SeaArt – Long term establishment of SEAgrass ecosystems through biodegradable ARTificial meadows
Seagrass meadows are important ecosystems which provide a wide variety of ecosystem services including coastal protection by wave reduction and sediment stabilisation. Despite these important services, seagrass meadows are under threat from anthropogenic pressures. Consequently, a global decline has been observed over the last decades. Restoration efforts are inherently difficult as the absence of seagrass leads to enhanced hydrodynamic energy and turbidity levels which restrict seagrass growth.
To overcome this negative feedback loop, we will develop artificial seagrass (ASG) which looks and feels similar to natural seagrass and provides the ecosystem services that enable natural seagrass to establish within and around the artificial structure: The artificial seagrass will provide suitable hydrodynamic and light conditions as well as stabilise the sediment to allow natural seagrass to either grow from seeds, take root after transplantation or expand existing meadows more easily.
A key aspect of the project is the use of fully biodegradable materials for the development of the ASG to ensure that no potentially harmful non-degradable substances will be introduced into the system and no structures remain in the system. The aim of the proposed method is to establish a purely natural seagrass meadow long-term without the need to manually remove initial structures as they will disintegrate over time.
It is anticipated that the ASG will be globally applicable in seagrass restoration projects. In order to produce a first prototype and confirm its functionality, we will focus on the species Zostera marina which is native to the Eastern North Atlantic. To achieve this aim, the project will (i) Assess the required and critical biological and environmental conditions for seagrass establishment with field and mesocosm measurements. (ii) Design ASG including an anchoring system that can provide these conditions by mimicking the natural shape and motion and assess anchoring and sediment stabilisation mechanisms in the laboratory. (iii) Identify biodegradable materials and evaluate their potential use as ASG through assessing their degradation behaviour in the marine environment and the role of additives in this process. (iv) Explore means of commercial use of the ASG and output materials (e.g. seagrass detritus) as such use requires sufficient material availability and commercial production techniques to be viable.
Each work package bridges across scientific disciplines and consequently the project team combines expertise from seagrass ecology, hydrodynamics, sedimentology and material sciences to achieve high quality results within this interdisciplinary project. Moreover, the team includes partners from industry to ensure commercially viable production of ASG in sufficient quantities in the future. The above work packages will contribute to prototype development and it is envisaged to produce a prototype during the second half of the project and test its performance and stability under controlled, yet extreme, conditions in a full scale flume experiment (in the Large Wave Flume (GWK), Hannover). We anticipate that positive prototype testing will build the foundation for a consecutive project which will deploy the ASG in a transplantation effort at a pilot field site.