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The highly dynamic French Guiana littoral under Amazon influence: the last decade of multidisciplinary research

Submission status
Closed

The North-Western coast of South American is subject to intense hydro-morpho-sedimentary dynamics under the direct influence of the massive discharge of sediment from the Amazon River. Mangrove forest development, which represents 80% of the Guianese coast, depends on the dynamics of the mud banks transiting along the coast East to West from the Amazon to the Orinoco. These dynamics are defined by alternating periods of several years of coastal advance and retreat: each part of the coast is therefore subject to an alternation of siltation (passage of a bank) and erosion (phase called “interbank”). Mangroves only develop cyclically through successive phases: colonization of bare mud as soon as it is sufficiently consolidated, extension of the pioneering mangrove, maturity of the forest, then uprooting of trees and regression of the mangrove as a result of substrate erosion caused by off-shore waves. It is therefore a very dynamic ecosystem, in constant evolution. It is locally unstable and short-lived but is paradoxically characterized by high productivity, a high standing biomass (up to 350 t/ha), and long-term resilience at the system level. At each phase of erosion, large quantities of plant debris, and sedimentary organic matter, are exported to the adjacent waters and sediments, which in turn feed the biological productivity of the Guianese coastal zone. French Guiana mangrove forests are one of the best preserved natural systems in the world, and its particular dynamics make it a unique model for studying the natural resilience of a continental scale, coastal ecosystem. The history of human settlement and habitation modes along the shoreline also highlight the major influence of the intense coastal dynamics of the area on human populations.

Due to its well-expressed processes and global importance, this environment was the subject of a previous special issue in the journal of Marine Geology in 2004 (Volume 208, Issues 2–4). Recent technologies associated with new imaging methods, in situ probes (and analytical procedures adapted to this dynamic environment), have allowed the acquisition of new data sets and permitted re-evaluation of ecological concepts applicable to the Guiana's coastlines. Here we provide a set of 17 manuscripts from different disciplinary perspectives but fields, centered on the highly dynamic coast under the Amazon influence. These contributions deal with processes associated with the world’s largest mudflats, mangroves ecosystems, coastal productivity and fisheries resources, the migration of sensitive species and, human-environment relationships and adaptability.

This set of papers utilizes multidisciplinary approaches to improving our understanding of this natural dynamic system, encompassing: anthropology, geomorphology, sedimentology, geography, engineering, biogeochemistry, biology, ecology, ecotoxicology, biodiversity and biology and ecology of conservation.

Editors

  • Robert C. Aller Robert C. Aller , 

    Robert C. Aller

    School of Marine and Atmospheric Sciences Stony Brook University Stony Brook, NY, USA robert.aller@stonybrook.edu

  • Philippe Cuny Philippe Cuny  &

    Philippe Cuny

    Mediterranean Institute of Oceanography (MIO, UM110) OSU Institut Pythéas, Aix-Marseille University Marseille, France

  • Emma Michaud Emma Michaud

    Emma Michaud

    National Center of Scientific Research (CNRS) Laboratory of Environmental Marine Sciences Plouzané, France

Articles (7 in this collection)