Word: oxygenation
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According to the Gaia hypothesis, earth's atmosphere would be unstable for life if it were not regulated by the biosphere, the envelope of life surrounding earth. Oxygen levels have remained at roughly 21% of the atmosphere for 200 million years, Lovelock asserts, whereas they should have fluctuated wildly, according to some geochemical models of the atmosphere. Were oxygen levels to rise above 25%, spontaneous fires would break out; if they dropped below 15%, many higher life-forms would suffocate. Climatologist Tyler Volk of New York University argues that life controls earth's temperature as well. In a study recently...
Gaia's critics have by no means been silenced. Some dispute the degree to which life-forms stabilize the atmosphere and temper the climate. Others contend that the emergence of oxygen in earth's atmosphere contradicts Gaia because it made the air poisonous for anaerobic creatures of primordial times. Evolutionary scholar Richard Dawkins argues that earth cannot be considered an organism because it does not reproduce. Gaian proponents respond that the increase of oxygen in the atmosphere was slow enough to allow the mix of life- forms to adjust, and physician-author Lewis Thomas answers Dawkins by coyly suggesting that...
...been poisoned before, 3 billion years ago, when the blue-green algae began manufacturing oxygen. That was the first ecological crisis. Life survived then. Life will not vanish now, but this may be the last chance for humans to go along gracefully...
...regional director of the Wilderness Society, "but it has to be done." Florida's research shows that high levels of phosphates and nitrates from farm runoff have transformed more than 20,000 acres of Everglades saw grass into cattails. These intruders, which thrive in high-nutrient water, suck the oxygen from the marsh and suffocate aquatic life at the bottom of the Everglades food chain. On shallow ponds and canals, nutrient-fed algae grow so thick that they block the sun from underwater plants. So far, most of the damage is confined to Loxahatchee National Wildlife Preserve -- an Everglades habitat...
...Harlem Brundtland dropped her paperwork, moved to the back of the plane, and for the next 45 minutes tended the victim. She swaddled him in blankets on the floor of the narrow aisle, administering oxygen, monitoring his pulse, ordering the pilots to radio Oslo for an ambulance. When another photographer tried to shoot the scene, her aides waved him off. This was not a photo...