Scientific newssheets
Page navigation
- 1
- 2
-
Page 1 : Results 1 to 5 on 9
419 - When mangroves no longer protect the coastline
December 2012
The mangroves of Guyana, in South America, are gradually disappearing. Contrary to the coastline of its near neighbour, French Guiana, which is still relatively protected, that of Guyana has been largely developed. In order to develop agriculture and aquaculture, earth dikes were built, destroying the greater part of the mangrove forest.
A study( 1) conducted by IRD researchers and the University of Aix-Marseille shows that the reduced protection provided by mangroves against the swell will lead to the large-scale erosion of 370 km of the country's coastline. Only one ecosystem restoration programme will help contain this phenomenon.
418 - Pearl culture, the black gold of French Polynesia?
December 2012
The second greatest economic resource of French Polynesia after tourism, black pearl culture has been facing a major crisis since the first decade of this century. Overproduction, falling prices, reduced activity that had boosted many remote atolls... In response, IRD researchers and their partners( 1) are helping to maintain and sustain the sector.
In particular, scientists have been studying the Ahe atoll lagoon (north of Tahiti) since 2008. Specifically, they coordinated studies on the plankton resources available to feed oysters and on water flow in the lagoon.
These projects contribute to decision-making tools intended for oyster farmers, for the sustainable exploitation of the "Tahitian treasure".
416 - Who deforested Central Africa: Man or climate?
November 2012
It is a much debated question: why did Central African forests become partially fragmented between 2,500 and 2,000 years ago, leaving room for more open forest landscapes and savannah? Recently, a publication attempted to explain that it was the farming Bantu peoples who were responsible for this, through the large-scale clearing that they undertook. But several IRD experts and their partners( 1) contest this argument in Science magazine. The fragmentation of the Central African forest was the result of drastic climate change. In fact, during this period a phase of general desiccation spread from the equatorial region right to the edges of the Sahel. Numerous data show that it was only 500 years later, in other words some 2,000 years ago, that Bantu colonisation became widespread. The first Bantu populations therefore merely took advantage of the opening up of the forest to enter these areas and start growing their crops.
410 - Predicting outbreaks of dengue fever according to climate
July 2012
Dengue fever, transmitted by the Aedes mosquito, affects hundreds of millions of people in around one hundred tropical countries and causes 25 000 deaths per year. In the absence of a vaccine, determining the factors that influence epidemics to predict them better is a real public health challenge. One scientific study, conducted in New Caledonia, demonstrates the essential role of the local climate in epidemic dynamics. IRD researchers and their New Caledonian colleagues( 1) analysed epidemiological and climatological data gathered in Noumea over forty years. They highlighted the correlation between specific weather conditions and dengue fever outbreaks.
This work enabled statistical models to be drawn up explaining and predicting viral episodes. The Caledonian public health authorities have already integrated these tools into their decision-making strategies and a similar approach in other South Pacific countries is being developed, with a new collaborative regional programme.
408 - The Agulhas Current is said to attenuate the effect of melting ice
July 2012
Some good news in the world of climate research: the “Agulhas Current” off the coast of South Africa, is said to stimulate North-South ocean circulation in the Atlantic. This “conveyor belt” which redistributes and controls heat around the globe, is threatening to slow down due to melting ice. As has been shown in a recent study however, published in Nature Climate Change ( 1) based on satellite altimeter measurements, this famous current is accelerating. Located at the interface between the Indian and Atlantic Oceans, this current multiplies injections of warm and above all highly salt water into the Atlantic from the Indian Ocean. The phenomenon, also caused by global warming, could in return be offsetting the effects of glacial melting on thermohaline circulation( 2) and the global climate. More locally, it will considerably change the climate in southern Africa.
Page navigation
- 1
- 2
-
-
