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An Animal That Lives Without Oxygen
Julie188 writes "Scientists have found the first multicellular animals that apparently live entirely without oxygen. The creatures reside deep in one of the harshest environments on earth: the Mediterranean Ocean's L'Atalante basin, which contains salt brine so dense that it doesn't mix with the oxygen-containing waters above."
There is no Mediterranean Ocean. There is however a Mediterranean Sea.
There are other articles with more coverage -- Live Science, BMC Biology (PDF of 20-page article with pictures available), New Scientist, Nature, and others. The provisional PDF available at BMC Biology is the full article as it was accepted, and details the experimental procedure that confirmed that these were completely anaerobic organisms.
The summary discusses an article which is talking about an abstract of the provisional paper available at http://www.biomedcentral.com/content/pdf/1741-7007-8-30.pdf .
Even David Attenborough who himself narrated the Blue Planet were animals were shown that lived independent of the sun, narrated happily on Planet Earth that all lives needs the sun... It is just that for us it is so true that we forget that it isn't.
Fact: Hetero males have more anal sex then homosexual men. See how that fits in your little hetero world. Thinking the universe revolves around you is more common then you think.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
Actually, plant life needs carbon dioxide, not oxygen. when the planet first formed, it didn't have an oxygen-rich atmosphere. The oxygen in our atmosphere had to be generated by plants. Life existed for hundreds of millions of years before any life that required oxygen evolved.
I've abandoned my search for truth; now I'm just looking for some useful delusions.
This probably does not answer your questions, but it covers a bit more details than the original post. Also, if you click on the title, you will link to the source article.
http://thedragonstales.blogspot.com/2010/04/anaerobic-metazoans.html
I like my dinosaurs feathery, and my pterosaurs hairy (or is it pycnofibery?)
The thing is that multicellular organisms require a lot more energy than unicellular organisms and for that there's the citric acid cycle. However there's no citric acid cycle without oxygen. This is the reason we haven't found any multicellular anoxiphiles (?) so far. I think. BTW there's a horrible mistake on the second sentence of the original article and they say it went thru peer-review. WTF! Hint: google "anoxia tolerance"
There is no such thing as "Mediterranean Ocean"
"Although a few metazoans can survive temporarily in the absence of oxygen, it is believed that multi-cellular organisms cannot spend their entire life cycle without free oxygen."
I did Google for a bit, and couldn't find anything to disagree with this, except the word 'temporarily'. While I'm not particularly familiar with anoxia tolerance, my quick searching suggests that certain species of turtle can have up to 3months without oxygen in cold water. There may be others out there, but this is the largest number I found. This is clearly a temporary phase in the life cycle of the organism. Are you trying to argue that they are implying that this is more than merely 'temporary' but a major chunk of the life cycle? Personally, were I reviewing the paper, I'd not have had a problem with allowing that phrase to be used (with the caveat that there is no information that I am not privy to currently, and there is no controversy in this area currently).
Ultimately, these animals are still dependent on a source of energy such as a sun. These animals are not capable of capturing such energy themselves, but rely on photosynthetic organisms such as plants or algae at the bottom of the food chain. As another poster pointed out, carbon dioxide is necessary for this photosynthesis, not oxygen. This is converted into sugar, which animals subsequently consume. Hydrogenosomes function similarly to mitochondria in converting sugar into ATP (more accessible energy), but differ in that they produce (surprise, surprise) hydrogen as a byproduct.
These creatures apparently are essentially immobile, attaching firmly to marine sediments. This applies to their aerobic relatives as well, so it seems that lack of motility likely has little to do with their anerobic respiration. A more active organism would probably struggle to survive using hydrogenosomes, however since the hydrogenosome reaction only makes ATP for energy via substrate-level phosphorylation. In aerobic respiration, most of the ATP ultimately produced is from oxidative phosphorylation, where a series of reduction-oxidation reactions are used to create a proton gradient that powers an ATP synthase to make ATP. For all known aerobic eukaryotes, this process uses diatomic oxygen as the final electron acceptor.
There are (single-celled) prokaryotes that use alternatives- nitrates, sulfates, iron ions, etc., but it would appear that this organism has not adopted anything of the sort. That would have required many fundamental changes in its biochemistry, whereas a hydrogenosome seems to be an adaptation from a mitochondrion (and specifically, an adaptation largely by subtraction, where most of the sophisticated electron carriers of a mitochondrion are absent)
The hydrogenosome basically gives this organism a pathway to convert one molecule of pyruvate to acetate and produce 1 molecule of ATP. Combined with the net of 2 ATP from susbtrate-level phosphorylation in glycolysis, that would suggest the creature can make 3 ATP per molecule of glucose. Depending on specifics, aerobic eukaryotes can produce 36-38 ATP per molecule of glucose. So an animal relying on hydrogenosomes instead of mitochondria could very roughly be expected to subsist on about 1/12 the energy for the same amount of food.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
Actually, plant life needs oxygen. Plants respire just like most other multicellular organisms. They just also happen to produce oxygen through photosynthesis as a byproduct of their food production.
There is a link to the PDF of the whole article if you click on the word "published" in the mini-article.