Talk:Primary production

Production vs. Productivity

Production (or rate of production) is a quantitative term e.g. "...the annual production was..."

However,

Productivity (i.e. fertility) is a qualitative term e.g. "a period of high productivity"

I disagree. At least in oceanography, "Productivity" is used as quantitative term, and it is synonymous with "rate of production". From Lalli and Parsons (1997) "Biological Oceanography An Introduction", the glossary defines the words production and productivity like this:

Primary Production The amount of organic material synthesized from inorganic substances per unit volume of water or unit area.

Productivity The rate at which a given quantity of organic material is produced by organisms.

This definition of productivity (a quantitative rate of production) is also consistent with the NASA animation attached to this article. On the other hand, this particular textbook definition of Primary Production does not contain reference to time, so I believe that it directly contradicts the statements in the "Gross primary production and net primary production" section that these quantities are rates (units of mass per unit area per unit time interval). In other words, the difference between Production and Productivity is analogous to the difference between displacement and speed (amount vs. rate). I suspect that usage may be inconsistent within the literature, but I think that the definition (and units) of production should either be changed to match the textbook definition or presented as inconsistent (if conflicting textbook definitions or scientific usages can be found). Rudkins 09:32, 29 March 2017 (UTC) — Preceding unsigned comment added by Rudkins (talk • contribs)

Photosynthesis vs. Chemosynthesis

I believe that primary production was restricted only to photosynthesis and doesn't include chemosynthesis?

I've a feeling that's just a practical consideration. Chemosynthesis isn't quantitatively significant (as far as we know), and in the ocean occurs far away from the surface (so doesn't play a role in the biological pump). But it does still represent the transfer of external (chemical) energy to chemical energy (in organisms), so legitimately is primary production. Cheers, --Plumbago 17:29, 14 March 2006 (UTC)

Quality standards

Over the past week, I've tried to upgrade and extend this article to more comprehensively cover the topic. It's still missing some information (e.g. terrestrial measurement techniques), but otherwise is a marked improvement over what we had before (he says, arrogantly). Anyway, unless anyone objects, I'll remove the "Quality" flag currently on the article. Cheers, --Plumbago 17:52, 16 March 2006 (UTC)

Wiki Chapter

This is a tough topic... hitting this page a couple weeks ago got me started on Wiki's. We practically need a chapter to cover it, not just a page... especially with both terrestrial and aquatic production together. I'm sure someone will come along and add some chemosynthesis information soon. If this is an overview, it should be included... Take care Kefisher 22:30, 25 April 2006 (UTC)

Well, I don't know that we need a chapter on it. Like other articles in the WP, this is essentially a summary of the topic. Most articles only skim the surface of their topics. If you want, one obvious way forward is to dismember the article into oceanic, terrestrial and chemosynthetic articles, and leave the overview material here. But I don't think that's entirely necessary : much of what could be added (e.g. photosynthesis itselF) is covered in other articles already. Still, separating out production in different biomes might be one way to go.

I should add that I'm grateful to the anon who added a whole lot more to the oceanic production end of things. I think your text could be tightened a bit, but it's a sterling addition. Cheers, --Plumbago 08:17, 26 April 2006 (UTC)

That anon was me... before I figured out how to register... but someone else hit it after I did and tightened up some of it. I wrote pretty fast... I'm supposed to be working, but this is abit addictive... Take care- Kefisher Kefisher 20:31, 3 May 2006 (UTC)

I think it might have been me "tightening up". I'm sort-of one for paring things down to essential information (so as to avoid article bloat), but I probably remove too much at times, so please revert any changes I make that you disagree with. Cheers, --Plumbago 08:09, 4 May 2006 (UTC)

Merge (May 2006)

I reckon primary productivity should be redirected here, and what information there is on it moved here - it's basically a stub. I'll do this later this week unless there are any objections. Cheers, --Plumbago 08:26, 10 May 2006 (UTC)

Somebody please check this statement...

"Most frequently, a biome's peak standing biomass is assumed to measure net primary production."

