Talk:Seawater

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The most interesting aspect of this approach is how the sewage is treated. Saline water cannot be treated (in a waste water treatment plant) by the usual methods. Then HOW is saline water treated? This cracked me up, it's supposed to be really interesting but whoever wrote it didn't even explain WHY its interesting! Justinhoude 19:38, 29 November 2005 (UTC)

wow, just what I was going to say. this section needs expansion.Pedant 03:12, 6 April 2006 (UTC)

how can to prepare pure water from sea water

maybe a discussion of reverse osmosis, electrodialysis, and other seawater purification methods?Pedant 03:12, 6 April 2006 (UTC)

Sea water is not uniformly saline throughout the world. The planet's freshest sea water is in the Gulf of Finland in the Baltic Sea. The most saline sea is the Red Sea, where heat increases the rate of surface evaporation and there is little fresh inflow from rivers.

This interesting statement is dying for a statistic but I don't know the source of this statement to investigate further. Google's 3rd hit on 'ocean salinity' is a NASA website at [1] which has a world map showing the annual mean ocean surface salinity, with some illegible numbers sprinkled around it, and stating the saltiest seawater is in the Sargasso Sea, Persian Gulf, Red Sea, and Mediterranean Sea, and that the lowest salinity seawater is in the Baltic Sea and Gulf of Bothnia. All interesting, but not as specific as the above paragraph, and the statistical ranges are not legible to me. Anyone else? Tempshill 23:16, 9 Mar 2004 (UTC)

http://www.usask.ca/geology/classes/geol206/geol206rr2.html has some info on mineral content but I'm no chemist.Pedant 03:12, 6 April 2006 (UTC)

and http://www.seafriends.org.nz/oceano/seawater.htm Pedant 03:12, 6 April 2006 (UTC)

I've added the molar solution strength of sea-water, assuming that the main solute is NaCl. I'm think the wording could be improved, however I feel that it was more important to add this. CS Miller 15:25, 8 October 2005 (UTC)

Ocean salinity has been stable for millions of years, ...

This beginning sentence is quite ambiguous and indeed wrong. For example, when rain falls on the ocean, the salinity decreases, evaporation causes salinity to increase, spring runoff in rivers also causes local salinity decreases. What is the author trying to say here? My two guesses are either that:

1. Total salinity has remainned relatively constant (i.e. the ocean as a whole is not becoming either more or less salty) for millions of years.

2. In the ocean, the proportions of ions contributing to salinity have remained relatively constant for millions of years.

Mustard 18:07, 9 December 2005 (UTC)

1 Some editing
2 minerals
3 Mining seawater
4 Seawater spelling
5 SI symbols
6 Temperature
7 Drinking seawater
8 Unification of Charts
9 Salinity
10 Electrostriction?

[edit] Some editing

Hello, this is my first try on editing a wiki page. On this discussion page I want to give a reason for every change I am proposing:

The molarity of sea water, if we assume it is 3.5 g (NaCl)/L, is 0.06 M NaCl, not 0.6.
It is not the osmolarity that makes it a bad idea to drink sea water. Otherwise what would you think of swallowing honey or a sweet limonade? This point is also discussed in the section "Cultural Aspects", which
should be renamed "Potability"
Because the introductory first section already deals with salinity the section "Ocean salinity" may be renamed to "Geochemical explanations"
The explanation by "chemical buffering" (line 3) of the pH is of little value if the nature of the buffer system is not explained. The hint may be omitted. A new section on pH buffering int he oceans would be fine.
The term "fresh" (2nd paragraph) needs an explanation.

Lumbricus 06:56, 27 December 2005 (UTC)

[edit] minerals

You should have a table of minerals in salt water

[edit] Mining seawater

I have read in a chemistry textbook about the concept of mining materials from seawater. The salt in seawater is mostly sodium chloride, but other materials are also present, including magnesium, sulfur, carbon, copper, uranium, gold, and even radium. However, most of these are very dilute in seawater. Currently, only sodium, chlorine, magnesium, and possibly bromine are made from seawater industrially. However, there are ideas about using microbes to extract uranium, gold, and othere materials form seawater. As supplies of some of these minerals on land decrease and lower concentrations have to be used, ocean mining could become significant for more materials. Should this be mentioned in the article? Polonium 20:15, 3 May 2006 (UTC)

Probably not until it actually happens. Mining the sea has been proposed for years (centuries?), so until it happens, best wait. However, if you can track down any sources (preferably scientific papers) dealing with these microbes and their use as oceanic miners, then I reckon it's probably worth putting something in. I'd just avoid going over the top because it's not being done on an industrial scale yet. Cheers, --Plumbago 08:14, 4 May 2006 (UTC)

[edit] Seawater spelling

Is seawater spelt seawater, sea water or sea-water? I've noticed all three spellings throughout wikipedia. As you can see I prefer the one word spelling, though I'm no grammar expert. (Piyrwq 21:52, 15 May 2006 (UTC))

I'm with you. Seawater is best to my mind. However, the OED disagrees with us, and favours sea-water. But it's not terribly consistent across words prefixed by sea, so I don't think that should necessarily stop us. My favourite arbiter in these matters, Google, "favours" seawater over both sea-water and sea water. Anyway, if this were a "redirect" vote, I'd be saying yes. Do you need a hand making the changes? Cheers, --Plumbago 08:01, 16 May 2006 (UTC)

