Subterranean Timekeeping

[Snargash Moonclaw]

I'm currently working on getting the description of the dwarven race and culture for my setting into a coherent form and running into (again) a major stumbling block: how subterranean races perceive, measure and mark the passage of time in the complete absence of observable diurnal and seasonal phenomena. Those races living (or originating) deep in the Underdark would be removed even from such cyclic yearly patterns as spring melt-off seeping downward from the surface into underlying strata. I think that the methods and functions of timekeeping would have a significant influence on many aspects of culture which would be retained in some form even long after the culture has moved upward to the surface and been exposed to other markers of time's passage. The only thing that comes to mind for me is something along the lines of some discernible cyclic fluctuation in magnetic field or the like. Even an organic manifestation of a very fixed duration (such as growth, spore release and decay of a common species of fungus) would still be responding to some influence present in the natural environment regulating that cycle. Any ideas out there?

[Haphazzard]

I think the key here is to look at the underground environment.  Time passage is based off of physical, noticable traits (plants dying, animals leaving, the lighting changing, etc.).  So, what's noticeable underground?  Does there seem to be more condensation and wetness in the "spring?"  How about what lives down there?  Another measure is biological tics.  We know it's time to sleep because lots of people get tired about the same time frame.  The ancient Hebrews measure months by the female menstrual cycle.  Things like those all help mark the passage of time.

[Stargate525]

iving organisms evolved an internal biological clock, called the Circadian rhythm, to help their bodies adapt to the daily cycle of day and night (light and dark) as the Earth rotates every 24 hours. The term 'circadian' comes from the Latin words for about (circa) a day (diem).

Circadian rhythms are controlled by "clock genes" that carry the genetic instructions to produce proteins. The levels of these proteins rise and fall in rhythmic patterns. These oscillating biochemical signals control various functions, including when we sleep and rest, and when we are awake and active. Circadian rhythms also control body temperature, heart activity, hormone secretion, blood pressure, oxygen consumption, metabolism and many other functions.

Pulled that off of a random website I found by googling. In theory, then, if your species simply had a very precise Circadian rhythm, it wouldn't need an outside observance; people would simply know what time it is.

Looking at it, the Underdark cannot possibly be a closed system; all the crap living down there gets base energy from somewhere, most likely the above-ground world and light. Therefore, there is a chain of organisms and biospheres that leads down to the depths. they set their internal clocks by each other, and so the time settings trickle down. Your fungus takes its cue from a different fungus that grows higher up, which takes its from the air currents made by bats, who move according to the migration of bugs down into caves from the heat.

Other, more direct ways of it would be geothermal phenomena; like Old Faithful. Pressure builds until the water is released.

[Snargash Moonclaw]

The problem with the natural circadian rhythms is that the triggers for the release of various hormones and neurochemicals (primarily serotonin and melatonin, but much more complex then simply these two) is the stimulation (or absence thereof) of the optic nerve by full spectrum light (e.g., sunlight or artificial lights designed to emit the full spectrum of light waves present in sunlight). I recall morning bird song in Denver beginning suddenly about 2 hours before dawn when only the slightest faint trace of lightening at the horizon could be seen. The absence of this is part of why I'm having trouble coming up with a rational for the Underdark. Granted - a whole lot about the Underdark is unrealistic and no doubt utterly impossible in terms of natural earth sciences, but hey, its a game. I doubt that real celestial physics would actually support the sort of orbit and effects I'm proposing for the planet and its binary suns, though it meets reason on the surface of things. . . I initially considered the variation of water seepage but don't thing it would be noticeable in the Underdark, though it would be a determinate in caverns closer to the surface.

Ultimately, a good Underdark biosystem certainly cannot be a closed system, but it proves quite a challenge to put all the links of the chain together in a plausible enough manner to foster a "willing suspension of disbelief." The trickle down concept proposes some good possibilities to explore since there needs to be some means of creating cyclic change in an environment which by and large changes very little. Variations in temperature are geothermal, and change over the course of movement into a different environment - a given location will pretty much remain a constant temperature as determined by whatever (pretty much constant) thermal influences are present. I don't know much about the ecosystems actually present in caverns on earth, and they might offer some ideas to start from, but I realize that they would not extend down nearly as far as what is proposed as the Underdark. Pressure build up and release in some areas could create a very localized natural clock and beings in the area would certainly make use of it - particularly if it poses a periodic hazard, the timing of which they would have to be aware of. I'm not sure that I can come up with a decent rational for a phenomenon of this sort which would essentially remain consistent world-wide though. Faint, miniscule alterations in air pressure would occur close to the surface on a regular basis though, and even if undetectable by intelligent inhabitants these could trigger some sort of chain reaction.

[Epic Meepo]

Pulled that off of a random website I found by googling. In theory, then, if your species simply had a very precise Circadian rhythm, it wouldn't need an outside observance; people would simply know what time it is.

Looking at it, the Underdark cannot possibly be a closed system; all the crap living down there gets base energy from somewhere, most likely the above-ground world and light.[/quote]It's base energy is probably geothermal; heat from magma and all that. (Then again, since we're talking about a fantasy world, maybe the base energy just seeps in from the Elemental Plane of Earth.)

[Snargash Moonclaw]

Hmm - gravitational forces, even if not consciously noticeable could certainly produce observable cyclic phenomena. I recall an article in National Geographic many years (as in decades) ago regarding a similar study but don't remember any conclusions beyond the subject very quickly developing difficulties - the sleep cycle did spread out over a longer period of time but I don't think they managed to correlate it with any external cycles. The clearest conclusion seemed to be that the experience royally sucked for the subject. . .

In the absence of light to produce photosynthesis geothermal pockets would propose a reasonable source of energy to drive some similar process in subterranean flora - both in terms of establishing a basis for the food change and to solve the problem of limited oxygen and O2/CO2 transfer.