I'm pretty sure this is blatantly incorrect, but don't have time to check on it. If you do, please do so. Standing biomass and primary production can be entirely unrelated, the best example being estuaries, where biomass is low but productivity extremely high. This statement came from the NPP article, which also has other errors and problems. Jeeb 02:40, 11 August 2006 (UTC)

My bad. I lifted it from the (somewhat ropey, to my eye) page on net primary productivity when I was expanding the terrestrial production section (which previously simply pointed the reader in the direction of the article). I'm not au fait with methods on terrestrial systems at all, so please edit away. As you can probably tell from my edits (and the length of the section I've worked and reworked), it's oceanic production that I'm more familiar with! Cheers, --Plumbago 12:20, 11 August 2006 (UTC)

...and you've made a real valuable contribution there, I might add, since most people are more familiar with terrestrial systems than oceanic (I'm guessing). And I realize you were just trying to beef up the pointer to the NPP article that I inserted. If I get time I'll work on it, but I'm not really a methods person either, so it involves some reading.

I also think a discussion of energy use efficiency (i.e. % of available energy captured at each step of the process) would be a valuable addition to the article. Jeeb 15:58, 11 August 2006 (UTC)

Just an aside, might it be an idea to combine the net and gross primary production articles into a single article? The distinction between them is fairly straightforward (... to explain, but not to measure), and I'd feel a bit better directing readers to a single comprehensive article on terrestrial production rather than two smaller ones. Just a thought. --Plumbago 09:19, 12 August 2006 (UTC)

Another idea might be to just incorporate the concepts of GPP and NPP into this article (which they already are to a limited extent), and do away with both. Actually I see three possible dichotomies in which 2 articles result: (1) PP concepts vs PP measurement/methods, (2) terrestrial PP vs aquatic PP, or (3) GPP vs NPP. I think I lean toward the first... Jeeb 15:29, 12 August 2006 (UTC)

I think your suggestion of (1) is a good one. Number (2) is reasonable, but number (3) would just be confusing and an unnecessary complication. My only concern with (1) is that the article on measurement might be a bit short. Although I rewrote a fair chunk of the measurement section, I'm skating close to the limits of my expertise (I'm a modeller, not an observationalist), so wouldn't be able to add much more to flesh it out. Anyway, in the first instance, maybe fusing GPP and NPP here would be useful. Probably not make it terrestrial specific, as the same applies in aquatic systems (although the actual mechanisms that separate GPP and NPP can be somewhat different, at least when it comes to measurement). If the result gets too long, then we can consider splitting it. Cheers, --Plumbago 08:15, 15 August 2006 (UTC)

The most important overall point, IMO, is that the topic be presented clearly and be well-organized. I agree that fusing GPP and NPP into this article (is that what you meant?) is useful. In fact, I don't see why we necesarily need 2 articles at all at this point, my comments above notwithstanding. I'm limited on the time I can give to it in the near future, so have at it if you can...Jeeb 19:29, 17 August 2006 (UTC)

Merge (March 2007)

It seems that both the gross primary production and net primary production articles should be merged with this one. GPP is currently flagged for possible merging, but not NPP. It seems especially odd that the NPP article is strictly terrestrial, since the concept is not. Also, there is data on the trophic level page about the productivity of different ecosystems that would be more appropriate here. Cheers, Justinleif 03:22, 13 March 2007 (UTC)

I just noticed that this conversation was already occurring, above, under a different heading. I support the merge proposal, and think that they should be made into a single article, or else the methods for measuring PP could be put in a separate more technical article (Jeeb's suggestion 1). I think the other divisions would be artificial, confusing, and might prevent people from encountering all the information. This conversation seems to have gone cold. Is there still any interest in the merging?Justinleif 02:15, 14 March 2007 (UTC)

Okay, I went ahead and merged NPP and GPP with this article. I added a brief section explaining the difference, and then pasted most of the material from the old NPP site into the terrestrial measurements section. Cheers Justinleif 02:35, 30 April 2007 (UTC)

