Among the world’s great ecosystems, Georgia’s coastal salt marshes rank near tropical rainforests in fertility and productivity. Covering some 400,000 acres, Georgia’s salt marshes — a third of all salt marsh along the entire Atlantic coast — yield nearly 20 tons of biomass per acre, four times more than the best fertilized farmland.
The amazing fecundity gives sustenance and refuge to untold numbers of shrimp, blue crabs, clams, oysters, all manner of finfish, birds and other species. Some 75 percent to 80 percent of the shrimp, blue crabs and other economically important fish and shellfish species along the Southeast coast depend on salt marshes as nurseries for their young.
The salt-tolerant, cane-like grass known as Spartina alterniflora, or cordgrass, is the base of this productivity. Spartina makes up more than 90 percent of the vast salt marsh meadows that stretch for miles between the mainland and barrier islands.
Now, however, we must confront the unthinkable — the horrible specter that Georgia could lose this magnificent resource. A new University of Georgia study, using data collected by a NASA Landsat satellite, shows that the amount of Spartina on Georgia’s coast has dropped by some 35 percent during the past 30 years.
The decline, the UGA scientists said, is primarily due to climate change marked by prolonged droughts and warmer temperatures. They worry that the loss of Spartina will have a ripple effect throughout the complex salt marsh ecosystem.
Without salt marshes, marine nursery habitats would be wiped out and food webs horribly broken. Entire populations of shrimp, crabs and fish — and the birds and other animals that depend on them — would vanish. Without Spartina to hold the marsh together, marsh soil would erode and choke creeks and rivers. Mainland areas would be highly vulnerable to flooding. Coastal property values would plummet as spectacular marsh vistas turned into moonscapes. Tourism would nosedive.
The very heart of coastal Georgia would be lost.
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In the sky: From David Dundee, Tellus Science Museum astronomer: The moon will be last-quarter Wednesday. Mercury and Venus are low in the west, Mars and Jupiter are in the southwest and Saturn is high in the west around nightfall.
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