scholarly journals Effect of seeding methods and hatchery periods on sea cultivation of Saccharina latissima (Phaeophyceae): a Norwegian case study

2019 ◽  
Vol 32 (4) ◽  
pp. 2201-2212 ◽  
Author(s):  
Silje Forbord ◽  
Kristine B. Steinhovden ◽  
Torfinn Solvang ◽  
Aleksander Handå ◽  
Jorunn Skjermo
Keyword(s):  
Quality Control ◽  
Protein Content ◽  
Biomass Yield ◽  
Production Method ◽  
Saccharina Latissima ◽  
Seedling Production ◽  
Direct Seeded ◽  
Near Future ◽  
Frond Length

Abstract To reach the goal of an industrialised macroalgae industry in Norway and other high-cost countries in the near future, a standardised seedling production method to improve quality control and predictability of cultivated biomass is essential. A total of 11 different treatments for seeding twine or rope with meiospores, gametophytes or juvenile sporophytes from the kelp Saccharina latissima were measured for growth (frond length, frond area, biomass yield and density) and protein content after 80 and 120 days at sea. Meiospore- and gametophyte-seeded twines were pre-cultivated in the hatchery for 14–42 days prior to deployment, while juvenile sporophytes of different ages were seeded on ropes directly on the day of deployment using a commercial binder to attach the seedlings. The results showed that seeding with meiospores pre-cultivated in the hatchery for 42 days (S42) before deployment gave significantly longer fronds (77.0 ± 6.7 cm) and a higher biomass yield (7.2 ± 0.1 kg m−1) at sea compared to other treatments. The poorest growth was measured for the direct-seeded sporophytes pre-cultivated in free-floating cultures for 35 days prior to deployment (D35; 34.4 ± 2.4 cm frond length and 1.6 ± 0.4 kg m−1). Image analysis was used to measure the coverage of the twine substrate before deployment, and a correlation was found between substrate coverage and frond length at sea, indicating that this can be used as a tool for quantity and quality control during the hatchery phase and before deployment. The protein content did not reveal any large differences between the treatments after 120 days of cultivation.

scholarly journals Latitudinal, seasonal and depth-dependent variation in growth, chemical composition and biofouling of cultivated Saccharina latissima (Phaeophyceae) along the Norwegian coast

2020 ◽  
Vol 32 (4) ◽  
pp. 2215-2232 ◽  
Author(s):  
Silje Forbord ◽  
Sanna Matsson ◽  
Guri E. Brodahl ◽  
Bodil A. Bluhm ◽  
Ole Jacob Broch ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Latitudinal Gradient ◽  
Biomass Yield ◽  
Saccharina Latissima ◽  
Seaweed Farming ◽  
Membranipora Membranacea ◽  
Salinity Levels ◽  
Biomass Yields ◽  
Tissue Nitrogen ◽  
Frond Length

Abstract The Norwegian coastline covers more than 10° in latitude and provides a range in abiotic and biotic conditions for seaweed farming. In this study, we compared the effects of cultivation depth and season on the increase in biomass (frond length and biomass yield), chemical composition (protein, tissue nitrogen, intracellular nitrate and ash content) and biofouling (total cover and species composition) of cultivated Saccharina latissima at nine locations along a latitudinal gradient from 58 to 69° N. The effects of light and temperature on frond length and biofouling were evaluated along with their relevance for selecting optimal cultivation sites. Growth was greater at 1–2 m than at 8–9 m depth and showed large differences among locations, mainly in relation to local salinity levels. Maximum frond lengths varied between 15 and 100 cm, and maximum biomass yields between 0.2 and 14 kg m−2. Timing of maximum frond length and biomass yield varied with latitude, peaking 5 and 8 weeks later in the northern location (69° N) than in the central (63° N) and southern (58° N) locations, respectively. The nitrogen-to-protein conversion factor (averaged across all locations and depths) was 3.8, while protein content varied from 22 to 109 mg g−1 DW, with seasonality and latitude having the largest effect. The onset of biofouling also followed a latitudinal pattern, with a delayed onset in northern locations and at freshwater-influenced sites. The dominant epibiont was the bryozoan Membranipora membranacea. Our results demonstrate the feasibility of S. latissima cultivation along a wide latitudinal gradient in North Atlantic waters and underscore the importance of careful site selection for seaweed aquaculture.

Statistical approach for describing failures and lifetimes of water mains

1998 ◽  
Vol 38 (6) ◽  
pp. 209-217 ◽  
Author(s):  
Jianhua Lei ◽  
Sveinung Sægrov
Keyword(s):  
Data Base ◽  
Ductile Iron ◽  
Counting Process ◽  
Statistical Approach ◽  
Process Models ◽  
Average Lifetime ◽  
Maintenance Practice ◽  
Water Mains ◽  
Near Future

This paper demonstrates the statistical approach for describing failures and lifetimes of water mains. The statistical approach is based on pipe inventory data and the maintenance data registered in the data base. The approach consists of data pre-processing and statistical analysis. Two classes of statistical models are applied, namely counting process models and lifetime models. With lifetime models, one can estimate the probability which a pipe will fail within a time horizon. With counting process models one can see the deteriorating (or improving) trend in time of a group of “identical” pipes and their rates of occurrence of failure (ROCOF). The case study with the data base from Trondheim municipality (Norway) demonstrates the applicability of the statistical approach and leads to the following results: 1). In the past 20 years, Trondheim municipality has experienced approximately 250 to 300 failures per year. However, the number of failures per year will significantly increase in the near future unless better maintenance practice is implemented now. 2). Unprotected ductile iron pipes have a higher probability of failures than other materials. The average lifetime of unprotected ductile iron pipes is approximately 30 to 40 years shorter than the lifetime of a cast iron pipe. 3). Pipes installed 1963 and 1975 are most likely to fail in the future; 4) The age of a pipe does not play a significant role for the remaining lifetime of the pipe; 5). After 2 to 3 failures, a pipe enters a fast-failure stage (i.e., frequent multiple between failures).

scholarly journals ArcGIS Urban: an application for plan assessment

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Ellen Soward ◽  
Jianling Li
Keyword(s):  
United States ◽  
The United States ◽  
Spatial Context ◽  
Future Studies ◽  
Planning Profession ◽  
Gis Tools ◽  
Comprehensive Plans ◽  
Near Future ◽  
The City

AbstractMost cities in the United States rely on zoning to address important planning-related issues within their jurisdictions. Planners often use GIS tools to analyze these issues in a spatial context. ESRI’s ArcGIS Urban software seeks to provide the planning profession with a GIS-based solution for various challenges, including zoning’s impacts on the built environment and housing capacity.This research explores the use of ArcGIS Urban for assessing the existing zoning and comprehensive plans in meeting the projected residential growth in the near future using the City of Arlington, Texas as a case study. The exploration provides examples and lessons for how ArcGIS Urban might be used by planners to accomplish their tasks and highlights the capabilities and limitations of ArcGIS Urban in its current stand. The paper is concluded with some suggestions for future studies.

Sign in / Sign up

Export Citation Format

Share Document