Temporal and spatial changes in grain size on a macro-tidal channel-flat complex: results from Kingsport, Nova Scotia, Bay of Fundy

摘要

Understanding the processes that lead to seasonal changes in grain size on muddy macro-tidal flat and channel complexes will assist efforts to predict future changes caused by climate change and construction of infrastructure like tidal power generators, wind farms, and causeways. Surficial sediment samples were collected for disaggregated inorganic grain size (DIGS) analysis every month for 1year from a tidal flat and from a tidal channel and its banks in Kingsport, NS, Canada, which is located in the Minas Basin of the Bay of Fundy. A process-based parameterization of the DIGS distribution was used to determine floc fraction, representative of the percentage of fine-grained material deposited to the seabed in flocs. Small changes in floc fraction occurred seasonally in the channel. Values were higher in late winter and lower in late summer. A more pronounced seasonal variation in floc fraction was observed on the tidal flats. Observed changes in floc fraction correlated with elevation. Results from this study are discussed in terms of the controls on floc fraction which include suspended particulate matter concentration (SPM), turbulence, and stickiness in the water column, all of which can be used to understand the formative processes responsible for shaping the bottom sediment texture.