Common Eelgrass (Zostera marina)
Seagrass is the only group of marine flowering plants often located in shallow sheltered areas along many coasts of the world. These plants grow bright green leaves which form dense underwater meadows that cover sandy sea beds. Seagrass is a keystone species forming the critical base of an entire ecosystem and habitat. The meadows that forms can support thousands of marine species including, crustaceans, shellfish, polychaete worms, and fish. Compared to neighbouring sandy habitats seagrass meadows can have over 30 times more species living within them.
Not only do seagrasses make fantastic habitats they are also a key part of aspect of global carbon storage. While seagrass only covers 0.1% of the seafloor, they are responsible for 11% of the organic carbon storage in the ocean. Combined with mangrove and wetland habitats these ecosystems are responsible for more carbon capture then the rainforests.
We are aiming to restore seagrass to the Tees estuary and surrounding coastline. In order to do this, we are using two methods based: planting seagrass bags and transplanting seagrass shoots.
Seagrass bag planting
This method involves fixing large biodegradable hessian bags on the seafloor filling each with a mixture of sediment and seagrass seeds. Under the protection of the bags the seeds will be left to established and develop under natural conditions.
Each year we keep some seeds back to grow in our seagrass facility. Once the seedlings have developed a root mass we can transfer them to our planting site. By planting developed plants the seagrass will be less susceptible to uprooting from storms or wavy conditions
Our Seagrass Facility
Our first facility is built within a 40ft shipping container. This is a closed system. Water from the estuary is pumped into a sump which is circulated between 6 growing tank. we can control the light, temperature and salinity in this system. It is used for rotting out seagrass spathes to access the seeds and germinating seeds under controlled condition. We have also run experiments on germination success using different sediments and salinities.
Our seagrass nursery is supplied with water directly from the estuary in a flow through system. Once the seagrass has germinated in our container system it is moved out into the nursery to give natural grow under natural lighting and in the water it will eventually be planted in. Some of the plants from the nursery will be transplanted into the estuary. Others will be kept back to produce seeds for future planting.
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