<p>"Sea" versus "lake" versus "just part of the ocean" is a bit fuzzy, but there are two things that are universal about seas:</p>

<ul>
<li>They are saline.</li>
<li>They are either <a href="https://en.wikipedia.org/wiki/Endorheic_basin" rel="noreferrer">endorheic</a> or have a sea-level (tidally-influenced) connection to the ocean.</li>
</ul>

<p>Now, let's see how the Great Lakes look under these criteria.</p>

<ul>
<li>Saline?  No, salinity is <a href="https://ponce.sdsu.edu/lakesalinityworld.html" rel="noreferrer">0, give or take measurement error</a>.  Even the Baltic Sea, the least-salty of the generally-recognized seas, is far more saline, at 0.5%.</li>
<li>Endorheic?  No, they're connected to the ocean by way of the <a href="https://en.wikipedia.org/wiki/Saint_Lawrence_River" rel="noreferrer">Saint Lawrence River</a>, and have been for at least 10,000 years.</li>
<li>Sea-level connection?  No, the Saint Lawrence River has <a href="https://en.wikipedia.org/wiki/Saint_Lawrence_River#Geography" rel="noreferrer">about 500 km of non-tidal flow below the outlet of Lake Ontario</a>, over which it descends 75 meters.</li>
</ul>

<p>Score: 0 out of 3.  Not surprising that the Great Lakes are considered lakes, not seas.</p>

CC BY-SA 4.0
2018-05-21T10:00:30.827Z
I would say 0 out of 2, since 2 is the maximum score.
Communisty
CC BY-SA 4.0
2018-05-21T17:19:27.723Z
The Sea of Galilee is not saline.  Also note that Ontario is separated from Erie (and hence the upper lakes) by the Niagara River and a 167 ft/51 m waterfall.
jamesqf
CC BY-SA 4.0
2018-05-21T20:46:51.903Z
Correction is in order here. The Great Lakes DO in fact experience tidal effects, though they are greatly diminished by barometric factors and wind. about 5 cm, depending on the positions of the sun and moon....https://oceanservice.noaa.gov/facts/gltides.html
htm11h
CC BY-SA 4.0
2018-05-21T21:15:12.190Z
@htm11h, the Great Lakes experience tides, but it's the *connection* between them and the oceans that I'm referring to.  Contrast the Saint Lawrence River with the Dardanelles.
Mark
CC BY-SA 4.0
2018-05-22T15:42:56.673Z
If you note the first few comments on this post, there is a clear distinction. In fact Lake Superior was only connected by a rapids, http://www.saulttourism.com/the-sault/index.aspx?l=0,21,22,25 I don't know of many if any seas that are naturally connected in one direction and bare the same name. The Sault St Marie canal later provided passage. Virtually all of the connectivity was man made, except for Michigan, Huron, and Erie lakes.
htm11h
CC BY-SA 4.0
2018-05-20T20:53:01.877Z
2018-05-21T09:39:50.403Z
2018-05-21T09:39:50.403Z
Mark
<p>From a geological point of view, the two are very different.</p>

<p>The Caspian Sea is thought to be the remnant of an ocean that got cut off from the ocean system (similar to how the Mediterranean might have been periodically cut off and re-connected to the oceans) due to tectonic uplift and a drop in sea levels. The Black Sea was part of the same ocean, but has a much lower inflow than it loses to evaporation - hence the Black Sea has a salinity much higher than the oceans, while the Caspian Sea has a salinity significantly lower than the oceans.</p>

<p>The Great Lakes could be considered a <em>failed</em> ocean. They are in a place where rifting started to create a new ocean, but it never got connected to the ocean system (and flooded), and that was still the case when the rifting eventually stopped. Those rifts were then further (much later) "excavated" by glaciers. The large depressions got filled with melt water (at the end of the last ice age) and rainwater over time, as is typical of many other large/deep lakes. Unsurprisingly, the glacier-sourced melt water wasn't very salty.</p>

<p>In the future, the Caspian Sea will probably get slightly saltier, and filled with sediment. While the influx of fresh water has driven the salinity relatively low compared to the oceans, the sea now only loses water through evaporation - so there's no way for the (tiny amounts) of incoming salts and (relatively large amounts) of sediment to go. As the depth decreases, there might be some expansion of the surface area, but that's mostly temporary - it increases the evaporation rate without increasing the inflow, so water is lost over time.</p>

