describe that if Oxygen is decreased in the air it will not spoil the food quickly as microbes will not grow?
151805
I don't know who told you this but it simply isn't true. Microbes certainly will grow in food if there is no oxygen.  \n\n\nIn fact one of the worst food poisoning microbes will ONLY grow if the food conatibns no oxygen.  That microbe is called Clostridium botulinum and is reposnsible for the disease botulism.\n\nTher are also many, many othermicrobs that will live and grow quote happily in food with no oxygen.
786686
Oxygen? Nothing really. But a high concentration of oxygen would mean a low concentration of carbon dioxide, meaning the oxygen would be blocking the stomata, allowing less CO2 to get in. Meaning in high O2 environmant, C4 plants would hve advantage in that they can still compete for CO2.
222105
a) cyanobacteria \n\nOur atmosphere would have virtually no free oxygen nor any eukaryotes if not for them....
188594
I'm also amazed at the answers including the preceding one. It's true it's all about bouyancy. But is bouyancy affected significantly by the dissolved oxygen in the tissues? According to the ref., bouyancy is just about lung capacity, bone, fat and muscle ratios. And of course the salinity of the water. Also, panic-induced body tension can reduce lung capacity and muscle performance.  \nAnyway, a change in tissue oxygen level would happen slowly; it's a diffusive process. Second, the density difference of water with and without dissolved oxygen has to be minute since oxygen is only sparingly soluble.
1038325
It's depends on the availability of oxygen.  In the presence of O2, bacteria will convert most of the organic material to carbon dioxide gas (CO2).  In the absence of O2, they'll mostly produce methane gas (CH4).
284891
Living cells cannot absorb oxygen directly.  It has to be disolved in water.  Fish do not have any mechanism for disolving the oxygen in the air (they don't need it, since they live in the water), and so cannot survive on air.\n\nOur lungs have a lining of special mucous which is produced specifically to disolve oxygen and put it into a liquid so it can be used by our bodies.  It is remarkably similar to sea water... evolution has basically preserved the underlying transfer mechanism, and given us a way to carry our own little bit of ocean around with us!\n\nThe hylan membranes make this special fluid.  These membranes are not needed in the womb and so grow late in fetal deveolpment; hylan membrane disease results when a child is born before these membranes are fully developed, and they are at risk of suffocating in the air, just as a fish would.
986563
all right... so here's the deal.\n\naccording to the local health department (i'm quite sure this is a standard), any food that hits the floor becomes trash.  there is no 5 second rule.\n\nadditionally, bacteria isn't the only thing on the ground.  perhaps there is dirt, and fire doesn't kill dirt.  dirt may be sterile, but it's still gross.\n\nimportantly, let's imagine that there is a chemical on the ground, like a cleanser.  that won't cook off either.  and that is poison.  \n\ncooking food to high enough temperatures will indeed kill bacteria, but here is another myth debunked.\n\nsuppose you leave some food out at room temperature for 12 hours, then you cook it up to boiling.  you kill all the bacteria, right?  right, you will kill all the bacteria.  so the food is safe to eat, right?  wrong.  bacteria produce biproducts which are poisonous, deadly even, and these chemicals are in fact dead already and heat does not necessarily destroy them.\n\nso heat is not a cure all for food, and the 5 second rule is crap.
290177
Such a thing does occur among small animals such as planaria. The exchange of gases and therefore the exertion and movement such animals can perform is very limited. Microbes do not have a real respiratory system nor a circulatory systems in the terms we consider customary. It does limit the range and degree of motion. Gas exchange and work is severely limited. I see no advantages unless one wishes to become a planarian.
1161700
None at all. You have bought into an urban myth. Trees in the Amazon don't produce any oxygen. Not even one little bit.\n\nAN OFT-HEARD WARNING with regard to our planet's future is that by cutting back tropical forests we put our supply of oxygen gas at risk. Many good reasons exist for placing deforestation near the top of our list of environmental sins, but fortunately the fate of the Earth's O2 supply does not hang in the balance. Simply put, our atmosphere is endowed with such an enormous reserve of this gas that even if we were to burn all our fossil fuel reserves, all our trees, and all the organic matter stored in soils, we would use up only a few percent of the available O2. No matter how foolishly we treat our environmental heritage, we simply don't have the capacity to put more than a small dent in our O2 supply. Furthermore, the Earth's forests do not play a dominant role in maintaining O2 reserves, because they consume just as much of this gas as they produce. In the tropics, ants, termites, bacteria, and fungi eat nearly the entire photosynthetic O2 product. Only a tiny fraction of the organic matter they produce accumulates in swamps and soils or is carried down the rivers for burial on the sea floor.
