The impact of seaweed cultivation on ecosystem services - a case study from the west coast of Sweden

Abstract

Seaweed cultivation attracts growing interest and sustainability assessments from various perspectives are needed. The paper presents a holistic qualitative assessment of ecosystem services affected by seaweed cultivation on the Swedish west coast. Results suggest that supporting, regulating and provisioning services are mainly positively or non-affected while some of the cultural services are likely negatively affected. The analysis opens for a discussion on the framing of seaweed cultivation - is it a way of supplying ecosystem services and/or a way of generating valuable biomass? Exploring these framings further in local contexts may be valuable for identifying trade-offs and designing appropriate policies and development strategies. Many of the found impacts are likely generalizable in their character across sites and scales of cultivation, but for some services, including most of the supporting services, the character of impacts is likely to be site-specific and not generalizable.

Seaweed resources of the Baltic Sea, Kattegat and German and Danish North Sea coasts

“…In Sweden the efforts are mainly concentrated in the west coast, where the salinity is >20. The "Seafarm project" -involving five Swedish universities -was launched in 2014 to foster research around a cultivated Saccharina latissima biorefinery supply-chain, which resulted in the establishment of a first experimental seaweed farm in the Koster archipelago in Skagerrak (Hasselstrom et al 2018). A number of studies conducted in Denmark also estimated the regional potential of cultivated kelps or Ulva lactuca for production of biogas, bioethanol, biobutanol and more advanced biorefineries (Bruhn et al 2011, Alvarado-Morales et al 2013, Hou et al 2015.…”

“…In addition, exploitation of the bio-mitigation capacity of cultivated seaweed in the framework of integrated multitrophic aquaculture (IMTA), or as a compensation for increased animal aquaculture is coming more and more into focus (e.g. Sandow 2007, Holdt and Edwards 2014, Marinho et al 2015a, Hasselstrom et al 2018, Buck and Grote 2019. For example, seaweed cultivation is explicitly mentioned in Denmark's National Strategic Plan for the Development of Sustainable Aquaculture 2014-2020 as a compensation measure to bioremediate waste nutrients of fish and shellfish aquaculture (Ministeriet for Fødevarer Landbrug og Fiskeri 2016) and the Danish Government is currently seeking to facilitate investment in the creation of zones with integrated aquaculture (Ferdouse et al 2018).…”

“…The goal is to prevent a deterioration of water quality in the Danish marine areas despite a predicted increase in fish aquaculture by at least 25% by 2020. Also in Sweden, the ecosystem services that can be provided by seaweed farming are increasingly recognized as relevant benefits (Pechsiri et al 2016, Hasselstrom et al 2018.…”

“…The nonprovisioning ecosystem services that can be provided by seaweeds (Rönnbäck et al 2007) are also increasingly recognized and valued in the area. Support and stabilization of marine biodiversity, coastal protection and even an increased aesthetic value of cleaner and less degraded coastal environments are all services that can be provided to different degrees by the various types of natural seaweed ecosystems that exist in the area (Rönnbäck et al 2007), as well as by the artificial habitats formed by seaweed aquaculture (Hasselstrom et al 2018). However, conflicting interests to use coastal environments in other ways currently also emerge (e.g.…”

Socioeconomic prospects of a seaweed bioeconomy in Sweden

“…It does not need land, fresh water, fertilisers, or pest-insect-or fungicides to grow, and the biomass can be used for many purposes, such as food 2 , feed 3 , materials 4 , biofuels 5 , or as gelling or stabilising substance in a range of applications 6 . Additionally, seaweed farming provides positive externalities in terms of ecosystem services such as generating habitats for fish and crayfish species and sequestering nutrients 7 . In a recent study, it is suggested that phosphorus uptake from large-scale seaweed cultivation in China can significantly contribute to mitigating coastal eutrophication 8 , and it has also been suggested as a potential carbon sink 9,10 .…”