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Development of environmental impact assessment methods for marine sourced products

Nils Préat (UGent)
(2021)
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(UGent) , (UGent) , (UGent) and (UGent)
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Abstract
To sustain the needs of growing world population, seas and oceans are becoming heavily exploited. Initially exploited for food and transportation, offshore marine areas are nowadays supplying energy and minerals. Whilst the extraction of terrestrial natural resources led to major environmental consequences (i.e. biodiversity loss), it is crucial to ensure the global environmental sustainability of marine products on their entire life cycle. Life Cycle Assessment (LCA) methods have the potential to provide such information and to identify hotspots of environmental impacts in the value chain of the product under analysis. At the endpoint level, LCA results consider impacts on three areas of protection (AoP): human health, ecosystem quality and natural resources. However, LCA methods have been traditionally applied to industrial processes and thus, are limited to include site-specific aspects (e.g. disturbance of the local ecosystem) in the scope of the assessment. The application of LCA to assess the environmental sustainability of marine products including ecosystem-specific life cycle impact assessments (LCIAs) in the evaluation of impacts belonging to the three AoP. Moreover, quantitative data on mass and energy flows associated to the entire life cycle of the products (production / extraction of raw materials and their processing to final commodities) are required to perform global environmental sustainability assessments. The overall objective of this PhD is to reinforce LCA capacity to assess the global sustainability of marine products. Two operational frameworks are proposed to include site-specific aspects related to the sourcing of marine raw materials, and data related to the processing of wet biomass are provided. In this way, the evaluation of the global environmental sustainability of marine products through LCA will be more inclusive and meaningful for comparative assessments with terrestrial alternatives. The PhD starts with a general introduction (Chapter 1) divided into four sections. First, an overview of marine activities is provided. The most important marine activities in terms of economic importance are described and the concept of the industrial revolution of the seas and oceans is introduced. This refers to the growing importance of the marine-sourced materials and energy for the global economy. Indeed, the importance of the marine economy is expected to follow a two-fold increase by 2030. On a longer time horizon, the potential recovery of deep-sea minerals might significantly increase our dependence on marine commodities. The second section provides background information related to the classification of natural resources and their link with ecosystem services. Natural resources are classified according to renewability, exhaustibility and their form at the moment of extraction (biotic / abiotic). Marine natural resources are presented according to this classification and in the context of ecosystem services. Deep-sea minerals are extensively presented as they might become substantial for our economy in a near future. The ecological pressures on marine ecosystems are discussed in the third section. Direct drivers of impact caused by the marine economy are highlighted, such as the reduction of commercial fish stock size. The fourth section introduces the global concepts of LCA and the development of site-specific LCIA pathways to assess changes in local ecosystem quality, measured through biodiversity related metrics. The main limitations for global environmental sustainability assessments of marine products are exposed. The needs for site-specific marine LCIAs and further data regarding the processing of marine raw materials are highlighted. Chapter 2 quantifies trade-offs amongst seaweed farming and wild catches fisheries. Both are considered as marine natural resources and marine ecosystem services. The reduction in fisheries yields caused by the harvesting of net primary production (NPP) (i.e. seaweed) is estimated through a trophic food web approach. A site-specific LCIA framework relying on the seasonal ecosystem NPP, seaweed biomass growth and fish landings is proposed to assess the Lost Potential Yield (LPY) of the area under study. LPY are reported in terms of biomass, economic value and eco-exergy, a metric measuring the genomic complexity of the organisms. The framework is illustrated for the Greater North Sea and shows a net positive contribution of seaweed farming in terms of marine natural resources (i.e. the production of seaweed exceeds the decrease in fisheries landings for the three LPY metrics). Further research could consist in the development of additional impact pathways to NPP reduction (e.g. habitat provision) and on the consideration of ecosystem carrying capacity. The following chapter (Chapter 3) develops a site-specific LCIA framework to assess impacts of deep seafloor disturbance on regional and global biodiversity as proxy for ecosystem quality. Changes in ecosystem quality are measured through a biodiversity-related metric: the potentially disappeared fraction of species (PDF), expressing relative changes in species richness caused by the intervention. The framework builds on existing LCIAs assessing impacts on ecosystem quality from land-use (i.e. land transformation and