IHCantabria researchers confirm the important role of vegetated coastal ecosystems in mitigating climate change

An international study involving a team of researchers from IHCantabria -composed of Inés Mazarrasa, Maria Recio, Araceli Puente y José A. Juanes– has identified the variability in the magnitude and rates of carbon accumulation in sediments of estuarine habitats of the European Atlantic coast, as well as the biotic and abiotic factors that determine this capacity in five estuaries located in the Netherlands, Spain and Portugal.

The research is published in the journal Science of The Total Environment and contributes significantly to the global Blue Carbon inventory The carbon sequestered by coastal and marine ecosystems – the name given to carbon sequestered by coastal and marine ecosystems – because it adds data from an under-represented region (Europe) and from little-explored habitats (such as moorlands and intertidal seagrass beds).

In addition, by identifying factors that determine the variability in carbon storage in these ecosystems, this study can contribute to the development of climate change mitigation strategies based on these coastal ecosystems. For example, the positive relationship, which was identified between the proportion of forested and natural watershed area and the magnitude of estuarine habitat carbon pools, indicates that a major opportunity for promoting coastal carbon sinks would be the conservation and restoration of terrestrial ecosystems at the watershed level.

The development of this study was carried out within the framework of the European LIFE ADAPTABLUES project, whose main objective is to demonstrate that the conservation and restoration of estuarine ecosystems is an efficient measure to achieve adaptation to climate change in the coastal areas of the European Atlantic.

Coastal vegetated ecosystems

Coastal vegetated ecosystems – such as salt marshes, seagrass meadows and mangroves –are important carbon sinks; that is, like terrestrial forests, they absorb CO2 and store it over the long term, mainly in the form of organic matter buried in the sediment.

They also provide other ecosystem services to society, such as maintaining biodiversity, sustaining fisheries or coastal protection. However, these ecosystems are subject to continuous impacts from human activities, such as conversion to other uses or pollution.

The loss and degradation of these ecosystems not only causes the loss of their capacity to act as natural carbon sinks, but also their possible conversion to CO2 sources. Therefore, efforts aimed at the conservation and restoration of these ecosystems are increasingly valued as strategies for climate change mitigation, since they favor the removal of CO2 from the atmosphere and avoid emissions derived from the degradation of these ecosystems.

Future projection of this line of research

Knowing how much carbon coastal ecosystems store and at what rate is the first step in designing and implementing climate change mitigation strategies based on these ecosystems. However, for this mitigation to be effective, certain questions still need to be resolved. For example, it is necessary to know the impact of different threats -such as dams that impede natural tidal flow or the expansion of invasive species- on the carbon sink function of estuarine habitats, as well as the potential of different restoration actions in the recovery of this function. IHCantabria will continue to support the development of this line of research, to contribute with its studies to generate key knowledge for the development of climate change mitigation measures based on the conservation and restoration of these valuable coastal ecosystems.