Conceptual Biome: hyper nutricious

I have a compost bin at home. It is a hotbin, it works by insulating its contents, allowing microbial life to heat it up to around 50°c, or even higher. In turn this allows the microbes to digest plant matter impressively fast. Now, I was digging through this to get the ripe, cooler compost at the bottom out. During this journey I found an impressive array of crawly critters and found inspiration for a biome.

What if life had the opportunity to develop in such an environment, continuously replenished with fresh biomatter, and involved vertebrate animals?

Do we have environments like it in real life? Bogs and swamps are the first pick as are forest floors, but these biomes still enjoy sunlight. Some runoff caves might have it on a smaller scale, as would sewers, or the bottom of a runoff pond. 

What would feed there, what would thrive without light but surplus heat? If the matter would not have been digested too thoroughly invertebrates like earthworms, slugs and pillbugs could certainly feed very well. But what if the nutrients were more chemically pure? In such a case microbial mats would be necessary as an intermediate. Whatever animal would live in these slimy hollows would need to either live on a cheese like meal of bacteria or on the animals that graze on this mass.

What kind of animals would live here - do we have real life parallels? Obviously, plenty of invertebrates fit the description, certainly more alien looking animals like rat-tailed maggots and sea cucumbers would thrive in the slime of such a place. Of vertebrate animals amphibians and fish might survive in the strangeness, their water dependent body suffering no harm from the moisture. Cave dwelling animals are often either of those, as they can go for long times without food, an adaptation unnecessary in the nutrient hollows. Mammals like moles or ferrets, strongly adapted to burrowing and living in tunnels and often insectivores, could thrive in less moist parts of such hollows.

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Microbial mat: the replacement for plants in this biome almost completely devoid of light. These undulating mats rise and bubble and solidify into solid chunks of a pale, smelly cheese.

Spongiform bacteria growths, poisonous and brightly colored to convey this to would be grazers. The brightly colored cheeses it produces could be considered a detritus, for the sake of creature simplicity.

King earthworm: a tight cluster of earthworms, wound together for safety. Individuals are dropped to live on their own sometimes, to in time either become a meal to kittypillars or bundle together with other worms to become a new king earthworm.

Steely springy poly: armored grazer. Produces a deluge of eggs ever so often, some unfertilised and edible to distract from the viable eggs. Jumps and sticks to the ceiling to avoid predators.

Fishbowl toad: this slow animal grazes at fungal, and microbial blooms and eats animal eggs. When threatened a swarm of wisp flutterfish swarm out of the pores in its back, protecting their plump and slow hive. - fish drawn at five times their size.

Predatory kittypillar: the true predator of these sumpy hollows. The pitter pattering of its many little toebeans are drums of encroaching horror to the bugs and pillbugs of the deep.

Creature possibilities: a colonial breed of naked molerat ettins would thrive in the dark, warm and a little noxious environment. Naked molerats even have natural resistance against co² to protect them in their little ventilated tunnels. A serpentine grendel could slink through the moist and narrow tunnels, feeding slowly on both microbes and wildlife. A shelled norn could drum on fishbowl toads, calling out the fluttering morsels inside.

Admittedly, the garbage dump is comparable, but not the same. It still holds light, and the allround toxic ecosystem does not allow natural life to thrive.

Arnout and I have been working on an interesting mixed project that would fit quite well in both the garbage dump and the hypothetical nutrient hollows. I shall write a little story and post it soon!