世界経済・社会統計 = World development indicators

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Genetics and analysis of quantitative traits

As a low-cost adsorbent, biochar can be used as a low-cost adsorbent for wastewater treatment, particularly with respect to treating heavy metals in wastewater. A number of studies have demonstrated effective removal of heavy metals from aqueous solutions by biochar and, in some cases, proven the superiority of biochars to activated carbons. Among several factors affecting the sorption ability of biochars, feedstock materials play a significant role. This review incorporates existing literature to understand the overall sorption behavior of heavy metals on biochar adsorbents. Depending on the biochar type, heavy metal can be removed by different mechanisms such as complexation, physical sorption, precipitation and electrostatic interactions. Mathematical sorption models can be used to understand the efficiency of biochar at removing heavy metals, and promote the application of biochar technology in water treatment.

A review of biochar as a low-cost adsorbent for aqueous heavy metal removal

Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.

https://link.springer.com/content/pdf/10.1007%2Fs10811-016-0974-5.pdf

Algae as nutritional and functional food sources: revisiting our understanding

Women's well-being and household benefits from seaweed farming in Indonesia

Consequences of congeneric quantitative variation in secondary metabolites of seaweeds on diet specificity and host association in specialist marine herbivores have received little attention. We investigated quantitative variation in caulerpenyne and oxytoxin 1 in 7 species of green seaweeds from the genus Caulerpa, along with the feeding preferences and host associations of 4 co-occurring sacoglossan molluscs. C. taxifolia and C. sertularioides contained high concentrations of metabolites and were preferred least by all herbivores. Algae with intermediate metabolite concentrations (C. racemosa, C. serrulata, and C. cupressoides) were preferred by Elysia tomentosa and Lobiger viridis. Oxynoe viridis and Stiliger smaragdinus had strong preferences for different low concentration Caulerpa species (C. racemosa var. laetevirens and C. lentillifera), suggesting not all feeding preferences are based exclusively on the major metabolites. In situ host associations of L. viridis and S. smaragdinus mirrored their feeding preferences, but this was not the case for E. tomentosa. Furthermore, those algal species with the highest and lowest metabolite concentrations had the lowest overall densities of sacoglossans. The results imply that the direct influence of quantitative variation in Caulerpa chemistry may only be limited to host associations in some sacoglossans. However, feeding pressure from multiple herbivore species with unique preferences could still contribute to variation in chemical defence amongst congeneric algae.

/pdf/feeding-preferences-and-host-associations-of-specialist-3c59p99rjz.pdf

Feeding preferences and host associations of specialist marine herbivores align with quantitative variation in seaweed secondary metabolites

Two distinct climatic seasons in the tropics generate extreme environmental fluctua- tions in land-based aquaculture and corresponding challenges for integrated aquaculture. Here we assessed the influence of environmental and culture variables on productivity of Cladophora coelothrix at multiple scales, firstly in an operational settlement pond and subsequently in labora- tory and flow-through mesocosm experiments. Classification and regression tree (CART) analyses were used to partition the influence of key variables on growth. In situ productivity correlated pri- marily with nitrogen concentration, position in the pond and stocking density, with a lesser influ- ence of salinity, temperature and the ratio of nitrate-nitrogen (NO3 � -N) and total ammonium nitro- gen (TAN). We subsequently evaluated the resilience of C. coelothrix in laboratory and mesocosm environments by manipulating salinity, temperature and nutrients across a broader range of val- ues derived from a year-long survey of the settlement pond. Here temperature had the greatest influence on growth, followed by nitrogen concentration and salinity. Growth rates of C. coelothrix were high, irrespective of season, except at the extremes of each season, for example, at the lowest annual temperature and with the combination of high temperature and low salinity. Growth was also limited by ~20% when NO3 � -N and TAN were available simultaneously. The use of CART analyses for both in situ and controlled environment data provided a formal dissection of the relative contribution of each environmental variable to growth, demonstrating the year-round potential for bioremediation and identifying the critical combinations of environmental variables for management of this system.

/pdf/seasonal-growth-dynamics-and-resilience-of-the-green-tide-2sl9t0222f.pdf

Seasonal growth dynamics and resilience of the green tide alga Cladophora coelothrix in high-nutrient tropical aquaculture

We compared protocols to isolate and concentrate protein from the green seaweed Ulva ohnoi. We quantified the effect of three factors on protein and essential amino acid yields and concentrations in protein isolates and residuals in a factorial experimental design. The three factors were starting material (as dry and milled or fresh and pulped), aqueous solvent-to-biomass ratio (20:1 or 5:1 v/w) and the incubation time in the aqueous solvent (incubated for 16 h at 30 °C or incubated for <1 min at ambient temperature). The protein isolation protocols increased the concentration of protein, total essential amino acids, methionine and lysine ~3 to 5-fold compared to whole U. ohnoi and were considerably more effective than the different protein concentrating combinations, which only increased protein and amino acid concentrations by 30–40 % in the residual biomass. The use of fresh and pulped biomass as the starting material, an incubation time of <1 min at ambient temperature and a low aqueous solution volume resulted in the highest protein isolate yield of 22 % of the protein found in seaweed. This study demonstrated that proteins from U. ohnoi were most effectively isolated by adopting protocols for terrestrial leaves compared to the protocols employed for seed crops as traditionally applied to seaweeds.

Nicholas A. Paul

Papers

Women's well-being and household benefits from seaweed farming in Indonesia

Feeding preferences and host associations of specialist marine herbivores align with quantitative variation in seaweed secondary metabolites

Seasonal growth dynamics and resilience of the green tide alga Cladophora coelothrix in high-nutrient tropical aquaculture

A comparison of protocols for isolating and concentrating protein from the green seaweed Ulva ohnoi

Meta-analysis of the use of seaweeds and their extracts as immunostimulants for fish: a systematic review