There has probably been a whole host of exciting things happening on the reserve this week that have gone unseen by the Forvie staff. I (Emma) have been away for most of it, Cat and Daryl are on a well-deserved holiday, and for Joe, our seasonal warden, Wednesday was his last day working at Forvie NNR after three seasons in a row!
I know I don’t just speak for myself when I say that Joe will be sorely missed by everyone here – for his helpfulness, knowledge, and enthusiasm – which helped to ring a record number of terns this year! I couldn’t have had a better mentor showing me the ropes at weekends. We wish him thanks, and all the very best as he takes on his PhD.

So, instead of a report of this week’s events, for today’s blog, I have delved into the murky waters of how the muddy, marshy habitats here at Forvie NNR contribute to carbon capture and storage. This topic is inspired by Climate Week North East, which began yesterday and is running a whole host of climate change-related events until October 4th. However, I feel I have opened a can of lugworms with this one, as carbon is more complex than it appears at surface level…
Looking out over the Ythan Estuary from Waterside at low tide, you can see extensive mudflats edged by vegetated saltmarsh, woven with creeks, and scattered with the discarded shells of munched mussels and other molluscs.

The importance of these coastal wetland habitats has often been overlooked. Viewed as unproductive and uninspiring, many wetlands have been ‘reclaimed’ and put to use for our own activities. Thankfully, the lower Ythan estuary has largely escaped this and is one of the most important ‘natural’ estuarine and tidal environments in North-east Scotland.
For those living or working near to an estuary like the Ythan, it is difficult to remain ignorant to its beauty and value. The most obvious sign of this is that the estuary is teeming with life. Especially at this time of year, when migratory wading birds are arriving from their breeding grounds in the arctic to overwinter here and take advantage of the plentiful food found lurking within the mud.

At first glance, the expansive estuary can seem quiet, but last week’s wader count taught me to look closer. As I squinted into the sun, the mud started moving and revealed that it was, in fact, covered in over one thousand golden plover!

The fact that these muddy, marshy habitats provide food, resting places, and nesting sites for different bird species hints at their deeper importance. They harbour a great diversity of life beneath the water and mud too, like bivalve molluscs (mussels, cockles and clams), snails, shrimps, worms, and crabs. Then not forgetting the fish supported by these smaller creatures or even starting on the microscopic life forms!

Wetlands also act as a buffer between the sea, land and river, somehow thriving in the harsh, salty, changeable conditions. They help to protect the land from coastal flooding and extreme weather, while filtering some of the pollutants washing off the land. The pressures of development, coastal change, and sea-level rise push wetlands to the limit of what even these remarkably resilient places can handle.

Though this gives us plenty of reasons to cherish our swirling mudflats and vibrant saltmarsh already, it turns out that they also store considerable amounts of carbon!
Recent research and policy are trying to shed light on the potential for ‘blue carbon’ habitats to help us adapt to and limit climate change. This summer’s heatwaves and wildfires have been a stark reminder of why this is important.
We are familiar with hearing about woodlands and peatlands as habitats that capture and store carbon. ‘Blue carbon’ essentially refers to marine, coastal, and estuarine habitats that do the same. ‘Blue carbon’ can be absorbed from the air or water and stored in vegetation, sediment and marine animals – like the shells of mussels, which, when there is enough of them, form a habitat of their own known as mussel beds.

Of the carbon-capturing habitats found at Forvie NNR, saltmarsh seems to have the most potential for locking away carbon directly from the atmosphere, and at an impressive rate! Saltmarsh plants (like those pictured below) absorb carbon dioxide as they grow, storing carbon in their tissues and roots. Some of this carbon becomes trapped in the waterlogged soils of the marsh, alongside carbon from other sources in the estuary.
There are claims that saltmarsh in the UK captures carbon 40 times faster than woodland. However, the rates of carbon capture seem to be extremely variable, so I think the main takeaway is that although saltmarsh makes up a relatively small area in the UK, it is an important carbon store well worth our protection.




Intertidal mud and sandflats capture carbon a little differently. While algae living on the surface can capture carbon through photosynthesis (like plants do), the sediments themselves mainly store carbon that has come from the land, sea or river, including the remains of decaying plants and animals. The magic of the mud is the sheer amount of carbon it stores, but more research is needed to understand how fast it is added or lost.

As the shells of mussels contain carbon, it follows that the mussel beds in the Ythan Estuary could be carbon stores too. However, the process of developing the shell, made largely of calcium carbonate, releases carbon dioxide. So, mussel beds may actually release more carbon than they store overall!
Nevertheless, we are still very grateful to the mussel beds for feeding the eider population, among many other bird species, found here at Forvie!

There is an estimate from N.H. Trewin (in his guide to the geology of the Aberdeen area, 1987) that around 38 tonnes of shell fragments from eider poo were produced each year in the Ythan Estuary. I’m not sure how this figure was calculated, but it is quite a contribution!

The main concern with organic carbon stored within mud and sand is that it could be disturbed by development, erosion, or other coastal changes, and released back into the water or atmosphere. Fortunately, the Ythan estuary is protected by multiple nature conservation designations that recognise its important habitats and wildlife. That being said, some changes remain beyond our immediate influence.
When I look at the estuary, the mudflats, the saltmarsh, the shingle and shells, I see the marks left by coastal processes that shape this place, and I see the wildlife that relies on them. I admit, I don’t tend to think about the carbon locked quietly in the unassuming habitats, a foundation for life. When I wonder how changes in the future will impact the estuary, and how we can support these crucial habitats, maybe I need to consider the carbon stored there too. Another reason to value this remarkable place, and another way in which it connects us to everything else.

















































































































































