Spatial Distributions of Surface Sedimentary Organics and Sediment Profile Image Characteristics in a High-Energy Temperate Marine RiOMar: The West Gironde Mud Patch
Résumé
The spatial distributions of (1) surface sediment characteristics (D0.5, Sediment Surface
Area (SSA), Particulate Organic Carbon (POC), Chlorophyll-a (Chl-a), Phaeophytin-a (Phaeo-a),
Total and Enzymatically Hydrolyzable Amino Acids (THAA, EHAA), δ13C) and (2) sediment
profile image (apparent Redox Potential Discontinuity (aRPD), numbers and depths of biological
traces) characteristics were quantified based on the sampling of 32 stations located within the West
Gironde Mud Patch (Bay of Biscay, NE Atlantic) in view of (1) assessing the spatial structuration of
a temperate river-dominated ocean margin located in a high-energy area, (2) disentangling the
impacts of hydrodynamics and bottom trawling on this structuration, and (3) comparing the West
Gironde Mud Patch with the Rhône River Prodelta (located in a low-energy area). Results support
the subdivision of the West Gironde Mud Patch in a proximal and a distal part and show (1) the
existence of depth gradients in surface sedimentary organics characteristics and bioturbation
within the distal part; (2) no evidence for a significant effect of bottom trawling, as opposed to
Bottom Shear Stress, on the West Gironde Mud Patch spatial structuration; and (3) major discrepancies
between spatial structuration in the West Gironde Mud Patch and the Rhône River Prodelta,
which were attributed to differences in tidal regimes, sedimentation processes, and local hydrodynamics,
which is in agreement with current river-dominated ocean margin typologies
Domaines
Océan, Atmosphère
Origine : Publication financée par une institution