MULTIPROXY STUDY OF CONTRASTING ENVIRONMENTAL REGIMES IN THE CARIBBEAN AND THE EASTERN TROPICAL PACIFIC

Abstract

Understanding past changes in Earth's climate requires the reconstruction of climatic patterns in both marine and terrestrial settings. However, transitional zones like coastal seas have received limited attention specially when addressing geographical gradients. Here we present results from a multiproxy study of surface sediments from the southern Caribbean and the eastern tropical Pacific (equator？16？N, and 62？W？85？W) in order to understand the terrestrial and marine influence on coastal environments with different physico-chemical characteristics. We used biomarkers of both bacterial and archaeal origin, branched (br) and isoprenoid (iso) glycerol dialkyl glycerol tetraethers (GDGTs), respectively (Schouten et al. 2013), as well as n-alkanes to assess terrestrial inputs and marine productivity between the two contrasting study areas. We integrated these biomarker data with geochemical elemental composition and marine and terrestrial palynomorph assemblages' information to provide a more comprehensive understanding of the differences between the two ecosystem dynamics.Clear differences can be observed in terms of terrestrial input, marine productivity and diversity between the two study areas highlighting the potential of the multipxoy approach to trace back hydrological changes and weathering over the continental tropical South America as well as its consequences in coastal environments.