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!
Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Life Sciences
17.10.2017 | Life Sciences
17.10.2017 | Earth Sciences