PROVIDENCE, R.I. [Brown University] Coastal dead zones, an increasing concern to ecologists, the fishing industry and the public, may not be as devoid of life after all. A Brown scientist has found that dead zones do indeed support marine life, and that at least one commercially valuable clam actually benefits from oxygen-depleted waters.
Andrew Altieri, a post-doctoral researcher in the Department of Ecology and Evolutionary Biology at Brown University, studied dead zones in Narragansett Bay, one of the largest estuaries on the U.S. East Coast. In a paper published this month in the journal Ecology, he found that quahog clams (Mercenaria mercenaria) increased in number in hypoxic zones, defined as areas where dissolved oxygen in the water has been depleted. The reasons appear to be twofold: The quahogs' natural ability to withstand oxygen-starved waters, coupled with their predators' inability to survive in dead zones. The result: The quahog can not only survive, but in the absence of predators, can actually thrive.
A recent study shows that dead zones have been expanding rapidly along the coastal United States and worldwide due to climate change and human-caused pollution. Scientists have typically focused on documenting the death of species and loss of fisheries in these oxygen-poor areas, but they haven't looked at how certain, hardy species such as quahogs can persist and thrive until now. There may be other commercially important species that persist and perhaps benefit from dead zones in other regions.
The research (listen to the podcast on the Ecological Society of America Web site here) also underscores that some key species can be more adaptive and resilient than expected when challenged environmentally, which could have important implications for conservation efforts.
"You'd be hard pressed to say dead zones are good," Altieri said, "but with this study you just can't say that dead zones are simply
|Contact: Richard Lewis|