| 1. |
- Both, Adrianus, 1985-, et al.
(author)
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Detrital Subsidies in the Diet of Mytilus edulis : Macroalgal Detritus Likely Supplements Essential Fatty Acids
- 2020
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In: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7, s. 1-22
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Journal article (peer-reviewed)abstract
- Detritus is a frequent, poorly defined, component of bivalve growth and carrying capacity models. The purpose of this study was to determine the proportional contributions of detrital material derived from primary producers (phytoplankton, macroalgae, Spartina alterniflora, and terrestrial leaf litter) to particulate organic matter (POM) and blue mussel’s (Mytilus edulis) diet within a temperate bay (Saco Bay, ME, United States). We assessed which detrital sources, if any, warranted incorporation into modeling efforts. Stable isotopes (δ13C and δ15N) and fatty acid biomarkers (FA) of mussels, size fractionated (<100 μm) POM, and primary producer endmembers (phytoplankton, Saccharina latissima, Ascophyllum nodosum, Chondrus crispus, Spartina alterniflora and leaf litter) collected between 2016 and 2017 were used to estimate endmember contributions to POM and mussel diets. Based on FAs dinoflagellates were the most abundant phytoplankton in Saco Bay, even during the fall diatom bloom. Diatoms within the bay were primarily centric, but pennate diatoms were at times present in the water column (e.g., in September). Following abundances of dinoflagellates, and centric and pennate diatoms, 22:6ω3 (DHA) was the most abundant essential FA (8.6 ± 0.1% total FAs), followed by 20:5ω3 (EPA: 7.0 ± 0.1%) and 20:4ω6 (ARA: 0.3 ± 0.1%). On average, phytoplankton derived organic matter contributed 22.1 ± 0.3% of the total POM in the bay. The concentration of non-fresh phytoplankton organic matter, or remaining organic matter (REMORG), was positively correlated with all endmember biomarkers. However, the proportion (%) of vascular plant, macroalgal, and detrital FAs was negatively correlated with the concentration of REMORG. This finding suggests in periods of low productivity, vascular plant and macroalgal detritus are proportionally more important contributors to POM. Mussels were broad spectrum omnivores, consuming phytoplankton, zooplankton, and detrital material. Detrital contributions to mussel diets were important (minimum of 16% of diet). Although small, macroalgae’s dietary contribution (8%) to M. edulis may be important. Macroalgal detritus contained essential FAs (20:5ω3 and 20:4ω6) that could supplement mussel diets, as M. edulis in Saco Bay were likely limited by 20:5ω3. Consideration of how macroalgal detritus affects the availability of essential FAs in POM may be useful to incorporate into aquaculture site selection.
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| 2. |
- Both, Adrianus, 1985-, et al.
(author)
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Solubilization of nutritional lipids from three coastal and estuarine primary producers using sodium taurocholate as a model surfactant to mimic typical consumer gut-fluids
- 2022
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In: Journal of Experimental Marine Biology and Ecology. - : Elsevier. - 0022-0981 .- 1879-1697. ; 548
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Journal article (peer-reviewed)abstract
- Coastal and estuarine food webs receive large inputs of both autochthonous and allochthonous detritus, which serves as an important dietary input for a variety of detritivorous and omnivorous organisms. Surfactants, which aid digestion by solubilizing hydrophobic lipids, are found in the gut-fluids of many fish and invertebrate consumers. To develop a biomimetic assay to explore how source of primary production and age may affect the bioavailability of nutritional lipids from detrital food sources, we assessed the capacity of a model surfactant, sodium taurocholate (STC), to solubilize fatty acids from three primary producers, a haptophyte (Isochrysis galbana), a rock-weed (Ascophyllum nodosum), and a marsh grass (Spartina alterniflora). Comparing lipids solubilized by a constant concentration of STC to traditional Folch-extracted yields, we assessed relative bioavailability of nutritional lipids from fresh and decayed material of each primary producer. We focused on the solubilization of storage triacylglycerols (TAG) and the fatty acid constituents of all lipids (FA). With a temperature of 5 °C, 28.7 mM STC solubilized 44 ± 12% of total FA from S. alterniflora and about half that fraction for I. galbana and A. nodosum after 15 h in the dark unstirred. In the form of TAG, STC solubilized 53 ± 19% of pure triolein as a reference and similar proportions from S. alterniflora (56 ± 19%) and I. galbana (48 ± 2%) but only 9 ± 3% from A. nodosum. Both approaches (TAG and FA) thus show significant differences in bioavailability among these three sources. Two months of decay had inconsistent effects on overall lipid yields but substantial effects on composition. Degradation led to decreased total phospholipids and long-chain polyunsaturated FA and increased break-down products (free FA and diacylglycerols), saturated and monounsaturated FA, and bacterial FA. Lower FA bioavailability and reduced degradation rates in A. nodosum may be due to its higher polyphenol and alginate concentrations. Although we mimicked only one component of the digestion process of lipids, this study represents a first step in developing a biomimetic assay to assess the relative bioavailability of nutritional lipids.
