The research was made by the Portugal’s Interdisciplinary Centre of Marine and Environmental Research (CIIMAR) and Marine and Environmental Sciences Centre (MARE).

For the first time, researchers have measured the amount of carbon sequestered by seaweed in these underwater ecosystems, according to a report by Euronews.

The researchers measured the amount of carbon stored by seaweed in the underwater ecosystems; however, the scientists have also mentioned that the ability to store the carbon may be affected by climate changes.

The capability of storing carbon

The study was published in the journal Scientific Reports and focus on two main kelp species, in Portugal, that have the capacity of storing carbon underwater. According to Euronews, the species involved are Laminaria hyperborea an Saccorhiza polyschides.

Francisco Arenas, co-leader of the research, quoted by Euronews, stated that "these habitats are common on the north coast of Portugal, where there are unique conditions for their development, and represent the southernmost frontier for some of the species found here.”

The study concludes that the underwater ecosystems store, on average, 16.48 gigagrams (Gg) of carbon across 5,189 hectares. According to Euronews, even though the occupation of this kelp species is reduced, on a global scale, the forests in Portugal can capture as much carbon as other, more extensive ecosystems.

The carbon stored by the kelp habitats represents 14 percent of the blue carbon inventory of Portugal, which was, in the past, limited to salt marshes and seagrass meadows.

Forests in risk

Despite this, the scientists behind the study say the contribution of marine forests to climate mitigation efforts has historically been overlooked. Arenas claims that these species are "often unknown and undervalued, despite their extremely important ecological and economic value on the north coast of Portugal.”

However, climate change may be affecting the species that are considered to have major importance for the underwater ecosystems.

"A process of tropicalisation [warming of sea temperatures] has already been detected in Portuguese waters, which puts the associated biodiversity at risk, as well as the ecological services that these forests provide, including the ability to capture and store carbon, known as blue carbon, contributing to climate change mitigation," Arenas adds, quoted by Euronews.

The study has also proposed measures for surveillance, protection and even restoration of the zones, highlighting the importance of the species as carbon repositories. The researchers advised that kelp forests should also be included in marine protection and blue carbon frameworks.

"With the European Union's Nature Restoration Law in its early stages of implementation, it is urgent to develop and implement effective ecological restoration techniques, particularly in habitats that are highly vulnerable but also have high potential for providing ecosystem services, such as marine forests," says Arenas.