Toxic effects of decomposing red algae on littoral organisms   总被引：2，自引：0，他引：2  

Britta Eklund  Andreas P. Svensson  Conny Jonsson  Torleif Malm   《Estuarine, Coastal and Shelf Science》2005,62(4):621-626

Large masses of filamentous red algae of the genera Polysiphonia, Rhodomela, and Ceramium are regularly washed up on beaches of the central Baltic Sea. As the algal masses start to decay, red coloured effluents leak into the water, and this tinge may be traced several hundred meters off shore. In this study, possible toxic effects of these effluents were tested on littoral organisms from different trophic levels. Effects on fertilisation, germination and juvenile survival of the brown seaweed Fucus vesiculosus were investigated, and mortality tests were performed on the crustaceans Artemia salina and Idotea baltica, as well as on larvae and adults of the fish Pomatoschistus microps. Fucus vesiculosus was the most sensitive species of the tested organisms to the red algal extract. The survival of F. vesiculosus recruits was reduced with 50% (LC50) when exposed to a concentration corresponding to 1.7 g l⁻¹ dw red algae. The lethal concentration for I. baltica, A. salina and P. microps were approximately ten times higher. The toxicity to A. salina was reduced if the algal extract was left to decompose during two weeks but the decline in toxicity was not affected by different light or temperature conditions. This study indicates that the filamentous red algae in the central Baltic Sea may produce and release compounds with negative effects on the littoral ecosystem. The effects may be particularly serious for the key species F. vesiculosus, which reproduce in autumn when filamentous red algal blooms are most severe.  相似文献   

Three aspects of the law of the sea : Islands, delimitation and dispute settlement     

Andreas J. Jacovides 《Marine Policy》1979,3(4):278-288

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A simple boom assembly for the shipboard deployment of air-sea interaction instruments     

Edgar L. Andreas  John H. Rand  Stephen F. Ackley 《Ocean Engineering》1984,11(3):227-237

We have developed a simple boom for use in measuring meteorological variables from a ship. The main structural member of the boom, a triangular communications tower with rollers attached along its bottom side, is deployed horizontally from a long, flat deck, such as a helicopter deck, and will support a 100-kg payload at its outboard end. The boom is easy to deploy, requires minimal ship modifications, and provides ready access to the instruments mounted on it. And because it is designed for use with the ship crosswind, oceanographic work can go on at the same time as the air-sea interaction measurements.We describe our use of the boom on the Mikhail Somov during a cruise into the Antarctic sea ice and present some representative measurements made with instruments mounted on it. Theory, experiment, and our data all imply that instruments deployed windward from a rear helicopter deck can reach air undisturbed by the ship. Such an instrument site has clear advantages over the more customary mast, bow, or buoy locations.  相似文献   

Predicting significant wave height off the northeast coast of the United States   总被引：1，自引：0，他引：1  

Edgar L Andreas  Sinny Wang 《Ocean Engineering》2007,34(8-9):1328-1335

To develop a simple method to predict the significant wave height, we analyze 18 years of hourly observations from 12 different buoys that are off the northeast coast of the United States. Water depths ranged from 19 to 4427 m for these moored buoys. We find that, on average, all of these buoys exhibit a region of constant wave height for 10-m wind speeds between 0 and 4 m s⁻¹. That wave height does, however, depend on water depth. For wind speeds above 4 m s^–1, the wave height increases as the square of the wind speed; but the multiplicative factor is again a function of water depth. We synthesize these results in a prediction scheme that yields the significant wave height from simple functions of water depth and 10-m wind speed for wind speeds up to 25 m s^–1.  相似文献   

Sedimentary environment dynamics and the formation of coal in the Pennsylvanian Variscan foreland in the Ruhr Basin (Germany, Western Europe)     

M. Peter Suess  Guenter Drozdzewski  Andreas Schaefer   《International Journal of Coal Geology》2007,69(4):267-287

During the Pennsylvanian, formation of coal was a phenomenon that was spread over many continents. It is the aim of this paper to illustrate factors that led to the formation of coal seams in paralic clastic sedimentary environments in the Ruhr Basin (German Variscan foreland) during the Pennsylvanian in terms of sequence stratigraphy and the structural evolution of the basin. Lithostratigraphic sections from exploration wells in the currently explored zone of the coal basin allowed the generation of volumetric lithofacies models, using geostastical methods. These models support the analysis of sedimentary facies and a sequence stratigraphic interpretation of the successions that are widely correlated throughout the basin. We then evaluate the relation of the sequence stratigraphic elements derived from the facies models with the abundance of coal seams.  相似文献   

Geo- and cosmochemistry of the twin elements yttrium and holmium     

Andreas Pack  Sara S. Russell  Mark van Zuilen 《Geochimica et cosmochimica acta》2007,71(18):4592-4608