occupation). According to existing literature, the framework identifies three kinds of impacts: transformation, occupation and permanent impacts that can be summed to obtain the total impact on regional and global ecosystem quality. The regional biodiversity impacts are first assessed and converted to global biodiversity impacts considering the vulnerability and the scarcity of the ecosystem impacted. The framework is operationalized in a case study consisting to polymetallic nodules mining in the Clarion Clipperton Fracture Zone (CCZ). Despite the very limited knowledge on benthic recovery from deep-sea mining, the framework shows consistency with existing LCA characterization models for biodiversity. The total impact on regional and global biodiversity is mostly influenced by the permanent impact on biodiversity because of the absence of recovery of a significant fraction of species. This framework can be integrated into LCA studies in order to understand the global environmental sustainability of deep-sea activities. Next to the development of additional LCIAs, the availability of detailed and transparent datasets is another challenge to assess the global environmental sustainability of marine products. Chapter 4 computes mass and energy flows associated with the harvesting and the processing of microalgae under eight biorefinery scenarios to produce lipids, proteins, energy and dried biomass. Two cell disruption methods are tested and two solvents for lipid extraction are compared. Complete flowsheets are provided for each step of the downstream processing of the raw biomass. The chapter highlights the impact of the cell disruption method on the total energy demand but also, the influence amongst downstream processes in a cascade design. Lipid extraction has influence on protein extraction, this latter improving energy production as it has a more favourable carbon to nitrogen ratio. In addition, lipids are extracted with a conventional solvent (hexane) for some scenarios and with a biobased solvent (2-methytetrahydrofuran) for other scenarios. The azeotropic distillation required for the recovery of the biobased solvent (and thus its extra energy demand) shows that solvent selection is crucial to control the total energy demand of the process, but lipid profiles will vary according to solvent properties. The last chapter (Chapter 5) consists of the conclusions and perspectives of the manuscript. Whilst the conclusions discuss the main outcomes of the three (published) research chapters (Chapter 2, Chapter 3 and Chapter 4), the perspective section opens a discussion on the requirement for an exhaustive classification of marine ecosystems. In a similar way as for the terrestrial ecosystems, such classification will facilitate the development of databases for marine ecosystem attributes and hence, the implementation of site-specific LCIAs. Furthermore, the section discusses alternatives to species richness related metrics to monitor changes in the ecosystem quality. Different types of biodiversity are defined according to the combination of biodiversity level (i.e. genetic, species, communities and landscape) and biodiversity attribute (i.e. composition, structure, function). Consequently, it is not possible to grasp the entire complexity of biodiversity through a single indicator such as species richness in LCA methods. The use of potential additional indicators for ecosystem quality and the main challenges arising from it are discussed. Finally, the discussion highlights the importance of aligning the scope of LCA studies with the descriptors used by European policy makers to assess the environmental status of marine ecosystems (under the Marine Strategy Framework Directive, MSFD). It emphasizes the needs for additional marine LCIAs to consider all descriptors identified by the MSFD (11) in LCA studies of marine products. The challenge of integrating marine ecosystem services in the scope of LCA studies is considered. Because of the complexity of quantifying ecosystem services and their link with biodiversity, the use of regional biodiversity as midpoint indicator for ecosystem services is proposed. Finally, the section concludes by discussing the challenge of evaluating the total cumulative impact caused by different stressors on a given marine ecosystem. Whilst existing LCIAs do not consider interactions amongst each other, it is relevant to make use of ecological risk assessment tools to model the final ecosystem response to various disturbances occurring in parallel. To conclude, this work has emphasized two main challenges for the global environmental sustainability assessment of marine products: the implementation of site-specific LCIA frameworks and the development of datasets regarding further processing of the harvested products.
Keywords
LCA, biodiversity, natural resources, marine environment

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MLA
Préat, Nils. Development of Environmental Impact Assessment Methods for Marine Sourced Products. Universiteit Gent. Faculteit Bio-ingenieurswetenschappen, 2021.
APA
Préat, N. (2021). Development of environmental impact assessment methods for marine sourced products. Universiteit Gent. Faculteit Bio-ingenieurswetenschappen.
Chicago author-date
Préat, Nils. 2021. “Development of Environmental Impact Assessment Methods for Marine Sourced Products.” Universiteit Gent. Faculteit Bio-ingenieurswetenschappen.
Chicago author-date (all authors)
Préat, Nils. 2021. “Development of Environmental Impact Assessment Methods for Marine Sourced Products.” Universiteit Gent. Faculteit Bio-ingenieurswetenschappen.
