Editing Atlantic Ocean (section)

=== Water masses ===
{| class="wikitable floatright" style="font-size: 0.9em; text-align: center;"
|+ Temperature-salinity characteristics for Atlantic water masses<ref>{{Harvnb|Emery|Meincke|1986|loc=Table, p. 385}}</ref>
|-
 ! Water mass !! Temperature !! Salinity
|-
 ! colspan="3" | Upper waters ({{cvt|0|-|500|m|ft|-2|disp=or}})
|-
 | align=left | Atlantic Subarctic<br />Upper Water (ASUW) || 0.0–4.0&nbsp;°C || 34.0–35.0
|-
 | align=left | Western North Atlantic<br />Central Water (WNACW) || 7.0–20&nbsp;°C || 35.0–36.7
|-
 | align=left | Eastern North Atlantic<br />Central Water (ENACW) || 8.0–18.0&nbsp;°C || 35.2–36.7
|-
 | align=left | South Atlantic<br />Central Water (SACW) || 5.0–18.0&nbsp;°C || 34.3–35.8
|-
 ! colspan="3" | Intermediate waters ({{cvt|500|-|1500|m|ft|-2|disp=or}})
|-
 | align=left | Western Atlantic Subarctic<br />Intermediate Water (WASIW) || 3.0–9.0&nbsp;°C || 34.0–35.1
|-
 | align=left | Eastern Atlantic Subarctic<br />Intermediate Water (EASIW) || 3.0–9.0&nbsp;°C || 34.4–35.3
|-
 | align=left | Mediterranean Water (MW) || 2.6–11.0&nbsp;°C || 35.0–36.2
|-
 | align=left | Arctic Intermediate Water (AIW) || −1.5–3.0&nbsp;°C || 34.7–34.9
|-
 ! colspan="3" | Deep and abyssal waters (1,500&nbsp;m–bottom or 4,900&nbsp;ft–bottom)
|-
 | align=left | North Atlantic<br />Deep Water (NADW) || 1.5–4.0&nbsp;°C || 34.8–35.0
|-
 | align=left | Antarctic Bottom Water (AABW) || −0.9–1.7&nbsp;°C || 34.6–34.7
|-
 | align=left | Arctic Bottom Water (ABW) || −1.8 to −0.5&nbsp;°C || 34.9–34.9
|}

The Atlantic Ocean consists of four major, upper [[water mass]]es with distinct temperature and salinity. The Atlantic subarctic upper water in the northernmost North Atlantic is the source for subarctic intermediate water and North Atlantic intermediate water. North Atlantic central water can be divided into the eastern and western North Atlantic central water since the western part is strongly affected by the Gulf Stream and therefore the upper layer is closer to underlying fresher subpolar intermediate water. The eastern water is saltier because of its proximity to Mediterranean water. North Atlantic central water flows into South Atlantic central water at [[15th parallel north|15°N]].<ref name="Emery-Atlantic">{{Harvnb|Emery|Meincke|1986|loc=Atlantic Ocean, pp. 384–386}}</ref>

There are five intermediate waters: four low-salinity waters formed at subpolar latitudes and one high-salinity formed through evaporation. Arctic intermediate water flows from the north to become the source for North Atlantic deep water, south of the Greenland-Scotland sill. These two intermediate waters have different salinity in the western and eastern basins. The wide range of salinities in the North Atlantic is caused by the asymmetry of the northern subtropical [[gyre]] and a large number of contributions from a wide range of sources: Labrador Sea, Norwegian-Greenland Sea, Mediterranean, and South Atlantic Intermediate Water.<ref name="Emery-Atlantic" />

The [[North Atlantic Deep Water|North Atlantic deep water]] (NADW) is a complex of four water masses, two that form by deep convection in the open ocean{{snd}}classical and upper Labrador sea water{{snd}}and two that form from the inflow of dense water across the Greenland-Iceland-Scotland sill{{snd}}Denmark Strait and Iceland-Scotland overflow water. Along its path across Earth the composition of the NADW is affected by other water masses, especially [[Antarctic Bottom Water|Antarctic bottom water]] and Mediterranean overflow water.<ref>{{Harvnb|Smethie|Fine|Putzka|Jones|2000|loc=Formation of NADW, pp. 14299–14300}}</ref>
The NADW is fed by a flow of warm shallow water into the northern North Atlantic which is responsible for the anomalous warm climate in Europe. Changes in the formation of NADW have been linked to global climate changes in the past. Since human-made substances were introduced into the environment, the path of the NADW can be traced throughout its course by measuring tritium and radiocarbon from [[nuclear weapon test]]s in the 1960s and [[chlorofluorocarbon|CFCs]].<ref>{{Harvnb|Smethie|Fine|Putzka|Jones|2000|loc=Introduction, p. 14297}}</ref>