September 17, 2008

Hurricane Ike Wreaks Havoc On Texas’ Coastal Ecosystem

Experts say Hurricane Ike caused massive damage to Texas' coastal ecosystem that could take a generation to heal.

As scientists and land managers start to assess the storm's impacts on beaches, dunes and marshes, they are seeing signs of present damage and future worries to a coast already hammered by decades of pollution, population growth and habitat loss.

Jim Sutherlin, superintendent of the Texas Parks and Wildlife Department's 24,250-acre J.D. Murphree Wildlife Management Area, near Port Arthur, said the impacts are going to be phenomenal

"We're going to take the critters that crawl or walk, and for the full stretch of the coastal zone that got the full impact of the coastal flood, they're just eliminated."

Unfortunately, the upper Gulf Coast of Texas was already under stress from many sources like coastal development and subsidence "“ a drop in the land's surface level as petroleum and groundwater are pumped out "“ have degraded large areas of marsh.

Earlier this month, scientists from three American universities concluded in the journal Science that a global sea level rise of 31.5 inches by the year 2100 should be the assumption. The highest conceivable rise, they estimate, is 6.5 feet.

Much of the existing Texas coastline would be permanently under water even at the lower figure, and a hurricane's strongest force would reach farther inland.

"I'm sure what we'll see [from Ike] is more evidence of what happens when we don't maintain those natural barriers," said Larry McKinney, executive director of the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University-Corpus Christi.

Dr. McKinney likened a hurricane to a kind of a small-scale climate-change model. "We really need to start pulling together a long-term plan for responding to climate change."

Coastal ecosystems adapt to the effects of hurricanes and even use them to flush out marshes and estuaries, changing water chemistry and plant communities.

Storms can restart the cycles of succession, or the natural rhythm of birth, maturity, death and rebirth in an ecosystem.

What happens to the dunes, estuaries and marshes along the upper Gulf Coast can be felt across the entire hemisphere for years.

Experts said Ike's storm surge threatened to take out in a few hours the dune buildup of years, and to drown under seawater the marshes that survive on a mixture of fresh and saltwater. The death of more marshes and the loss of the natural protection they provide is a certainty.

Mr. Sutherlin, the wildlife area superintendent, said the marshes were not in a healthy, dynamic state to start with because of human impacts." Hundreds of acres, perhaps thousands, will be lost, he added.

"Everything's still under water. It looks like an ocean out there," said Sutherland.

Once scientists measure water quality in the gulf, the hurricane's effect on the complex natural system of the Texas coast will be apparent.

Steve DiMarco of Texas A&M's Department of Oceanography, said the northernmost reaches of the Texas shoreline frequently becomes a "dead zone" with extremely low oxygen levels, but a hurricane quickly restores the oxygen.

He said the Texas dead zone is linked to organic material of uncertain origin stirred up from coastal marshes. Sea level rise will complicate the problem.

"Over the long run, as the seawater flushes in, more organic material will get out," Dr. DiMarco said. But as to whether that will mean a bigger dead zone, "I won't go that far."

Reducing the threats of a hurricane range from restoring marshes to keeping people away from vulnerable areas. Yet, Texas coastal experts fear that they have fewer choices with each successive storm, each census showing coastal population increasing, and each new, higher projection of sea-level rise.

Dr. McKinney says we have some options, but they're running out. "We need to take advantage of this disaster to learn."


Image Caption: The Brown Pelican (Pelecanus occidentalis) can be seen at times throughout the Murphree Wildlife Management Area. Courtesy Wikipedia


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