How will their metabolism change during the summer when the deep water becomes anoxic?
BySome species of bacteria that live at the surface of sediment on the bottom of lakes are facultative anaerobes; that is, they are capable of either aerobic or anaerobic respiration. How will their metabolism change during the summer when the deep water becomes anoxic? If the bacteria continue to grow at the same rate, will glycolysis increase, decrease, or remain the same after the lake becomes anoxic? Explain why.
(1) Who states that the deep water will necessarily go anoxic because of summer? Generally the top water is first to go anoxic during summer because it gets warmer and can therefore hold less dissolved oxygen. The warmer temperatures also encourage algal and bacterial growth, which further depletes oxygen levels. The colder deep water retains its oxygen longer. Under certain conditions, deep water has been found to be anoxic, but I don’t think that summer has been established as the cause. One factor that has been identified as an underlying cause for deep water anoxia is overgrowth of the bacteria you mention, likely the result of eutrophication (too many nutrients from fertilizer runoff and sewage and such) of the water. Some deep waters have been found to be anoxic due to volcanic activity. Since the temperature of the deep water does not change all that much during summer vs. during winter, I doubt that season of the year has all that much to do with the process.
(2) Just because a bacterium can go anaerobic when conditions require does not necessarily mean that the organism will thrive under such conditions. In fact, the opposite generally occurs. I do not expect that they would continue growing at the same rate.
That being said, if we accept your basic premise assumptions then I would expect glycolysis to carry on at much the same rate because it is integral to both aerobic and anaerobic respiration.
1 Comments
June 22nd, 2009 at 6:16 pm
(1) Who states that the deep water will necessarily go anoxic because of summer? Generally the top water is first to go anoxic during summer because it gets warmer and can therefore hold less dissolved oxygen. The warmer temperatures also encourage algal and bacterial growth, which further depletes oxygen levels. The colder deep water retains its oxygen longer. Under certain conditions, deep water has been found to be anoxic, but I don’t think that summer has been established as the cause. One factor that has been identified as an underlying cause for deep water anoxia is overgrowth of the bacteria you mention, likely the result of eutrophication (too many nutrients from fertilizer runoff and sewage and such) of the water. Some deep waters have been found to be anoxic due to volcanic activity. Since the temperature of the deep water does not change all that much during summer vs. during winter, I doubt that season of the year has all that much to do with the process.
(2) Just because a bacterium can go anaerobic when conditions require does not necessarily mean that the organism will thrive under such conditions. In fact, the opposite generally occurs. I do not expect that they would continue growing at the same rate.
That being said, if we accept your basic premise assumptions then I would expect glycolysis to carry on at much the same rate because it is integral to both aerobic and anaerobic respiration.
References :
M.S. Biology