Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Closed artificial ecosystem

In the context of the methane discussion I just edited a new page called Closed artificial ecosystem.

• Options
1.
edited October 2013

Thanks a lot! That looks like an interesting subject.

Some bureaucratic stuff:

The convention for threads on this forum, as well as articles on the wiki, is to start the title with a capital letter, and use singular rather than plural. So, "Closed ecosystem" is better than "Closed ecosystems". But in fact it's even better to make the forum thread have a title that matches the wiki article, so people can easily search for discussions of wiki articles here. So, I'll change the title of this thread to "Closed artificial ecosystem".

I'm mainly mentioning this so new members, who don't know our conventions, will learn them. We spent a lot of time discussing this early on, and people can read it all on How to, but of course most people won't think of doing this unless I tell them...

Comment Source:Thanks a lot! That looks like an interesting subject. Some bureaucratic stuff: The convention for threads on this forum, as well as articles on the wiki, is to start the title with a capital letter, and use singular rather than plural. So, "Closed ecosystem" is better than "Closed ecosystems". But in fact it's even better to make the forum thread have a title that matches the wiki article, so people can easily search for discussions of wiki articles here. So, I'll change the title of this thread to "Closed artificial ecosystem". I'm mainly mentioning this so new members, who don't know our conventions, will learn them. We spent a lot of time discussing this early on, and people can read it all on [[How to]], but of course most people won't think of doing this unless I tell them...
• Options
2.

I’m mainly mentioning this so new members, who don’t know our conventions, will learn them. We spent a lot of time discussing this early on, and people can read it all on How to, but of course most people won’t think of doing this unless I tell them…

Sorry I somehow missed that convention.

So

Page titles should be singular nouns or noun phrases, with only the first letter capitalized (unless there’s a darn good reason).

on naming convention means then

Page titles should be singular nouns or noun phrases with singular nouns, with only the first letter capitalized (unless there’s a darn good reason).

I actually don't remember that there were big discussions about the conventions, but anyway, since some people use a lot of wikis and each has its own conventions it may be helpful to put the how-to page in the top line, where one can find

Home Page | All Pages | Recently Revised | Authors | Feeds | Export |

A "help" or "how-to button" should be easily reachable and readable - at the moment you get to it if you go on the front page then on "help edit this wiki" and then on "how to" and then on "naming conventions" and then you have to read a long text.

I think in general people do read manuals not too much but rather look how other articles look like and then use the same custom look. May be it would be helpful to offer a standard template which could be used for orientation.

By the way I was hesitating to use the words "Closed artificial ecosystem" since wikipedia just uses "Closed ecosystem" and then explains that this usually means that it is an artificial or manmade system. I am not sure wether one should adopt that naming convention, finally I think there might be rather closed ecosystems which are not artificial and actually it might be interesting to investigate these as well. Even if sometimes some ecosystems may turn out to be not so different from the standard.

Comment Source:>I’m mainly mentioning this so new members, who don’t know our conventions, will learn them. We spent a lot of time discussing this early on, and people can read it all on How to, but of course most people won’t think of doing this unless I tell them… Sorry I somehow missed that convention. So >Page titles should be singular nouns or noun phrases, with only the first letter capitalized (unless there’s a darn good reason). on <a href="http://www.azimuthproject.org/azimuth/show/How%20to#naming">naming convention</a> means then >Page titles should be singular nouns or noun phrases with singular nouns, with only the first letter capitalized (unless there’s a darn good reason). I actually don't remember that there were big discussions about the conventions, but anyway, since some people use a lot of wikis and each has its own conventions it may be helpful to put the how-to page in the top line, where one can find Home Page | All Pages | Recently Revised | Authors | Feeds | Export | A "help" or "how-to button" should be easily reachable and readable - at the moment you get to it if you go on the front page then on "help edit this wiki" and then on "how to" and then on "naming conventions" and then you have to read a long text. I think in general people do read manuals not too much but rather look how other articles look like and then use the same custom look. May be it would be helpful to offer a standard template which could be used for orientation. By the way I was hesitating to use the words "Closed artificial ecosystem" since wikipedia just uses "Closed ecosystem" and then explains that this usually means that it is an artificial or manmade system. I am not sure wether one should adopt that naming convention, finally I think there might be <a href="http://www.foxnews.com/scitech/2010/08/13/super-bacteria-thriving-arsenic-laced-volcano/">rather closed ecosystems which are not artificial</a> and actually it might be interesting to investigate these as well. Even if sometimes some ecosystems may turn out to be not so different from the <a href="http://www.zmescience.com/science/chemistry/arsenic-life-gfaj-1-theory-04102012/">standard.</a>
• Options
3.

I'll ask Andrew Stacey if he can add a link to the "How To" page to every page here. That's a good idea, but I think only he can implement it.

