海洋
湖泊
所以回到这两个水体的问题上。一些人认为里海是一个湖，另一些人认为它是一个海。虽然从历史上看，它可能是海洋的一部分，但现在它是内陆的，所以它更适合称为里海盐湖，从而使它成为地球上最大的湖泊，也是最大的盐湖。至少对我来说，五大湖也是个问题。虽然世界上大多数人都认为它们是湖泊，而且它们在历史上是一个湖泊(实际上，连接它们的河流和小湖泊相比之下太小了，基本上是一个水体)，但伊利运河从那时起就把这些湖泊连接到圣劳伦斯河。所以叫它大淡水海更合适。我不知道它在面积上如何与地中海等其他海域相提并论，但它将是世界上为数不多的淡水海之一(与加利利海相连)。
那么为什么五大湖不被认为是淡水海，而除了淡水，它们本质上就像任何其他的海一样?< / p >
现在，让我们看看五大湖在这些标准下是什么样子。
得分:0 / 3。五大湖被认为是湖泊而不是海洋，这并不奇怪
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.