<p>In contrast, the Great Lakes have an outflow into the ocean, which carries away a lot of the dissolved salts and sediment. Right now, the outflow, combined with evaporation both natural and man made, is larger than the inflow. Overall, this means it's not going to get saltier over time - it keeps pretty much constant salinity, which is pretty much zero compared to the oceans. As erosion continues over the Saint Lawrence River, the outflow will probably increase, resulting in a drop in the water levels of the lakes. However, unlike e.g. the Black Sea, this will not increase the salinity, since the salts are lost through the outflow, rather than being concentrated by evaporation.</p>

CC BY-SA 4.0
2018-05-21T17:25:39.667Z
Re the future of the Caspian Sea, will not sea level rise eventually join the Caspian and Black Sea?
jamesqf
CC BY-SA 4.0
2018-05-21T18:11:35.277Z
@jamesqf We as a species are trying very hard to make that happen!
corsiKa
CC BY-SA 4.0
2018-05-21T19:32:15.703Z
@jamesqf it would take melting the East Antarctic ice shelf (the big stable one).  The low point for the blocking land between the two seas is 27m above sea level.  The unstable West Antarctic ice cap and Greenland ice caps combined would only get us about halfway there.  The East Antarctic Ice cap OTOH has about 60m of sea level rise in it; roughtly double what'd be needed to flood the Caspian basin.
Dan Is Fiddling By Firelight
CC BY-SA 4.0
2018-05-21T19:57:34.437Z
@DanNeely: Digging the Don-Volga Canal down to sea level and blowing up all the locks would also turn the trick.
Vikki
CC BY-SA 4.0
2018-05-21T19:58:47.920Z
Also, strictly-speaking, the Caspian Sea is actually an _ocean_, as it's floored with oceanic crust.
Vikki
CC BY-SA 4.0
2018-05-22T05:10:31.027Z
@Dan Neely: As I said, barring serious changes in human behavior (and assuming it's not already too late for those changes to have effects), sea level rise will eventually join the Caspian to the Black Sea.
jamesqf
CC BY-SA 4.0
2018-05-22T05:57:30.607Z
@Sean Humans might be able of doing a lot of things, yes. Remember that old German project to dry up the Mediterranean? The poor fools didn't quite consider the ecological and economical impact of that, and just imagined all the new land that would open to settlement. Fortunately, at that point, no country was powerful enough to force everyone to go ahead with that plan - and by the time they were, it was far easier (and faster) to just conquer the rest of Europe and start a massive genocide.
Luaan
CC BY-SA 4.0
2018-05-22T06:03:04.040Z
@jamesqf Don't forget the uplift - restoring the *same* sea level as before the Caspian and Black Seas were disconnected wouldn't be enough anymore. It's *possible* we could make the sea rise enough to overcome that, but quite unlikely - at the very least, as the sea levels rise, they would progressively destroy human population, industry and agriculture, and probably stop the warming entirely. Though it's hard to predict things like that - it might increase chemical weathering, or decrease it, for example. "All other things equal" models aren't very good at realistic predictions :P
Luaan
CC BY-SA 4.0
2018-05-22T18:57:03.547Z
@Luaan: Atmospheric CO2 is persistent, and its effects are cumulative.  By the time warming destroys enough human industry to stop the release of fossil CO2, a good bit of future warming will be locked in.
jamesqf
CC BY-SA 4.0
2018-05-23T05:13:46.480Z
@jamesqf Unless it also destroys a proportionate amount of photosynthesizers (possible), it will start dropping pretty quick - compared to the thawing timescales, that is. But really, given how many possible mechanisms can tag along, those predictions are pretty much wild guesses anyway. Say, if the circumpolar flow around the Antarctic is disrupted, the sea levels are going to rise even without any additional global warming. That probably *isn't* going to happen, but...
Luaan
CC BY-SA 4.0
2018-05-23T08:26:41.327Z
@Luaan: Doesn't work that way.  The fossil CO2 was sequestered over hundreds of millions of years.  Photosynthesis won't significantly decrease the amount, because almost all of what is turned into plant matter is eaten or decays in short order - a year for annual plants, maybe a few centuries for trees - releasing the CO2 again.
jamesqf
CC BY-SA 4.0
2018-05-23T12:32:48.513Z
@jamesqf That would be true if the pattern was the same as it is today - but I don't think that's likely. I'm not talking about trees or grasses of course - more likely, algae and plankton would be important. Just imagine the amount of new shelf seas that would be created, the increased sedimentation or the possible oxygen depletion of the oceans if the flows are disrupted. Mind you, I'm not saying that this is a *likely* scenario in absolute terms - such large scale disruptions will have unexpected impacts that break a lot of our assumptions. It seems to me about as likely as the reverse.
Luaan
CC BY-SA 4.0
2018-05-21T08:21:30.627Z
2018-05-21T08:21:30.627Z
Luaan
<p>Other answers have suggested some ways of classifying things into seas or lakes, which are good guides, but inevitably there are exceptions to all of them.</p>

