Combined effects of pumped-storage operation and climate change on thermal structure and water quality     

Kobler  Ulrike Gabriele  Wüest  Alfred  Schmid  Martin 《Climatic change》2019,152(3-4):413-429

Climatic Change - The assessment of ecological impacts of pumped-storage (PS) hydropower plants on the two connected water bodies is usually based on present climatic conditions. However,...  相似文献   

Ichnological data as a useful tool for deep-sea environmental characterization: a brief overview and an application to recognition of small-scale oxygenation changes during the Cenomanian�CTuronian anoxic event     

Francisco J. Rodr��guez-Tovar  Alfred Uchman 《Geo-Marine Letters》2011,31(5-6):525-536

The oceanic anoxic event at the Cenomanian?CTuronian transition (OAE-2) is a worldwide phenomenon related with variations in atmosphere?Cocean dynamics. This event coincides with significant changes in the palaeoenvironment determining marine mass extinction affecting numerous groups of organisms. Ichnological analysis of the Cenomanian?CTuronian boundary interval has been conducted in three selected sections from different ecological and depositional settings in the western Tethys. Indeed, a brief overview of existing knowledge in this domain highlights increasing recognition of the usefulness of trace fossils in the characterization of even minor-scale deep-sea environmental changes linked to sea-level dynamics. At the study sites, variations in ichnological features, including trace fossil composition, tiering patterns and ichnofabrics, can be related to fluctuations in bottom- and pore-water oxygenation during the Cenomanian?CTuronian interval. In the Barnasiówka section (Polish Outer Carpathians), changes between oxic/dysoxic??characterized by Chondrites, Planolites and even Thalassinoides??and euxinic conditions, without trace fossils or only with Chondrites, can be explained by variations in gravity flows influencing the benthic habitat. In the El Chorro and Hedionda sections (Betic Cordillera), longer anoxic intervals during the OAE-2, characterized by the absence of trace fossils, are interrupted by shorter dysaerobic and aerobic sub-events associated with Chondrites, Palaeophycus, Planolites, Thalassinoides, Trichichnus and Zoophycos, but showing significant differences between these two sections related to the palaeogeographically differentiated influence of upwelling conditions.  相似文献   

Subaquatic slope instabilities: The aftermath of river correction and artificial dumps in Lake Biel (Switzerland)     

Nathalie Dubois  Love Råman Vinnå  Marvin Rabold  Michael Hilbe  Flavio S. Anselmetti  Alfred Wüest  Laetitia Meuriot  Alice Jeannet  Stéphanie Girardclos 《Sedimentology》2020,67(2):971-990

River engineering projects are developing rapidly across the globe, drastically modifying water courses and sediment transfer. Investigation of the impact of engineering works focuses usually on short-term impacts, thus a longer-term perspective is still missing on the effects that such projects have. The ‘Jura Water Corrections’ – the largest river engineering project ever undertaken in Switzerland – radically modified the hydrological system of Lake Biel in the 19th and 20th Century. The deviation of the Aare River into Lake Biel more than 140 years ago, in 1878, thus represents an ideal case study to investigate the long-term sedimentological impacts of such large-scale river rerouting. Sediment cores, along with new high-resolution bathymetric and seismic reflection datasets were acquired in Lake Biel to document the consequences of the Jura Water Corrections on the sedimentation history of Lake Biel. Numerous subaquatic mass transport structures were detected on all of the slopes of the lake. Notably, a relatively large mass transport complex (0·86 km²) was observed on the eastern shore, along the path of the Aare River intrusion. The large amount of sediment delivered by the Aare River since its deviation into the lake likely caused sediment overloading resulting in subaquatic mass transport. Alternatively, the dumping since 1963 in a subaquatic landfill of material excavated during the second phase of river engineering, when the channels flowing into and out of Lake Biel were widened and deepened, might have triggered the largest mass transport, dated to 1964 or 1965. Additional potential triggers include two nearby small earthquakes in 1964 and 1965 (M_W 3·9 and 3·2, respectively). The data for this study indicate that relatively large mass transports have become recurrent in Lake Biel following the deviation of the Aare River, thus modifying hazard frequency for the neighbouring communities and infrastructure.  相似文献   

Highly nonlinear wind waves in Currituck Sound: dense breather turbulence in random ocean waves     

Osborne  Alfred R.  Resio  Donald T.  Costa  Andrea  Ponce de León  Sonia  Chirivì  Elisabetta 《Ocean Dynamics》2019,69(2):187-219

Ocean Dynamics - We analyze surface wave data taken in Currituck Sound, North Carolina, during a storm on 4 February 2002. Our focus is on the application of nonlinear Fourier analysis (NLFA)...  相似文献   

Impact of hydrographic parameters and seasonal variation in sediment fluxes on coral status at Chumbe and Bawe reefs,Zanzibar, Tanzania     

Alfred N.N. Muzuka  Alfonse M. DubiChristopher A. Muhando  Yohanna W. Shaghude 《Estuarine, Coastal and Shelf Science》2010