Vancouver
1.
Préat N. Development of environmental impact assessment methods for marine sourced products. Universiteit Gent. Faculteit Bio-ingenieurswetenschappen; 2021.
IEEE
[1]
N. Préat, “Development of environmental impact assessment methods for marine sourced products,” Universiteit Gent. Faculteit Bio-ingenieurswetenschappen, 2021.
@phdthesis{8706157,
  abstract     = {{To sustain the needs of growing world population, seas and oceans are becoming heavily exploited. Initially exploited for food and transportation, offshore marine areas are nowadays supplying energy and minerals. Whilst the extraction of terrestrial natural resources led to major environmental consequences (i.e. biodiversity loss), it is crucial to ensure the global environmental sustainability of marine products on their entire life cycle. Life Cycle Assessment (LCA) methods have the potential to provide such information and to identify hotspots of environmental impacts in the value chain of the product under analysis. At the endpoint level, LCA results consider impacts on three areas of protection (AoP): human health, ecosystem quality and natural resources. However, LCA methods have been traditionally applied to industrial processes and thus, are limited to include site-specific aspects (e.g. disturbance of the local ecosystem) in the scope of the assessment. The application of LCA to assess the environmental sustainability of marine products including ecosystem-specific life cycle impact assessments (LCIAs) in the evaluation of impacts belonging to the three AoP. Moreover, quantitative data on mass and energy flows associated to the entire life cycle of the products (production / extraction of raw materials and their processing to final commodities) are required to perform global environmental sustainability assessments. The overall objective of this PhD is to reinforce LCA capacity to assess the global sustainability of marine products. Two operational frameworks are proposed to include site-specific aspects related to the sourcing of marine raw materials, and data related to the processing of wet biomass are provided. In this way, the evaluation of the global environmental sustainability of marine products through LCA will be more inclusive and meaningful for comparative assessments with terrestrial alternatives.
The PhD starts with a general introduction (Chapter 1) divided into four sections. First, an overview of marine activities is provided. The most important marine activities in terms of economic importance are described and the concept of the industrial revolution of the seas and oceans is introduced. This refers to the growing importance of the marine-sourced materials and energy for the global economy. Indeed, the importance of the marine economy is expected to follow a two-fold increase by 2030. On a longer time horizon, the potential recovery of deep-sea minerals might significantly increase our dependence on marine commodities. The second section provides background information related to the classification of natural resources and their link with ecosystem services. Natural resources are classified according to renewability, exhaustibility and their form at the moment of extraction (biotic / abiotic). Marine natural resources are presented according to this classification and in the context of ecosystem services. Deep-sea minerals are extensively presented as they might become substantial for our economy in a near future. The ecological pressures on marine ecosystems are discussed in the third section. Direct drivers of impact caused by the marine economy are highlighted, such as the reduction of commercial fish stock size. The fourth section introduces the global concepts of LCA and the development of site-specific LCIA pathways to assess changes in local ecosystem quality, measured through biodiversity related metrics. The main limitations for global environmental sustainability assessments of marine products are exposed. The needs for site-specific marine LCIAs and further data regarding the processing of marine raw materials are highlighted.
Chapter 2 quantifies trade-offs amongst seaweed farming and wild catches fisheries. Both are considered as marine natural resources and marine ecosystem services. The reduction in fisheries yields caused by the harvesting of net primary production (NPP) (i.e. seaweed) is estimated through a trophic food web approach. A site-specific LCIA framework relying on the seasonal ecosystem NPP, seaweed biomass growth and fish landings is proposed to assess the Lost Potential Yield (LPY) of the area under study. LPY are reported in terms of biomass, economic value and eco-exergy, a metric measuring the genomic complexity of the organisms. The framework is illustrated for the Greater North Sea and shows a net positive contribution of seaweed farming in terms of marine natural resources (i.e. the production of seaweed exceeds the decrease in fisheries landings for the three LPY metrics). Further research could consist in the development of additional impact pathways to NPP reduction (e.g. habitat provision) and on the consideration of ecosystem carrying capacity.
