Cool water tends to hold more oxygen than warm water. Also fresh water holds more oxygen than seawater. Seawater at 25 deg C will have about 6 milligrams of oxygen per litre, while 5 deg C fresh water can hold more than twice that. Compare this to air, which has around 280 milligrams of oxygen per litre at 25 deg C, about 300 mg at 5 deg C.
dv said:
Cool water tends to hold more oxygen than warm water. Also fresh water holds more oxygen than seawater. Seawater at 25 deg C will have about 6 milligrams of oxygen per litre, while 5 deg C fresh water can hold more than twice that. Compare this to air, which has around 280 milligrams of oxygen per litre at 25 deg C, about 300 mg at 5 deg C.
quit your borax poindexter
dv said:
Cool water tends to hold more oxygen than warm water. Also fresh water holds more oxygen than seawater. Seawater at 25 deg C will have about 6 milligrams of oxygen per litre, while 5 deg C fresh water can hold more than twice that. Compare this to air, which has around 280 milligrams of oxygen per litre at 25 deg C, about 300 mg at 5 deg C.
And this is why fish stocks are normally greater in lower latitudes.
How low down do we have to go before we find an earth creature that doesn’t need oxygen?
How do you mean oxygen? The element, or the gas?
Peak Warming Man said:
How low down do we have to go before we find an earth creature that doesn’t need oxygen?
On evidence presented, not far; wookie doesn’t seem to require it.
wookie just pinches other people’s.
furious said:
- How low down do we have to go before we find an earth creature that doesn’t need oxygen?
How do you mean oxygen? The element, or the gas?
Well the element, fish utilise dissolved oxygen, land animals and dolphins etc breathe the gas.
I’m thinking that what is the highest order of creature that can live sans oxygen, except for compounds like water.
anaerobes surely? bacteria.
There are living things at the surface, on both land and sea, that do not require oxygen gas (dioxygen) to live.
Obv, all living things need oxygen as an element: it is part of DNA, for one thing.
Peak Warming Man said:
How low down do we have to go before we find an earth creature that doesn’t need oxygen?
if bacteria qualify as ‘earth creature’, then, for some, there’d be those that don’t need it, and for some oxygen is even toxic
https://en.m.wikipedia.org/wiki/Anaerobic_organism
Phil says it better than I can
dv said:
https://en.m.wikipedia.org/wiki/Anaerobic_organismPhil says it better than I can
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I don’t understand the question
dv said:
Cool water tends to hold more oxygen than warm water. Also fresh water holds more oxygen than seawater. Seawater at 25 deg C will have about 6 milligrams of oxygen per litre, while 5 deg C fresh water can hold more than twice that. Compare this to air, which has around 280 milligrams of oxygen per litre at 25 deg C, about 300 mg at 5 deg C.
OK
Air at 5 C has 50 times more oxygen per litre than seawater at 25 C.
HTH.
The Rev Dodgson said:
Air at 5 C has 50 times more oxygen per litre than seawater at 25 C.
The Rev Dodgson said:
dv said:
Cool water tends to hold more oxygen than warm water. Also fresh water holds more oxygen than seawater. Seawater at 25 deg C will have about 6 milligrams of oxygen per litre, while 5 deg C fresh water can hold more than twice that. Compare this to air, which has around 280 milligrams of oxygen per litre at 25 deg C, about 300 mg at 5 deg C.
OK
Air at 5 C has 50 times more oxygen per litre than seawater at 25 C.
HTH.
By Jove he’s right!
It hasn’t been mentioned in this thread yet. But oxygen content in water declines with depth for a while, and then increases again as you get even deeper. It’s said that the reason is that organisms in the middle of the water column use up all the oxygen there while they eat detritus that falls down from upper levels. The zone of minimum oxygen is seawater occurs at depths of about 200 to 1,000 metres.
Peak Warming Man said:
How low down do we have to go before we find an earth creature that doesn’t need oxygen?
Interesting question. And there are several different ways to answer it. We all know about obligate and facultative anaerobes among the bacteria. All¿ plants produce more oxygen than they consume. Fungi and animals consume oxygen, even the giant tube worms that live in the deep ocean despite their proximity to sulphur.