915738
no absolutely not !! rotting is an organic process initiated by microorganism in the air. in the space our food is specially sterized and air is constantly refined.So if food is itself is not contaminated i dont think it will rot
1128521
gas cools down if it expands suddenly.\n\nsimilar principle is used in AC and refrigerators.
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# Anoxic autotrophs: Obtain hydrogen from chemicals such as sulfur.\n[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[Dead Zones are areas where the bottom water (the water at the sea floor) is anoxic, meaning that it has very low (or completely zero) concentrations of dissolved oxygen.]]]]]]]]]]]]]]]]]]]]]]]]]\nDead Zones are areas where the bottom water (the water at the sea floor) is anoxic, meaning that it has very low (or completely zero) concentrations of dissolved oxygen. These dead zones are occurring in many areas along the coasts of major continents, and they are spreading over larger areas of the sea floor. Because very few organisms can tolerate the lack of oxygen in these areas, they can destroy the habitat in which numerous organisms make their home.\n\nThe cause of anoxic bottom waters is fairly simple: the organic matter produced by phytoplankton at the surface of the ocean (in the euphotic zone) sinks to the bottom (the benthic zone) where it is subject to breakdown by the action of bacteria, a process known as bacterial respiration. The problem is, while phytoplankton use carbon dioxide and produce oxygen during photosynthesis, bacteria use oxygen and give off carbon dioxide during respiration. The oxygen used by bacteria is the oxygen dissolved in the water, and that’s the same oxygen that all of the other oxygen-respiring animals on the bottom (crabs, clams, shrimp, and a host of mud-loving creatures) and swimming in the water (zooplankton, fish) require for life to continue.\n\nThe "creeping dead zones" are areas in the ocean where it appears that phytoplankton productivity has been enhanced, or natural water flow has been restricted, leading to increasing bottom water anoxia. If phytoplankton productivity is enhanced, more organic matter is produced, more organic matter sinks to the bottom and is respired by bacteria, and thus more oxygen is consumed. If water flow is restricted, the natural refreshing flow of "oxic" waters (water with normal dissolved oxygen concentrations) is reduced, so that the remaining oxygen is depleted faster.\n\nMany of the areas where increasing bottom water anoxia has recently been observed are near the mouths of major river systems. While Satellite images can’t see the bottom of the ocean, they can see the surface, where sediments from rivers mix with ocean waters. The images shown here are Satellite images (SeaWiFS) observations of the Mississippi River delta, the Yangtze River mouth in China (The Yangtze River mouth is not currently identified as an area with an associated dead zone, but such conditions could develop there in the future), and the Pearl River mouth in China, near Hong Kong.\n\nSeaWiFS can also observe areas where water flow is restricted, such as the Baltic Sea in Europe. The image on the left features Denmark after strong storms caused flooding and increased sediment suspension in the Baltic. On the right is an overview of the Baltic Sea, including a plankton bloom in the Skagerrak just north of Denmark.\n\nThe apparent cause of the creeping dead zones is agriculture, specifically fertilizer. While fertilizer is necessary to foster bumper agricultural crops, it also runs off the fields into the streams and rivers of a watershed. When the fertilizer reaches the ocean, it just becomes more nutrients for the phytoplankton, so they do what they do best: they grow and multiply. Which leads to more organic matter reaching the bottom, more bacterial respiration, and more anoxic bottom water.\n\nThese effects can be magnified by catastrophe. When the heavy rains of Hurricane Floyd caused extensive flooding in North Carolina in September 1999, the heavy load of nutrients (from dead animals, flooded animal waste ponds, and numerous other sources) reached the sounds that lie between the coast and the Outer Banks, oxygen levels in the water plummeted. The picture at the top of the page shows the heavy load of sediments flowing into Pamlico Sound. SeaWiFS captur
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Lower temperatures reduce rates of reactions. This includes ezyme reactions in the foods that cause them to further ripen and spoil and growth of bacteria that can cause spoilage and food poisoning. It also keeps insects off the food and dust.
589663
To the best of my knowledge any Bacteria such as mentioned above can not survive in the air. They die very quickly once exposed to the environment.
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An obligate anaerobe requires absence of oxygen to thrive. Presence of oxygen will be like a death sentence to them. A facultative anaerobe, on the other hand, is an organism that can grow in the presence of oxygen, but will do better without it.
778274
Bacteria does not grow at freezing temperatures, but the temperature does not kill it. Heat  will kill bacteria if it is hot enough, but there is a range where bacteria like to grow. In food microbiology, we are told not to keep food between 40 and 140 F because that is where bacteria will grow.\nAs far as ice gathering bacteria, if it is open to the air, the temperature makes no difference.
629137
an oxygen monitor is how to monitor O2 . since the atmosphere is thinner the higher you go there is less of an oxygen content. so less oxygen in the air = less in the blood