I'll do it in a couple days providing no one objects; I think we have websters on our side [2]. Anything other than one word looks off to me. Piyrwq 14:48, 16 May 2006 (UTC)

Whew. I've just spent half an hour fixing up "sea water" / "sea-water" $\rightarrow$ "seawater" links. There are a lot of them out there. Actually, it's quite an interesting way to see hitherto untravelled parts of WP. Anyway, thanks for fixing the pages up. Cheers, --Plumbago 08:53, 6 June 2006 (UTC)

[edit] SI symbols

In the table entitled Total Molal Composition of Seawater the units are written incorrectly. ISO 31 and ISO 1000 specify that you can either use the names or the symbols of SI units but you must not mix them in an expression. You have moles/kg, which not allowed. The second error is that you have put a subscript on the kg, namely "sol". Again, ISO 31 and ISO 1000 specifically say that this is not allowed. You may not attach supplementary information to SI units. Blaise 16:03, 24 May 2006 (UTC)

[edit] Temperature

Could we mention that the average temperature of seawater is 17C? [3]

SillyWilly 08:54, 26 June 2006 (UTC)

Where's that then? I presume you mean (annual) surface seawater. Would a plot of mean annual surface SST be more useful? I can knock one up in Matlab if so. Cheers, --Plumbago 09:00, 26 June 2006 (UTC)

Done. How's that? You could add the average temperature in the caption. --Plumbago 10:52, 26 June 2006 (UTC)

[edit] Drinking seawater

"Seawater can be turned into drinkable (potable) water by one of a number of desalination processes, or by dilluting it with fresh water to reduce the salinity. Otherwise, it should not be drunk because of its high dissolved mineral content. In the long run, more water must be expended to eliminate these minerals (through excretion in urine) than is gained from drinking the seawater itself."

Contrary to this, I read recently in Mike Dash's (User:Mikedash) Batavia's Graveyard (see our article atBatavia (ship)) that it is "safe" to drink up to about one pint of seawater a day. A quick google hunt for confirmation brings up this (which says about 32oz (~2 UK pints)) and mentions a Dr Bombard. A google of that turns up Alain Louis Bombard on Everything2 (where it says about a litre (1.5 pints))and Alain Bombard here. Jooler 09:15, 6 August 2006 (UTC)

[edit] Unification of Charts

I thin that the various charts of information should be cleaned up,and then combined into one congruous chart, to provide for easy-access information. The chart near the bottom is a good and useful chart, but is in the wrong place(potability) and bleeds into the next section. if anyone disagrees, let me know...--Vox Causa 15:19, 29 September 2006 (UTC)

Good idea. The lower table is the more useful of the two, but the upper table's information could be configured into an extra column for the lower one. And you're right about the lower table's position, move it up to the composition section. Cheers, --Plumbago 15:28, 29 September 2006 (UTC)

[edit] Salinity

This article talks about there being NaCl in seawater. I was very firmly taught during my chemistry lessons that there are ions of Na, Cl and a host of other things in the water. It so happens that NaCl is the least soluble combination of these ions, so it precipitates out first when the water is evaporated. But if, for example, NaSO4 and KCl happened to be the less soluble than NaCl, we'd think of seawater as being composed of those things. Is this correct? If it is, doesn't the start of this article need a complete rewrite? David Colver 11:43, 25 November 2006 (UTC)

NaCl is actually one of the most soluble combination of ions in seawater, thus the high concentration of Na and Cl(Na and Cl ions are high conservative). If you were to evaporate the seawater, about 90% of the salt would be NaCl. The order of precipitation upon evaporation of seawater is found here. I think you're right in that the defintiion of seawater should not focus so much on just two components of seawater (Na and Cl), but they are by far the most concentrated and people can relate easily with these ions as they compose table salt. Also, for years people determined the salinity of seawater by measuring Cl.Piyrwq 18:00, 26 November 2006 (UTC)

150.203.236.39 08:03, 30 January 2007 (UTC)Adi

The percentages in ‘Elemental composition of Earth's ocean water (by mass)' table under the section 'Geochemical explanations' exceed 100%! (>101.4%)

I have changed these values using the data in a periodic table (MS Excel .xls format) available at http://www.radiochemistry.org/periodictable/downloads.html

Looks like a good source, I couldn't find any publications for the topic. If someone, finds more accurate data or from a primary literature source please update the table as necessary.

[edit] Electrostriction?

The intro was just edited to include electrostriction as a reason for the higher density of seawater relative to fresh water. I've never heard of this. Reference? Rracecarr 21:22, 31 January 2007 (UTC)

I just put in a ref for now, I hope to find a better one. This week I'd like to write the electrostriction (seawater) article, but it looks like a lot of work for me as it presently only discusses a totaly different meaning. Maybe someone can help me set up a disambiguation page? If that's what's needed. Piyrwq 20:32, 2 February 2007 (UTC)

Explanation section "Scientists recently discovered that the high salinity of the Red Sea is also caused by the levels of whale semen ejaculated during mating season." Give me a break here. Either add a solid reference or pull this off-color but humorous claim. JimboPueblo 02:03, 15 February 2007 (UTC)

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