Tidal Flat-Barrier Spit Interactions in a Fetch-Limited, Macro-tidal Embayment, Lubec, Maine, USA

Abstract

This report describes two sand and gravel spits and associated tidal flat environments in a fetch-limited, macrotidal setting in Lubec, Maine, USA. The spits have been remarkably dynamic since the late eighteenth century despite the low wave energy. The beaches were originally sourced from erosion of glacial and post-glacial bluffs, but the contemporary spits are apparently growing from clasts reworked from former barrier sites on the tidal flat. Attached algae coupled with strong tidal currents permits landward-directed floating and dragging of cobble-sized clasts that could not otherwise move, underscoring the potential importance of algal-assisted transport. This paper underscores the unexplored potential of algal transport across macrotidal flats as a mechanism to permit barriers to transgress in a punctuated manner from one location to another.