The Lives and Deaths of Peat Bogs

Spending over a month doing restoration work on Little Woolden Moss has inspired me to find out more about the ecology of peat bogs – what they are, how they come to life, how they function, how exploitation by humans has led to the deaths of 80% of them, and how they are currently being revived.

The information that follows has been gleaned almost exclusively from the IUCN Peatland Programme’s Conserving Bogs: The Management Handbook, which can be downloaded for free HERE.

What is a Peatland?

A peatland is ‘first and foremost’ a ‘wetland’. Water is essential because peat does not form when the land is dry. Peat is ‘a wetland soil composed largely of semi-decomposed organic matter deposited in-situ, having a minimum organic content of 30% and a thickness greater than 30cm’ and a peatland ‘an area with or without vegetation but possessing a naturally accumulated peat layer at the surface.’

The EU Habitats Directive distinguishes between ‘active bog’ as ‘a system that supports a significant area of vegetation which is normally peat forming’ and ‘non-active bog’ which does not. It is my intuition that a peat-forming bog is a living bog and a bog that is not forming peat is dead.

The most common type of peat bog is raised bog ‘accumulations of peat’ ‘within a non-peat landscape’ or ‘a fen-peat landscape’ mainly found in the lowlands. Such bogs form distinct domes that rise above the surrounding landscape by as much as 10 metres.’ The ‘classic type’ is basin raised bog – ‘formed within a shallow lake that has then infilled through terrestrialisation’.

Other types include floodplain raised bog, estuarine raised bog, and the evocatively named Schwingmoor ‘swinging bog’ which forms as ‘a floating raised dome’ ‘over a deeper lake basin’.

A rarer type of bog is blanket bog which forms as mantles of peat in the uplands. Types include watershed bog, saddle bog, valleyside bog, spur bog, minerotrophic bog, and ladder fen.

How Do Peat Bogs Form?

The UK’s ‘classic’ basin raised bogs developed over basins created in the aftermath of the last Ice Age by the melting of dead ice, surrounded by sediment, which was left when the glaciers retreated. These basins filled with water and became lakes which were ‘colonised by a fringe of fen vegetation’.

As this vegetation decayed the lakes were filled in with ‘fen peats and sediment’. The plants at the centre were ‘cut off from the nutrients at the lake margins.’ These nutrient poor, waterlogged conditions were perfect for sphagnum mosses to come to dominate, forming a thick carpet.

As the sphagnum began to slowly decompose it resulted in an accumulation of peat. When this reached a thickness of half a metre above the original level of the lakes the bogs were separated from the groundwater and became ombotrophic (rain-fed) so dependent on precipitation alone. Slowly they expanded, escaping their lake basins, to become the lowland raised bogs we know of today.

Blanket bogs formed in a similar way in waterlogged areas of our uplands such as saddles and spurs.

The Structure of Living Peat Bogs

All living peat bogs have a ‘diplotelmic structure’ (telm is Greek for marsh, pool, standing or stagnant water’). The acrotelm (from Greek acro ‘topmost’) is the surface of peat-forming vegetation and the catotelm (from Greek cata ‘down’) is the ‘inert, permanently waterlogged peat store’.

This structure is created, mainly, by sphagnum mosses. Their densely packed heads, known as capitula, form a thick carpet around 2cm deep. Sphagnum leaves are specially designed to cope with water logging due to their ‘large and empty hyaline cells’ ‘sandwiching smaller photosynthetic cells’. This provides a ‘large surface area for cation exchange’ – absorbing ‘nutrients dissolved in water’.

Their swapping of scarce nutrients for hydrogen ions acidifies their surroundings making them more favourable for sphagnum colonisation and unfavourable for decomposer micro-organisms. This leads to conditions that are favourable for peat formation. Sphagnum mosses also release a ‘pectin-like substance’ called sphagnan which coats the upper parts of the plant and the water and ‘inhibits nitrogen uptake in decomposer bacteria’ further slowing the processes of decomposition.

