Soil- beyond dirt into biodiversity

A Euzetes species of oribatid mite, Somerset, UK

Below our feet exists a dark, delicate, remarkable and mostly unexplored world of soil biodiversity. Within its hidden depths, a myriad of different lives and networks exist.

Unidentified oribatid mite, Street, Somerset, UK

Worms burrow, pulling detritus down from the surface into the depths. Seeds germinate, roots spreading downwards, questing blindly for nutrients and water, even as they push a first point out into the sunlight above. Fungal mycelia thread their way through the soil, across wet logs and the fallen leaves. Uncountable tiny creatures run between the clumping soil particles, darting down the worm burrows, following the dead spread of decaying roots or slowly feel their way in the darkness, alien senses alert for food, sex and danger. And through it all, everything excretes, adding even more to the soil.

Dicyrtomina saundersi, Wells, Somerset, UK

Fungal hyphae, Somerset, UK

Through the work of fungi, bacteria, protists and soil animals, minerals and organic matter in the soil are broken down, nutrients released and the soil enriched. Plants are sustained above in the daylight, and grazing animals survive on them in turn.

And so the food web extends outwards across the planet, lives passed up from the soil to feed life, prey to predator. And when each life is extinguished, it returns in one way or another back into the dark, to be broken down, recycled and repurposed once more. Soils are both the slow, steady heartbeat of the world and its truest witness.

Pseudoscorpion with Arrhopalites pygmaeus prey, Somerset, UK

Cepheus dentatus and micro snail, Somerset

Oribatid mite with water droplet, Somerset, UK

As above, so below. Soil mesofauna

Mesofaunal soil life often echoes the larger world above. Predators down in the darkness are as silent, ruthless and as focused as any cat or eagle. Mesostigmatan and prostigmatan mites and pseudoscorpions are effective and fast hunters, able to pursue symphylans and pauropods through the underworld tangle of roots, mycelium and the upper soil layers. Often though, their mesofauna quarry are made up from the relatively easy pickings of the soil’s grazing springtails, plentifully consuming their way through decay, even as they are being picked off, one by one. Everything is connected. Interaction, symbiosis and complexity. Life feeds life.

Linopodes motatorius mite, Ebbor Gorge, Somerset, UK

Soil animals have been been part of soil food webs and enabling nutrient exchange between the plants above for at least 400 million years. At their start, in the Devonian period, many complex plants had yet to evolve. By the end of the period, true leaved and rooted plants had appeared, as had seed bearing plants. We are in the presence of animals and ecosystems almost unchanged from those unimaginably early days, when their ancient ancestors first took advantage of damp, simple soils and began to terraform the land, making it suitable for the ensuing explosion of life.

T. britannicus, East Pennard, Somerset, UK

It’s both humbling and awe-inspiring to realise that we are only just beginning to understand the real complexity of soil animals, and their place in the world. We need to protect and sustain soil life if we are to continue to grow ourselves. We are at a turning point. Thanks to the UN, the FAO, the GSBI, the BSSS and many others, we are in a position to change.

So, my small contribution to World Soil Day is this rather poetic blog post, and a small celebration of the animals that I love through photographs, mainly taken around South Somerset in the UK, where I live.

Tomocerus species Somerset, UK

Land planarian, Burrington Combe, Somerset, UK

Cepheus dentatus Somerset UK

Dicyrtomina species Slovenia