need info on the physical phenomenon that causes oxygen levels to be higher at night in ponds or pools?
107400
Gasses are more soluble in cold water than hot water.\nAt night, the water cools down and more gas is able to dissolve.
75302
Couple of things come to mind. 1) pH and/or total alkalinity are out of sorts. Check with a reliable test kit and adjust accordingly. 2) If it is a chlorine pool you may have a sensitivite to chlorine. Lots of people do. Curious, though, that it is only on your face? If you are using sunscreen on your face prior to swimming perhaps it is the sunscreen. Look for something like that, too.
419431
B.\n\nCellular respiration uses Oxygen and releases CO2, and at Nighttime, Photosynthesis cannot occur(since there is a lack of light) and therefore cannot convert CO2 to O2, hence lowering the concentration
601562
If there were high nitrate levels... the lake would eventually become a wetland or swamp.  Plants like nitrates... aquatic life does not.  Some lakes are suffering from nitrate run-off (it usually comes from farmers fields or where other types of nitrogen rich fertilizers or substances aren't kept in check)  Those nitrates then in turn generate weed growth.  The weed growth will then choke off the lake.  Ever notice the wierd shade of green in a pond next to houses or apartment complexes.  They're using chemicals to keep the water's P-H on the acidic side to curb vegetation and maintain the proper aesthetics that they want of open water.  If you want further information pertaining to your more immediate area... contact your local county agricultural agent.  He or she should be listed in the white pages under county government.
830149
Could be Liquid Gas. Need more info.
799733
Algae provide food and oxygen for many creatures that live in the same environment. Some examples of algae are seaweed and pond scum. However, in intense algae blooms due to nitrogen run off from farms, a plant fertilizer that cause the algae to grow out of control it leads to oxygen depletion in the water known as hypoxia. When the algae die off bacteria attack the algae and use up all the oxygen. It is a delicate balance.
1183018
yes, they "kind of" sleep at nights by not photosynthesing. and yes fish can "kind of" drown by the lack of oxygen..
756075
Good answers so far, but one thing nobody has mentioned yet is oxygen depravation.  Unless the pond is extremely shallow - Ice will only form a top layer a few feet thick.  This layer however effectively seals off the water from the air interface - preventing oxygen exchange.  Amphibians and some turtles will hibernate, but invertebrates and fish will remain active throughout the year.\n\nThe fish should live initially, but if there are a lot of fish in your pond, or other animals for that matter, and the ice forms and remains for too long - the available oxygen in the water may be depleted - resulting in a noticable fish kill when the ice melts next spring.  Photosynthesis by algae and rooted plants may continue to provide some oxygen as long as the ice is transparent enough to let light through, but thick ice covered with snow pretty much shuts down this process.\n\nThis does happen very rarely in small northern lakes and ponds (I'm talking northern Minnesota or Canada here).  One trick often used by fisheries agencies is to dump loads of coal dust ontop of the ice.  The black dust helps to melt the snow and ice quicker in the spring on suspect lakes.
209798
it's the bending of light as it passes from one medium to another, caused by the differing densities.\n\nA good example is standing in a pool and looking down into the water - notice how distorted your legs look
102988
Since Oxygen is a gas, it is less dense than water...hense it will float.\n\nIf you produced Oxygen underwater, as it is produced, it will buble up.  If you place some type of container (filled with water) above the bubbles, the Oxygen will collect there and displace (push out) the water.\n\nThis picture should give you the idea,\nhttp://intro.chem.okstate.edu/1314F00/Lecture/Chapter5/Gasoverwater1.GIF
1082336
its the way the light reflects of the bits of water
16564
Water magnifies the power of UV rays in light.
501395
The colour of the blood underwater is moreover black. The reason behind it is- Red colour of blood is due to presence of oxygen. Thus heamoglobin at this moment is called oxy-haemoglobin. and its colour is red. When under water the amount of Oxygen is less and thus colour becomes more of blackish due to accumulation of CO2 and other gases along with hormones.
540178
I am proud to say that I have witnessed this event on countless occasions as it took place. As lighting falls from the sky, it carries an enormous quantity of energy. It is enough energy to bring together two Oxygen molecules. The ultimate result is a molecule of Ozone. This process is commonly called Nuclear Fusion because the nuclei of the participants come together and a portion of matter is turned into energy in the process.
104763
well, i do know there's this blue chemical called biochemical oxygen demand(BOD) which is used to see how polluted water is from different sources. like, if you compare drain water and pond water. so if you put few drops in each water, and wait for one day, you'll realise that drain water isnt as blue as pond water coz drain water is more polluted. since there are more waste compared to pond water, so there'll be less oxygen. so yeah.
1012137
topock marsh. might want to fish at night for cats and crappie. too hot in the daytime
908662
good one... like there is Tsunami...a low pressure area in water body.Why there is no air movement.\nThere may be a little movement which is not highly noticeable.