If coastal salt marshes are like savings accounts, with sediment as the principal, all eight Atlantic and Pacific coast salt marshes studied are "in the red," researchers found.Scientists working on a rapid assessment technique for determining which US coastal salt marshes are most imperiled by erosion were surprised to find that all eight of the Atlantic and Pacific Coast marshes where they field-tested their method are losing ground, and half of them will be gone in 350 years’ time if they don’t recapture some lost terrain.