The Eden Estuary Salt Marshes

The Eden Estuary salt marshes act as a blue carbon store, nature reserve and flood defence for surrounding land. Out of Scotland’s 249 salt marshes, the Eden estuary is the 22nd largest surficial organic carbon store.1 However the Eden salt marshes are currently being damaged from the effects of erosion. Anthropogenic activity such as the construction of hard engineering techniques has eroded some of the upper salt marsh.2 In addition, climate change and sea-level rise are reducing the abundance of healthy salt marsh area. It is predicted that by the 22nd century , the Eden estuary will lose 56% of its salt marsh area due to sea-level rise.3 Salt marsh degradation triggers the release of stored blue carbon into Earth’s atmosphere. Moreover, the loss of this vegetated area puts the land behind at risk of flooding and erosion, this includes the St Andrews Links golf courses. It is therefore crucial that the Eden estuary salt marshes are protected to prevent the loss of stored blue carbon, biodiversity and valuable land assets

The Green Shores team transplant various native grasses into the barren areas of salt marsh with the aim of enhancing sedimentation and the binding of sediment. As a volunteer at the Green Shores Project, I work with Helena Simmons (Outreach Officer), in a polytunnel next to the salt marsh, preparing transplants.

Saltmarsh Grass (Puccinellia maritima) from the Tay, Dornoch Firth and the Eden are propagated to produce numerous transplants.  Below are images of propagated Saltmarsh Grass in the Green Shores polytunnel:

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Additionally, Sea Club Rush (Bolboschoenus maritimus) is also propagated for transplanting. The strength of the plants roots allows it to thrive in the harsh environment of a salt marsh.

Sea Club Rush being propagated in the Green Shores polytunnel

Transplants are prepared a year in advance. To enhance plant growth, newly propagated plants are given fresh water and grown in a warmer environment. Thereafter, the transplants must experience a gradual adjustment to salt marsh environments before being transplanted in the salt marsh to prevent shock. Before propagated plants are ready to be transplanted, they undergo salt water and cold temperature treatments outside the polytunnel.

The work carried out by the Green Shores Project is being continuously monitored. Sediment cores from the restored salt marsh are analysed for organic carbon content in the University’s Geography and Geoscience labs. To learn more about the Green Shores Project or to get involved volunteering click here.


  1. Austin, W., Smeaton, C., Riegel, S., Ruranska, P. and Miller, L. (2021). Blue carbon stock in Scottish saltmarsh soils Scottish Marine and Freshwater Science Vol 12 No 13. [online] doi: 
  2. Maynard, C., McManus, J., Crawford, R.M.M. and Paterson, D. (2011). A comparison of short-term sediment deposition between natural and transplanted saltmarsh after saltmarsh restoration in the Eden Estuary (Scotland). Plant Ecology & Diversity, 4(1), pp.103–113. doi:
  3. Austin, W., Smeaton, C. and Houston, A. (2022). Scottish saltmarsh, sea-level rise and the potential for managed realignment to deliver blue carbon gains. [online] doi:https://doi.rg/10.7488/era/2370

Shoreline flooding and erosion prevention methods: Cost-Benefit Analysis

Author: Ariana Ressallat White

The importance of wetlands in our battle against climate change

Author : Maariya Hussain

Wetlands of all types have inspired creative works in the form of literature, art, myths and legends for centuries. An example of this is Charles Dickens’ novel ‘Great Expectations’. The opening line: “Ours was the marsh country, down by the river, within, as the river wound, twenty miles of the sea.” (Dickens, 1861) establishes ‘Great Expectations’ as a gothic work of art for many, deeply revered even today. The marsh setting effectively provides an evocative sense of mystery and danger, similar to the ‘Dead Marshes’ that accommodated the ‘Battle of Dagorlad’ in Tolkien’s ‘The Lord of the Rings’(J R R Tolkien, 2018). 

While prominent stories like these show how intertwined wetlands are with our creative history, these thriving ecosystems are sometimes overlooked for the role they play in the mitigation of climate change and protecting against coastal erosion.

In this blog post, we will discuss the critical need for wetlands, specifically mangroves and salt marshes, to be used as natural defences for vulnerable coastal communities; and then discuss their ability to reduce greenhouse gases in the atmosphere. Wetlands deserve all of the attention they have received from writers and artists; however, I hope that by the end of this blog, you can also appreciate them in an ecological sense, encouraging you to support and pursue their protection. To conclude, we will take a look at the current restoration projects already happening in Scotland, focusing on our local Eden Estuary. 

The Threat

By 2100, at least 410 million people are predicted to be living in low-lying areas that are less than 2m above sea level, putting them at risk of coastal flooding. This assumes a 1m mean sea level rise by the end of the century and does not consider the rising population (Hooijer and Vernimmen, 2021). Traditionally, hard engineering strategies have been implemented to protect communities, but it appears that they are ineffective long-term solutions. For example, bulkheads on the North Carolina Coast were not able to withstand the impacts of Hurricane Irene without damage. Interestingly, the marshes only suffered from a temporary reduction in vegetation density, but no effect on the levels of sediment was observed (Gittman et al., 2014). Similarly, from 2020 to 2021, Pacific Island countries were faced with 3 cyclones. Their sea walls crumbled instead of protecting urban settlements, resulting in some locals being forced to leave their homes. (Khadka, 2021) What was once seen as a secure climate change adaptation strategy, now needs to be reconsidered as global temperatures rise and tropical hazards become more frequent and intense.

Why do hard-engineering strategies need to be re-envisioned?

