How Salt Marshes Reduce the Impact of Ocean Waves
Context
Research published in Nature by scientists at Wageningen University and Research examined how salt marshes reduce the force of incoming waves. The findings highlight their role as natural coastal barriers that help protect shorelines against storms and erosion.
Key Highlights
- Salt marshes as coastal barriers: Salt marshes are coastal wetlands found in intertidal zones, where salt-tolerant vegetation grows in waterlogged soils and helps stabilise coastal sediments.
- Experimental study: Researchers studied a 306-square-metre salt marsh in the Netherlands and exposed it to artificially generated waves using a 300 m long wave flume.
- Role of vegetation and roots: The study found that a marsh elevation of around 7 mm, combined with dense vegetation and interconnected roots, helped reduce wave energy and stabilise sediments.
- Reduction in wave height: The marsh reduced the height of 75 cm waves by approximately 22%, whereas the reduction was only about 6% for waves measuring 2 metres.
- Effectiveness under specific conditions: Salt marsh vegetation could reduce incoming wave heights by more than 10% under certain conditions. In some cases, the reduction reached 50% when waves were around one metre high.
- Importance of conservation: The findings emphasise the need to conserve salt marshes as nature based solutions for coastal protection, particularly as climate change increases the intensity of coastal hazards.
Key Concepts
- Salt Marshes: Coastal wetlands dominated by salt tolerant grasses and other vegetation that provide habitats and help stabilise shorelines.
- Blue Carbon Ecosystems: Coastal and marine ecosystems that capture and store carbon, including mangroves, seagrasses and salt marshes.
- Nature Based Solutions: The protection and restoration of natural ecosystems to address climate risks and environmental challenges.
- Coastal Resilience: The ability of coastal communities and ecosystems to withstand and recover from storms, erosion, flooding and sea level rise.