HALIOLOIRE1
Type | Oceanographic cruise |
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Set | This cruise is part of the set HALIOLOIRE |
Ship | Haliotis |
Ship owner | Ifremer |
Dates | 04/09/2012 - 29/09/2012 |
Chief scientist(s) | MAILLET Grégoire |
LABORATOIRE DE PLANÉTOLOGIE ET GÉODYNAMIQUE - UMR 6112 - ANGERS Université d'Angers 2 boulevard Lavoisier 49000 Angers |
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DOI | 10.17600/12120050 |
Objective | The objective of the HalioLoire 1 mission is to characterize a morphosedimentary and structural baseline state for the Loire estuary, from Nantes to Pointe St Gildas, with special focus on mudflat zones in the mid-estuary, the main worksite zones for the teams working in the Axe 2 (biogeochemistry) theme of the RS2E (environmental surveillance and monitoring network) programme of OSU Nantes Atlantique, as basis of this mission. The team's goal is to utilize the data acquired by RV Haliotis in order to: 1) Analyze the zone's topography to identify and qualify forcings which govern the processes of deposit/remobilization of sediments (multibeam echosounder). 2) Characterize the type of surface sediments (sonar and RoxAnn). 3) Study the volumes and architecture of the sedimentary bodies making up the most recent sealing or smothering period in the Loire estuary (seismics). 4) Assess the degree of morphological stability of the zones studied and the nature of sediments that could potentially be remobilized (diachronic approach). 5) Determine how representative the biogeochemical study worksite zones are (spatial approach). The focus on mudflat is justified by their geotechnical specificities (high water content, highly variable plasticity) and their high adsorbent capacity (storage / release of pollutants, fixing of organic matter whose degradation controls the oxygenation of the benthic compartment, etc.). That said, data must be acquired over a larger area than that of the mudflats alone, to enable them to be put into context along an upstream/downstream continuum and to distinguish between the intrinsic variability of the zone and that linked to evolutions in the forcing conditions over time and space. |