Merge attempt

It looks like editor Rickproser recently tried to merge the content of this article into productivity, but that editor Raz1el reverted this edit. First of all, such a major change to the article should be discussed here before any such action is undertaken. This didn't happen. Secondly, the merge is extremely unhelpful since primary production is fundamentally different from other "production" in ecology and merits a full article in which it is delineated (my POV, of course). Primary production is essentially the conversion of inorganic materials such as CO₂ and H₂O into biologically "valuable" organic molecules which then fuel the rest of the ecosystem. As such, it involves both completely different biochemical pathways and organisms. After this initial production, the ecosystem largely acts to degrade the organic material back to base inorganic molecules for the cycle to begin again. While I can certainly see a need for the productivity article, this one should be kept free of it. In part because it's simply too large a subject to be well-treated by a combined uber-article. Cheers, --PLUMBAGO 08:45, 27 November 2009 (UTC)

I know i did not discuss the merge but usually it takes time for a consensus so I took a long shot. My intentions were pure: to achieve compactness and improve the overall coherence of the article for the average reader. Note that most ecology textbooks contain a chapter titled "productivity" or "production". Cheers. Rickproser (talk) 15:30, 27 November 2009 (UTC)

Consensus is less likely to take long here given that this isn't (really) a contentious subject.

Anyway, I understand the rationale for trying to shoehorn all ecological "production" into a single article, but I don't think that it works. Mostly because this is already a reasonably long article about the most significant step in biological production, and one that includes information about gross/net production and how primary production is actually measured. Secondary production (which isn't really "production" at all, merely inefficient transfer to another trophic level) has quite different issues related to it, and jamming the two together would require a serious rewrite to rebalance the resulting article.

My suggestion is that perhaps you could write a general article, say Production (ecology) or Productivity (ecology), that introduces primary production, secondary production, etc., but that leaves the specifics (e.g. how different forms of it are measured in different ecosystems) to more specialised articles like this one. One article that covers the various forms of production, which organisms are doing them and how they can be measured is a big ask. Much better, I reckon, to leave the details to articles like this one but also have one that outlines the general picture. Cheers, --PLUMBAGO 17:31, 27 November 2009 (UTC)

P.S. Further to the above, I've begun a stub article on productivity. Not quite as easy as I'd imagined, but I still think it's the better way. Best regards, --PLUMBAGO 17:57, 27 November 2009 (UTC)

"All life"

In the heading there is a sentence: "All life on earth is directly or indirectly reliant on primary production."

While it can be quantitatively considered true, it's not on logical terms. I recall two examples right now:

- Life near fumarolas rely on the energy and matter coming from the volcanic source and is independent in all aspects from primary production.

- Some microbes were discovered in rocks deeper than 2000m that live and rely on local fission and have no connection at all with the surface.

I'd suggest changing the quoted sentence and add the word 'almost' to make it accurate.

(bgs@bgs.hu) 195.70.62.77 (talk) 13:07, 27 May 2010 (UTC)

Yes and no. If the article were to say all life was reliant on photosynthetic primary production then your point would be correct. But the article leaves it a little more open by distinguishing photosynthesis and chemosynthesis, and then summing these together as "primary production". So, as well as adding your qualification, it might be an idea to mention light in there somewhere, since almost all of what's labelled primary production is light-based (at least so far as we know). --PLUMBAGO 16:42, 27 May 2010 (UTC)

I get your point and it definitely clears up my first example. I wouldn't bet on the second one though. Needs some research (at least for me). 2000m down in the rock you don't have connection with atmospheric carbon dioxide. (bgs@bgs.hu) 195.70.62.77 (talk) 19:40, 27 May 2010 (UTC)

I don't want to flood this discussion, but I found what I needed. The link just below is an article about the discovery. It clearly states that the ecosystem found 2800m deep has been totally separated from the surface for millions of years. So it's a chemosynthesis independent from atmospheric and aquatic carbon dioxide. Link: http://www.planetary.org/news/2006/1027_Bacteria_Found_Thriving_Deep.html (bgs@bgs.hu) 195.70.62.77 (talk) 20:11, 27 May 2010 (UTC)

I think something is wrong here.. please check it

"The other two vessels are incubated, one each in under light and darkened. After a fixed period of time, the experiment ends, and the oxygen concentration in both vessels is measured. As photosynthesis has not taken place in the dark vessel, it provides a measure of ecosystem respiration. The light vessel permits both photosynthesis and respiration, so provides a measure of net photosynthesis (i.e. oxygen production via photosynthesis subtract oxygen consumption by respiration). 'Gross primary production is then obtained by subtracting oxygen consumption in the dark vessel from net oxygen production in the light vessel.'

