Profitability of multi‐loop aquaponics: Year‐long production data,economic scenarios and a comprehensive model case     

Gsta Baganz  Daniela Baganz  Georg Staaks  Hendrik Monsees  Werner Kloas 《Aquaculture Research》2020,51(7):2711-2724

This case study examined the productivity and economic performance of a double recirculation aquaponic system in Germany with a total interior area of about 540 m². Calculations were carried out as an ex post analysis based on one‐year production data. The initial situation was not profitable; therefore, two scenarios were developed, which envisaged a significantly improved productivity of the fish as well as of the plant unit and a more than threefold enlargement of the greenhouse to make maximum use of the fish effluent. An ex ante analysis was performed and showed that the second scenario was profitable with a payback period of about 12 years. On the basis of this scenario, a simple but comprehensive model case with the complete set of economic key indicators showed that aquaponics is feasible if it exploits its potential, regardless of the high initial investment costs. The model case would cover an overall space of about 2,000 m², which is suitable for professional aquaponics in urban and peri‐urban areas with their limited space availability. Furthermore, multi‐loop aquaponics with its inherent circles fits into the circular city concept and implements resource‐efficient and sustainable food production into the urban fabric, which is important with increasing urbanization.  相似文献   

Behavioural responses of eel (Anguilla anguilla) approaching a large pumping station with trash rack using an acoustic camera (DIDSON)     

Olvin Alior van Keeken  Ralf van Hal  Hendrik Volken Winter  Ingrid Tulp  Arie Benjamin Griffioen 《Fisheries Management and Ecology》2020,27(5):464-471

European eel, Anguilla anguilla L., migrating to the sea encounter many man‐made structures that can hamper and delay migration or induce mortality. Studying small‐scale behavioural movements in front of these man‐made structures could provide insight in further mitigating adverse effects. The behaviour of eel approaching a trash rack in front of a large pumping station was investigated using a dual‐frequency identification sonar (DIDSON). Eels approaching the trash rack swam through the rack (40.5%) but also showed turning behaviour at (44.7%) or in front of the rack (14.7%). Eels approaching the rack had varying body positions, predominantly head or tail first, but also curled up into a ball or drifted sideways. After turning in front or at the trash rack, eels showed upstream and downwards swimming towards the canal bottom. The results suggest a stepwise response to potential cues, when firstly the body position is changed in such a way that secondly, later on, enhances eventual fast upstream escapement when perceived necessary. Implications for management of these behavioural observations are discussed.  相似文献   

Population‐level consequences of seismic surveys on fishes: An interdisciplinary challenge     

Hans Slabbekoorn  John Dalen  Dick de Haan  Hendrik V. Winter  Craig Radford  Michael A. Ainslie  Kevin D. Heaney  Tobias van Kooten  Len Thomas  John Harwood 《Fish and Fisheries》2019,20(4):653-685

Offshore activities elevate ambient sound levels at sea, which may affect marine fauna. We reviewed the literature about impact of airgun acoustic exposure on fish in terms of damage, disturbance and detection and explored the nature of impact assessment at population level. We provided a conceptual framework for how to address this interdisciplinary challenge, and we listed potential tools for investigation. We focused on limitations in data currently available, and we stressed the potential benefits from cross‐species comparisons. Well‐replicated and controlled studies do not exist for hearing thresholds and dose–response curves for airgun acoustic exposure. We especially lack insight into behavioural changes for free‐ranging fish to actual seismic surveys and on lasting effects of behavioural changes in terms of time and energy budgets, missed feeding or mating opportunities, decreased performance in predator‐prey interactions, and chronic stress effects on growth, development and reproduction. We also lack insight into whether any of these effects could have population‐level consequences. General “population consequences of acoustic disturbance” (PCAD) models have been developed for marine mammals, but there has been little progress so far in other taxa. The acoustic world of fishes is quite different from human perception and imagination as fish perceive particle motion and sound pressure. Progress is therefore also required in understanding the nature and extent to which fishes extract acoustic information from their environment. We addressed the challenges and opportunities for upscaling individual impact to the population, community and ecosystem level and provided a guide to critical gaps in our knowledge.  相似文献   

Chronic exposure to nitrate significantly reduces growth and affects the health status of juvenile Nile tilapia (Oreochromis niloticus L.) in recirculating aquaculture systems          下载免费PDF全文