(The anti-microbial properties of sphagna led to the use of packs of sphagnum as dressings in World War I).

Sphagnum mosses ‘grow from the top of the plant – the apices – and die at the base’ at around 10cm. The stems and branches collapse, flatten, and break down to form peat. This is the point of transfer to the catotelm. The living layer of the acrotelm can be between 10cm and 40 cm deep. The catotelm can extend up to several metres (the deepest peat bog, in the Netherlands, is nearly 7m deep).

Sphagnum are the dominant species of mosslands and our lowland raised bogs include species such as S. magellanicum, S. papillosum, S. capillifolium, S. tenellum, and S. cuspidatum. Other plants that can survive in these conditions include common cottongrass (Eriophorum angustifolium), hare’s-tail cotton-grass (Eriophorum vaginatum), cross-leaved heath (Erica tetralix), bog rosemary (Andromeda polifolia), and round-leaved sundew (Drosera rotundifolia). Sundews are carnivorous bog plants ‘which gain extra nutrients (particularly nitrogen) by catching and absorbing insects.

Ombotrophic bogs gain their water not only from rainfall but from ‘occult precipitation’ – mist and fog.

Exploitation and Death

Humans have been exploiting peat bogs for fuel for many centuries. This began with domestic peat cutting. ‘Turves’ were cut by hand with a spade from banks 10m to 100m long, then stacked nearby to dry. The banks were reached by ‘peat tracks’ and carried by horse and cart or in creels or baskets

Traditional cutting has been replaced by ‘tractor-driven machines’ that ‘cut slits beneath the surface’ to extract ‘sausages’ of peat that are left on the surface to dry before their use as burning briquettes’.

Commercial peat extraction for horticulture and energy is currently taking place on a far greater scale and is far more damaging. Peat accumulates at ‘2mm a year’ and ‘a hundred times that depth’ is removed each year by modern extraction methods such as peat milling. This begins with the drainage of the land by ‘regularly spaced deep drains’. Once the upper peat has dried ‘the surface vegetation is removed’ to create ‘bare black fields’ then the top layers are ‘rotovated’ or ‘milled’ to allow further drying before the peat is ‘bulldozed into long ridges’ then bagged or taken to power stations.

Drainage of the land for human benefits has deadly results. The immediate effect is water loss from, and the drying out of, the acrotelm, leading to the decline in sphagnum and other peatland species.

Loss of water from the catotelm is slower (up to one million times slower than the speed of a snail!). However, water in the spaces between peat fragments seeps into the drain. This causes peat adjacent to the drain to collapse and shrink. This process is called ‘primary consolidation’.

The ‘drier catotelm peat adjacent to the drain itself becomes a heavy load on the peat beneath because the drained layer no longer floats buoyantly within the bog water table.’ It ‘compresses the peat beneath it and squeezes more water from the peat into the drain, causing the bog surface to subside still further.’ The entire depth of the catotelm subsides. This is ‘secondary compression’.

Drainage ‘allows oxygen to penetrate the catotelm’ which is usually prevented by waterlogged conditions. ‘Preserved plant material is thus lost in the form of carbon dioxide (CO 2 ), leading to further subsidence as the peat material itself vanishes into the atmosphere.’ This is ‘oxidative wastage’.

‘The three drainage processes – primary consolidation, secondary compression and oxidative wastage – cause the peat to subside progressively and continuously across an ever-expanding area. Drainage in effect continually widens the dimensions and impact of the drain.’

‘Where drainage leads to the loss of the peat-forming layer, carbon sequestration may cease’ and there are increases in the production of dissolved and particulate organic carbon (DOCs and POCs).

A peat bog in this state is termed haplotelmic. Without an acrotelm it is no longer living.

Sadly ‘80% of UK peat bogs now lack an active living surface as a result of human impacts’ and ‘therefore now have little or no capacity for resilience in the face of future climate change.’

Reviving Peat Bogs

Peat bogs can be revived by blocking drains and building dams and bunds to prevent water loss and begin the long process of silting up with vegetation that will lead to the development of sphagnum.

Bare peat can be re-vegetated by planting hardy species such as common cottongrass and hair’s tail cottongrass.

Sphagnum mosses can then be planted amongst the common cottongrass to form new hummocks and once these have formed species such as cross-leaved heath and bog rosemary can be planted on them.

Doing this research has provided me with a greater depth of understanding of the workings of peat bogs and the impact of my work on Little Woolden Moss. It has shown me how restoring a living acrotelm of sphagnum is essential to reviving a bog and reinstating the process of peat formation which sequesters carbon in the depths of the catotelm rather than releasing it into atmosphere.

I look forward to revisiting the mossland in years to come and watching its return to life.

The Peat Pit – the Fish Pond of Gwyn ap Nudd

For nearly a decade I have been writing enthusiastically about two topics – the lost wetlands of Lancashire (lakes, marshlands, wet woodlands, peat bogs) and my patron god, Gwyn ap Nudd. I didn’t realise there was a link until I watched the first of Gwilym Morus-Baird’s videos on Gwyn’s folklore.

Here he shared three poems by the Welsh poet Dafydd ap Gwilym (1315-1350). Whilst I had read ‘Y Dylluan’, ‘The Owl’, and ‘Y Niwl’, ‘The Mist’, I was unfamiliar with ‘Y Pwll Mawn’, ‘The Peat Pit’. In this masterfully crafted and, in places, humorous poem, Dafydd ap Gwilym narrates how he and his ‘grey-black horse’ foolishly get lost on a ‘cold moor’ in the darkness and fall into a peat-pit.

Unfortunately much of the craftsmanship of the poem in Welsh is lost in translation. The original is written in strict metre with seven syllables in each line, follows an AA BB rhyme scheme, and also contains internal rhyme (possibly cynghanedd – it is beyond my skill to judge). It also features repetition.

Gwae fardd a fai, gyfai orn,
Gofalus ar gyfeiliorn.
Tywyll yw’r nos ar ros ryn,
Tywyll, och am etewyn!
Tywyll draw, ni ddaw ym dda,
Tywyll, mau amwyll, yma.
Tywyll iso fro, mau frad,
Tywyll yw twf y lleuad.

Woe to the poet (though he might be blamed)
who’s lost and full of care.
Dark is the night on a cold moor,
dark, oh, that I had a torch!
It’s dark over there, no good will befall me,
it’s dark (and I’m losing my senses) over here.
Dark is the land down below (I’ve been duped),
dark is the waxing moon.

Here, in the first verse, we see that not only are the rhyme and metre lost in the English translation but also the repetition of tywyll ‘dark’ at the beginning of six of the eight lines.

Dafydd ap Gwilym goes on to lament his ‘woe’ ‘that the shapely girl, of such radiant nature, / does not know how dark it is’ before admitting his foolhardiness for venturing out on the moors at night.

It’s not wise for a poet from another land,
and it’s not pleasant (for fear of treachery or deceit)
to be found in the same land as my foe
and caught, I and my grey–black horse.

Here we gain a sense of unhomeliness, of the poet having ventured far from home, to an arallwlad ‘other-land’ – to the land of his ‘foe’, who we might surmise is the otherworldly Gwyn, from the following lines and those in other poems. In ‘Y Niwl’ the mist is described as ‘his two harsh cheeks’ which ‘conceal the land’ ‘thick and ugly darkness as of night / blinding the world to cheat the poet.’

After speaking of how he and his horse drowned in the peat-pit, Dafydd ap Gwilym goes on to describe evocatively and curse the place of his undoing and to associate it directly with Gwyn and his spirits.

Such peril on a moor that’s an ocean almost,
who can do any more in a peat-pit?
It’s a fish–pond belonging to Gwyn ap Nudd,
alas that we should suffer it!