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| 3. |
- Chopin, Thierry, et al.
(author)
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Deep-ocean seaweed dumping for carbon sequestration: Questionable, risky, and not the best use of valuable biomass
- 2024
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In: One Earth. - : Elsevier BV. - 2590-3330 .- 2590-3322. ; 7:3, s. 359-364
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Journal article (peer-reviewed)abstract
- Deep-ocean seaweed dumping is not an ecological, economical, or ethical answer to climate-change mitigation via carbon “sequestration.” Without sound science and sufficient knowledge on impacts to these fragile ecosystems, it distracts from more rational and effective blue-carbon interventions. We call for a moratorium on sinking seaweeds to deep-ocean ecosystems until its efficacy is established, and there is robust, evidence-based assessment of its environmental, economic, and societal sustainability.
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| 4. |
- Hedberg, Nils, 1981-
(author)
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Sea cages, seaweeds and seascapes : Causes and consequences of spatial links between aquaculture and ecosystems
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Aquaculture is of growing importance in the global seafood production. The environmental impact of aquaculture will largely depend on the type of environment in which the aquaculture system is placed. Sometimes, due to the abiotic or biotic conditions of the seascape, certain aquaculture systems tend to be placed within or near specific ecosystems, a phenomenon that in this thesis is referred to as aquaculture system - ecosystem links. The exposed ecosystems can be more or less sensitive to the system specific impacts. Some links are known to be widespread and especially hazardous for the subjected ecosystem such as the one between the shrimp aquaculture and the mangrove forest ecosystem. The aim of this thesis was to identify and investigate causes and consequences of other spatial links between aquaculture and ecosystems in the tropical seascape.Two different aquaculture system - ecosystem links were identified by using high resolution satellite maps and coastal habitat maps; the link between sea cage aquaculture and coral reefs, and the one between seaweed farms and seagrass beds. This was followed by interviews with the sea cage- and seaweed farmers to find the drivers behind the farm site selection. Many seaweed farmers actively choose to establish their farms on sea grass beds but sea cage farmers did not consider coral reefs when choosing location for their farms. The investigated environmental consequences of the spatial link between sea cage aquaculture and coral reefs were considerable both on the local coral reef structure, and coral associated bacterial community. Furthermore, coral reef associated fish are used as seedlings and feed on the farms, which likely alter the coral food web and lower the ecosystem resilience. Unregulated use of last resort antibiotics in both fish- and lobster farms were also found to be a wide spread practice within the sea cage aquaculture system, suggesting a high risk for development of antibiotic resistant bacteria. The effects of seaweed farms on seagrass beds were not studied in this thesis but have earlier been shown to be rather substantial within the borders of the farm but less so outside the farm.Further, a nomenclature is presented to facilitate the discussion about production system - ecosystem links, which may also be used to be able to incorporate the landscape level within eco-certifying schemes or environmental risk assessments. Finally - increased awareness of the mechanisms that link specific aquaculture to specific habitats, would improve management practices and increase sustainability of an important and still growing food producing sector - the marine aquaculture.
