The popular public radio show This American Life had a great segment recently in which the practice of two or more people discussing a subject with an air of authority that far outstrips the actual knowledge contained in the discussion is known as “writing for Modern Jackass magazine.” This is not only a clever and funny description for a phenomenon we’ve all experienced, but a great idea for yet another recurring segment on Pax Arcana. We’ll see if this one fares better than any of the others. Those wishing to write their own articles for Modern Jackass need simply to choose a topic and hold forth.
Just after breakfast this morning, I took a dip in the water off Beach Haven, New Jersey. The water felt cold as I waded in. Much colder than yesterday, which was already much colder than the previous day.
This provoked a question — how can the temperature of the ocean vary so much from one day to the next? After all, the ocean itself contains more than 62 trillion gallons of water, making it very difficult to raise or lower the temperature without a massive influx or reduction of heat energy.
The answer can be found in tidal patterns. As the tides wax and wane, tidal shifts occur under the surface, sending water from the colder depths of the ocean to the shallow surf closer to shore. This process is known, I believe, as oceanic subduction.
A curious side effect of oceanic subduction is that it also changes the salination of the water itself. You may have noticed that the relative salty taste of ocean water seems to change from day to day. This is because as the phenomenon of oceanic subduction moves water from deep ocean zones to shallower ones, the water loses salination. The reason deeper water is less salty than shallow water has everything to do with barometric pressure and is probably best explained in a separate article.