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| 2. |
- Goddek, Simon, et al.
(författare)
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Aquaponics and Global Food Challenges
- 2019
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Ingår i: Aquaponics Food Production Systems. - : Springer Verlag. - 9783030159436
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Bokkapitel (refereegranskat)
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| 3. |
- Goddek, Simon, et al.
(författare)
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Decoupled aquaponic systems
- 2019
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Ingår i: Aquaponics Food Production Systems. - London : Springer. - 9783030159436
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Bokkapitel (refereegranskat)
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| 4. |
- Goddek, S., et al.
(författare)
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Nutrient mineralization and organic matter reduction performance of RAS-based sludge in sequential UASB-EGSB reactors
- 2018
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Ingår i: Aquacultural Engineering. - : Elsevier BV. - 0144-8609 .- 1873-5614. ; 83, s. 10-19
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Tidskriftsartikel (refereegranskat)abstract
- There is a recognized need for mineralizing aquaculture-derived sludge in aquaponics systems in order to reduce waste production. Many recent studies of aquacultural waste treatment have focused only the production of biogas as opposed to the potential for mineralization of nutrient-rich sludge. Upflow anaerobic sludge blanket (UASB) reactors provide one possible solution for breaking down sludge into bioavailable nutrients that can subsequently be delivered to plants. As such, this study examines the mineralization performance of sequential UASB reactors that are designed with an expanded granular sludge bed (EGSB) and compared to standard aerobic and anaerobic batch reactors. Results of our experiments demonstrate that only chemical oxygen demand reduction is significantly different. An unexpected drop in pH of one of the three reactor systems revealed that a pH below 6 was able to significantly increase the mineralization and mobilization of nutrients. Approximately 25% of phosphorus, potassium, and calcium could also be recovered from the sludge under lower pH conditions, as compared to the mineralization performance of standard UASB reactors running at a higher pH. However, the opposite effect was observed with respect to organic sludge reduction, where diminished performance was observed in the low-pH reactor. The current study implies that anaerobic reactors operating at low pH can potentially contribute towards improved nutrient recovery in multi-loop aquaponics systems and reduction of additive agents for pH control of the hydroponic subsystem. © 2018 Elsevier B.V.
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| 7. |
- Joyce, Alyssa, et al.
(författare)
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Molluscan bivalve settlement and metamorphosis: Neuroendocrine inducers and morphogenetic responses
- 2018
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 487, s. 64-82
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Tidskriftsartikel (refereegranskat)abstract
- Surprisingly little is known about the nature and function of neurohormones in molluscs despite the fact that many of the neurotransmitters, including serotonin, catecholamines and estrogenic compounds that regulate reproduction in humans are also found in bivalve molluscs. Although mammalian and fish sex neurotransmitters have been comparatively well-studied, their role in molluscs is an emerging field where recent molecular and genetic research reveals an increasingly nuanced understanding of neuroendocrine pathways and morphogenetic processes. This knowledge is important in eco-toxicology given the prevalence of anthropogenic pollutants such as pharmaceuticals in wastewater, as well as pesticides and insecticides that are known to interfere with neuroendocrine signalling in a wide range invertebrate and vertebrate species. Knowledge of these pathways in molluscs is also important when developing anti-fouling compounds for marine applications. In the last few decades, the use of chemical inducers in bivalve aquaculture has transformed hatchery technology not only by increasing survival rates at metamorphosis, but also by using neurohormones to create ‘cultchless’ or ‘single-seed’ spat in some species (e.g. oysters) to bypass normal pathways that involve attachment to a substrate. Hatchery protocols for inducing settlement and metamorphosis with a range of chemical inducers in commercial shellfish species have been developed primarily from empirical studies based on trial and error, but such an approach is not reliably effective in all species, and trial and error is particularly time-consuming when developing protocols for new species. During the transition from larval to juvenile to adult life stages, neuroendocrine and immune functions mediate complex metabolic processes, and recent research on hematopoiesis, immune-competence, neuroendocrine pathways and gene regulation give insights into these complexities. In this review, we provide a current overview of research regarding the neuroendocrine basis for physiological mechanisms involved in bivalve settlement and metamorphosis, given it is a period when hatcheries often experience the greatest losses. Despite a plethora of empirical studies on specific species, the processes and neurotransmitters involved are surprisingly not well explored. We focus on metamorphosis as a key developmental period by highlighting some of the most promising new research in this area, with a focus on the value of these insights for commercial applications in aquaculture. © 2018 The Authors
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| 8. |
- Joyce, Alyssa, et al.
