What major processes maintain the balance of carbon dioxide in the atmosphere? Hint
What element is the basis of all organic molecules? Hint
What ecosystem has the greatest potential for preserving continuous, undisturbed records of climate and environmental change? Hint
What is produced when carbon dioxide reacts with water? Hint
Researchers have identified a simple feedback effect that may help control oxygen levels in the atmosphere by altering the productivity of marine organisms. By adjusting the internal oceanic recycling of a key nutrient in response to changing levels of oxygen, the feedback effect would regulate the growth of ocean plants that produce oxygen as a by-product of photosynthesis. What is the key nutrient involved? Hint
What processes alter the ratio of the oxygen isotopes in seawater? Hint
During glacial periods, does seawater contains more or less oxygen 18 than during nonglacial periods? Hint
