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Project

Underground connections: how fungal symbionts shape tropical rainforests.

Tropical rainforests are the most diverse and productive ecosystems on Earth. These system account for one third of carbon assimilation on land, and harbor two-thirds of global plant diversity. Understanding the ecological processes underlying these vital properties will be essential for addressing the twin challenges of biodiversity loss and man-made climate change. Mycorrhizal fungi act as a major conduit of carbon into soil, and affect competition between trees through connecting them belowground. This plant-fungal interaction is one of the most abundant symbioses on earth and is tightly linked to plant nutrient limitation. Ecosystems are increasingly enriched with CO2 and nitrogen and subject to climate change, which could alter abundance and functional properties of mycorrhizas in yet unknown ways. This in turn could have large consequences for the soil carbon economy and plant interactions.Forests in French Guyana represent are unique in being among the most pristine and well-studied lowland tropical rain-forests on Earth. Major gradients of one of the most important drivers of mycorrhizas, soil phosphate availability, have already been identified within and among established research sites. This offers a unique opportunity to unveil the interplay between soil nutrients, mycorrhizal fungi, and soil carbon stocks. Here I propose to accomplish this through measuring abundance of mycorrhizal fungi through biomarkers (membrane lipids) that broadly distinguish mycorrhizal type, accompanied by next generation sequencing of DNA markers to reveal shifts in community composition. Moreover, I will conduct experiments to assess the effect of mycorrhizas on litter decomposition and on adult-seedling interactions, which may have a major influence on tree biodiversity.Together, these experiments will greatly increase our understanding of the importance of this plant-fungal symbiosis for soil carbon sequestration and seedling performance. This knowledge will allow better prediction of the interdependence of soil fertility, plant-fungal relationships, and their combined effect on plant diversity and soil carbon levels.
Date:1 Oct 2015 →  30 Nov 2015
Keywords:TROPICAL RAINFOREST
Disciplines:General biology, Plant biology