Hi Ray,
I'm writing to follow up on this automated email and share my perspective on your results.
(First let me apologize for the delay in getting this to you -- literally the day after I shipped this batch of samples to the sequencing facility, they sent out a notice that they'd been tasked with covid19 testing and sequencing services would be delayed. Interesting times!)
I'll start with diversity. Your tank had a high score, higher than a majority of tanks I've sampled. You're familiar with the debates on this subject, I'm sure -- how much diversity is needed? How much is enough? I won't claim to have an answer to those! Speaking for myself, I consider diversity beneficial, and would be happy with a score like this in my tanks. I'd feel confident ruling out low diversity as an explanation for any problems in the tank.
In contrast, your balance score was low. In other words, focusing on the major families of Bacteria and Archaea that are present in a typical aquarium, we find that these are present at very different levels in your tank than in the "typical" (average) tank.
Overall, your tank has the diversity of a healthy tank, but the levels of the different families are very different than expected. There is a bloom of one type dominating the community. You can see this clearly in the community barplot (part 2 in the report), in fact this way of graphing it kind of exaggerates the effect (the other families are present at low levels, but barely visible).
Your tank is dominated by Alteromonadaceae. These are a normal part of the aquarium microbiome, but typically they make up a minor fraction of the community. In your sample, the great majority of DNA sequences came from this single family. In fact, 99% of them were a single type, a member of the family not identified below the Family level (i.e. its in the database, but no one has assigned a genus or species name). Regardless of the specific identity, this is the classic signature of a bloom -- a single bacterial type that increases in abundance until it dominates the community.
These free living heterotrophic bacteria can live on a wide range of nutrients including many different sugars and amino acids, and are especially known for blooming in high glucose conditions. When a bloom occurs in a saltwater aquarium, this is one of the most common groups to bloom.
What does this mean? Does it matter? The different groups metabolize different nutrients, so we can infer that your tank will have a different capacity for processing nutrients (in the broad sense) than a tank with a more typical community. So I would only want to adjust the community balance if my tank was not processing nutrients in the way I wanted (e.g. if I had nuisance algae growth, cyano, etc). I will say that adding live mud was effective for reducing the dominance of this group, and promoting increases in the relative abundance of the others, in my tanks.
Nitrifying microbes -- your tank had high levels of ammonia-oxidizing microbes (AOM), and also plenty of nitrite-oxidizing bacteria (NOB). In many tanks the NOB are present at such low levels they are not detectable, so I interpret your results as an aquarium with relatively large nitrifying communities compared to many tanks.
Your tank shows no evidence of cyanobacteria, or any known pathogens of coral or fish in your tank. In addition to the known pathogens (what is described in the report), I also checked your sample for the bacteria associated with the Caribbean disease SCTLD, and only found one of these (Planktotalea sp.), which is found in a large fraction of tanks (16%) including some of mine. I do not think this bacterium by itself is a cause for concern. So overall, after your recent tank crash, I find no evidence of any bacterial
pathogens. One thing we can check off the list, at least.
I hope this was useful and will be happy to discuss further,
-Eli
Very cool getting his thoughts! Didn’t know he did this
I sent a couple questions will share those once he has a chance to reply.
