Megabenthic recolonization in an experimentally disturbed abyssal manganese nodule area 1     

Hartmut Bluhm  Gerd Schriever  Hjalmar Thiel 《Marine Georesources & Geotechnology》2013,31(4):393-416

The near total removal of manganese nodules during commercial deep‐sea mining will destroy the habitat of the benthic hard‐bottom fauna within the mined areas and result in the formation of a soft‐bottom community of lower diversity. In 1989 the first large‐scale and long‐term experiment, DISCOL, was initiated in the abyssal tropical southeastern Pacific Ocean to study the impact of disturbances similar to ocean mining on the deep‐sea fauna. The megabenthic assemblage and the recolonization of the disturbed area were monitored during three cruises of the German research vessel SONNE by use of an Ocean Floor Observation System with real‐time TV and “photo‐on‐command” capabilities. The results of the image analyses of the baseline and three postimpact studies demonstrate not only a direct impact within the disturber tracks, but also an apparent impact on areas that were not primarily disturbed. Commercial mining will create a sediment plume, which will drift away with near‐bottom currents and also affect animals outside the mined areas. Reduction of environmental effects remains an important objective during development of future nodule collector systems.  相似文献   

Variations of the Ashen Light of Moon and the Earth's albedo     

Heinz Hilbrecht  Gerd Küveler 《Earth, Moon, and Planets》1985,33(3):229-230

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Variations of the Earth's albedo deduced from the ashen light of the Moon     

Heinz Hilbrecht  Gerd Küveler 《Earth, Moon, and Planets》1985,32(1):1-7

An analysis of 1210 visual brightness estimations of the Moon's ashen light is presented, performed by a working group of amateur astronomers from June 1972 to December 1973. In the Moon phase interval 0.1 T _b 0.7 the brightness expressed in a semi-empirical scale, S _G, is found to be linearly related to the phase. Monthly deviations from the mean brightness show well defined winter maxima (January) and summer minima (July). Within the referenced period the brightness of the ashen light tends to increase, whereas the solar magnetic activity decreased. In addition, minor correlations and, respectively, anti-correlations are found at stratospheric temperature and, respectively density. On account of the nature of the ashen light its variations are regarded as fluctuations of the Earth's albedo.  相似文献   

Preparative isolation and characterization of heavy metal complexes from acid mine drainage and surface wastewater     

Marcus Wengel  Gerd Gleixner 《洁净——土壤、空气、水》2006,34(6):568-578

A preparative method was developed to sample dissolved organic carbon (DOC) and heavy metals (Ni, Mn) from polluted surface waters. Main focus was set on the preparative production of freeze‐dried samples mainly composed of organic ligands from heavy metal complexes. First characterizations were done in the aqueous phase. Finally, freeze‐dried samples provide stable organic matter for multiple characterizations. Acid mine drainage of the former mining area of Ronneburg (Germany) hold elevated concentrations of heavy metals and low concentrations of DOC. Municipal wastewater, passing the spoil pile, held elevated concentrations of DOC and low concentrations of heavy metals. Dissolved components smaller than 0.45 μm and larger than 1 nm were concentrated by nanofiltration. Organic heavy metal complexes were isolated from this solution by size‐exclusion chromatography (SEC). Different size classes of molecules were collected from the column effluent, depending on their elution time, and were characterized by UV spectroscopy, ICP‐OES, and DOC measurements. All samples held organic heavy metal compounds with different retention times. The organic heavy metal complexes in acid mine drainage had higher retention times than complexes from municipal wastewater. Most interestingly, we found different affinities of heavy metals to different size classes of DOC. This affinity of the heavy metals differs with size and origin of the DOC.  相似文献   

Variability of the Northern Annular Mode's signature in winter sea ice concentration     

Gerd Krahmann  Martin Visbeck 《Polar research》2003,22(1):51-57

Historical winter sea ice concentration data are used to examine the relation between the Northern Annular Mode (NAM) and the sea ice concentration in the Nordic seas over the past 50 years. The well known basic response pattern of a seesaw between the Labrador Sea and the Greenland, Iceland and Barents seas is being reproduced. However, the response is not robust in the Greenland and Iceland seas. There the observed variability has a more complex relationship with surface temperatures and winds. We divide the sea ice response into three spectral bands: high (P< year), band (515 year) filtered NAM indices. This division is motivated by the expected slow response of the ocean circulation which might play a significant role in the Greenland and Iceland seas. The response to the NAM is also examined separately for the periods before and after 1976 to identify variations due to the relocation of the northern centre of the North Atlantic Oscillation.  相似文献   

A model approach for in- and outflow calculation of upper lake constance: —An investigation of a 60 year time span and observations about the flood of 1999     

Gustav Wagner  Heinz Gerd Schrder  Joachim Gurtz 《Limnologica》2002,32(1)

The revised empirical model for in- and outflow calculation of Upper Lake Constance has provided satisfying results supported by measured values. The given model was implemented to simulate total water inputs of the lake during the period from 1941 to 2000 with emphasis on the flood conditions of 1999. Analysis of annual water input development reveals a tendency toward slight increases until the 1960s. Thereafter, a reduction in inputs can be noted. This trend probably continues to hold true to present. Weather conditions of given individual years have caused distinct fluctuations to the water budget.Unusual meteorological conditions led to extreme flooding in early May of 1999. Daily water inputs of up to 200 mio m³ generated the highest water levels ever observed for this time of the year. Continual extraordinarily high water inputs occurring from February until July and then again from September until the end of 1999 resulted in the second largest annual total water input recorded since 1941.  相似文献   

Infra-red radiometry in the German Bight     

Dipl.-Oz. Gerd Axel Becker  Dr. Klaus Huber  Dipl.-Oz. Hans Krause 《Ocean Dynamics》1979,32(1):19-26

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Die ozeanische Polarfront des Ostgrönlandstromes und die Frage ihrer Steuerung durch die submarine Topographie     

Dr. Gerd Sommerhoff 《Ocean Dynamics》1974,27(3):114-121

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Statistische Untersuchungen für abhängige Beobachtungsmerkmale am Beispiel authigener Quarze     

Matthesius  Gerd  Schneider  Werner 《International Journal of Earth Sciences》1974,63(3):1232-1248

International Journal of Earth Sciences - Die dargestellten Regressions- und Korrelationsrechnungen ermöglichen eine Beurteilung von Beobachtungsmerkmalen hinsichtlich ihrer gegenseitigen...  相似文献   

IGS Near Real-Time Products and Their Applications   总被引：2，自引：2，他引：2  

Peng Fang  Gerd Gendt  Tim Springer  Tony Mannucci 《GPS Solutions》2001,4(4):2-8

The primary IGS products, including precise GPS orbits, Earth orientation parameters, and estimated and predicted GPS satellite clocks, are no longer used exclusively for essential geodetic support of scientic research. They are increasingly being used by a wide range of non-academic applications. In these applications, timeliness is extremely critical. To address the timeliness issue, the strengths and weaknesses of current IGS production processes are discussed, new ways to improve the timeliness and quality are explored, and recommendations are proposed to fulfill the application requirements. ? 2001 John Wiley & Sons, Inc.  相似文献