Assessment of the marine biodegradation and suitability of textile carrier substrates for Zostera marina transplantation

• Autor(a) principal: Rautenbach, Sarah A.
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/17795
• topic: Seagrass; Restoration; Zostera marina; Cost-effective; Geotextiles; Biodegradation.; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

Seagrass meadows provide essential eco-system services for humankind but have been declining over the past and still ongoing, mainly attributed to anthropogenic disturbances. The development of cost-effective and large-scale strategies for seagrass restoration has been challenging. In this study fundamental knowledge was generated to identify textile fabrics from natural derivatives to serve as carrier substrate for transplantation purposes. In a series of experiments the biodegradation behavior of textiles was assessed, differing in material and design. Specimen were buried in the intertidal of the Ria Formosa Lagoon and retrieved after set intervals. Weight, tensile strength and oxygen consumption rate were used as descriptors for biodegradation. The least degraded fabric was composed from coir, followed by the jute and sisal layouts, which performed similarly. The response of Zostera marina shoots towards the textiles was analyzed by placing shoots, incorporated into the fabrics, into mesocosms. Survival rates along with the development of new leaves was higher in shoots growing on sisal layouts than in controls and shoots in coir nets. This study demonstrated that the fixation of the plants onto a dense mesh as the sisal one offers significant support for shoots to grow on, resulting in superior health compared to single lose shoots. Additionally, earlier induced biodegradation in sisal layouts possibly fostered shoots with plant-growth-supporting substrates, according to the health state of these shoots. Hence, time of biodegradation was found to be vital for seagrass transplantation. Rapid degradation, leaving no carrier substrate as in controls and fertilized shoots, was proven to reduce survival chances. Retarded degradation like in coir fabrics, decelerates the supply of growth supporting substrates. Concluding, the dense sisal mesh was found to be the most successful fabric for transplantation of Zostera marina due to its biodegradation rate, high tensile strength, facilitating handling, along with sufficient fixation of the shoots.