Spatial and Temporal Sediment Dynamics in a Subarctic Salt Marsh (Gulf of St. Lawrence, Canada)

Abstract

ABSTRACT Gibeault, C.; Neumeier, U., and Bernatchez, P., 2016. Spatial and temporal sediment dynamics in a subarctic salt marsh (Gulf of St. Lawrence, Canada). Sediment transport in the salt marsh and the lagoon of Penouille is driven by tidal currents, waves, wind, and ice rafting, which interact with topography and vegetation to control the spatial distribution of surface sediments. Multiple linear regressions of 203 samples of marsh surface sediments show that grain size gets finer and organic matter content increases with distance from the lagoon inlet, the sandy peninsula, the closest creek, and the lagoon. The vegetation parameters and surface microtopography have only a minor influence. Locally, grain size can get finer with elevation, while organic matter content increases. However, across the entire marsh, grain size exhibits the opposite trend with elevation, a consequence of aeolian transport and ice rafting. The 94 samples covering the lagoon show a trend of finer grain size with distance from...