Publicação
Environmental sustainability evaluation of wild seaweed
| Resumo: | Aligned with European strategies such as the Green Deal, Farm to Fork, and the Blue Economy agenda, seaweed is increasingly recognised as a sustainable food source. Yet, the environmental performance of wild harvested species remains underexplored compared with cultivated brown seaweeds. This study presents one of the first life cycle assessments (LCA) of wild harvested Ulva spp. (fresh and dried) and Porphyra spp. (dried), based on primary operational data from a seaweed producing company in Galicia, Spain, where the seaweed are both harvested and processed. A cradle to gate approach was applied, covering harvesting, processing, and packaging into seaweed food products, and impacts were calculated using the EF 3.1 method. The climate change impact of producing fresh Ulva was 0.284 kg CO2 eq/kg fresh product, while whole dried Ulva and Ulva flakes/powder showed impacts of 0.687 kg CO2 eq/kg dry weight and 0.67 kg CO2 eq/kg dry weight, respectively. Porphyra products had the highest impacts, at 1.77 kg CO2/kg dry weight, reflecting species specific yields and moisture contents that increase the relative burden of drying energy. Across all products, preservation was the dominant hotspot: refrigeration contributed ~65 % of climate change impacts in fresh Ulva, driven by electricity use, while drying accounted for >80 % in dried Ulva and Porphyra. Within drying, electricity consumption in the condenser was the main driver of climate change, acidification, and fossil resource use; wood pellet production drove freshwater ecotoxicity, and pellet combustion was most relevant for marine eutrophication. Cleaning contributed ≈70 % of freshwater ecotoxicity, linked to wastewater treatment and composting emissions, while packaging added up to 40 % of fossil resource use, mainly from polypropylene granulate production. When compared with existing studies, fresh Ulva showed higher impacts than other wild harvested species due to the explicit inclusion of refrigeration, often excluded from previous system boundaries. Dried Ulva performed below published ranges, suggesting efficient processing, while dried Porphyra fell in the mid-range, consistent with literature highlighting the influence of drying intensity and species-specific yields. Overall, the findings confirm that conservation processes, particularly refrigeration and drying, are the pivotal levers shaping the environmental profile of wild harvested seaweed. By targeting these stages through renewable energy use, heat recovery, and process optimisation, producers can substantially reduce impacts. The results provide both a benchmark for future LCAs and practical guidance for industry and policymakers to support the sustainable development of seaweed value chains. |
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| Autores principais: | Ferreira, Vital Francisco Faria |
| Assunto: | Dry seaweed Environmental impact Fresh seaweed Life cycle assessment Porphyra spp Seaweed Sustainability Ulva spp Wild harvest |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Aligned with European strategies such as the Green Deal, Farm to Fork, and the Blue Economy agenda, seaweed is increasingly recognised as a sustainable food source. Yet, the environmental performance of wild harvested species remains underexplored compared with cultivated brown seaweeds. This study presents one of the first life cycle assessments (LCA) of wild harvested Ulva spp. (fresh and dried) and Porphyra spp. (dried), based on primary operational data from a seaweed producing company in Galicia, Spain, where the seaweed are both harvested and processed. A cradle to gate approach was applied, covering harvesting, processing, and packaging into seaweed food products, and impacts were calculated using the EF 3.1 method. The climate change impact of producing fresh Ulva was 0.284 kg CO2 eq/kg fresh product, while whole dried Ulva and Ulva flakes/powder showed impacts of 0.687 kg CO2 eq/kg dry weight and 0.67 kg CO2 eq/kg dry weight, respectively. Porphyra products had the highest impacts, at 1.77 kg CO2/kg dry weight, reflecting species specific yields and moisture contents that increase the relative burden of drying energy. Across all products, preservation was the dominant hotspot: refrigeration contributed ~65 % of climate change impacts in fresh Ulva, driven by electricity use, while drying accounted for >80 % in dried Ulva and Porphyra. Within drying, electricity consumption in the condenser was the main driver of climate change, acidification, and fossil resource use; wood pellet production drove freshwater ecotoxicity, and pellet combustion was most relevant for marine eutrophication. Cleaning contributed ≈70 % of freshwater ecotoxicity, linked to wastewater treatment and composting emissions, while packaging added up to 40 % of fossil resource use, mainly from polypropylene granulate production. When compared with existing studies, fresh Ulva showed higher impacts than other wild harvested species due to the explicit inclusion of refrigeration, often excluded from previous system boundaries. Dried Ulva performed below published ranges, suggesting efficient processing, while dried Porphyra fell in the mid-range, consistent with literature highlighting the influence of drying intensity and species-specific yields. Overall, the findings confirm that conservation processes, particularly refrigeration and drying, are the pivotal levers shaping the environmental profile of wild harvested seaweed. By targeting these stages through renewable energy use, heat recovery, and process optimisation, producers can substantially reduce impacts. The results provide both a benchmark for future LCAs and practical guidance for industry and policymakers to support the sustainable development of seaweed value chains. |
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