A recent study has examined more than 400 ocean dead zones around the world. An ocean dead zone is a phenomenon that happens during the summer when water temperature increases to the point that some species of wildlife cannot survive. Typically this results in a catastrophic killing of fish, crab, oyster, and shrimp—all of which rely heavily on oxygenated water. As the water heats up, so do their body temperatures, which boosts metabolism. The animals eat more—especially oxygen-producing algae—which, in turn, results in less oxygen in the water; an effect which “could quickly cause stress and mortality and, at larger scales, drive an ecosystem to collapse.” In their study, the team indicates “Climate change will drive expansion of dead zones, and has likely contributed to the observed spread of dead zones over recent decades.” The also note, “Temperature is perhaps the climate-related factor that most broadly affects dead zones.” Ocean “Over 40 percent of the world’s population lives in coastal areas,” reports Keryn B. Gedan, co-director of a conservation program through the University of Maryland. The Smithsonian Environmental Research Center researcher continues, “We depend on these resources. No one wants to see a fish kill or harmful algal bloom at their local beach.” Gedan—along with Andrew H. Altieri of the Smithsonian Tropical Research Institute, in Panama—co-authored the study. Together, they found that the number of dead zone events around the globe have doubled since the middle of the last century. Most importantly, she hints that human influence has probably contributed more to this growth in size and intensity. Gedan adds “We just don’t know how much of this doubling is due to climate change or nutrient runoff.” She attests that scientists need more “sophisticated modeling” to keep up with the changes in order to determine these factors. dumb-out.net/study-finds-ocean-dead-zones-dangerously-doubling/11591
Posted on: Tue, 25 Nov 2014 09:02:08 +0000
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