Talk:Primary production

message: 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)
thread_title:  Production vs. Productivity 

message: 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)
thread_title: Photosynthesis vs. Chemosynthesis

message: 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)
thread_title:  Quality standards 

message: 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)
thread_title:  Merge (May 2006) 

message: 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)
replies: text: 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)
replies: text: 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)
thread_title:  Merge (March 2007) 

message: 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)
replies: text: 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)
replies: text: 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)

text: 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)
thread_title:  "All life" 

message: 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)
thread_title:  Merger proposal 

message: 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)
replies: text: 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)

text: Done. Does this do it? --PLUMBAGO 09:15, 25 September 2018 (UTC)
thread_title:  Units of primary production 

message: 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)
thread_title:  Possibly outdated numbers in "Primary production and plant biomass for the Earth" 

message: 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)
replies: text: 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)
thread_title:  NPP: tons of WHAT? 

message: Male voice 223.196.194.151 (talk) 02:08, 19 October 2022 (UTC)
thread_title:  Primary production