The hydrological regime of the inner delta of the River Niger, situated in Mali, is subject to strong annual and indeed intra-annual variability. This delta ecosystem has a characteristic feature, a three-phase cycle. The first, a period of flood, starts in July marking the beginning of the cycle; then, after several months of rising water-levels, the flood recedes, between November and January; finally, a period of low water prevails between March and June.
The river’s various fish species are adapted to this cycle of alternating conditions. Feeding, growth and mortality depend on that rhythm. The flood scatters the fish away from the river bed and brings abundant food. It provides refuge areas, environments where reproduction can take place undisturbed. Growth then proceeds until the waters are in recession, a period of high natural mortality. Fishing effort has to follow the rhythm set by the succession of flood and recession. Most campaigns are concentrated in the period of flood retreat which heralds the return of fish into the fluvial zone and their unavoidable movement through the channels fishermen know well – and when their capturability is highest. Activity diminishes and the season ends with the onset of the next flood, when again the fish are dispersed into flooded areas.
Fishing activity is therefore dependent on the hydrological seasons. Two measurable hydrological parameters can express these: rainfall and river discharge. IRD scientists have sought to determine the extent to which these two variables can provide the basis for a model for predicting annual capturable fish stocks. The team focused first on defining which of the indicators was most pertinent, secondly on finding the number of years’ worth of data necessary for obtaining a reliable forecast.
Marie-Lise Sabrie | alphagalileo
Emissions from road construction could be halved using today’s technology
18.05.2020 | Schwedischer Forschungsrat - The Swedish Research Council
When every particle counts: IOW develops comprehensive guidelines for microplastic extraction from environmental samples
11.05.2020 | Leibniz-Institut für Ostseeforschung Warnemünde
In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".
Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...
Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.
researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...
Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.
When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...
Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.
Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...
Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.
A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...
19.05.2020 | Event News
07.04.2020 | Event News
06.04.2020 | Event News
27.05.2020 | Information Technology
27.05.2020 | Physics and Astronomy
27.05.2020 | Earth Sciences