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This is interesting and more along the lines of what I would expect - ie that diversity decreases with time - rather than increasesGot my @AquaBiomics results back last week for 3 tanks.
All 3 tanks are doing quite well (images are in my sig); tests were done primarily out of curiosity.
Tank 1: ForeReefWall, 2 years 7 months, 100 g, mixed reef, live & dry rock, algae refugium, no carbon dosing, intermittent ozone use, no uv.
230 types, 0.62 diversity, 0.24 balance.
So this tank has good diversity, but it's quite different than the given distribution for the 'average' tank.
In particular, there is a high proportion of vibrionaceae and decreased pelagiobacteriaceae and flavobacteriaceae.
First, is the 'average' tank data valid? Were enough healthy reefs sampled to represent the spectrum of successful tanks?
Second, assuming my tank is off from some projected optimum ratios, what's the significance of this? In particular, the tank has virtually no pelagiobacteriaceae while others have quite a lot; is this important?
Cyanobacteria slightly elevated. However there is no cyano visible on the sand or rocks. It's possible there was some on the return nozzle at the time the sample was taken, and this would have been blown to the water sampling location. Otherwise it's hard to explain.
One fish pathogen was present! Photobacterium damselae. Looked it up, it's in the vibrio group and a fairly nasty actor. Causes outbreaks in commercial fisheries. Hemorrhagic ulcerations and sores. It's interesting because I have no sick fish currently, have never had any fish with red sores, and no fish deaths in this tank in almost 2 years. There are apparently different strains of this bacterium, and the most virulent ones contain a specific plasmid coding for toxins. It's possible that the strain or strains in my tank don't have this plasmid.
Can also infect humans who come in contact with water/fish, causes necrotizing fascitis sometimes requiring amputation and even several fatalities! Wow. Guess I should start using gloves.
Tank 2: BackReefArches, 1 year 9 months, 100 g, mixed reef, dry rock, algae refugium, no carbon dosing, intermittent ozone use, no uv.
134 types, 0.15 diversity, 0.41 balance.
This tank has low diversity, but is closer to the average tank data as far as balance.
The low diversity surprised me a bit, as the tank is thriving with a large population of fish, corals and anemones.
But on the other hand, it was started with all dry rock, so this may have been a factor.
Interestingly, even though the balance is better, this tank also has virtually no pelagiobacteriaceae. Significance?
No cyano, fish pathogens or coral pathogens.
Tank 3: NanoReefGarden, 5 months, 20 g, zoas & acans, dry rock, no refugium, no carbon dosing, no ozone or uv.
184 types, 0.38 diversity, 0.24 balance.
This tank has reasonable diversity, surprising considering how new it is, but again, not very similar to the reference data.
Again missing the pelagiobactericeae and flavobacteriaceae.
The tank has a very large proportion of methylophilaceae. No idea why or if it's significant.
No cyano, fish pathogens or coral pathogens.
So, all in all, the results were a bit surprising to me. I would have expected more diversity in the two larger older tanks. And I'm not at all clear on why certain bacterial families are virtually missing while others are in excess. Also not clear what can be done about it, or even if taking any specific action is worthwhile, likely to succeed, or make any difference. Anecdotal evidence suggests that bottled bacterial supplements are unlikely to increase diversity much. Adding pieces of live rock would probably be more beneficial, but this comes with the not insignificant risk of introducing pests which might have far more disastrous consequences than bacterial imbalance would.
Interesting data but we've still barely gotten started on what all this means.
I've already ordered some more kits; will test again in perhaps 3 months, whether I take any specific action or not.