Hendrik Monsees  Laura Klatt  Werner Kloas  Sven Wuertz 《Aquaculture Research》2017,48(7):3482-3492

Studies on chronic or acute toxicity of nitrogen species on fish in recirculating aquaculture systems (RAS) usually focused on adverse effects of total ammonia nitrogen (TAN: sum of NH₃ + NH₄⁺) and nitrite (), while underestimating the potential effects of high nitrate accumulation on growth and health status of fish. In our study, Nile tilapia (Oreochromis niloticus) were exposed to five different nitrate concentrations (0, 10, 100, 500 and 1000 mg L^?1 ‐N) over 30 days. Growth parameters (feed conversion ratio (FCR), specific growth rate (SGR), hepatosomatic index (HSI)), blood samples (concentrations of haemoglobin, methaemoglobin, plasma /) and the histology of the gills were studied to evaluate growth and health status of the fish. At the highest nitrate concentration, the fish showed significantly reduced growth and impaired health status (SGR, FCR, plasma /, haemoglobin and methaemoglobin concentration), demonstrating that too high nitrate concentrations can negatively influence tilapia production in RAS. Here, we recommend not exceeding concentrations of 500 mg L^?1 ‐N in juvenile tilapia culture to ensure an optimal health and growth status of the fish, as below that concentration no effects on the tilapia have been observed.  相似文献   

SAR of Sponge-Inspired Hemibastadin Congeners Inhibiting Blue Mussel PhenolOxidase     

Hendrik Niemann  Jens Hagenow  Mi-Young Chung  Claire Hellio  Horst Weber  Peter Proksch 《Marine drugs》2015,13(5):3061-3071

Hemibastadin derivatives, including the synthetically-derived 5,5′-dibromohemibastadin-1 (DBHB), are potent inhibitors of blue mussel phenoloxidase (PO), which is a key enzyme involved in the firm attachment of this invertebrate to substrates and, thus, a promising molecular target for anti-fouling research. For a systematic investigation of the enzyme inhibitory activity of hemibastadin derivatives, we have synthesized nine new congeners, which feature structural variations of the DBHB core structure. These structural modifications include, e.g., different halogen substituents present at the aromatic rings, different amine moieties linked to the (E)-2-(hydroxyimino)-3-(4-hydroxyphenyl)propionic acid, the presence of free vs. substituted aromatic hydroxyl groups and a free vs. methylated oxime group. All compounds were tested for their inhibitory activity towards the target enzyme in vitro, and IC₅₀ values were calculated. Derivatives, which structurally closely resemble sponge-derived hemibastadins, revealed superior enzyme inhibitory properties vs. congeners featuring structural moieties that are absent in the respective natural products. This study suggests that natural selection has yielded structurally-optimized antifouling compounds.  相似文献   

Nasal swelling due to plasma cell infiltrate in a cat without plasma cell pododermatitis     

Jan Declercq  Hendrik De Bosschere 《Veterinary dermatology》2010,21(4):412-414

A cat with an upper respiratory infection was presented for examination. Close examination of the face revealed a firm, haired rounded swelling on the bridge of the nose. Serum protein electrophoresis demonstrated a mild hypergammaglobulinaemia. The cat tested negative for feline immunodeficiency virus. Skin biopsy of the nasal lesion revealed nodular angiocentric infiltrates in the deep dermis and subcutis. The mixed infiltrate had numerous plasma cells. Presence of calicivirus antigen could not be demonstrated within the skin lesion by immunohistochemical staining. The cat was treated for upper respiratory infection and 1 month later the nasal lesion had resolved. A firm and rounded swelling over the bridge of the nose may be a feline cutaneous plasmacytic reaction pattern.  相似文献   

马铃薯广谱抗病Rpi-blb1 同源基因抗性被进化晚疫病菌株克服     

朱素贤  祝军  李颖  Nijenhuis Maarten  Bergervoet Marjan  Rietman Hendrik  Jacobsen Evert 《园艺学报》2010,37(2):241-246