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| 5. |
- Krause, Gesche, et al.
(author)
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Prospects of Low Trophic Marine Aquaculture Contributing to Food Security in a Net Zero-Carbon World
- 2022
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In: Frontiers in Sustainable Food Systems. - : Frontiers Media SA. - 2571-581X. ; 6
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Journal article (peer-reviewed)abstract
- To limit compromising the integrity of the planet, a shift is needed towards food production with low environmental impacts and low carbon footprint. How to put such transformative change towards sustainable food production whilst ensuring food security into practice remains a challenge and will require transdisciplinary approaches. Combining expertise from natural- and social sciences as well as industry perspectives, an alternative vision for the future in the marine realm is proposed. This vision includes moving towards aquaculture mainly of low trophic marine (LTM) species. Such shift may enable a blue transformation that can support a sustainable blue economy. It includes a whole new perspective and proactive development of policy-making which considers, among others, the context-specific nature of allocation of marine space and societal acceptance of new developments, over and above the decarbonization of food production, vis a vis reducing regulatory barriers for the industry for LTM whilst acknowledging the complexities of upscaling and outscaling. This needs to be supported by transdisciplinary research co-produced with consumers and wider public, as a blue transformation towards accelerating LTM aquaculture opportunities in a net zero-carbon world can only occur by considering the demands of society.
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| 6. |
- Troell, Max, 1962-, et al.
(author)
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Perspectives on aquaculture's contribution to the Sustainable Development Goals for improved human and planetary health
- 2023
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In: Journal of the World Aquaculture Society. - 0893-8849 .- 1749-7345. ; 54:2, s. 251-342
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Research review (peer-reviewed)abstract
- The diverse aquaculture sector makes important contributions toward achieving the Sustainable Development Goals (SDGs)/Agenda 2030, and can increasingly do so in the future. Its important role for food security, nutrition, livelihoods, economies, and cultures is not clearly visible in the Agenda 21 declaration. This may partly reflect the state of development of policies for aquaculture compared with its terrestrial counterpart, agriculture, and possibly also because aquaculture production has historically originated from a few key hotspot regions/countries. This review highlights the need for better integration of aquaculture in global food system dialogues. Unpacking aquaculture's diverse functions and generation of values at multiple spatiotemporal scales enables better understanding of aquaculture's present and future potential contribution to the SDGs. Aquaculture is a unique sector that encompasses all aquatic ecosystems (freshwater, brackish/estuarine, and marine) and is also tightly interconnected with terrestrial ecosystems through, for example, feed resources and other dependencies. Understanding environmental, social, and economic characteristics of the multifaceted nature of aquaculture provides for more context-specific solutions for addressing both opportunities and challenges for its future development. This review includes a rapid literature survey based on how aquaculture links to the specific SDG indicators. A conceptual framework is developed for communicating the importance of context specificity related to SDG outcomes from different types of aquaculture. The uniqueness of aquaculture's contributions compared with other food production systems are discussed, including understanding of species/systems diversity, the role of emerging aquaculture, and its interconnectedness with supporting systems. A selection of case studies is presented to illustrate: (1) the diversity of the aquaculture sector and what role this diversity can play for contributions to the SDGs, (2) examples of methodologies for identification of aquaculture's contribution to the SDGs, and (3) trade-offs between farming systems' contribution to meeting the SDGs. It becomes clear that decision-making around resource allocation and trade-offs between aquaculture and other aquatic resource users needs review of a wide range of established and emergent systems. The review ends by highlighting knowledge gaps and pathways for transformation that will allow further strengthening of aquaculture's role for contributing to the SDGs. This includes identification and building on already existing monitoring that can enable capturing SDG-relevant aquaculture statistics at a national level and discussion of how a cohesive and comprehensive aquaculture strategy, framed to meet the SDGs, may help countries to prioritize actions for improving well-being.
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