Erosion and human activities are inducing large amounts of terrigenous sediment input to the southwest lagoon of New Caledonia. Such deposits can pose a threat to the lagoon’s ecological balance and biological richness. Scientists from the IRD’s Noumea centre have for several years been applying modelling techniques in order to unravel the system of current circulation and sediment transport (1). Satellite remote sensing provides reliable quantified data on the concentration of suspended matter in water. The researchers compared the data transmitted by the Landsat satellite with figures from in situ measurements made in the lagoon. The results show the possibility of making a detailed map of the water turbidity using optical remote sensing, with uncertainty rate less than 20%. The satellite images therefore provide key data for calibration, refining and validation of the numerical sediment-transport models elaborated. This dual approach furthermore arrives at a spatial distribution of the potential for sea-floor sediments to return into suspension. This advance opens up new prospects for research.
The lagoon which surrounds New Caledonia is known for its high biodiversity and for the fragility of its coral reefs. What effects do human activities, stemming mainly from urbanization and the mining industry, coupled with sediment input from rivers resulting from natural soil erosion, have on the lagoon ecosystems ? Scientists from the Camélia Unit of IRD’s centre at Noumea took on this question. Their work is focused mainly on the southwest lagoon, off the capital Noumea, where half the country’s population live. Investigations involve several aspects, including notably the accumulation of metals in marine organisms, currents responsible for dispersing materials brought by the rivers, and also quality analysis on the sea water (dissolved elements, suspensions). Turbidity is a factor that limits the development of corals because it reduces light penetration into the water. Moreover, the fine suspended particles carry in metals that can pollute aquatic ecosystems.
In research on particular environments, numerical models can give an accurate picture of events and situations on a range of scales and offer predictions of their impact. The effectiveness of modelling requires validation of the method’s results, by means of comparison against sets of data determined in situ. It is also possible to compare, at the ocean surface, digital simulations with satellite images. Combination of these data and in-situ measurements with model-derived information results in a three-dimensional picture and description of the processes under investigation.
Hélène Deval | EurekAlert!
Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy