I've meant to start this discussion thread for a while... so here we go.
Reef hobbyists have a lot of ideas about biodiversity and what it means in a reef system. A lot of these ideas (mine included) are reasoning from personal experience of myself and others, and how we think it ought to work. Mostly this is because the concepts are fuzzy and we just don't have much data - so reasoning from collective experience is the best we've got in these data-sparse areas.
But that's changing - there are a lot of concepts in this discussion that we now actually have pretty good data to ground ourselves in and think more concretely about - surrounding the concepts of biodiversity, maturity, balance etc. BRS did a series of 11 videos (full playlist) in 2022 "Biome Cycling" involving 12 side by side aquaria run in parallel for 10 months, with detailed observations and data. This was done at a scale and expense that the hobbyist can't duplicate and I think the results are of good quality, and the data is worth digesting even if I don't buy all his reasoning and conclusions. Given how much we think and talk about these ideas like the "ugly phase", biodiversity, maturity, balance etc - this data deserves way more discussion than it has received so far. It's a ton of data, observations, and reasoning to sift through. Way more than one post,
So I'll try to occasionally pull one big idea at a time that I think is well demonstrated by the data, and is worth talking about.
Short summary of the overall exercise. (meet the tanks - Ep 3)
They started 12 tanks from different initial ingredients:
1) Dry sand and Rock - control
2) Dry sand and Rock + Coral frags/colonies
3) Dry rock, live sand in a bag
4) Synthetic live rock cured in seawater
5) Dry Rock and sand + live rock rubble cured in the dark, in dark sump
6) Live Rock and Sand directly from established tank
7) Dry rockand sand + 2 cups of established tank sand
8) Paper-wet indonesian live rock and dry sand
9) Gulf live rock shipped in water and dry sand
10) Dry rock and sand + Aquaforest reef mud
11) Dry rock and sand + 100% water from established system
12) Dry rock and sand + biobrick from established system
All tanks were given two clownfish and were kept dark for 4 weeks, then moderate "LPS lighting" from weeks 5-10, then high "SPS lighting" from weeks 11-15.
They tested each tank via aquabiomics at week 2, week 4, 10, and 15.
(What aquabiomics is and what was measured - Ep 4)
Idea 1: Biodiversity is dead, Balance is the new "biodiversity"
Aquabiomics gives two overall statistical measures/scores:
Biodiversity is a statistical measure of the bacterial families that make up more than 1% of the measured genetic material.
Balance is a measure of how much the present bacterial families look similar to those in established reef systems.
Here's the backwards thing that kills many ideas about biodiversity (like mine). In essentially every system that was started with any live material, The Biodiversity fell while the Balance rose. The biodiversity is initially higher especially in tanks started with a lot of live material like the live rock, but gradually falls. The Balance score - on the other hand, starts extremely low, but in every decent-looking tank climbs over time to more closely resemble typical reef tanks.
So early on, the high biodiversity likely represents a disturbed system, with many food sources of dead, disturbed and out of place organisms, and quick bacterial growth in response - but those early bacterial families look nothing like the eventual expected families that will make up a well-established tank.
Put another way, it is the death and loss of early bacterial diversity that helps shape the microbiome to look more like eventual reef systems. The Balance is a far better measure of this process of moving towards an established system than the biodiversity is, and perhaps the balance score isn't a terrible marker for biofilm maturity and system stability overall.
Ryan explains this idea of high biodiversity in tanks that look awful, and the balance being a better indicator here Ep 7 3:01-3:48
This data is in the videos Ep 5, 6, 7.
And here's Idea 2a and 2b in post 51
Reef hobbyists have a lot of ideas about biodiversity and what it means in a reef system. A lot of these ideas (mine included) are reasoning from personal experience of myself and others, and how we think it ought to work. Mostly this is because the concepts are fuzzy and we just don't have much data - so reasoning from collective experience is the best we've got in these data-sparse areas.
But that's changing - there are a lot of concepts in this discussion that we now actually have pretty good data to ground ourselves in and think more concretely about - surrounding the concepts of biodiversity, maturity, balance etc. BRS did a series of 11 videos (full playlist) in 2022 "Biome Cycling" involving 12 side by side aquaria run in parallel for 10 months, with detailed observations and data. This was done at a scale and expense that the hobbyist can't duplicate and I think the results are of good quality, and the data is worth digesting even if I don't buy all his reasoning and conclusions. Given how much we think and talk about these ideas like the "ugly phase", biodiversity, maturity, balance etc - this data deserves way more discussion than it has received so far. It's a ton of data, observations, and reasoning to sift through. Way more than one post,
So I'll try to occasionally pull one big idea at a time that I think is well demonstrated by the data, and is worth talking about.
Short summary of the overall exercise. (meet the tanks - Ep 3)
They started 12 tanks from different initial ingredients:
1) Dry sand and Rock - control
2) Dry sand and Rock + Coral frags/colonies
3) Dry rock, live sand in a bag
4) Synthetic live rock cured in seawater
5) Dry Rock and sand + live rock rubble cured in the dark, in dark sump
6) Live Rock and Sand directly from established tank
7) Dry rockand sand + 2 cups of established tank sand
8) Paper-wet indonesian live rock and dry sand
9) Gulf live rock shipped in water and dry sand
10) Dry rock and sand + Aquaforest reef mud
11) Dry rock and sand + 100% water from established system
12) Dry rock and sand + biobrick from established system
All tanks were given two clownfish and were kept dark for 4 weeks, then moderate "LPS lighting" from weeks 5-10, then high "SPS lighting" from weeks 11-15.
They tested each tank via aquabiomics at week 2, week 4, 10, and 15.
(What aquabiomics is and what was measured - Ep 4)
Idea 1: Biodiversity is dead, Balance is the new "biodiversity"
Aquabiomics gives two overall statistical measures/scores:
Biodiversity is a statistical measure of the bacterial families that make up more than 1% of the measured genetic material.
Balance is a measure of how much the present bacterial families look similar to those in established reef systems.
Here's the backwards thing that kills many ideas about biodiversity (like mine). In essentially every system that was started with any live material, The Biodiversity fell while the Balance rose. The biodiversity is initially higher especially in tanks started with a lot of live material like the live rock, but gradually falls. The Balance score - on the other hand, starts extremely low, but in every decent-looking tank climbs over time to more closely resemble typical reef tanks.
So early on, the high biodiversity likely represents a disturbed system, with many food sources of dead, disturbed and out of place organisms, and quick bacterial growth in response - but those early bacterial families look nothing like the eventual expected families that will make up a well-established tank.
Put another way, it is the death and loss of early bacterial diversity that helps shape the microbiome to look more like eventual reef systems. The Balance is a far better measure of this process of moving towards an established system than the biodiversity is, and perhaps the balance score isn't a terrible marker for biofilm maturity and system stability overall.
Ryan explains this idea of high biodiversity in tanks that look awful, and the balance being a better indicator here Ep 7 3:01-3:48
This data is in the videos Ep 5, 6, 7.
And here's Idea 2a and 2b in post 51
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