"ADVANCED TOPIC" Bacterial differences on reefs, day vs night

[Flippers4pups]

I came across this interesting read this morning of studies done on bacterial concentrations on reefs during the day and at night. Quite surprised at the findings.

https://phys.org/news/2019-04-bacteria-coral-reefs-synchrony-great.html

 

[Ron Reefman]

I'm not so surprised at the day vs night were quite different. But I didn't see any reason why the differences; or what effect the difference has on the reef. Now that would be interesting.

 

[Cory]

Ill bet the changes are due to two factors:

1) glucose release from photosynthesis durring the day
2) lack of oxygen durring the night

 

[Flippers4pups]

I'm leaning towards your first guess.

 

[Flippers4pups]

I'm not so surprised at the day vs night were quite different. But I didn't see any reason why the differences; or what effect the difference has on the reef. Now that would be interesting.

It's surprising that theres a drop. Is the mortality of the bacteria just such that numbers drop because of the lack of photosynthesis cause die off or they just recede to who knows where? Water collum?

 

[Dan_P]

I came across this interesting read this morning of studies done on bacterial concentrations on reefs during the day and at night. Quite surprised at the findings.

https://phys.org/news/2019-04-bacteria-coral-reefs-synchrony-great.html

Thanks for the link.

Interesting article. Very surprising results. To change the population make up so quickly is amazing. I continue to underestimate what bacteria can do. I would like to see the hour by hour make up of the bacteria populations.

 

[Dan_P]

Here is the link to the paper. Potentially, even more fascinating.

https://www.nature.com/articles/s41467-019-09419-z

 

[Ron Reefman]

It's surprising that there's a drop. Is the mortality of the bacteria just such that numbers drop because of the lack of photosynthesis cause die off or they just recede to who knows where? Water column?

Don (Flippers4pups) I agree! My guess is like so much other life, when it gets dark they find a place to hide out. But that probably anthropomorphize them way too much!

Dan, although way too much of that article either goes way over my head, or in one ear and out the other, it did stir up some interesting ideas in me. They cover a lot of info about the benthic community.

1) It makes me wonder if people who vacuum their sand are potentially doing more harm than good?

2) A few people here have asked about doing 2 day/night cycles every 24 hours as a way to faster growth in corals. That could also be causing issues related to this article and the need for a dark period in order for the benthic community to do their work?

 

[brandon429]

no alternate option comes close to the volume of invasion fixes we turn out with complete sandbed destruction rinsing, we would have to tell the thousands of DSB owners with cyano invasions to wait longer...it would end the deliberate reefing we apply to take control over wrecked tanks

Maybe one day though, tank surgery is hard work and people want an easier way without having to burn calories to get there / large tankers need a non invasive option /

Sandbed cleaning is the backflushing of the aquarium just as a zoo must backflush and clear their filth from the large filter systems so filtration can be restored vs clogging

It’s not that we’re not removing bac, we are, we are removing excess bac and waste and the results are all positive

To leave the sandbeds uncleared in the name of preserving clogging waste and bac is to leave five thousand cyano challenges unfixed just due to wanting bacteria that provide no benefit but instead command biological oxygen during power outages and compete with fish at those times, it’s also leaving massive amounts of waste that can be upturned if rocks fall or if a pump dislodges, that waste and bac kills tanks. We know that one of every fifty arrangements reduces nitrate, the 49 are where the need exists for help

The rinsed sandbed tanks function better for the masses collected in work threads, to not rinse them maintains the fully invaded condition they presented with and the liability that makes people hope they never have to disturb a dsb

 

[brandon429]

oceanic studies on sandbeds extrapolated out to reef tanks is how we got the 20+ yr DSB craze- we had to invent sand rinsing to defeat all the problems since DSB mechanics don't translate into aquariums with any consistency whatsoever

oceanic microbial studies translated into the cramped boxes we call tanks seems similar possibility

 

[Nano sapiens]

OP - Very interesting article and thanks for posting.

While these types of articles are very informative, my take is to remain cautious and say that our reef aquariums *may* have similar microbial day/night shift characteristics. Since a good amount of microbial variability exists between geographically similar island reefs day and night, I have to wonder just how much variability exists between our different captive reef systems.

Ron Reeferman - The effects of sand bed vacuuming on the microbial community is an interesting topic. What we can say is that removal of some bacteria does occur (as well as some macro organisms), but the majority of essential nitrifing/denitrifying bacteria remains in sufficient quantity to rapidly repopulate. The periodic 'flushing of the system' is analogous to the seasonal storms that frequent tropical reefs and, to a lesser but more frequent extent, daily tidal current influences that redistribute and also transport detritus away from the reef itself. Having said that, larger systems that employ creatures that frequently turn over the sand bed (and actively suspend detritus which can then be trapped and removed from the system) may not require the sand bed vacuuming that helps smaller systems to remain viable long term.

 

[Flippers4pups]

What about bare bottom tanks?

 

[Nano sapiens]

What about bare bottom tanks?

That's a good question. If one were to baseline multiple reef tanks, with and without sand, would we find that the microbial community would be made up of quite different microbial species percentages day and night? Possibly different species?

From all I've read regarding reef microbial life the takeaway for me is that if there's a niche, a species (most likely multiple species) will fill it. Many microbes are amazingly multi-talented and can adapt very quickly to meet the current conditions.

 

[MnFish1]

It's surprising that theres a drop. Is the mortality of the bacteria just such that numbers drop because of the lack of photosynthesis cause die off or they just recede to who knows where? Water collum?