We have analyzed the Y/Ho-ratios in bulk chondrites, chondrules and four Ca- and Al-rich inclusions (CAIs) from carbonaceous and unequilibrated ordinary and enstatite chondrites (EC) by laser ablation inductively coupled mass spectrometry (LA-ICPMS). We demonstrate that bulk rock sample preparation by containerless melting is a suitable method for preparation of bulk rock samples for high-precision LA-ICPMS. Bulk chondrites have variable Y/Ho-ratios. Carbonaceous chondrites (CI1, CM2, CV3, and CK4) have a common Y/Ho-ratio (25.94 ± 0.08, 2σ) that is regarded as the solar system Y/Ho-ratio. The Y/Ho-ratio increases from carbonaceous, through ordinary (LL, L, H) to enstatite chondrites (EL6), which show the highest Y/Ho-ratio of 27.25. We discuss the result with respect to the origin of fractionation of Re and Os between chondrite groups. Within analytical error, Y and Ho show a good correlation in OC and CV3 chondrules and define an Y/Ho-ratio of 26.22 ± 0.40 (2σ). Y/Ho-fractionation in Ca- and Al-rich inclusions is related to differences in volatility. The bulk silicate Earth is suggested to have a solar Y/Ho-ratio and links the Earth with carbonaceous chondrites. Y/Ho variations in primitive and differentiated terrestrial igneous rocks are discussed in framework of incompatibility of Y and Ho during partial melting. Applicability of Y/Ho as tracer for or against a sedimentary origin of the putative host rock of the Earth’s oldest traces of life from the island of Akilia is briefly discussed.  相似文献   

Predicting particulate pools of nitrogen,phosphorus and organic carbon in lakes     

Andreas C. Bryhn  Dag O. Hessen  Thorsten Blenckner 《Aquatic Sciences - Research Across Boundaries》2007,69(4):484-494

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On the turbulent Prandtl number in the stable atmospheric boundary layer     

Andrey A. Grachev  Edgar L Andreas  Christopher W. Fairall  Peter S. Guest  P. Ola G. Persson 《Boundary-Layer Meteorology》2007,125(2):329-341

This study focuses on the behaviour of the turbulent Prandtl number, Pr _t , in the stable atmospheric boundary layer (SBL) based on measurements made during the Surface Heat Budget of the Arctic Ocean experiment (SHEBA). It is found that Pr _t increases with increasing stability if Pr _t is plotted vs. gradient Richardson number, Ri; but at the same time, Pr _t decreases with increasing stability if Pr _t is plotted vs. flux Richardson number, Rf, or vs. ζ = z/L. This paradoxical behaviour of the turbulent Prandtl number in the SBL derives from the fact that plots of Pr _t vs. Ri (as well as vs. Rf and ζ) for individual 1-h observations and conventional bin-averaged values of the individual quantities have built-in correlation (or self-correlation) because of the shared variables. For independent estimates of how Pr _t behaves in very stable stratification, Pr _t is plotted against the bulk Richardson number; such plots have no built-in correlation. These plots based on the SHEBA data show that, on the average, Pr _t decreases with increasing stability and Pr _t < 1 in the very stable case. For specific heights and stabilities, though, the turbulent Prandtl number has more complicated behaviour in the SBL.  相似文献   

Intercomparison of Two Hydroxyl Radical Measurement Techniques at the Atmosphere Simulation Chamber SAPHIR     

Eric Schlosser  Birger Bohn  Theo Brauers  Hans-Peter Dorn  Hendrik Fuchs  Rolf Häseler  Andreas Hofzumahaus  Frank Holland  Franz Rohrer  Lutz Olaf Rupp  Manfred Siese  Ralf Tillmann  Andreas Wahner 《Journal of Atmospheric Chemistry》2007,56(2):187-205

At the atmosphere simulation chamber SAPHIR in Jülich both Laser-Induced Fluorescence Spectroscopy (LIF) and Long-Path Differential Optical Laser Absorption Spectroscopy (DOAS) are operational for the detection of OH radicals at tropospheric levels. The two different spectroscopic techniques were compared within the controlled environment of SAPHIR based on all simultaneous measurements acquired in 2003 (13 days). Hydroxyl radicals were scavenged by added CO during four of these days in order to experimentally check the calculated precisions at the detection limit. LIF measurements have a higher precision (σ= 0.88×10⁶ cm^–3) and better time resolution (Δt = 60 s), but the DOAS method (σ= 1.24×10⁶ cm^–3, Δt = 135 s) is regarded as primary standard for comparisons because of its good accuracy. A high correlation coefficient of r = 0.95 was found for the whole data set highlighting the advantage of using a simulation chamber. The data set consists of two groups. The first one includes 3 days, where the LIF measurements yield (1 – 2) ×10⁶ cm^–3 higher OH concentrations than observed by the DOAS instrument. The experimental conditions during these days are characterized by increased NO_x concentration and a small dynamic range in OH. Excellent agreement is found within the other group of 6 days. The regression to the combined data of this large group yields unity slope without a significant offset.  相似文献   

Assessing the reliability of the modified three-component spatial autocorrelation technique   总被引：3，自引：0，他引：3  

Andreas Köhler  Matthias Ohrnberger  Frank Scherbaum  Marc Wathelet  Cecile Cornou 《Geophysical Journal International》2007,168(2):779-796

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