<p>Ultimately, the difference is not an oceanographic or hydrological one, but a semantic and cultural one. The names bodies of water have are historical, so what they are called is down to what somebody saw fit to call them in the past - not any modern taxonomy.</p>

CC BY-SA 4.0
2019-06-06T19:55:31.247Z
2019-06-06T19:55:31.247Z
Semidiurnal Simon
<p>From me looking at maps, excluding the Caspian sea and the Great Lakes, I see these in common for seas and lakes:</p>

<p>Seas</p>

<ul>
<li>Most are saltwater</li>
<li>Connected to the rest of the ocean via either an isthmus, strait, river, or
gulf</li>
<li>Bigger and deeper than lakes</li>
</ul>

<p>Lakes</p>

<ul>
<li>Most are freshwater</li>
<li>Landlocked</li>
<li>Not nearly as big or deep as any sea</li>
</ul>

<p>So back to these 2 bodies of water in question. Some people consider the Caspian sea to be a lake and others consider it to be a sea. While historically, it might have been part of a sea, it is landlocked now so it would be more suited to call this the Caspian Salt Lake, thus making it the largest lake on Earth and also the largest saline lake.</p>

<p>The Great Lakes are also in question, to me at least. While the majority of the world considers them lakes and they were historically a lake (really, the rivers and small lakes in that area connecting them are so small in comparison that it is basically 1 body of water), the Erie canal has since then connected the lakes to the St. Lawrence River. So it would be more suited to call this the Great Freshwater Sea. I have no idea how this would rank up to other seas like the Mediterranean Sea in area but it would be one of the world's few freshwater seas (Joining the Sea of Galilee).</p>

<p>So why are the Great Lakes not considered a freshwater sea when other than the freshwater, they are essentially like any other sea?</p>

CC BY-SA 4.0
2018-05-20T19:47:39.217Z
You are wrong WRT the Great Lakes.  The Erie Canal did not connect them to the St. Lawrence River (which was and is the natural outlet of the lakes to the sea).  It connects the Hudson River drainage to Lake Erie (actually the Niagara River upstream of the Falls): https://en.wikipedia.org/wiki/Erie_Canal  Also, while the upper lakes are effectively a single body, Ontario is quite distinct, being separated from Erie by a significant https://en.wikipedia.org/wiki/Niagara_Falls  For the rest, it's a question more suited to the English Language & Usage site.
jamesqf
CC BY-SA 4.0
2018-05-21T07:53:03.720Z
Just because the Caspian sea is named "sea" doesn't mean it's considered a sea. Don't get too hung up on the name - it's a very old name, long before modern definitions of what a sea is or isn't (and even today, some experts consider it a sea, while others consider it a lake). In many languages, the distinction doesn't even exist in the first place (e.g. the High German "See" means simply "large body of water", which is quite typical for cultures that didn't live close to the sea - they either used the same name, or imported/created a better name later, e.g. "Meer").
Luaan
CC BY-SA 4.0
2018-05-21T13:24:10.260Z
If they were in fact seas, wouldn't they then become Small Seas rather than Great Lakes? :) Sounds far less interesting.
Viktor Mellgren
CC BY-SA 4.0
2018-05-21T15:18:45.050Z
As one "sea" they would share a common surface elevation, but they do not. The great lakes have 4 distinct surface elevations between them, although 3 of the 4 elevations are pretty close, so while they are one system, they are not really one lake (or sea).
Anthony X
CC BY-SA 4.0
2018-05-21T17:13:16.430Z
@Luaan: Also consider such "seas" as the Dead Sea and the Sea of Galilee, both of which are equivalent to medium-sized lakes.
jamesqf
CC BY-SA 4.0
2018-05-21T18:53:29.487Z
"Connected to the rest of the ocean via either an isthmus, strait, river, or gulf" How can an isthmus connect a sea to the ocean? A canal is neither a strait, river, nor gulf. The Erie Canal has 35 locks, so the water does not flow freely.
Acccumulation
CC BY-SA 4.0
2018-05-21T21:13:05.203Z
@Luaan please note that German has two different words, "die See" (sea) and "der See" (lake).
Paŭlo Ebermann
CC BY-SA 4.0
2019-06-06T19:59:54.123Z
To the people voting to close this: Sure, one can argue that it's off-topic (because it's about historic naming, not earth science) or that it's opinion-based (because it's about why things are named that way, not earth science) - but that's only the case if you *already know the answer*. For somebody under the impression that there is a clear taxonomy between lakes, seas, oceans, etc., then it's a perfectly good on-topic question. So let's keep it, and explain this misconception in the answers.
Semidiurnal Simon
CC BY-SA 4.0
2019-06-06T20:06:54.117Z
@Luaan consider making your comment an answer?
Semidiurnal Simon
CC BY-SA 4.0
2022-01-26T13:25:16.487Z
Lake Michigan is an inland sea!Meats all criteria as such!It was referred to as a lake because the explorers That discovered it thought it was a lake.there ignorance was as vast as the sea itself.there reason for calling it a lake?Fresh water.
R.Ray Scott
<oceanography><lakes>
Why are the Great Lakes not considered a sea?
Caters
# Why are the Great Lakes not considered a sea?

