SPS corals "anticipating" lights out and extending polyps...

[jroovers]

Has anyone noticed their SPS extend their feeder polyps just prior to lights out in anticipation - I've noticed that several of my SPS do this. My lights are on timers so lights out is consistent. It seems the coral learns when lights out will happen and gets a head start by extending their feeders just prior to the lights actually going out. Pretty remarkable really, considering that it isn't just a purely sensory response if this is what is truly happening. I think in humans measuring time is a fairly upper central nervous system response... controlled in the brain... how does a coral do it? Has anyone else observed this?

 

[Acronic]

Perhaps once a coral is in a constant environment it "remembers" how much energy it produces/stores in a given day?

Maybe they are telling you that the days (light cycle) should be getting shorter? As do throughout the seasons.

Possibly coincidence...

Could the main lights (T5) shutting off cause an increase in macro/micro fauna in the water column?

Thats all i got for now

 

[Amphiprion]

I've noticed many corals doing this. Not sure how this response occurs or how any sort of potential internal clock functions in animals like corals. It seems they are certainly capable of estimating things on a circadian rhythm.

http://www.biolbull.org/content/151/1/236.abstract

 

[jroovers]

Yes, it does seem like they have some sort of circadian rhythm, much like plants open and close in response to light... however, to me it seems reactive in plants, they start closing when the light starts to fade, that doesn't happen in our tanks.

 

[DopeCantWin]

Yes, it does seem like they have some sort of circadian rhythm, much like plants open and close in response to light... however, to me it seems reactive in plants, they start closing when the light starts to fade, that doesn't happen in our tanks.

Using dimmable Leds you could do a full sunset and sunrise. My lights slowly turn on over around 3 hours. I haven't noticed much difference in polyp extension, maybe I'm not looking close enough.

 

[leveldrummer]

Im sure the corals definitely have a rythym that they fall into with feeding from light and the increase in pod movement once lights go off.

 

[franklypre]

My lights are basic on and off, SPS polyps are out all day but get much better length about 30 minutes before lights out. I get amazing PE about an hour after lights out, I attributed it to my feeding pappone at nights with AA around lights out. I do know it takes a few days to get this schedule down if the lighting timers are adjusted so I would figure it was the coral getting used to a schedule.

 

[footballdude2k3]

In every system I have had, I have noticed this, I thought people generally accepted this. Plants adjust, is it really surprising that corals do as well?

 

[sanchoy]

Yes, mine are on a time schedule.

 

[animalkingdom]

why do we keep comparing corals to plants...lol...think of jellyfish...much closer related to corals as they are cnidarians as well. They will often come out of the depths or return to the depths just before a change in daylight output. Also as was mentioned, circadian rhythm is a remarkable phenomenon that affects practically every cellular process. I wouldn't go as far as saying the learn when the lights go on and off due to pattern, but more so that nerve net of theirs has succumbed to a circadian rhythm influenced by your light schedule causing a preemptive reflex to an outside stimuli. I'm not a biologist (I'm a biochemist) so I dont know for sure, but those are my thoughts.

 

[Dog boy Dave]

My corals and fish as well anticipate the lights out.

 

[jroovers]

why do we keep comparing corals to plants...lol...think of jellyfish...much closer related to corals as they are cnidarians as well. They will often come out of the depths or return to the depths just before a change in daylight output. Also as was mentioned, circadian rhythm is a remarkable phenomenon that affects practically every cellular process. I wouldn't go as far as saying the learn when the lights go on and off due to pattern, but more so that nerve net of theirs has succumbed to a circadian rhythm influenced by your light schedule causing a preemptive reflex to an outside stimuli. I'm not a biologist (I'm a biochemist) so I dont know for sure, but those are my thoughts.

It is pretty remarkable and a lot of what you are saying makes sense. Even in vertebrates "learning" can occur at the basic lower nervous level - in corals it must be something similar. Somehow they are able to gauge time, pretty fascinating IMO. I've noticed that not all my corals do this, just some of them.

 

[jroovers]

Yes, it does seem like they have some sort of circadian rhythm, much like plants open and close in response to light... however, to me it seems reactive in plants, they start closing when the light starts to fade, that doesn't happen in our tanks.

I should clarify, I don't have dimmers in my tank.

 

[mesocosm]

Greetings Everyone

Predictable shifts in physiology (like polyp extension) and behavior (like feeding) in corals is well documented. Such rythms are often referred to as "Diel cycles". For example ...

Hoadley KD, Szmant AM, Pyott SJ (2011) Circadian Clock Gene Expression in the Coral Favia fragum over Diel and Lunar Reproductive Cycles. PLoS ONE 6(5): e19755. doi:10.1371/journal.pone.0019755
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019755


HTH ... :bounce3:

 

[jroovers]

Greetings Everyone

Predictable shifts in physiology (like polyp extension) and behavior (like feeding) in corals is well documented. Such rythms are often referred to as "Diel cycles". For example ...

Hoadley KD, Szmant AM, Pyott SJ (2011) Circadian Clock Gene Expression in the Coral Favia fragum over Diel and Lunar Reproductive Cycles. PLoS ONE 6(5): e19755. doi:10.1371/journal.pone.0019755
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019755


HTH ... :bounce3:

Never heard diel cycle... thanks for posting that link though. Pretty fascinating stuff (what I understood anyway). Interesting that the circadian clock exists all the way down at the molecular level through gene expression, and that the patterns in the studied favia are most similar to those observed in fruit flys!