Reconstruction of climate and hidden biodiversity in lakes: development of innovative paleoaproaches
Increase of temperature and biodiversity loss are major threats in the early warning systems of the planet, the high-altitude ecosystems. The analysis of sediment records provides evidence on past response of species to climatic changes, offering a unique framework to anticipate/expand our ability to manage these ecosystems. Among the commonly used paleoindicators, the analysis of cladoceran subfossils has relied on classical morphological counting. However, recent advances in mass-spectrometry, which now need much lower sample sizes, and in molecular biology, with the use of sedimentary DNA, offer unprecedented opportunities to develop innovative approaches based on these REMAINS. The main goal of this project is to provide new advances to i) use cladoceran chitin as a paleothermometer and ii) establish a standard methodology to use their DNA in sediments. The intellectual merits of this proposal are threefold. First, it will use cutting-edge technology to measure subfossil chitin in lab assays, in situ calibration and validation phases. Second, it will address a new biological group not previously studied in ancient DNA. Last, by establishing new analytical methods for a very common component of lake sediments, the project will open up a new field in Paleolimnology and highlight how much hitherto untapped information is stored in paleorecords. The research approach will involve (i) the quantification of contribution of water-diet to H and O isotopes in chitin (ii) the field calibration between isotopic composition of chitin and temperature (iii) the paleothermometer validation in the sediment (iv) the establishment of a library of cladocerans by a genome skimming and (v) the development of a specific assay to identify them in sedimentary DNA. Framed in the “Environment & Climate Action” area from HORIZON 2020, the project addresses gaps in the knowledge needed to understand past changes and to protect natural resources, illustrated here by Sierra Nevada Mountains