(författare)
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The role of exopolymers in hatcheries: an overlooked factor in hatchery hygiene and feed quality
- 2015
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 446, s. 122-131
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular Polymeric Substances (EPS),(1) or exopolymers, play vital roles in the productivity of commercial hatcheries, yet have received little attention in aquaculture outside of their role in the biofilters of recirculating systems. Hatcheries have long dealt with EPS in microalgal cultures or larval rearing systems when quantities manifest themselves visually as biofilms or mucilaginous aggregates. The same polymers in lesser, visually undetectable quantities have the ability to attract commensal bacteria and sequester micronutrients, which can be essential in hatcheries for hygiene, stability of rearing environments, and the production of microalgae for live feeds. EPS may also serve an important role in nutrition both directly in the particle selection of filter feeders, and indirectly through their contribution to microflora in the larval gut of both fish and invertebrates. EPS have been well-studied in marine ecosystems, but their presence in hatcheries has until recently been largely overlooked, perhaps on account of their invisibility using normal microscopy and their extremely small size, both factors which may explain why they are sometimes also referred to as transparent exopolymeric substances (TEPs). This review examines recent literature for ways in which EPS affect hatchery processes, with suggestions as to how further research and development of biosensor technologies for EPS have the potential to improve production processes. (C) 2015 The Authors. Published by Elsevier B.V.
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| 9. |
- Joyce, Alyssa, et al.
(författare)
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Toward Selective Breeding of a Hermaphroditic Oyster Ostrea chilensis: Roles of Nutrition and Temperature in Improving Fecundity and Synchrony of Gamete Release
- 2015
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Ingår i: Journal of Shellfish Research. - : National Shellfisheries Association. - 0730-8000 .- 1943-6319. ; 34:3, s. 831-840
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Tidskriftsartikel (refereegranskat)abstract
- Physiological characteristics of gametogenesis, fertilization, and early larval development in Ostrea chilensis (Philippi, 1845) pose a number of challenges for selective breeding, despite strong commercial potential. In wild populations, this larviparous protandric hermaphrodite exhibits asynchronous gonadal maturation and relatively low fecundity. Reproductive success and genetic diversity in a hatchery population are primarily determined by female fecundity and fertility, as well as synchrony of female gonad development. Better hatchery control of the reproductive cycle can lead to more cost-effective and reliable breeding. This study examined factors such as feed and temperature in an attempt to increase reproductive rates and female sex ratios in brood stock. Oysters held under two different hatchery conditioning regimes-flow-through outdoor nursery ponds and temperature-controlled indoor tanks-spawned earlier and had higher reproductive rates than natural or farmed populations. Oysters were sampled over 6 months with histological analysis used to assess seasonal gamete patterns. Magnetic resonance imaging was also trialed and compared with histology findings. Significant increase in female gonad proportion and improved synchrony of egg maturation was observed through manipulation of feed and temperature. The implications of these findings for implementing a cost-effective selective breeding program in this species are outlined.
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| 10. |
- Linders, Torsten, 1971, et al.
(författare)
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Particle sources and transport in stratified Nordic coastal seas in the Anthropocene
- 2018
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Ingår i: Elementa: Science of the Anthropocene. - : University of California Press. - 2325-1026. ; 6:1
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Forskningsöversikt (refereegranskat)abstract
- Particles of all origins (biogenic, lithogenic, as well as anthropogenic) are fundamental components of the coastal ocean and are re-distributed by a wide variety of transport processes at both horizontal and vertical scales. Suspended particles can act as vehicles, as well as carbon and nutrient sources, for microorganisms and zooplankton before eventually settling onto the seafloor where they also provide food to benthic organisms. Different particle aggregation processes, driven by turbulence and particle stickiness, composition, abundance and size, impact the transport and sinking behavior of particles from the surface to the seafloor. In deep coastal waters, the deposition, resuspension, and accumulation of particles are driven by particle stickiness, composition and aggregate structure. In contrast, wave-driven and bottom current-driven processes in the nepheloid benthic boundary layer of shallow waters are of greater importance to the settling behavior of particles, while the retention capacity of benthic vegetation (e.g., seagrasses) further influences particle behavior. In this review, we consider the various processes by which particles are transported, as well as their sources and characteristics, in stratified coastal waters with a focus on Nordic seas. The role of particles in diminishing the quality of coastal waters is increasing in the Anthropocene, as particle loading by rivers and surface run-off includes not only natural particles, but also urban and agricultural particles with sorbed pollutants and contaminants of organic, inorganic and microplastic composition. Human activities such as trawling and dredging increase turbidity and further impact the transport of particles by resuspending particles and influencing their vertical and horizontal distribution patterns. An interdisciplinary approach combining physical, chemical and biological processes will allow us to better understand particle transport and its impact on coastal waters and estuaries at an ecosystem level. There is a need for development of novel analytical and characterization techniques, as well as new in situ sensors to improve our capacity to follow particle dynamics from nanometer to millimeter size scales.
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