Return of the Dead (Zones)
Posted February 15, 2008 in Reviving the World's Oceans
The West Coast is continuing its George Romero tribute festival with four straight years of Dead Zones. The Dead Zone in the Gulf of Mexico is perhaps the most famous of the Dead Zones. In the Gulf, nutrients flowing down the Mississippi mix in the warm, shallow waters to create a fertile brew for algae, which flourish and die taking oxygen out of the sea as they decompose. Scientists are also familiar with the "oxygen minimum zone" -- deep, dark waters of the sea below 600 meters where oxygen is scarce and marine life has adapted to live slowly and breathe less.
This region has been considered one of the worlds most productive, with the California current driving the temperature and nutrient supply that feeds our crabs and rockfish. We thought we were immune to dead zones until 2002, and unfortunately, it looks like they're here to stay. Dr. Francis Chan and his Oregon colleagues found persistent hypoxia over 80% pf the water column in shallow depths, up to 60 meters. Submersible surveys in 2006 found rock reefs devoid of their usual rockfish and an increase in sulfur-oxidizing bacterial mats. Tasty.
This is all-too consistent with the recent work by Dr. Bill Gilly on the rise Humboldt squid (aka jumbo squid) in California waters. Kevin Drum wonders what the benefits are of "massive oxygen starved zones" and if you're a jumbo squid, that benefit is free suffocated food at the edge of that anoxic zone. Like a jubilee for cephalopods.
Ken Weiss's excellent piece in the LA Times has this quote from Newport fishermen Dennis Krulich, who found tiny baby octopuses climbing up their crab lines from the dead zone:
"I'd tell my crewmen, be careful with these cute little things," said Dennis Krulich, a longtime fishermen in Newport. "Peel them off the rope, and we'll put them back." Only later did he realize that these babies were coming up from oxygen-depleted waters that hover near the seafloor, climbing to save their lives.
Bad signs that the winds of change are blowing and they're already affecting the deep patterns that govern the sea. I'm not ruling out zombie fish.
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