Guilds: A Functional Way to Think About Your Gut

Your gut isn’t a list of species or a pie chart. It’s not a “good vs. bad bacteria” morality play. It’s an ecosystem — a shifting, breathing, fermenting community of microbes that behave less like a census and more like a set of teams.

Ecologists call these teams guilds: groups of organisms that do similar jobs, even if they’re not related. Birds, bats, and butterflies all pollinate. Wolves and hyenas both scavenge. Guilds are about function, not family trees.

Your gut works the same way.

And because Aeris measures gases — the outputs of microbial metabolism — it’s often more useful to think in terms of what the microbes are doing rather than who they are. Below are six functional guilds that show up again and again in gut physiology, and the kinds of gas patterns we might see with Aeris when each one is in the spotlight.

None of this is diagnostic. It’s just a way of making sense of a very complex system. Plus, Guilds are kind of cool, and way easier to type than microbiota. Let’s meet a few of our players:

The Fermentation Guild

The workers.

These microbes break down carbs and fibers into hydrogen and short‑chain fatty acids. They’re the engine of the gut.

What Aeris might see:

• A clear rise in H₂ after meals

• Bigger peaks after fiber‑rich foods

• Lower, flatter curves during fasting or low‑carb stretches

• Chaotic, multi‑peak curves when things are out of rhythm

Fermentation is normal. It’s supposed to happen. The shape of the curve tells you more than the height.

The Methanogen Guild

The minimalists.

A tiny group of archaea that consume hydrogen and produce methane. They don’t do much else, but they influence motility more than you’d expect.

What Aeris might see:

• A steady CH₄ baseline

• Blunted H₂ peaks (because methanogens grab the hydrogen)

• Slow, smooth curves that take their time returning to baseline

Higher methane often corresponds to slower transit. Lower methane, the opposite.

The Sulfur‑Reducer Guild

The bullies.

These microbes use sulfur compounds to make hydrogen sulfide. In small amounts, H₂S is a signaling molecule. In larger amounts, it’s… less friendly.

What Aeris might see:

• Elevated H₂S, especially after protein‑heavy meals

• Suppressed or unstable H₂ (sulfur‑reducers compete for hydrogen)

• Low CH₄ (methanogens get pushed out)

• More volatility in general

When this guild gets loud, the neighborhood feels it.

The Butyrate‑Producer Guild

The healers.

These microbes turn fermentation intermediates into butyrate — a postbiotic that supports the gut lining and keeps inflammation in check.

What Aeris might see:

• Lower, steadier H₂S

• Smoother H₂ curves

• Less day‑to‑day volatility

• A general sense of “calm” in the gas patterns

When this guild is thriving, the whole ecosystem tends to behave better.

The Mucin‑Support Guild

The architects.

These microbes help maintain the mucus layer that lines the gut. They’re quiet, sensitive, and essential.

What Aeris might see:

• Low, stable H₂S

• Smaller post‑meal swings

• Consistent day‑to‑day patterns

• Less noise in the VOC channel

When the mucosal barrier is happy, the gas signatures often look more predictable.

The VOC Guild

The opportunists.

Not always harmful, but quick to take advantage of stress, low fiber, or high protein. They produce a grab‑bag of volatile compounds.

What Aeris might see:

• Spikes in VOCs, especially after protein‑heavy meals

• Irregular H₂ patterns

• Occasional rises in H₂S if sulfur‑reducers join in

• More noise overall

They’re a reminder that ecosystems respond to what you feed them — and how you feel.

Why this matters

Aeris doesn’t tell you which species you have. It tells you what your ecosystem is doing right now. Thinking in terms of guilds makes the signals easier to interpret:

• A high H₂S day might mean the sulfur‑reducers are throwing their weight around.

• A smooth H₂ curve might mean fermentation is efficient and predictable.

• A rising CH₄ baseline might reflect slower transit.

• A noisy VOC channel might suggest a shift toward protein fermentation.

None of these are “good” or “bad” on their own. They’re just patterns, and patterns are how ecosystems speak.

Aeris can help us listen.