(Asked by: username_0 on 2018-05-20)

From me looking at maps, excluding the Caspian sea and the Great Lakes, I see these in common for seas and lakes:

Seas

* Most are saltwater
* Connected to the rest of the ocean via either an isthmus, strait, river, or
  gulf
* Bigger and deeper than lakes

Lakes

* Most are freshwater
* Landlocked
* Not nearly as big or deep as any sea

So back to these 2 bodies of water in question. Some people consider the Caspian sea to be a lake and others consider it to be a sea. While historically, it might have been part of a sea, it is landlocked now so it would be more suited to call this the Caspian Salt Lake, thus making it the largest lake on Earth and also the largest saline lake.

The Great Lakes are also in question, to me at least. While the majority of the world considers them lakes and they were historically a lake (really, the rivers and small lakes in that area connecting them are so small in comparison that it is basically 1 body of water), the Erie canal has since then connected the lakes to the St. Lawrence River. So it would be more suited to call this the Great Freshwater Sea. I have no idea how this would rank up to other seas like the Mediterranean Sea in area but it would be one of the world's few freshwater seas (Joining the Sea of Galilee).

So why are the Great Lakes not considered a freshwater sea when other than the freshwater, they are essentially like any other sea?

**Tags:** oceanography, lakes

> **Comments:**
> **username_1**: You are wrong WRT the Great Lakes.  The Erie Canal did not connect them to the St. Lawrence River (which was and is the natural outlet of the lakes to the sea).  It connects the Hudson River drainage to Lake Erie (actually the Niagara River upstream of the Falls): https://en.wikipedia.org/wiki/Erie_Canal  Also, while the upper lakes are effectively a single body, Ontario is quite distinct, being separated from Erie by a significant https://en.wikipedia.org/wiki/Niagara_Falls  For the rest, it's a question more suited to the English Language & Usage site.  
> **username_2**: Just because the Caspian sea is named "sea" doesn't mean it's considered a sea. Don't get too hung up on the name - it's a very old name, long before modern definitions of what a sea is or isn't (and even today, some experts consider it a sea, while others consider it a lake). In many languages, the distinction doesn't even exist in the first place (e.g. the High German "See" means simply "large body of water", which is quite typical for cultures that didn't live close to the sea - they either used the same name, or imported/created a better name later, e.g. "Meer").  
> **username_3**: If they were in fact seas, wouldn't they then become Small Seas rather than Great Lakes? :) Sounds far less interesting.  
> **username_4**: As one "sea" they would share a common surface elevation, but they do not. The great lakes have 4 distinct surface elevations between them, although 3 of the 4 elevations are pretty close, so while they are one system, they are not really one lake (or sea).  
> **username_1**: @username_2: Also consider such "seas" as the Dead Sea and the Sea of Galilee, both of which are equivalent to medium-sized lakes.  
> **username_5**: "Connected to the rest of the ocean via either an isthmus, strait, river, or gulf" How can an isthmus connect a sea to the ocean? A canal is neither a strait, river, nor gulf. The Erie Canal has 35 locks, so the water does not flow freely.  
> **username_6**: @username_2 please note that German has two different words, "die See" (sea) and "der See" (lake).  
> **username_7**: To the people voting to close this: Sure, one can argue that it's off-topic (because it's about historic naming, not earth science) or that it's opinion-based (because it's about why things are named that way, not earth science) - but that's only the case if you *already know the answer*. For somebody under the impression that there is a clear taxonomy between lakes, seas, oceans, etc., then it's a perfectly good on-topic question. So let's keep it, and explain this misconception in the answers.  
> **username_7**: @username_2 consider making your comment an answer?  
> **username_8**: Lake Michigan is an inland sea!Meats all criteria as such!It was referred to as a lake because the explorers That discovered it thought it was a lake.there ignorance was as vast as the sea itself.there reason for calling it a lake?Fresh water.  