But I can’t help wondering if there are parasitic metazoans that can survive in an anaerobic environment. Certainly some animals such as tardigrades can hibernate successfully for a very long time when completely deprived of oxygen. I wonder perhaps about other hibernating animals. Perhaps insects like the weta. Bears can’t survive without oxygen even in hibernation. It could be that some hibernating frogs can survive without oxygen for long periods, and possibly even some hibernating rodents or even bats.
Spotted this on wikipedia:
http://en.wikipedia.org/wiki/Cryptobiosis
Anoxybiosis
In situations lacking oxygen (a.k.a., anoxia), many cryptobionts (such as M. tardigradum) take in water and become turgid and immobile, but can still survive for prolonged periods of time just as with other cryptobiological processes. While survival rate studies of organisms during supposed anoxybiosis in anoxia have historically given some conflicting results, the current consensus in the scientific community seems to be in favor of the opinion that certain ectothermic vertebrates and some invertebrates (for example, sea monkeys, copepods, nematodes, and sponge gemmules) are capable of successfully surviving in a seemingly inactive state during anoxic conditions for periods of time ranging from months to decades.
Note that, as previously mentioned IIRC, oxygen is part of nucleic acids, so life as we know it is absolutely dependent on oxygen.
Note that in many anaerobes, chemicals containing sulphur replace those containing oxygen as a source of energy. For example, sulphate-reducing bacteria obtain energy by oxidizing organic compounds or molecular hydrogen (H2) while reducing sulfate (SO4—) to hydrogen sulfide (H2S). In a sense, these organisms “breathe” sulfate rather than oxygen in a form of anaerobic respiration.
In facultative anaerobes, the main source of energy is often fermentation, which doesn’t require oxygen.
In lichens, the algae produce more oxygen than they use and the fungi use up oxygen. It has been suggested that some lichens could thrive in an anaerobic environment, and experiments with lichen in outer space have been conducted. They don’t actually grow very well in outer space, but they do survive.
While on the topic of advanced organisms that can survive in an anoxic environment for a long time, many plant seeds may fit that description.
The European common lizard, Lacerta vivipara, survives being frozen solid, so may be able to live a long time without oxygen. Some other lizards seem to, as well.
———-
I’m interested in all this because I believe that atmospheric conditions on Earth during times of mass extinction got so bad that only animals that could live without breathing for weeks survived. For example, fish living near the surface of the ocean all karked it. Next major extinction all the marine mammals are sure to go extinct. Some crocodilians can survive for weeks without breathing.
mollwollfumble said:
Note that in many anaerobes, chemicals containing sulphur replace those containing oxygen as a source of energy. For example, sulphate-reducing bacteria obtain energy by oxidizing organic compounds or molecular hydrogen (H2) while reducing sulfate (SO4—) to hydrogen sulfide (H2S). In a sense, these organisms “breathe” sulfate rather than oxygen in a form of anaerobic respiration.In facultative anaerobes, the main source of energy is often fermentation, which doesn’t require oxygen.
In lichens, the algae produce more oxygen than they use and the fungi use up oxygen. It has been suggested that some lichens could thrive in an anaerobic environment, and experiments with lichen in outer space have been conducted. They don’t actually grow very well in outer space, but they do survive.
While on the topic of advanced organisms that can survive in an anoxic environment for a long time, many plant seeds may fit that description.
The European common lizard, Lacerta vivipara, survives being frozen solid, so may be able to live a long time without oxygen. Some other lizards seem to, as well.
———-
I’m interested in all this because I believe that atmospheric conditions on Earth during times of mass extinction got so bad that only animals that could live without breathing for weeks survived. For example, fish living near the surface of the ocean all karked it. Next major extinction all the marine mammals are sure to go extinct. Some crocodilians can survive for weeks without breathing.
When earth was a snowball, how did life survive to comeback?
We know it did but which were the basic components of this survival?
Some crocodilians can survive for weeks without breathing.
which ones? and a ref.