The following chapter (Chapter 3) develops a site-specific LCIA framework to assess impacts of deep seafloor disturbance on regional and global biodiversity as proxy for ecosystem quality. Changes in ecosystem quality are measured through a biodiversity-related metric: the potentially disappeared fraction of species (PDF), expressing relative changes in species richness caused by the intervention. The framework builds on existing LCIAs assessing impacts on ecosystem quality from land-use (i.e. land transformation and occupation). According to existing literature, the framework identifies three kinds of impacts: transformation, occupation and permanent impacts that can be summed to obtain the total impact on regional and global ecosystem quality. The regional biodiversity impacts are first assessed and converted to global biodiversity impacts considering the vulnerability and the scarcity of the ecosystem impacted. The framework is operationalized in a case study consisting to polymetallic nodules mining in the Clarion Clipperton Fracture Zone (CCZ). Despite the very limited knowledge on benthic recovery from deep-sea mining, the framework shows consistency with existing LCA characterization models for biodiversity. The total impact on regional and global biodiversity is mostly influenced by the permanent impact on biodiversity because of the absence of recovery of a significant fraction of species. This framework can be integrated into LCA studies in order to understand the global environmental sustainability of deep-sea activities.
Next to the development of additional LCIAs, the availability of detailed and transparent datasets is another challenge to assess the global environmental sustainability of marine products. Chapter 4 computes mass and energy flows associated with the harvesting and the processing of microalgae under eight biorefinery scenarios to produce lipids, proteins, energy and dried biomass. Two cell disruption methods are tested and two solvents for lipid extraction are compared. Complete flowsheets are provided for each step of the downstream processing of the raw biomass. The chapter highlights the impact of the cell disruption method on the total energy demand but also, the influence amongst downstream processes in a cascade design. Lipid extraction has influence on protein extraction, this latter improving energy production as it has a more favourable carbon to nitrogen ratio. In addition, lipids are extracted with a conventional solvent (hexane) for some scenarios and with a biobased solvent (2-methytetrahydrofuran) for other scenarios. The azeotropic distillation required for the recovery of the biobased solvent (and thus its extra energy demand) shows that solvent selection is crucial to control the total energy demand of the process, but lipid profiles will vary according to solvent properties.
The last chapter (Chapter 5) consists of the conclusions and perspectives of the manuscript. Whilst the conclusions discuss the main outcomes of the three (published) research chapters (Chapter 2, Chapter 3 and Chapter 4), the perspective section opens a discussion on the requirement for an exhaustive classification of marine ecosystems. In a similar way as for the terrestrial ecosystems, such classification will facilitate the development of databases for marine ecosystem attributes and hence, the implementation of site-specific LCIAs. Furthermore, the section discusses alternatives to species richness related metrics to monitor changes in the ecosystem quality. Different types of biodiversity are defined according to the combination of biodiversity level (i.e. genetic, species, communities and landscape) and biodiversity attribute (i.e. composition, structure, function). Consequently, it is not possible to grasp the entire complexity of biodiversity through a single indicator such as species richness in LCA methods. The use of potential additional indicators for ecosystem quality and the main challenges arising from it are discussed. Finally, the discussion highlights the importance of aligning the scope of LCA studies with the descriptors used by European policy makers to assess the environmental status of marine ecosystems (under the Marine Strategy Framework Directive, MSFD). It emphasizes the needs for additional marine LCIAs to consider all descriptors identified by the MSFD (11) in LCA studies of marine products. The challenge of integrating marine ecosystem services in the scope of LCA studies is considered. Because of the complexity of quantifying ecosystem services and their link with biodiversity, the use of regional biodiversity as midpoint indicator for ecosystem services is proposed. Finally, the section concludes by discussing the challenge of evaluating the total cumulative impact caused by different stressors on a given marine ecosystem. Whilst existing LCIAs do not consider interactions amongst each other, it is relevant to make use of ecological risk assessment tools to model the final ecosystem response to various disturbances occurring in parallel. 
To conclude, this work has emphasized two main challenges for the global environmental sustainability assessment of marine products: the implementation of site-specific LCIA frameworks and the development of datasets regarding further processing of the harvested products.}},
  author       = {{Préat, Nils}},
  isbn         = {{9789463574112}},
  keywords     = {{LCA,biodiversity,natural resources,marine environment}},
  language     = {{eng}},
  pages        = {{XIX, 209}},
  publisher    = {{Universiteit Gent. Faculteit Bio-ingenieurswetenschappen}},
  school       = {{Ghent University}},
  title        = {{Development of environmental impact assessment methods for marine sourced products}},
  year         = {{2021}},
}