Nahant: Location

The Marine Science Center of Northeastern University is respected as one of the best coastal study sites in the eastern United States.  It located in Nahant, MA just north of Boston Harbor (Figure 1).  Northeastern has owned the site since 1967, prior to which it was a hotel and military-defense construction site.  Like most of New England, Nahant has a multifaceted geological history that gives its coast spatial complexity.  Extreme physical conditions make it difficult to colonize, resulting in relatively low biodiversity.  This simplicity makes the site exemplary for studying all levels of ecological activity.

What gives rise to the structural complexity and extreme physical conditions is surprisingly exciting geologic history.  Areas west of the Connecticut River were once two separate slices of land, known as exotic terranes. Over 300 million years ago these exotic terranes collided with the proto-North American continent as tectonic plates converged.  According to The Paleontological Research Institution, the terranes were “squeezed, crumpled, deformed and intensely metamorphosed [making] for … complex geology in New England.”  Only 25000 to 23000 years ago, New England was covered by a glacial ice sheet.   By 15000 years ago the ice sheet had rapidly retreated to uncover southern New England and parts of the Gulf of Maine.  Its passing scoured the mixed rocks of the New England coast, leaving them intricate and jagged.  Deposited rock debris from the glaciers, called drift, is still evident.  Glaciation prevented colonization, so the ecosystem in Nahant has only been evolving for 15000 years.  This, combined with the northern latitude, creates a relatively simple intertidal community.

The north-eastern shore is located in a slightly-protected cove encircling Canoe Beach (Figure 1. red outline).  The rocky shores contain numerous tide pools and channels.  Principal macroalgae species include Ascophyllum nodosum, Fucus spp, Chondrus crispus, Hildenbrandia rubra,  and Clathomorphum circumscriptum (Figure 2). Principal herbivores include Littorina spp and Tectura testudinalis. Other noteworthy species are Nucella lapis, Carcinus maenus, and Hemigrapsus sanguineous.