Innovative technique for the recovery of Posidonia Oceanica seagrass meadows

Year

2016

Organisation

Red Eléctrica de España

Description

Posidonia Oceanica is a seagrass species that provides essential functions to the Mediterranean ecosystem, most notably it acts as a natural carbon sink. REE has developed and applied a methodological guide to restore large-scale degraded areas and ensure the non-invasive recovery of Posidonia Oceanica, according to R&D results.  

 

Highlights:

  • After one year of planting, the survival rate was over 60%; 51% of the fragments planted in 2016 had generated new shoots after 6 months, 18% of the fragments had generated new shoots after 1 year
  • REE will publish a methodological guide on developing an open sea grass meadow recovery method including technical, material and economic viability  

 

Scope:

The practice has been implemented at the Balearic Islands but can be enlarged to the entire Mediterranean Sea, providing the first step towards a new understanding of reforestation in the marine environment.  

 

Main information:

Wind farms and submarine cables can contribute to the degradation of seagrass meadows, which suffer from a 1% to 5% annual estimated rate of loss globally. Posidonia Oceanica forms large underwater meadows that are an important part of the ecosystem due to their ability to sequester about half a million tonnes of CO2 in the Mediterranean Sea per year.  

Restoration projects, such as the one REE is undertaking, have the potential to increase carbon sequestration capacities, and to protect sediment carbon stocks of seagrass meadows.  

To address these challenges, REE conducted research on the use of Posidonia Oceanica seedlings and developed an open seagrass meadow recovery method. The method involves the collection and cultivation of Posidonia Oceanica fragments and seeds grown under laboratory-controlled conditions or obtained directly from natural seagrass meadows. Subsequently, the seedlings can be transplanted into degraded meadow areas, for example into trenches opened on the seafloor due to works associated to the laying of submarine electricity cables.  

 

Additional information:

  • REE, the Spanish transmission system operator, developed the practice in collaboration with the Spanish National Research Council (CSIC) from 2012 until 2016 
  • Large-scale implementation of the methodology throughout the Balearic Islands is currently being planned