A better understanding of mud cracking processes gained from in situ measurements on an intertidal mudflat in French Guiana - Archive ouverte HAL Access content directly
Journal Articles Journal of Coastal Research Year : 2009

A better understanding of mud cracking processes gained from in situ measurements on an intertidal mudflat in French Guiana

Abstract

Recent work has revealed that desiccation processes can occur over elongated off-shore mud bars that form on Amazon-derived mud banks. Once mud cracks appear there, opportunistic mangroves, i.e. Avicennia germinans, commence the colonization process. Through the advantage of buoyancy of the mangrove propagules which can be trapped by the mud cracks, propagules can establish sometimes 1-2 kilometres offshore of the adult colonies. In a few months, these pioneer colonies become new sources of propagules, promoting rapid ecosystem expansion. Thus, mud cracking may be seen as an important factor in mangrove resilience. To investigate this phenomenon, a field experiment was conducted during the 2008 equinoctial spring tide in French Guiana in a study area located on the landward face of an elongated mud bar. A digital elevation model (DEM) was computed from DGPS and high-resolution laser station data. Meteorological data including air temperature and humidity, wind speed and orientation, rainfall, solar radiation, temperatures of the mud surface and at a depth of 30-cm, were recorded. Additionally, the water content of the upper mud layer was monitored along a topographic transect. An installed camera took instant photographs every half hour. Preliminary results show that climatic conditions are not the main parameter controlling the desiccation process. Strengthening and consolidation of mud are mainly controlled by mud elevation (water loss by draining) and by the local tidal signal (determinant in spatial behaviour). The DEM enabled computation of the tidal frequency emersion signal, an important tool in analyzing the spatio-temporal patterns of mud cracking and mangrove colonization.
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Dates and versions

halsde-00419502 , version 1 (24-09-2009)

Identifiers

  • HAL Id : halsde-00419502 , version 1
  • PRODINRA : 318017

Cite

Antoine Gardel, Christophe Proisy, Sandric Lesourd, Sylvie Philippe, Jacinthe Caillaud, et al.. A better understanding of mud cracking processes gained from in situ measurements on an intertidal mudflat in French Guiana. Journal of Coastal Research, 2009, SI 56 (1), pp.424-428. ⟨halsde-00419502⟩
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