 马铃薯晚疫病广谱抗性基因Rpi-blb1（克隆于Solanum bulbocastanum）及其两个同源抗病基因Rpi-sto1（克隆于Solanum stoloniferum）和Rpi-pta1（克隆于Solanum papita）的抗性可能已被高度进化的晚疫病菌株所克服。为证实此观点,将从荷兰田间和墨西哥野外S. bulbocastanum 和S. stoloniferum 病株上采集的晚疫病菌株重新接种于具有共同遗传背景（感病栽培品种Desiree）的Rpi-blb1 及其同源基因转化体和3个野生种植株上,测试Rpi-blb1 及其同源基因的抗性是否已被克服。结果表明,采自墨西哥野外S. stoloniferum的两个菌株Pic99189 和Pic99192 已经克服了Rpi-blb1 及其同源基因的抗性;在野生种植株的测试中,只有S. papita 的抗性明显地被菌株Pic99192 所克服。同时发现在转基因植株离体叶片接种试验中,高抗晚疫病菌的转化体需要在多个转化体间进行选择。从采自中国4 个不同地区晚疫病菌株接种sto1.Desiree 转化体的小规模测试中可推断,Rpi-blb1 及其同源抗性基因在中国仍具有潜在的应用价值。  相似文献   

Bibliography on Paleopedology: A. Ruellan (Editor). Paleopedology Commission,INQUA, c/o Ecole Nationale Supérieure d'Agronomie,Rennes, 1974, 439 pp., FF. 50 (postage included)     

Hendrik J. Bruins 《Geoderma》1976,16(5):445-446

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Biomechanical evaluation of a novel nucleus pulposus prosthesis in canine cadaveric spines     

Smolders LA  Bergknut N  Kingma I  van der Veen AJ  Smit TH  Koole LH  Hazewinkel HA  Meij BP 《Veterinary journal (London, England : 1997)》2012,192(2):199-205

Partial disc replacement is a new surgical technique aimed at restoring functionality to degenerated intervertebral discs (IVDs). The aim of the present study was to assess biomechanically the behaviour of a novel nucleus pulposus prosthesis (NPP) in situ and its ability to restore functionality to the canine IVD after nuclectomy alone or after combined dorsal laminectomy and nuclectomy. Nine canine T13-L5 specimens (L2L3 group) and 10 L5-Cd1 specimens (LS group) were tested biomechanically in the native state, after nuclectomy (L2L3 group) or after combined dorsal laminectomy and nuclectomy (LS group), and after insertion of the NPP. Range of motion (ROM), neutral zone (NZ), and neutral zone stiffness (NZS) were determined in flexion/extension, lateral bending, and axial rotation. Nuclectomy alone and combined dorsal laminectomy and nuclectomy caused significant instability in all motion directions. Implantation of the NPP resulted in significant restoration of the parameters (ROM, NZ, and NZS) towards the native state; however, fragmentation/herniation of the NPP occurred in 47% of the cases. In conclusion, the NPP has the ability to improve functionality of the nuclectomized canine IVD. The high rate of NPP failure requires modifications directed at the integrity of the NPP and its confinement to the nuclear cavity.  相似文献   

Toward metrological traceability for DNA fragment ratios in GM quantification. 3. Suitability of DNA calibrants studied with a MON 810 corn model   总被引：2，自引：0，他引：2  

Charels D  Broeders S  Corbisier P  Trapmann S  Schimmel H  Emons H 《Journal of agricultural and food chemistry》2007,55(9):3268-3274

The quantification of GMOs by real-time PCR relies on an external calibrant. In this paper the suitability of two DNA calibrants, genomic DNA from plant leaves and plasmidic DNA, was investigated. The PCR efficiencies, the correlation coefficients of the calibration curves, and the ratios between PCR efficiencies of transgenic and endogenous sequences were compared for both calibrants using 59 data sets produced by 43 laboratories. There were no significant differences between plasmidic and genomic DNA except for the PCR efficiencies of the calibration curves for the transgene of the construct-specific real-time PCR method. In the GM system investigated, PCR efficiencies of plasmidic calibrants were slightly closer to the PCR efficiencies observed for the unknowns than those of the genomic DNA calibrant. Therefore, plasmidic DNA was the more suitable calibrant for the PCR measurements on genomic DNA extracted from MON 810 seeds. It is shown that plasmidic DNA is an appropriate choice for the calibration of measurements of MON 810 corn with respect to the DNA copy number ratio.  相似文献