As we have seen, sea walls may not be as durable against forceful storms as we once thought. Another issue is that by reflecting wave energy instead of absorbing and dissipating it, the sediment in front of the sea wall is eroded and the adjacent, unprotected shorelines suffer from increased erosion. What follows is a reduction in intertidal ecosystems (beaches, wetlands, dune systems) and the wildlife they host (Climate ADAPT, 2016). Salt marsh vegetation and mangrove roots, on the other hand, dissipate wave energy and stabilise soil, leading to less erosion. Further research is being carried out on these ecosystems to better understand their effectiveness as natural coastline defences. Another advantage is that they are cost-effective, allowing low-income countries to protect themselves. This needs to be a priority as it is the low-income countries that will struggle the most to adapt to our intensifying climate (Khadka, 2021). 

Protecting our planet for future generations

Temperature fluctuations have been seen throughout our planet’s history, but the rate of global warming seen today is unprecedented. As a result, rising sea levels and more extreme weather will become an impossible challenge to overcome soon if we do not mitigate climate change. The target outlined in the Paris Agreement is ‘to limit the temperature increase to 1.5°C above pre-industrial levels’ (UNFCCC, 2015). While this is an ambitious aim if we consider our current practices, making changes across the board will move us closer to this goal. This means incorporating nature-based solutions in our plans to tackle climate change. 

One way we could achieve this is by protecting natural carbon sinks – like wetlands!

How can wetlands help fight climate change?

We have already discussed the value that wetlands provide in protecting coastal land, but they are not limited in their uses. These ecosystems play a key role in the mitigation of climate change by sequestering carbon dioxide during photosynthesis. What sets wetlands apart from terrestrial forests, however, is their rate of carbon capture and their long-term ability to store carbon. 

High growth rates in wetlands mean lots of carbon dioxide is captured for photosynthesis. The carbon dioxide is converted into organic compounds in a process called carbon fixation. The process is critical to sustain plant function and therefore all life on Earth, as the compounds produced are carbohydrates which store energy. They are then broken down and the energy is released during respiration. Carbon dioxide is released back into the atmosphere as a byproduct. However, some of the organic carbon gets incorporated into the soil when the plants die. 

During the decomposition process, microbes will respire as they break down plant material, releasing more carbon dioxide into the atmosphere. However, in wetland habitats, this process is limited due to the anaerobic (low oxygen) conditions present in water-logged soils (due to the submergence of wetlands by tides). Instead, carbon gets trapped under layers of sediment that accumulate over thousands of years. This means that wetlands are more efficient carbon stores than terrestrial forests (National Ocean Service – National Oceanic and Atmospheric Administration, n.d.). 

Conservation is crucial. What are the current conservation projects occurring locally and in Scotland?

Such a dynamic ecosystem, with high value in the battle we are facing against climate change, needs to be restored and protected. We are fortunate to have the Eden Estuary’s salt marsh near the University of St Andrews, which has enabled it to be extensively researched. Dr Clare Maynard wrote her PhD thesis on exploring the effectiveness of replanting native salt marsh species in the degraded areas of the shoreline (Maynard, 2014). In light of the success of her research, she founded the Green Shores Project to restore the shorelines around the Dornoch Firth and the Tay estuaries as well as the Eden (, 2023). This is essential work as much of the salt marsh along the Eden’s shoreline has been diminished due to the dumping of industrial waste and fragments of old sea defences from the previous century (Maynard, 2014).

Unfortunately, salt marshes are still vulnerable today to rising sea levels and increasingly forceful waves. They are dealing with conditions out of their capacity which have resulted in their global decline (Campbell et al., 2022). Although, as we are realising their importance, cooperation from governments, businesses and the public is becoming a reality. The number of conservation projects in the UK and worldwide is increasing and there is no better time to get involved. The Green Shores project is a great way to do this in St Andrews. They are regularly hosting new volunteer opportunities which you can find out more about on the University of St Andrews Website.


Dickens, C. (1861). Great Expectations. Costa Mesa, Calif.: Saddleback Educational Pub.

J R R Tolkien (2018). The Two Towers. New York: Del Rey/Ballantine Books.

Hooijer, A. and Vernimmen, R. (2021). Global LiDAR land elevation data reveal the greatest sea-level rise vulnerability in the tropics. Nature Communications, 12(1). doi:

Gittman, R.K., Popowich, A.M., Bruno, J.F. and Peterson, C.H. (2014). Marshes with and without sills protect estuarine shorelines from erosion better than bulkheads during a Category 1 hurricane. Ocean & Coastal Management, [online] 102, pp.94–102. doi:

Khadka, N.S. (2021). Climate change: Low-income countries ‘can’t keep up’ with impacts. BBC News. [online] 7 Aug. Available at:

Climate ADAPT. (2016). Seawalls and jetties . [online] Available at:

UNFCCC (2015). THE PARIS AGREEMENT. [online] Available at:

National Ocean Service – National Oceanic and Atmospheric Administration. (n.d.). Coastal Blue Carbon. [online] Available at: [Accessed Apr. 14AD].

Maynard, C.E. (2014). Saltmarshes on the fringe : restoring the degraded shoreline of the Eden Estuary, Scotland. [online] Available at: [Accessed 19 Apr. 2024]. (2023). Green Shores Project – Green Shores. [online] Available at: [Accessed 19 Apr. 2024].

Campbell, A.D., Fatoyinbo, L., Goldberg, L. and Lagomasino, D. (2022). Global hotspots of salt marsh change and carbon emissions. Nature, [online] 612, pp.1–6. doi: