Washed away.

A year has passed since Hurricane Katrina devastated parts of Louisiana, Mississippi, and Alabama. While Gulf Coast residents continue to rebuild their cities, scientists are also hard at work on a recovery effort offshore.

During Hurricane Katrina, powerful waves eroded soil and ripped plants from 306 square kilometers (118 square miles) of marshy wetlands and barrier islands bordering the coast. The waves completely washed away some small islands, says Greg Miller, a scientist at the Coastal Restoration Office of the Army Corps of Engineers.

That worries Miller because the marshes act like a speed bump, protecting inland areas by slowing down a storm's destructive winds and waves before they strike shore. Researchers have recently found some new plant growth in damaged wetland areas--a sign that the marshes are starting to rebuild naturally. Hoping to speed this recovery, scientists are now dumping sediment from inland areas onto the eroded marshes. They are also setting rocks along the coastline to prevent ocean waves from washing away more land.

With another busy hurricane season predicted for 2006, replenishing these lands quickly is critical. "They're the first line of defense between the seas and our cities," says Miller.

GONE: Hurricane Katrina swept away coastal wetlands, as shown above in Louisiana's Chandeleur Islands.

EARTHRACE ROUTE: This March Bethune will depart Barbados for his 44,475 km (27,635 ml)-long journey. This fuel-efficient boat can travel up to 5,000 km (3,107 ml) on one tank of fuel. The blue dots show planned refueling stops.