---

## 3 answers

### Answer by username_9 on 2018-05-20. Score: 42

"Sea" versus "lake" versus "just part of the ocean" is a bit fuzzy, but there are two things that are universal about seas:

* They are saline.
* They are either [endorheic](https://en.wikipedia.org/wiki/Endorheic_basin) or have a sea-level (tidally-influenced) connection to the ocean.

Now, let's see how the Great Lakes look under these criteria.

* Saline? No, salinity is [0, give or take measurement error](https://ponce.sdsu.edu/lakesalinityworld.html). Even the Baltic Sea, the least-salty of the generally-recognized seas, is far more saline, at 0.5%.
* Endorheic? No, they're connected to the ocean by way of the [Saint Lawrence River](https://en.wikipedia.org/wiki/Saint_Lawrence_River), and have been for at least 10,000 years.
* Sea-level connection? No, the Saint Lawrence River has [about 500 km of non-tidal flow below the outlet of Lake Ontario](https://en.wikipedia.org/wiki/Saint_Lawrence_River#Geography), over which it descends 75 meters.

Score: 0 out of 3. Not surprising that the Great Lakes are considered lakes, not seas.

> **Comments:**
> **username_10**: I would say 0 out of 2, since 2 is the maximum score.  
> **username_1**: The Sea of Galilee is not saline.  Also note that Ontario is separated from Erie (and hence the upper lakes) by the Niagara River and a 167 ft/51 m waterfall.  
> **username_11**: Correction is in order here. The Great Lakes DO in fact experience tidal effects, though they are greatly diminished by barometric factors and wind. about 5 cm, depending on the positions of the sun and moon....https://oceanservice.noaa.gov/facts/gltides.html  
> **username_9**: @username_11, the Great Lakes experience tides, but it's the *connection* between them and the oceans that I'm referring to.  Contrast the Saint Lawrence River with the Dardanelles.  
> **username_11**: If you note the first few comments on this post, there is a clear distinction. In fact Lake Superior was only connected by a rapids, http://www.saulttourism.com/the-sault/index.aspx?l=0,21,22,25 I don't know of many if any seas that are naturally connected in one direction and bare the same name. The Sault St Marie canal later provided passage. Virtually all of the connectivity was man made, except for Michigan, Huron, and Erie lakes.  

---

### Answer by username_2 on 2018-05-21. Score: 9

From a geological point of view, the two are very different.

The Caspian Sea is thought to be the remnant of an ocean that got cut off from the ocean system (similar to how the Mediterranean might have been periodically cut off and re-connected to the oceans) due to tectonic uplift and a drop in sea levels. The Black Sea was part of the same ocean, but has a much lower inflow than it loses to evaporation - hence the Black Sea has a salinity much higher than the oceans, while the Caspian Sea has a salinity significantly lower than the oceans.

The Great Lakes could be considered a *failed* ocean. They are in a place where rifting started to create a new ocean, but it never got connected to the ocean system (and flooded), and that was still the case when the rifting eventually stopped. Those rifts were then further (much later) "excavated" by glaciers. The large depressions got filled with melt water (at the end of the last ice age) and rainwater over time, as is typical of many other large/deep lakes. Unsurprisingly, the glacier-sourced melt water wasn't very salty.

In the future, the Caspian Sea will probably get slightly saltier, and filled with sediment. While the influx of fresh water has driven the salinity relatively low compared to the oceans, the sea now only loses water through evaporation - so there's no way for the (tiny amounts) of incoming salts and (relatively large amounts) of sediment to go. As the depth decreases, there might be some expansion of the surface area, but that's mostly temporary - it increases the evaporation rate without increasing the inflow, so water is lost over time.

