Dynamics and Environmental Effects of Ice in the Cumberland Basin of the Bay of Fundy

Abstract

Ice occurs in the upper reaches of the Bay of Fundy from Dec.-April and conditions are influenced by the macrotides characteristic of the area. Drift ice forms on the seawater surface and because of almost constant movement in tidal currents is composed of small, rounded pieces. Shorefast ice develops from the stranding of drift ice between the neap and spring high water levels. Drift ice can also strand during ebb tide on intertidal salt marshes and mudflats which together comprise 2/3 of the Cumberland Basin area. Intertidal sediments can freeze to form a frozen crust, and sheet ice can form where salinity and tidal energy are low. Shorefast ice can significantly reduce the cross-sectional area of tidal rivers and encourage flooding. Stranded drift ice can import sediment and export plant debris from salt marshes. Mudflats are heavily scoured by ice all winter which causes erosion and mortality of benthic organisms. Construction of a tidal power project would change ice properties considerably.