Tall green grass. Subtle melodies of songbirds. Sharp whines of muskrats. Rustles of water running through the grasses. And at low tide, a pungent reminder of the treasures hidden beneath the surface.All are vital signs of the great salt marshes' natural resources. Now championed as critical habitats for plants, animals, and people because of the environmental service and protection they provide, these ecological wonders were once considered unproductive...