocene age and 301 ¹⁴C‐dates from palaeo‐surfaces, comprising palaeosols, buried peats and archaeological features from the whole sand‐belt, is plotted as histograms and kernel density plots and divided into sub‐phases by cluster analysis. This is also done separately for the dates from the areas west and east of the river Elbe. Our results show that aeolian activity did not cease with the end of the Younger Dryas but continued in the whole European sand‐belt until the Mid‐Atlantic (c. 6500 a BP), presenting evidence of vegetation‐free areas at least at the local scale. During the subsequent time period evidence of aeolian sedimentation is sparse, and surface stabilization is indicated by a cluster of palaeo‐surfaces ascribed to the early Subboreal (c. 5000 cal. a BP). The agglomeration of luminescence ages around 4000 years is probably connected with intensified land use during the Late Neolithic. Younger phases of aeolian sedimentation are indicated by clusters of luminescence ages around 1800 years, a group of luminescence ages from the Netherlands and NW Germany around 900 years, and a group of ages around 680 years in Germany. Among the dates from palaeo‐surfaces, clusters were identified around 2700, 1300 and 900 cal. a BP as well as around 690 cal. a BP in the western part and 610 cal. a BP in the eastern part of the sand‐belt. The clusters within the luminescence ages and the ¹⁴C‐dates coincide with phases where increased human impact can be deduced from archaeological and historical sources as well as from environmental history.  相似文献   

Soft proton scattering efficiency measurements on x-ray mirror shells     

Sebastian Diebold  Chris Tenzer  Emanuele Perinati  Andrea Santangelo  Michael Freyberg  Peter Friedrich  Josef Jochum 《Experimental Astronomy》2015,39(2):343-365

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Properties of nano- and microparticles emitted into the environment from open-pit mining of iron deposits     

V. V. Adushkin  P. G. Weidler  A. N. Dubovskoi  L. M. Pernik  S. I. Popel  F. Friedrich 《Geology of Ore Deposits》2010,52(5):373-380

The properties of nano- and microparticles (60 nm-200 μm) of the dust formed by mass blasting in the iron ore open pit of the Lebedinsky Mining and Concentrating Combine have been studied. Data on the morphology of particles, their magnetic properties, mineralogy, and dimensions have been obtained. Quartz, magnetite, and mica were identified among these particles. The dust mostly consisted of fragmented iron ore formation from the rock massif involved in the blasting.  相似文献   

Pressure,temperature and fluid composition variation of the mineralising system at the Kanmantoo Cu-Au deposit: Combining fluid inclusion analysis with Ti in quartz thermometry     

D. Focke  A. Schmidt Mumm  A. Tedesco  T. Seifert  R. Bradey 《Journal of Geochemical Exploration》2009

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Preliminary laboratory investigations into the attenuation of compressional and shear waves on near-surface marine sediments     

Arthur Ayres  Friedrich Theilen 《Geophysical Prospecting》2001,49(1):120-127

The attenuation of compressional and shear waves ( Q _p and Q _s) has been studied by several authors but most of these investigations were performed on deep buried reservoir sandstones in order to distinguish between gas and condensate reservoirs and water-saturated sandstones. We present a preliminary investigation into the use of seismic wave attenuation as a measure of the geotechnical parameters of the near-surface marine sediments, a little-studied geological setting. A 6.9 m-long gravity core was taken from the continental slope of the Barents Sea at a water depth of 2227 m. The core was primarily composed of brown to olive-grey clayey mud, having a high content of foraminifers and being locally bioturbated. The values of Q _p and Q _s were determined using the rise-time method at 19 and 18 different points of the core, respectively, and they were correlated with geotechnical parameters such as wet bulk density, porosity, water content, shear strength and C/P ratio (the ratio of shear strength to overburden pressure). The calculated correlation coefficients for all correlations ranged from −0.39 to 0.41, suggesting that the attenuation characteristics of seismic waves could not be used to derive geotechnical parameters of marine sediments. However, with such a small data set it is difficult to determine clearly whether attenuation is primarily a frequency-dependent parameter and consequently not related to sediment properties, or whether the limited number of data points is the main factor responsible for the low correlation coefficients observed. Moreover, several different methods are available for the computation of the quality factor Q , and the rise-time method may not be the most appropriate means of determining the attenuation on near-surface marine sediments.  相似文献   

Über das Vorkommen verschiedener Arten der GattungCyclops (s. restr.) in schweizerischen Seen     

Friedrich Kiefer  Ulrich Einsle 《Aquatic Sciences - Research Across Boundaries》1962,24(1):44-48

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