Gonçalo Silva Marinho1,2, Åsa Strand3, X. Anton Álvarez-Salgado4, Isabel Fuentes-Santos4 Isabel Sousa Pinto1,2
1Department of Biology, Faculty of Sciences, University of Porto, R. do Campo Alegre s/n, 4169-007 Porto, Portugal. 2CIIMAR Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros de Leixões, 4450-208 Matosinhos, Portugal. 3IVL Swedish Environmental Research Institute, Kristineberg 566, 451 78 Fiskebäckskil, Sweden. 4CSIC Institute of Marine Research, Eduardo Cabello 6, E36208 Vigo.
Correspondence: Isabel Sousa Pinto ispinto@ciimar.up.pt
The development of aquaculture has been supported by the demonstration that this activity can be sustainable from the environmental, economic and social perspective. Several Nature’s Contributions to People (NCP), a novel framework for Ecosystem Services, were identified and quantified for selected seaweed farms in the EU projects AquaVitae and GENIALG, to inform a sustainability assessment.
The work was divided into four sub-tasks: i) identification of the NCPs provided by seaweed aquaculture ii) selection of specific Case Studies iii) selection of indicators for NCPs quantification; iv) quantification and analysis of selected NCPs.
NCPs identified and quantified for seaweed aquacultures assessed were “Regulation of coastal water quality” quantified using the indicators “Nutrient cycling” and “Eutrophication index”; “Regulation of climate” estimated with “Carbon footprint” indicator, “Regulation of ocean acidification” used “Ocean acidification index” and “Food and feed provision” was estimated using food and feed production. The performance of the selected seaweed aquaculture systems was subsequently analysed and quantified. Offshore sugar kelp production removed 1.05–2.57 kg N and 0.15–0.47 kg P per t fresh weight (FW) biomass harvested, which correspond to a maximum eutrophication mitigation potential of -2.5 kg PO4-eq per t FW, presented an ocean acidification index of -93.1 to -96.5 kg CO2/t FW, a neutral biological carbon footprint and a negligible total carbon footprint. The N and P removal by Ulva rigida produced at a land-based IMTA facility was estimated at 5.31 kg/Mt and 0.26 kg/Mt, and an ocean acidification index of -159.6 kg CO2/t FW.
Based on the NCPs evaluated in this study, seaweed production showed great promise for future expansion, but a full evaluation including additional sustainability indicators (i.e., also social and economic) should be performed to ensure that an expansion does not lead to unpredicted negative effects.