How would tide-affected life forms function if transported to space?

September 15, 2015 1:09 PM

What life forms from Earth are specifically affected by the moon and tides, and do we know anything about how these plants, animals or other living creatures would be affected by putting them in outer space?

Asking as I work on a short fictional story about werewolves in space. I've come up with a number of imagined scenarios for how a werewolf might change or not change while in earth's orbit, and how that might be different once far from the gravitational pull of the earth and the moon. But I'd love to incorporate real science into my story, if any research or theories exist about non-fictional moon-influenced earth life forms when transported into space.

posted by croutonsupafreak to Science & Nature (5 answers total)

Best answer: Circatidal cycles change how marine life come out to eat and reproduce:

Another place, another timer: Marine species and the rhythms of life

During low tides, acoels emerge from the sand and expose themselves and their photosynthetic endosymbionts to the sunlight. Prior to the tide rising, acoels burrow again into the darkness of the sand. During the summer months, this migration cycle follows a circatidal rhythm of 12.4 h (Fig. 3). Experiments from the early 20th century showed that when adult animals were removed from their environment and placed in a glass container in the laboratory, they maintained free-running movement cycles for 5 days 8–10. This observation provides the first evidence for the existence of a circatidal clock in a marine organism...

Classical authors – starting with Aristotle – had already seen a connection between the different phases of the moon and the size of certain marine invertebrates. Zoological descriptions of the early and mid 20th century have since re-established the connection between the apparent size of marine animals with moon. More precisely, these studies have revealed that the maturation of gonads in these animals depends on a lunar cycle (see e.g. 15, 16 and Fig. 2). In species where the gonads contribute to a large proportion of the body mass, such as sea urchins, this effect is particularly prominent.

These behaviors cost energy and put the organism at risk of predators, so disrupting circatidal cycles might change how it behaves in the presence or absence of predators.

Disrupting the tidal cycles might also change their metabolism, how well they are able to process food, particularly when the availability of certain food can be tied to how other organisms' behaviors are timed:

Metabolic molecular markers of the tidal clock in the marine crustacean Eurydice pulchra

11 of the 13 known mitochondrially encoded, protein-coding genes were detected, and 10 revealed a clear, statistically significant circatidal pattern of expression (Figure 1D,E). Consistent with their co-regulation, the RNAs peaked with a common phase, coincident with the resting phase of the swimming rhythm, and with PRX overoxidation. Thus, expression of the components of complex I (NADH dehydrogenase) and complex IV (cytochrome c oxidase) are circatidally regulated within mitochondria. Nascent mitochondrial RNA is translated co-transcriptionally. It is likely, therefore, that the RNA rhythms are translated into tidal rhythms of abundance of proteins serving electron transport and oxidative phosphorylation, anticipating the demands of the tidal rest/activity cycle [5].

Taking a look at the references at the ends of those two articles should point to other research in this field.
posted by a lungful of dragon at 1:26 PM on September 15, 2015 [2 favorites]

Best answer: All of the examples I've heard of are, as in a lungful of dragon's examples, mediated by the tides. It's unlikely that the light of the moon makes a difference (because clouds would completely mess up the rhythm), and the direct gravitational effects of the moon are extremely small (in the range of 1 part per million). So as long as you kept moving water on and off of the creatures at the right times, they mostly wouldn't notice. If you stopped doing that... hmm... I don't happen to know.
posted by clawsoon at 1:35 PM on September 15, 2015 [1 favorite]

Best answer: The "Intertidal zone" is the name for an ecosystem that exists on ocean-side rocks between low tide and high tide. In some places it forms distinct lines, with some kinds of creatures living near the top, where they only get water a couple hours a day, and at the bottom, where they're immersed most of the time, and further bands in between.

If there were no tides, this wouldn't exist.
posted by Chocolate Pickle at 4:01 PM on September 15, 2015 [1 favorite]

Response by poster: Thanks, folks. I feel like I may have to send an actual werewolf into actual outer space to get a definitive answer to the question that plagues me, but I'll be googling the terms and examples you've shared to improve my theoretical understanding

I think I need to get a better grasp on what (if any) relationship exists between how full the moon is and the tides, too, if I want to be as scientific as possible with this very important research.
posted by croutonsupafreak at 3:30 PM on September 17, 2015

Best answer: Your last question: The visual lighting of the moon is a function of where it is in its orbit relative to the sun.

The sun creates tides on the earth, too, but they aren't very large by comparison. However, if the moon is full (directly away from the sun) or new (directly towards the sun) then the moon's tides and the sun's tides are in phase and add to one another, so the amplitude of the tide is greatest.

When the moon is one quarter or three quarters, then they are exactly out of phase, and the sun's high tide coincides with the moon's low tide, and vice versa.

None of this has anything to do with what the moon looks like. The lighting of the moon is a parallel side effect of the moon's position in its orbit.

I think it is worth your while to read the Wikipedia article about tides.
posted by Chocolate Pickle at 4:17 PM on September 17, 2015 [1 favorite]