You can consider this installment four of my previous question which is the third installment.
Throughout history, we have developed many methods of telling time. The most famous two examples being the clock and the sundial. The ancient Egyptians invented the clepsydra, an extremely simple device that uses dripping water as a way to tell how much time has passed. There are also, for example, hourglasses, which flow sand as a measurement of time.
Suppose, though, you were an intelligent dolphin and, for some reason, had to always have a time reference on you. Being under the water seems to present a challenge, for technology like clocks and hourglasses don’t seem to be possible to make under the water, a clepsydra certainly wouldn’t work since you can’t pour water underwater, and a sundial wouldn’t have the proper lighting. So you must improvise in order to find a way to keep track of time. How would you improvise in order to keep track of time.
Mammals have to breathe, so they are surfacing from time to time… so roughly they’ll know day from night.
Tides are mostly noticeable near land.
So you have deep sea creatures away from shore. They mostly won’t care about day and night as there’s no difference, with light not penetrating more that about 200 feet.
So below 200 feet, and away from shore you mostly can’t. But also it would not matter as there’s no difference
But if you were a human, in a submarine or a diving vessel where you needed to know, a clock or radio… would be about the options
Not all care, but it still impacts them.
Rhythms at the bottom of the deep sea: Cyclic current flow changes and melatonin patterns in two species of demersal fish
Beyond this, the diurnal cycle does filter down into the disphotic zone and does influence species. It does weaken with depth.
This sounds like a good way to keep track of time.
Oh hell yeah!
Neat thank you!!
And I learned a new word
Zeitgebers are external cues, such as light, that synchronize the circadian clock in organisms with the Earth’s day-night cycles.