Sustainable Microbiology, 2025

Coastal blue carbon ecosystems (BCEs) are among the most effective carbon (C) sinks, yet Irish saltmarshes, covering 4000–6500 hectares, remain understudied in terms of C sources. Understanding saltmarshes’ connectivity to marine and terrestrial sources, and the provenance of allochthonous (ex-situ-produced) carbon, is essential for assessing their long-term C sequestration potential and management. This study analysed organic carbon (OC) and bacteriohopanepolyol biomarkers (BHPs), microbial lipids that trace sedimentary OC sources, in sediment cores from Derrymore Island (DI) and North Bull Island (NBI). OC concentrations varied down-core, ranging from 0.26–26.68 wt% at DI, 0.44–12.19 wt% in NBI’s North Lagoon, and 0.07–26.45 wt% in its South Lagoon. The R_soil index values (0.02–0.24 at DI, 0.01–0.06 at NBI) indicate a predominantly marine OC origin, though soil-specific BHPs were present, with higher soil marker concentrations in deeper, older DI sediments. This suggests saltmarshes may gradually transition toward terrestrial characteristics over time. This study enhances our understanding of OC sequestration in two Irish saltmarshes, highlighting their dynamic nature. The allochthonous nature of sequestered sedimentary OC further underscores the importance of sustained tidal influence and connectivity with the wider marine environment. Further research into labile OC sources is recommended to enhance carbon assessments in these ecosystems.

NPJ Ocean Sustainability, 2025

Temperate coastal marine ecosystems have undergone severe global loss and degradation. We provide a framework for considering ecological connectivity in marine systems and evidence for ecological connectivity across temperate coastal seascapes, developed through expert consensus and structured review. We demonstrate that ecosystem functioning and the delivery of ecosystem services require the existence of a healthy mosaic of coastal habitats, maintained by the exchanges of matter and energy between them. We advocate a seascape approach, that restores connectivity and optimal structure-function relationships, is crucial for successful ecosystem restoration. Consequently, we provide recommendations to deliver seascape restoration of coastal habitats to support the targets set by the 2021-30 UN Decades of Ocean Science and Ecosystem Restoration. Acknowledging the interconnected nature of coastal ecosystems has implications for policy. We identify opportunities and actions to support nature recovery and integrate policy frameworks across climate and biodiversity agendas to achieve international goals for planetary resilience.

Our research has shown that a single restored saltmarsh in the UK can store as much carbon over four years as more than one million newly planted trees can capture in a decade.  

Saltmarshes are coastal wetlands shaped by the tides. These dynamic habitats create a unique watery mosaic of salt-tolerant plants and shrubs, interwoven with a network of creeks and pools. 

Today, Wednesday 11^th June 2025, marks the first ever World Saltmarsh Day. Led by our partners, WWT, we are raising awareness of the superpowers of these coastal wetlands. 

Saltmarshes play an important role in climate change mitigation and are capable of capturing and storing more carbon than the same sized area of forests on land. These valuable habitats can absorb the energy of the tides – protecting coastlines and manmade sea defences behind them – and provide a haven for wildlife. Saltmarshes are also a beautiful place to relax and lose yourself in the sights and sounds of nature. 

Dr Lucy McMahon, Research Fellow in Coastal Ecology at Manchester Met, said: “Despite the amazing benefits they provide, saltmarshes are largely unknown among the public – many people struggle to even recognise what saltmarsh is”.  

Dr Robert Sparkes, Senior Lecturer in Environmental Science added: “We have lost around 50% of saltmarshes in the UK to urban and agricultural developments. We hope World Saltmarsh Day will raise global awareness of these special but underappreciated habitats and inspire action which promotes their restoration and conservation”.  

Find out how, in the fight against climate change, our research has revealed the importance of forgotten natural resources: https://www.mmu.ac.uk/news-and-events/news/story/letting-nature-back  

Frontiers in Marine Science (Marine Ecosystem Ecology), 2023

Relative tidal height and saltmarsh vegetation communities are key drivers of carbon stock variability between restored saltmarshes – can this inform the location and design of future saltmarsh restoration schemes that aim to maximise climate change mitigation?

Political discourse around coastal wetland restoration and blue carbon management strategies has increased in the past decade, yet carbon storage has neither been a reason for restoration, nor a criterion to measure the success of current saltmarsh restoration schemes in the UK. To maximise climate change mitigation through saltmarsh restoration, knowledge on the key drivers of carbon stock variability is required. We use restored saltmarshes of similar age, paired with adjacent natural marshes as references, to identify drivers of carbon stocks following managed realignment within an estuary in southeastern England. From surficial soil cores (top 30 cm), we measured carbon stock alongside environmental characteristics. Carbon stock between natural and restored sites were similar after ~ 30 years when restored sites were above mean high water neap (MHWN) tidal levels. Elevated marsh platforms likely provide suitable conditions for the development of mature plant communities associated with greater capture and production of organic carbon. The restored site at Tollesbury (Essex, UK) had a 2-fold lower carbon stock than other restored sites in the estuary. We attribute this to the site’s low position in the tidal frame, below MHWN tidal levels, coupled with low sediment supply and the dominance of pioneer plant communities. As blue carbon is anticipated to become an important facet of saltmarsh restoration, we recommend that sites above MHWN tidal levels are selected for managed realignment or that preference is given to coastlines with a high sediment supply that may rapidly elevate realignment sites above MHWN. Alternatively, elevation could be artificially raised prior to realignment. Restoration schemes aiming to maximise climate change mitigation should also encourage the establishment of key plant species (e.g., Atriplex portulacoides in our study) to enhance carbon stocks. However, the overall goal of restoration ought to be carefully considered as trade-offs in ecosystem services may ensue if restoration for climate change mitigation alone is pursued.

This is a collection of reports, authored in collaboration with Jacobs and the Environment Agency, in which we present:

1. Sediment accumulation rates at 15 restored saltmarshes in England,
2. Carbon accumulation rates at these 15 sites,
3. Gaps in the scientific knowledge around saltmarsh restoration:
   • Habitat zones
   • Carbon stocks
   • Greenhouse gas fluxes
   • Effects of disturbance and land management
   • Countable carbon

In a lot of cases, protocols are generated by carefully reading the methods section of a published paper, but publications are often written very concisely and some of the steps taken in the lab could be left out or hard to follow. The step-by-step protocol is less likely to be published, but could be much more useful for those trying to build upon published studies.

To avoid that confusion, I have created a new section of the website dedicated to publishing the latest version of our laboratory standard operating procedures. These are published under a Creative Commons CC-BY 4.0 license so you are allowed – encouraged in fact – to use, adapt, improve and share these protocols.

I also welcome feedback regarding the protocols. Comments are enabled on each one and you are welcome to highlight steps that are unclear or could be improved.

Filtration of water samples to remove and measure suspended solids.

Extracting nutrients from sediment using de-ionised water.