Talk:Anoxic event

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It is pointless to make a new article on an existing subject. I'll have to review to remove redundant material and/or merge. This article is destined to become (at most) a redirect page unless you can justify how it differs from Oxygen depletion and Dead zone (ecology). - Marshman 04:26, 22 Mar 2005 (UTC)

OK. I see you are attempting to describe events in the geologic past. Maybe with some better text, this artricle would be justified as separate from the others I mention - Marshman 18:33, 22 Mar 2005 (UTC)
A better title: Oceanic anoxic event. Recently in the scientific news, the 500,000-year-long "OAE2" that divides Middle Cretaceous from Late Cretaceous, at 93.5 mya: [1] --Wetman (talk) 06:30, 19 July 2008 (UTC)

Author says interesting and important things but starts with a serious gross error. He refers to a tipping point of about 1000 ppm for historic mass extinctions. He should at least study the important introductory review Under A Green Sky, by Peter Ward, about $7 from Amazon. Most of paleozoic and mesozoic had ppm well above 1000 ppm without such a breakout and mass extinction. Ward argues hard for CO2 as a driver of breakout and expresses a gut feeling that about that would get us there again today, but his data and discussion make it clear that hitting 1000 ppm was NOT what we saw in the past. This being so, I am not sure what parts to believe and what not to believe here. The original paper by Lee Kung is more definitive in any case. (talk) 15:09, 14 January 2012 (UTC) pjwerbos, not representing anyone else 15:09, 14 January 2012 (UTC)


This section is needlessly wordy and very hard to follow. This encyclopedia is written for laymen, not for scientists. I would rewrite this section myself, except I couldn't understand it. For a good example of a well-written description of an Anoxic event, see the October 2006 Scientific American. I'm not suggesting that anybody copy from that article, but its terminology is much easier to understand. -- MiguelMunoz 07:48, 26 September 2006 (UTC)

Agreed. As an example, second paragraph:"At the same time it caused deep water circulation between piles and equator[3] to stop in a cataclysmic fashion." Great. A link for the word "equator", but what the heck are "piles"? And of course, those of us who don't have the background to understand this certainly would not have the background needed to rewrite it. DF —Preceding unsigned comment added by (talk) 16:46, 15 January 2009 (UTC)

Should not the link berween increased nutrients and anoxia be explained? Should not the link between anoxia and hydrogen disulfide be explained? I wonder why these lapses are so frequent in geology texts for the "general" public.. — Preceding unsigned comment added by (talk) 11:04, 11 January 2013 (UTC)

Chemical symbols[edit]

Removed most of the chemical symbols/equations for increased readability/understandability. So as opposed to referring just to H2S or O2 it now refers to the substance itself. -- Chris Lewins 18:47, 5 November 2006 (UTC)

Rewrite the article[edit]

I'm a geologist and my work focuses on OAEs. This article is very poor quality as is and contains many inaccuracies, biased opinions and a somewhat difficult language as has been mentioned. I'm thinking of completely rewriting it in a more logical fashion, with simpler language and with the latest ideas as published in the geologic literature. What do you think? Can I rewrite the whole thing and delete the extant article? Jonjonnl (talk) 14:41, 27 January 2009 (UTC)

I haven't spent much time editing Wikipedia so I might not the best person to answer this, but I say go for it. I think the article is quite problematic. However, maybe you can pick your favorite couple of paragraphs from the current article and stick them into your new version? At least you could include a few sentences from the current version. ArgentTurquoise (talk) 05:53, 20 February 2009 (UTC)
Thanks for your input. I will do it. I'd also like to propose to change the name of the article to "Oceanic Anoxic Events" since that is the name proposed by the late Schlanger and his co-worker Jenkyns back in 1976; as well as being the name used in the geological literature. I will keep anything that makes sense in the re-written article. Jonjonnl (talk) —Preceding undated comment added 10:18, 28 February 2009 (UTC).
The revision history shows no edits yet by your username. If you still want to rewrite the article, I suggest doing it a little at a time. If you delete the existing article and start over, that is more likely to trigger an edit war, or at least lead to inefficient subsequent editing, than if you pick one change, discuss it here first before making, and see how it goes over. I've seen other articles where well-meaning editors came in did massive rewrites, and then it was tedious for all the interested editors to debate all the changes one at a time after the fact. It's much better to pick the one change you think is most important, and see how other editors receive it, before doing the rest. Think of getting to know someone new - you don't reveal your entire life history, belief system, goals, etc., on the first date (I hope). First it's advisable to test the waters a little and see whether there is any chemistry for what you have in mind. Wikipedia's design lends itself very well to incremental editing, and it's best to take advantage of that. For example, if you discover you are running into entrenched opposition, your approach needs to be different than if everybody agrees with what you are doing, and it's better to detect the opposition with a small change, than to whip it into a frenzy with dozens of changes at once. This is not to question your competency, merely an observation on how Wikipedia tends to work. Even if everything you do is right and proper, you still have to convince everyone else of that. --Teratornis (talk) 20:23, 29 June 2009 (UTC)


This sentence from the article uses the word "unprecedented" in a way that makes little sense:

  • "Practically overnight the increase of temperature might have been reached and triggered a huge burn-off of planetary forests. This would have released unprecedented amounts of carbon-dioxide into the atmosphere."

Since more than one ocean anoxic event has occurred, only the first one could have been "unprecedented". All the following anoxic events would have followed the precedent of the first one. Perhaps the article really means to say "unprecedented within human history". --Teratornis (talk) 20:13, 29 June 2009 (UTC)

"Fires in the middle of rainstorms?"[edit]

The following two phrases seem to be in direct contradiction:

"Strata analysis suggests that in the era when Earth had a predominantly overheated climate,[1] with heavy daily rains and violent storms,[2] the global climate of the time resulted in far heavier erosion which in turn fed more nutrients into the world's waters."

"At even a few degrees warmer, rain forests are extremely vulnerable to fire hazards. These forests have little natural resistance to fires,[4] and some conjecture a critical tipping point. Practically overnight the increase of temperature might have been reached and triggered a huge burn-off[4] of planetary forests." — Preceding unsigned comment added by (talk) 17:41, 18 July 2011 (UTC)

"Article feedback"[edit]

This article needs some serious work. Parts are misleading and some downright incorrect. Currently attending a lecture course on this material.Stongtea (talk) 09:41, 5 November 2012 (UTC)

I completely agree. In particular, the entire section Anoxic_event#Occurrence is poorly and unreliably sourced with undue weight given to marginal theories that are contrary to an abundance of research on the topic. --mikeu talk 17:46, 26 November 2012 (UTC)
Yes, absolutely. The reference 'Meyer' yields only an abstract, but the abstract shows a contrast with our page. They said: "In rare, extreme cases, euxinia led to biotic crises, a hypothesis best supported by evidence from the end-Permian mass extinction". That is not what our article says. Our article suggests that biotic crises are a regular consequence of OAE. Incidentally, the main contributors are unregistered users, and we know how reliable they are. Macdonald-ross (talk) 19:26, 9 February 2013 (UTC)

Toxicity of hydrogen sulfide(s)[edit]

The article mentions "mildly poisonous hydrogen sulfides". Hydrogen sulfide (H2S) is not mildly poisonous, it has a toxicity comparable to that of hydrogen cyanide (see WP article on H2S). Are other compounds referred to here and if so, which? As it stands, the sentence gives the impression that H2S is much less toxic than is the case. Please rectify this. Wdanbae (talk) 22:05, 5 February 2013 (UTC)


I recently made the suggestion to rename Canfield ocean to Euxinia Currently Euxenia link to this page. Euxenia should have it's own page since this is the term for anoxia in presence of hydrogen sulfide genesis. Prokaryotes (talk) 20:41, 21 September 2013 (UTC)

Added Euxinia info under background section and info into lede. Prokaryotes (talk) 21:41, 11 April 2014 (UTC)

I am taking a graduate level class on biogeochemistry, and my group is planning to write a new page for Euxinia. I'll post a link as soon as we finish it. Hgossy (talk) 23:26, 30 January 2017 (UTC)

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