NPP = BPP - Respiration ...and respiration occur in the dark vessel, so I think you add the o2 consumption in the dark vessel to the GPP in the light vessel so that you obtain the GPP + the standing crop in the first vessel... please correct me if i´m wrong....

Merger proposal

I propose that Primary producers be merged into Primary production. The page on primary producers is basically a stub. Dberard (talk) 08:36, 26 January 2013 (UTC)

• Oppose – What is produced is not the same as what does the producing. The article is, in any case, one of a natural group of articles. Trophic levels in food chain are to do with autotrophs, heterotrophs and detritivores (by orientation), and producers, consumers and decomposers (by function). The article needs writing properly, not merging somewhere. --Epipelagic (talk) 10:35, 26 January 2013 (UTC)

Units of primary production

It would be nice if the units of primary production Gt C/y is explained, i.e. Gigatons of carbon per year. --kupirijo (talk) 20:56, 15 September 2018 (UTC)

Indeed. Although we should actually be using the preferred SI units of Pg C / y, i.e. petagrams of carbon per year. I'll see what I can do. --PLUMBAGO 08:00, 24 September 2018 (UTC)

Done. Does this do it? --PLUMBAGO 09:15, 25 September 2018 (UTC)

Possibly outdated numbers in "Primary production and plant biomass for the Earth"

The numbers in section "Primary production and plant biomass for the Earth" seem severely outdated. They refrence a reference which have the numbers from around 1975. Total annual terrestrial NPP is as far as I can tell currently estimated to about half what is written in that section. See total estimates here: http://files.ntsg.umt.edu/data/NTSG_Products/MOD17/GeoTIFF/MOD17A3/GeoTIFF_30arcsec/global_total_NPP.txt, from this source http://www.ntsg.umt.edu/project/modis/mod17.php . Or for another total comparing NPP and GPP on land (https://www.cell.com/current-biology/pdf/S0960-9822(07)00893-7.pdf). The numbers stated in the section are about equal to GPP og 2*NPP, so they are either outdated or misquoted as NPP instead of GPP? This would also make the section more coherent with the section above it called "Global" which seems to have more recent values. Rasmus.87 (talk) 10:21, 17 October 2018 (UTC)

NPP: tons of WHAT?

in Primary production and plant biomass for the Earth unit for "World NPP" is given as Gt/yr ... but Gt OF WHAT? My first guess would have been C, but with *N*PP given as 155+55 (land+sea), and *G*PP given as 56+49 *PgC/yr* a few para.s above, maybe it's Gt/yr of plant mass or CH2O ? Wda (talk) 10:44, 3 August 2019 (UTC)

It's a good question. Units should always identify what specific quantity is meant. Typically, for productivity, the unit is simply carbon, so 1 Gt / y is 1e9 * 1e6 g C / y = 1e15 g C / y = 8.3e13 mol C / y. But it should be written as "Gt C / y" for clarity (as elsewhere in the article), with the use of Pg C / y even clearer, since this uses the more SI-compliant of Pg instead of Gt (the latter may have some ambiguity because there are several definitions of "ton"). Looking at the offending section, while it gives the same marine productivity as other sources (as used in earlier sections), it's about double that for the land, so it's difficult for units alone to be the issue here (unless the table somehow differs internally in its use of them; which would be stupid). Speaking for the oceans, the date of the source (1996) is prior to good satellite coverage of ocean colour (late-1997 onwards), so I'm inclined to chalk it up as out of date. Further, looking through the scientific literature, I can only find work on productivity from "R.H. Whittaker" from the 1970s, when methodologies and coverage were much poorer. So I'm going to just delete the table and section as "outdated" — it's not helpful to have conflicting information, especially not when the units are unclear as well, and where the source (a commercially-published book; last edition 2001 as far as I can see) is not readily available. Thanks for picking this up. —PLUMBAGO 09:13, 9 August 2019 (UTC)