June 18, 2008
Pictured above is a stretch of thriving Spartina alterniflora or salt marsh cordgrass, off of Squantum, Massachusetts. Spartina alterniflora is an amazing organism capable of major coastal remodeling, given favorable conditions and adequate time. It’s a perennial grass that flourishes in intertidal mudflats and salt marshes, largely because it has no competitors in this incredibly harsh environment. It has evolved to tolerate cyclical partial and total salt-water immersion, exposure with evaporative hyper-salinity, harsh Sun in summer, and sea ice in winter. Among its important physical adaptations are tough stems that breakaway at the base when traumatized by ice and or storm waves. This protects the root system from mechanical disruption.
Biochemical adaptations allow its roots to tolerate the low-oxygen and high sulfide concentrations typical of coastal mudflats. Spartina alterniflora grows at the edge of a salt marsh. Its tough root system traps ocean sediment, fostering the development of a heavy peat-like material that's capable of supporting salt marsh organisms. In this way, over years, salt marsh expands seaward. As new-formed marshy areas dry up, other plant species, particularly Spartina alterniflora's high-marsh cousin, Spartina patens, colonizes the new land. In some locations, this seaward spread of salt marsh is undesirable, destroying oyster beds, clogging shipping channels, and out-competing native species. In such circumstances, chemical and mechanical eradication of Spartina alterniflora has proven quite difficult.