We all know about tides and waves. They are just one aspect of the groovy action of the sea. First the word ‘sea’ has many definitions. ‘The sea’ is often meant to encompass all the oceans. Then there are ‘seas,’ smaller bodies of water which are geographic demarcations in the oceans like the Caribbean Sea. There are inland seas too like the Caspian Sea and there are freshwater seas and dead seas. And there are even seas that are called seas but don’t really exist. Like the Aral Sea in Uzbekistan which was once the world’s sixth largest body of freshwater but was drained away by the Soviets leaving a briny, polluted mud puddle.
There are places we call seas on the Moon too like the Sea of Tranquility which is short of water but long on tranquility.
The Black Sea is the largest water body with a meromictic basin, which means the lower and upper layers don’t mix. The Black Sea gets its freshwater from inflowing rivers and rainfall and it gets saltwater from the Mediterranean. As the transfer takes place in the Bosporus and Dardanelles, the inflow of dense water from the Mediterranean fills the bottom of the basin, while the outflow of Black Sea freshwater happens at the surface. The divide is between 300 and 600 feet deep and was only discovered about 10 years ago. There are ancient ships with their hulls and masts intact on the bottom which have not rotted because there is no oxygen at all, hence no life to eat the wood.
The fresh water flow is technically a river, making it the sixth largest river in the world and there are others around the globe where the fresh and saltwater are separate.
The word ‘sea’ also refers to the wind driven local waves and is called ‘the sea’ meaning the waves just around your boat whereas the swell comes across the entire ocean in the Pacific driven by the worldwide wind patterns that cause the air to blow east in the north and west below the equator. Sometimes, as often happens outside the Golden Gate, you can have swells coming from two directions and they will stack to form mountains of water thirty feet high and more. A ‘running sea’ is the combination of the local waves and the swell moving in concert with the tide and currents. Add rain, snow, hail, fog, flying fish coming up, bird poop coming down and you have what’s called ‘the conditions.’ An ocean swell is a transfer of energy, not water, as opposed to a light wave which is actually the movement of photons in a wave pattern. Waves can be seen clearly in sports stadiums where everyone stays put but the wave moves through the crowd. This effect was actually invented by a guy named ‘Krazy’ George Henderson on October 15, 1981 at the televised A’s/Yankees playoff game in Oakland. The Washington Huskies claim to have invented it some two weeks later. I’m not a sports fan so I’m not taking sides here.
There are a great many ‘sea terms’ from a ‘following sea’ (waves or swells coming from the stern) to a ‘green sea’ (shipping so much water over the bow it retains it color) Then there are the ocean currents. Currents are due to the Earth’s rotation causing water to flow around the world and to go down drains in opposite directions in the north and south. Ancient mariners could clearly see this when they crossed the equator with a simple test.
Then there is the question of ‘sea level’. Sea level is the water level at mean tide as measured from the center of the earth. But the earth is a bit flattened because of its spin makes the equator bulge. Such a big deal is made of this though it’s only about 19 miles out of spherical. Sea level is different all over the globe and local conditions from tidal constrictions to melting glaciers and a warmer sea means that there really is no fixed number for global sea level. The height difference from the Pacific to the Atlantic is 8 inches at Panama.
Then there is sea level rise due to our propensity to treat our atmosphere as a carbon sewer. As a result, our planet is heating up and this causes the sea to rise for two reasons. One is the melting ice. The Arctic ice melts almost completely in the summer now but the added water doesn’t raise the sea level at all because it’s floating. The lack of white reflectivity does allow more heat in though. The Antarctica isn’t a huge contributor either as it’s so much colder than the Arctic because it has an average elevation of 5,000 feet. But a melting Greenland glaciers is the big bugaboo. Good ol President Trump once posed the question. “Can we trade Greenland for Puerto Rico?” That idea made sense to him in that we would ditch one of the shithole countries (his words, not mine) and pick up all that greenery.
But melting ice is only one cause of the rise. Seawater itself expands as it warms so the ocean is rising from the bottom as well as the top.
And here we find ourselves. Stuck between the devil and the deep blue sea.