Ecosystems

11 results

Mercury levels in tuna: Verifying the size, species, and origin!

Tuna is a widely-loved food around the world, but it can harbour a toxin: methylmercury. According to a recent study, the levels of this toxin in Central and Southwest Pacific tuna depends not only on the size and species of the fish, but also their geographic origin. These results are crucial for...

The effects of gold mining in rivers in French Guiana

A study conducted in the French Guiana basin where artisanal gold mining in occurs has shown there is mercury in the environment from these activities. It is even found in the piscivorous fish and indigenous communities that eat food from the rivers affected. These are important and innovative...

Amazon groundwater quantified at last!

As the Amazon basin is difficult to access, the condition of its water table remained virtually unknown. The mystery was solved thanks to an assessment made by an international team linked to several IRD units and led by LEGOS researchers. This result is all the more interesting in that access to...
recif-moorea-2018

The resistance of the Moorea corals

Experts in ocean ecology are investigating the health of coral reefs, put to the test by the increase in natural and anthropogenic disturbances. While there is growing concern about their overall future, certain reefs resist repeated attack, but however lose their diversity.
black-bass

Biodiversity of freshwater fish in turmoil

In the last few centuries, 15% of new fish species have been introduced by Man into rivers across the world. Researchers have found that these introductions alter the ecosystem to a much larger extent than originally anticipated.
barge-d-orpaillage-sur-le-maroni

The Maroni River threatened by gold mines

How have the environmental changes that have occurred in recent decades in French Guiana, including gold extraction in the hinterland, affected the Maroni River? A team involving IRD researchers analysed changes in sediment flows in this water course since 2000. Their findings are alarming.
Fruit trees and legumes combined with food crops

Carbon storage: what matters is the input!

After 15 years of climate smart agricultural practices in Madagascar, researchers are categorical: while these alternative methods help increase soil carbon storage, their effectiveness varies substantially. The assessment must therefore be carried out on the scale of the territory.
Root nodules of Discaria (Order: Rosales), a non-legume species capable of nitrogen-fixing symbiosis.

Nitrogen-fixing symbioses reveal themselves

Recent research has revealed the origin and evolution of symbiotic relationships between certain plants and soil bacteria in order to use atmospheric nitrogen. This knowledge could ultimately contribute to the development of sustainable agriculture minimising the use of chemical fertilisers.
The fruit clusters of Coccoloba uvifera give it its nickname of sea grape.

Unwavering symbiosis

Research conducted on the introduction of a tree from extreme environments into the sand dunes of Senegal shows its solid relationship with a fungus. This fungus naturally accompanies the tree from its environment of origin, on the other side of the Atlantic.
mesure-des-arbres-mule-hole

Roots in search of water

Why are there differences in the growth of a dozen tree species in an Indian forest? Their rooting depth and ability to overcome exceptional droughts. And the most resilient are not the ones we may have imagined…
peche-el-nino

El Niño and weather hazards

The El Niño events of 2015 and 2016, heralded by similar early signs, had very divergent amplitudes. Their modelling highlights the importance of unpredictable high-frequency winds. The ability to predict the phenomenon is therefore severely limited.