Coral reefs which are an important resource to coastal communities and nation at large are adversely affected by rate of sediment flux to the reefs. However, there is little information on seasonal trend in sediment flux and its impact at the reefs off Zanzibar. Two years’ monthly data on sedimentation at Chumbe and Bawe reefs were used to assess seasonal variability in sediment flux and its implication on the coral status. Sediment flux to the Bawe reefs for the duration of the study ranged from 0.2 to 41.5 mg cm⁻² d⁻¹, while it ranged from 0.8 to 65.8 mg cm⁻² d⁻¹ at the Chumbe reefs. Sediment fluxes at Bawe reefs were highest between November and March, while they were highest between April and September at Chumbe reefs. Generally, sediment fluxes at Bawe reefs were low compared to those at Chumbe. The total sediment input to the reefs ranged from 4615 to 123,403 kg d⁻¹ for Bawe reefs and 2750 to 79,636 kg d⁻¹ for Chumbe reefs. High sediment fluxes at Bawe reefs between November and March; and the Chumbe reefs between April and September can be attributed to water currents and wind pattern in the east African region which are under the influence of the monsoons. The observed trend suggests that the period for coral transplant as a management option for the two sites should be different. Coral transplant can be undertaken in such a way that stress of the corals due to sedimentation can be felt after they have overcome stress from transplant process and temperature. The results from this study contribute to the much needed information for coral transplant, restoration, and management.  相似文献   

Aerosol Optical properties at Sagres, Portugal during ACE‐2     

Christian M. Carrico  Mark J. Rood  John A. Ogren  Christian Neusüß  Alfred Wiedensohler  Jost Heintzenberg 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):694-715

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Pliocene and late Pleistocene (MIS 5e) decapod crustaceans from Santa Maria Island (Azores Archipelago: Central Atlantic): systematics,palaeoecology and palaeobiogeography     

Matúš Hyžný  Carlos S. Melo  Ricardo S. Ramalho  Ricardo Cordeiro  Patrícia Madeira  Lara Baptista  A. Cristina Rebelo  Cynthia Gómez  Alfred Uchman  Markes E. Johnson  Björn Berning  Sérgio P. Ávila 《第四纪科学杂志》2021,36(1):91-109

The presence of decapod crustaceans in the Pliocene and Pleistocene (MIS 5e) fossil record of Santa Maria Island (Azores Archipelago) is herein reviewed. Our study raises the number of fossil decapods from this island from one species to 10 taxa (three for the Pliocene and seven for the Last Interglacial). Four of these 10 taxa are reported for the first time in the fossil record, worldwide. A new species of a mud shrimp is also described (Upogebia azorensis n. sp.). Our study suggests that the Plio–Pleistocene decapod assemblages of the Azores did not differ significantly from modern ones, being dominated by species that are today widespread across the Webbnesia ecoregion, the Mediterranean Sea, and the eastern Atlantic shores, including the Azores. As far as can be judged from the limited fossil record, apparently no tropical crab species with a Cabo Verdean/Senegalese provenance reached the Azores during windows of opportunity associated with Glacial Termination 2 or with the initial setting of the Last Interglacial period. This contribution increases the total number of marine taxa reported for the Pliocene and Pleistocene outcrops of Santa Maria Island to 218 and 155, respectively, highlighting the scientific relevance of its palaeontological heritage.  相似文献   

Bemerkungen zu den Abhandlungen des Herrn C. Renz über den geologischen Bau Griechenlands,insbesondere zu der Schrift in den „Eclogae“ 38, 1945 (1946)     

Alfred Philippson 《International Journal of Earth Sciences》1949,37(1):121-123

Ohne Zusammenfassung  相似文献   

Das fundamentalsystem der schwere im lichte neuer reversionspendelmessungen     

Alfred Berroth 《Journal of Geodesy》1949,23(2):183-204

Ohne Zusammenfassung  相似文献   

Beitrag zu Bessels Bestimmung der Gleichheit Schwerer und Traeger Masse     

Prof. Dr. Alfred Berroth 《Pure and Applied Geophysics》1948,13(1-2):58-64

Summary The experiment ofFr. W. Bessel, 1832, with a fluid pendulum (water) is not in accordance with all other experiments, performed by solid pendulums. But the disaccordance is only an apparent one. With some little corrections to the experiment ofBessel with fluid it will be possible to attain full accordance with all other ones and therefore the general law of the equality of masses will be stated.

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Résumé L'expérience deFr. W. Bessel, faite en 1832 avec un pendule à eau diffère de tout'autre expérience effectuée avec des pendules solides. Mais il s'agit seulement d'une discordance apparente. En effet, au moyen de corrections peu sensibles, il est possible d'atteindre un plein accord entre les deux expériences et ainsi de confirmer la loi générale de l'égalité des masses.

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Ursprünglich geschrieben zum 100. Todestag vonFriedrich Wilhelm Bessel (geb. 22-7-1784 zu Minden, gest. 14-3-1846 in Königsberg).  相似文献