6 results match your criteria African Journal Of Aquatic Science[Journal]

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Ecological insights from three decades of animal movement tracking across a changing Arctic.

Science 2020 11;370(6517):712-715

National Park Service, Denali National Park and Preserve, Denali Park, AK, USA.

The Arctic is entering a new ecological state, with alarming consequences for humanity. Animal-borne sensors offer a window into these changes. Although substantial animal tracking data from the Arctic and subarctic exist, most are difficult to discover and access. Read More

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November 2020

ECOLOGY. Aquatic animal telemetry: A panoramic window into the underwater world.

Science 2015 Jun 11;348(6240):1255642. Epub 2015 Jun 11.

Ocean Tracking Network, Department of Biology, Dalhousie University, 1355 Oxford Road, Halifax, Nova Scotia B3H 4R2, Canada.

The distribution and interactions of aquatic organisms across space and time structure our marine, freshwater, and estuarine ecosystems. Over the past decade, technological advances in telemetry have transformed our ability to observe aquatic animal behavior and movement. These advances are now providing unprecedented ecological insights by connecting animal movements with measures of their physiology and environment. Read More

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Climate-driven ecosystem succession in the Sahara: the past 6000 years.

Science 2008 May;320(5877):765-8

Africa Research Unit, Institute of Prehistoric Archaeology, University of Cologne, Jennerstrasse 8, D-50823 Köln, Germany.

Desiccation of the Sahara since the middle Holocene has eradicated all but a few natural archives recording its transition from a "green Sahara" to the present hyperarid desert. Our continuous 6000-year paleoenvironmental reconstruction from northern Chad shows progressive drying of the regional terrestrial ecosystem in response to weakening insolation forcing of the African monsoon and abrupt hydrological change in the local aquatic ecosystem controlled by site-specific thresholds. Strong reductions in tropical trees and then Sahelian grassland cover allowed large-scale dust mobilization from 4300 calendar years before the present (cal yr B. Read More

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The ecology of early man in southern Africa.

R G Klein

Science 1977 Jul;197(4299):115-26

It is not possible at present to demonstrate hominid occupation of southern Africa prior to the middle or late Pliocene, perhaps 3 million years ago. It may be the case that much, if not most, of the subcontinent was in fact uninhabited before that. The earliest hominid known to have lived in southern Africa is Australopithecus africanus. Read More

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Lungfish Neoceratodus forsteri: activities of ornithine-urea cycle and enzymes.

Science 1967 Jul;157(3786):316-7

The level of activity of the ornithine-urea cycle is low in the liver of the permanently aquatic Australian lungfish. The rate of incorporation of (14)C-bicarbonate into urea by liver slices was only 100th of that previously observed in the estivating African lungfish Protopterus dolloi. The activities of enzymes of the ornithine-urea cycle were similarly reduced. Read More

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Ornithine-Urea Cycle Enzymes in the African Lungfish, Protopterus aethiopicus.

Science 1966 Apr;152(3720):358-9

The presence of all five enzymes of the ornithine-urea cycle has been demonstrated in the liver of the African lungfish Protopterus aethiopicus. Levels of activity of the rate-limiting enzymes, carbamoyl phosphate synthetase and argininosuccinate synthetase, are similar to those in the premetamorphic tadpole of Rana catesbeiana and considerably lower than the levels reported for other ureotelic animals. They are thus consistent with the predominantly ammonotelic metabolism of the lungfish in an aquatic environment. Read More

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