In contrast, the Great Lakes have an outflow into the ocean, which carries away a lot of the dissolved salts and sediment. Right now, the outflow, combined with evaporation both natural and man made, is larger than the inflow. Overall, this means it's not going to get saltier over time - it keeps pretty much constant salinity, which is pretty much zero compared to the oceans. As erosion continues over the Saint Lawrence River, the outflow will probably increase, resulting in a drop in the water levels of the lakes. However, unlike e.g. the Black Sea, this will not increase the salinity, since the salts are lost through the outflow, rather than being concentrated by evaporation.

> **Comments:**
> **username_1**: Re the future of the Caspian Sea, will not sea level rise eventually join the Caspian and Black Sea?  
> **username_12**: @username_1 We as a species are trying very hard to make that happen!  
> **username_13**: @username_1 it would take melting the East Antarctic ice shelf (the big stable one).  The low point for the blocking land between the two seas is 27m above sea level.  The unstable West Antarctic ice cap and Greenland ice caps combined would only get us about halfway there.  The East Antarctic Ice cap OTOH has about 60m of sea level rise in it; roughtly double what'd be needed to flood the Caspian basin.  
> **username_14**: @DanNeely: Digging the Don-Volga Canal down to sea level and blowing up all the locks would also turn the trick.  
> **username_14**: Also, strictly-speaking, the Caspian Sea is actually an _ocean_, as it's floored with oceanic crust.  
> **username_1**: @Dan Neely: As I said, barring serious changes in human behavior (and assuming it's not already too late for those changes to have effects), sea level rise will eventually join the Caspian to the Black Sea.  
> **username_2**: @Sean Humans might be able of doing a lot of things, yes. Remember that old German project to dry up the Mediterranean? The poor fools didn't quite consider the ecological and economical impact of that, and just imagined all the new land that would open to settlement. Fortunately, at that point, no country was powerful enough to force everyone to go ahead with that plan - and by the time they were, it was far easier (and faster) to just conquer the rest of Europe and start a massive genocide.  
> **username_2**: @username_1 Don't forget the uplift - restoring the *same* sea level as before the Caspian and Black Seas were disconnected wouldn't be enough anymore. It's *possible* we could make the sea rise enough to overcome that, but quite unlikely - at the very least, as the sea levels rise, they would progressively destroy human population, industry and agriculture, and probably stop the warming entirely. Though it's hard to predict things like that - it might increase chemical weathering, or decrease it, for example. "All other things equal" models aren't very good at realistic predictions :P  
> **username_1**: @username_2: Atmospheric CO2 is persistent, and its effects are cumulative.  By the time warming destroys enough human industry to stop the release of fossil CO2, a good bit of future warming will be locked in.  
> **username_2**: @username_1 Unless it also destroys a proportionate amount of photosynthesizers (possible), it will start dropping pretty quick - compared to the thawing timescales, that is. But really, given how many possible mechanisms can tag along, those predictions are pretty much wild guesses anyway. Say, if the circumpolar flow around the Antarctic is disrupted, the sea levels are going to rise even without any additional global warming. That probably *isn't* going to happen, but...  
> **username_1**: @username_2: Doesn't work that way.  The fossil CO2 was sequestered over hundreds of millions of years.  Photosynthesis won't significantly decrease the amount, because almost all of what is turned into plant matter is eaten or decays in short order - a year for annual plants, maybe a few centuries for trees - releasing the CO2 again.  
> **username_2**: @username_1 That would be true if the pattern was the same as it is today - but I don't think that's likely. I'm not talking about trees or grasses of course - more likely, algae and plankton would be important. Just imagine the amount of new shelf seas that would be created, the increased sedimentation or the possible oxygen depletion of the oceans if the flows are disrupted. Mind you, I'm not saying that this is a *likely* scenario in absolute terms - such large scale disruptions will have unexpected impacts that break a lot of our assumptions. It seems to me about as likely as the reverse.  

---

### Answer by username_7 on 2019-06-06. Score: 4

Other answers have suggested some ways of classifying things into seas or lakes, which are good guides, but inevitably there are exceptions to all of them.

Ultimately, the difference is not an oceanographic or hydrological one, but a semantic and cultural one. The names bodies of water have are historical, so what they are called is down to what somebody saw fit to call them in the past - not any modern taxonomy.


---