I love this image of ‘a moor that’s an ocean’. It reminds me of the German term schwingmoor ‘swinging wetland’. This evokes how a bog can sway with each step like the sea.

I am dying to know whether the reference to the peat-pit as a ‘fish pond belonging to Gwyn ap Nudd’ is a metaphor that Dafydd ap Gwilym has created or whether it comes from the oral tradition.

We know Nudd/Nodens, the father of Gwyn, is associated with fishing by the iconography at his temple in Lydney. A crown, which would have been worn by a priest of Nodens, features a strange fisherman with a long tail catching a salmon and images of fish and sea-serpents appear on a mural.

So it isn’t too surprising to find a reference to fish ponds belonging to Gwyn. However, anyone familiar with the ecology of peat bogs will be aware it is very rare to find fish in their waters due to the low oxygen levels. This raises the question: for what is Gwyn fishing?

I believe an answer can be found in a later English poem by Winthrop Mackworth Praed (1802 – 1839) called ‘The Red Fisherman’ which might also contain echoes of an older tradition.

This recounts how an abbot came to a pool with the ‘evil name’ ‘The Devil’s Decoy’ and encountered ‘a tall man’ on ‘a three-legged stool’ clad all in red with shrunken and shrivelled ‘tawny skin’ and hands that had ‘long ages ago gone to rest’ – ‘He had fished in the flood with Ham and Shem’.

With a ‘turning of keys and locks’ he took forth bait from his iron box’ and when he cast his hook ‘From the bowels of the earth / strange and varied sounds had birth’, ‘the noisy glee / of a revelling company’.

To this otherworldly music the red fisherman drew up ‘a gasping knight’ ‘with clotted hair’ ‘the cruel Duke of Gloster’. Casting off again, ‘a gentleman fine and fat, / With a big belly as big as a brimming vat’ ‘The Mayor of St Edmund’s Bury’. His next catch, with ‘white cheek’ ‘cold as clay’ and ‘torn raven hair’ was ‘Mistress Shore’ and, after countless others, finally a bishop. The abbot was cursed by the Red Fisherman to carry his hook in his mouth and from then on stammered and stuttered and could not preach.

If this poem derives from an older tradition based around the lore of his Gwyn and his father (like the Red Fisherman Gwyn was also identified with the devil) we might surmise he is fishing for the dead.

The mention of the noise of a revelling company is also pertinent as in ‘Y Pwll Mawn’ we find the lines:

A pit between heath and ravine,
the place of phantoms and their brood.
I’d not willingly drink that water,
it’s their privilege and bathing–place.

The term ellyllon is here translated as ‘phantoms’ but also means ‘elves’. It no doubt refers to Y Tylwyth Teg, ‘the fair family’ or ‘fairies’ over whom Gwyn rules as the Fairy King. ‘Brood’ has been translated from plant ‘children’ which is also suggestive of the family of Gwyn.

The peat-pit, like other bodies of water such as lakes, pools, springs, and wells, is a liminal place where Thisworld and the Otherworld meet, where the fair folk bathe, and their leader fishes for souls.

Finding out about this lore has deepened by intuition that Gwyn is associated with Lancashire’s lost peat bogs and former peat-pits, such as Helleholes, just north of my home.

At the end of his poem Dafydd ap Gwilym curses ‘the idiot’ who dug the peat-pit and swears he will never ‘leave his blessing in the peat bog’. This may refer to a practice taking place in his day – people leaving butter in peat bogs for the fairies, which may carry reminiscences of more ancient offerings to Gwyn and his family.

Contrarily, the next time I visit a peat bog, I intend to leave a blessing for Gwyn, the Blessed One.

*With thanks to Gwilym Morus-Baird for his video HERE and for pointing me in the direction of Dafydd ap Gwilym.net where ‘Y Pwll Mawn’ can be read in Welsh and English.