Small closed ecosystems are exciting to me because they could be nice test cases for mathematical biology, simpler than the huge ecosystems we usually see in the world. So far people need to do a lot of work to simulate just one bacterium!

Comment Source:I'll ask Andrew Stacey if he can add a link to the "How To" page to every page here. That's a good idea, but I think only he can implement it. Small closed ecosystems are exciting to me because they could be nice test cases for mathematical biology, simpler than the huge ecosystems we usually see in the world. So far people need to do a lot of work to simulate just one bacterium!
• Options
4.

There is a natural ecosystem with just one species called Desulforudis.

Comment Source:There is a natural ecosystem with just one species called [Desulforudis](http://en.wikipedia.org/wiki/Desulforudis).
• Options
5.

@Graham

Yes interesting this sulfate reducing bacterium, of particular interest is that according to wikipedia:

Its complete intolerance of oxygen suggests long-term isolation.

What does this mean? Does it die when exposed to oxygen? I could imagine that there is still a little oxygen in such depths, no? And if so could it adapt to oxygen, like for example if groundwater levels should dwindle into such depths, that it may be exposed to air ?

For that case due to sulfate reduction it would probably first nourish itself from the methane in the air if there is also enough sulfate in the air. A for the bacterium probably desired side-effect is the reduction of oxygene in the air.

Comment Source:@Graham Yes interesting this sulfate reducing bacterium, of particular interest is that according to wikipedia: >Its complete intolerance of oxygen suggests long-term isolation. What does this mean? Does it die when exposed to oxygen? I could imagine that there is still a little oxygen in such depths, no? And if so could it adapt to oxygen, like for example if groundwater levels should dwindle into such depths, that it may be exposed to air ? For that case due to sulfate reduction it would probably first nourish itself from the methane in the air if there is also enough <a href="http://en.wikipedia.org/wiki/Sulfate">sulfate in the air.</a> A for the bacterium probably desired side-effect is the reduction of oxygene in the air.
• Options
6.
edited October 2013

Models of the Late Permian and Early Triassic atmospheres show a significant but protracted decline in atmospheric oxygen levels, with no acceleration near the P–Tr boundary. Minimum atmospheric oxygen levels in the Early Triassic are never less than present day levels—the decline in oxygen levels does not match the temporal pattern of the extinction.[59]

The paper (p. 306) writes:

A drop in global atmospheric PO2 sufficient to drive major marine extinctions (ca. 85–90% decrease) would kill land animals indiscriminately, which didn't happen. Huey and Ward [111], however, argued that declining PO2 throughout the later Permian Period imposed hypoxic stress on tetrapod communities adapted to high oxygen tensions. Unfortunately, this intriguing and physiologically explicit hypothesis cannot be extended to include boundary events per se, as model estimates of PO2 show little change at this critical juncture[40,41].We know of no mechanism by which the direct effects of anoxia documented in shallow seaways could have propagated onto land.

I am not sure if I understand what they mean with those boundary events, however it seems they rely their reasoning to quite some extend on models. Does someone know wether there are also measurements related to the question of declining O2 levels and hypoxia?

Comment Source:<a href="http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event#Possible_explanations_of_these_patterns">Wikipedia writes on the PT-R event and atmospheric anoxia (shortage of oxygen)</a>: > Models of the Late Permian and Early Triassic atmospheres show a significant but protracted decline in atmospheric oxygen levels, with no acceleration near the P–Tr boundary. Minimum atmospheric oxygen levels in the Early Triassic are never less than present day levels—the decline in oxygen levels does not match the temporal pattern of the extinction.[59] The <a href="http://pangea.stanford.edu/~jlpayne/Knoll%20et%20al%202007%20EPSL%20Permian%20Triassic%20paleophysiology.pdf">paper (p. 306)</a> writes: >A drop in global atmospheric PO2 sufficient to drive major marine extinctions (ca. 85–90% decrease) would kill land animals indiscriminately, which didn't happen. Huey and Ward [111], however, argued that declining PO2 throughout the later Permian Period imposed hypoxic stress on tetrapod communities adapted to high oxygen tensions. Unfortunately, this intriguing and physiologically explicit hypothesis cannot be extended to include boundary events per se, as model estimates of PO2 show little change at this critical juncture[40,41].We know of no mechanism by which the direct effects of anoxia documented in shallow seaways could have propagated onto land. I am not sure if I understand what they mean with those boundary events, however it seems they rely their reasoning to quite some extend on models. Does someone know wether there are also measurements related to the question of declining O2 levels and hypoxia?
• Options
7.
Comment Source:Here a recent investigation about the PT-R event: <a href="http://phys.org/news/2014-03-methane-producing-microbes-responsible-largest-mass.html">Methane-producing microbes may be responsible for the largest mass extinction in Earth's history</a>