Ill bet the changes are due to two factors:

1) glucose release from photosynthesis durring the day
2) lack of oxygen durring the night

I thought this was an interesting article - I read it 3 times - and still am not totally sure whether they are measuring a percentage (which is what it seems to be) - or raw numbers of bacteria. When you look at the source data it is talking about the percentages of each bacteria - so its unknown (as far as I can tell) whether the total bacteria number stays stable - and the populations of individual bacteria are rising/falling - or whether one bacteria is more prevalent during the day - ie. the total number of bacteria is much higher during the day because one group of bacteria markedly increases (i.e. its percentage markedly increases) whereas others stay the same. Im surprised they didn't concentrate on (to me) the biggest difference between day and night - the potential effect of light on growth (either because there is more 'food' for the bacteria during periods of light vs dark, etc.). Its not clear whether bacteria are 'dying' from what I read - just that the percentage changes day-night.

It also is suggested that during the day fatty acid metabolism predominates - and at night its organic carbons....

I don't see how this would apply to vacuuming sand beds?

 

[MnFish1]

OP - Very interesting article and thanks for posting.

While these types of articles are very informative, my take is to remain cautious and say that our reef aquariums *may* have similar microbial day/night shift characteristics. Since a good amount of microbial variability exists between geographically similar island reefs day and night, I have to wonder just how much variability exists between our different captive reef systems.

Ron Reeferman - The effects of sand bed vacuuming on the microbial community is an interesting topic. What we can say is that removal of some bacteria does occur (as well as some macro organisms), but the majority of essential nitrifing/denitrifying bacteria remains in sufficient quantity to rapidly repopulate. The periodic 'flushing of the system' is analogous to the seasonal storms that frequent tropical reefs and, to a lesser but more frequent extent, daily tidal current influences that redistribute and also transport detritus away from the reef itself. Having said that, larger systems that employ creatures that frequently turn over the sand bed (and actively suspend detritus which can then be trapped and removed from the system) may not require the sand bed vacuuming that helps smaller systems to remain viable long term.

I agree with this - there is no way to know/suggest that this also happens in our tanks. I'm not sure that seasonal storms are the same as vacuuming the sand though, A water change might be similar to a seasonal storm (with regards to this article). Not sure about vacuuming. They weren't measuring bacteria in the sand - they were measuring bacteria in the water column. If anything - I would think vacuuming the sand would increase as compared to decreasing bacteria in the 'water column' itself - and it would tend to decrease slightly the bacteria in the sand. But - I don't understand how this relates at all to the article?

 

[Flippers4pups]

I thought this was an interesting article - I read it 3 times - and still am not totally sure whether they are measuring a percentage (which is what it seems to be) - or raw numbers of bacteria. When you look at the source data it is talking about the percentages of each bacteria - so its unknown (as far as I can tell) whether the total bacteria number stays stable - and the populations of individual bacteria are rising/falling - or whether one bacteria is more prevalent during the day - ie. the total number of bacteria is much higher during the day because one group of bacteria markedly increases (i.e. its percentage markedly increases) whereas others stay the same. Im surprised they didn't concentrate on (to me) the biggest difference between day and night - the potential effect of light on growth (either because there is more 'food' for the bacteria during periods of light vs dark, etc.). Its not clear whether bacteria are 'dying' from what I read - just that the percentage chaages day-night.

It also is suggested that during the day fatty acid metabolism predominates - and at night its organic carbons....

I don't see how this would apply to vacuuming sand beds?

My question is are they retreating deeper into the reef, rocks, sand during the night or there's mortality happening?

 

[MnFish1]

My question is are they retreating deeper into the reef, rocks, sand during the night or there's mortality happening?

Right - Thats what I found confusing about the article - I couldn't see the 'absolute numbers' of bacteria - only percentages - meaning the numbers of bacteria change relative to one another - but I couldn't see whether the total 'bacterial mass' changes or not. It seems this would help determine what is actually happening - but I may be misreading the article. If Im remembering correctly - it said that the most prevalent bacteria during the day was 'non-motile' meaning it can't swim - so Im not sure how it would be able to hide.

Here is another interesting article on the topic: https://www.sciencedaily.com/releases/2016/10/161012144511.htm

 

[Dan_P]

Don (Flippers4pups) I agree! My guess is like so much other life, when it gets dark they find a place to hide out. But that probably anthropomorphize them way too much!

Dan, although way too much of that article either goes way over my head, or in one ear and out the other, it did stir up some interesting ideas in me. They cover a lot of info about the benthic community.

1) It makes me wonder if people who vacuum their sand are potentially doing more harm than good?

2) A few people here have asked about doing 2 day/night cycles every 24 hours as a way to faster growth in corals. That could also be causing issues related to this article and the need for a dark period in order for the benthic community to do their work?

The article had quite a few terms I needed to look up to fully appreciate the paper, and even then...I agree, papers like this stimulate thinking on many other aspects of reef keeping.

1) I wonder how vacuuming compares to a storm surge in terms of upsetting the substrate. Maybe some mixing or turbulence of the substrate is more normal than a substate that remains stable a long time.

It would be interesting to see just how many organisms are removed by vacuuming. Maybe vacuuming is a rough way to provide predation on the population of organisms that live in the sand, preventing over population that might minimize diversity. Who knows, maybe vacuuming sand encourages a more diverse sand bed. I suppose an energetic person with time one their hands to sample the substrate to count types and numbers of organisms could quickly determine the impact of vacuuming. This could even be an advanced high school or college marine ecology science project.

2) In terms of lighting, I would provide what is natural for plants and animals and not risk risk their health. I am nervous about running ad hoc experiments on animals. Besides, what’s the hurry? Slow and easy.