EcoSphere

Ground made of carbon

The Fens

Cambridgeshire, England

Drained peat that has been sinking for three centuries — measured, not estimated, against an iron post driven down to the clay.

The ground under

The Fens, Cambridgeshire

52.4886, -0.2222 · keep going ↓

5 cmTopsoil

114.1g/kg

grams of organic carbon per kilogram of soil

The living layer: dead leaves, roots, bacteria, and the fungal threads that bind them into crumbs. Almost everything that happens to soil carbon happens here first.

30 cmThe stock

73t/haModerate

tonnes of organic carbon per hectare, top 30 cm

The ordinary range for productive farmland and managed gardens in temperate Europe.

ISRIC — World Soil Information

Modelled at 250-metre resolution from global soil surveys, and read from SoilGrids on 2026-09-01. SoilGrids publishes in versioned releases rather than continuously, so this figure is the current one until they publish again.

deeperThe network

7,833 fungal records near here

Each one is a specimen somebody found and wrote down. The species below are only the ones that fruit visibly; the threads that do the work almost never appear above ground at all.

GBIF — Global Biodiversity Information Facility

Each name links to the original record, with its collector, date and dataset.

Reading this figure

The figure above is carbon stock over the top thirty centimetres, and that is the wrong depth for peat. Peat here runs metres deep, so a reading taken from the first thirty centimetres of it captures a small fraction of what is actually stored and reports a peatland as though it were ordinary soil. Read it as a floor, not a total: the comparison it supports is with the other places on this site measured the same way, not with what is underneath this one.

Why this ground

Ground made of carbon

Peat is plant matter that never finished rotting, because water kept the air out. It is the densest carbon store on land, and it only holds while it stays wet.

The Fens were a wetland until seventeenth-century engineers cut channels through them. What was exposed underneath was peat, and it turned out to be some of the most productive arable land in England.

It is also disappearing. At Holme Fen an iron post was sunk in 1851 until its top was level with the ground. The ground is now around four metres below the top of that post. The peat did not wash away; most of it oxidised — reacted with air that drainage let in and left as carbon dioxide.

This is the cleanest illustration of a general rule the rest of this site keeps circling. Soil carbon is not a fixed property of a place. It is a balance between what is added and what is allowed to burn, and drainage moves that balance faster than almost anything else people do to land.

Read this against

Or measure somewhere else