Study of the biosorption efficiency of seaweed species collected from the Black Sea for heavy metals removal in industrial wastewaters

In this article, it will be presented the results obtained from research conducted in order to reduce the concentrations of metals in industrial wastewater resulted from heavy metal polluting industries, especially the metallurgical industry. Most of the world's water sources are profoundly negatively affected by human activities, and the population faces critical water supply and drinking water quality problems. Millions of people develop various diseases from drinking water from unsafe or poor quality sources, creating a global public health problem. Due to massive industrialisation, current water treatment methods are outdated, which is why water treatment and purification laws, regulations, and controls need to be updated to minimise and stop contamination of the food chain. It is the responsibility of the researchers to make the public aware of the dangers to which they are exposed due to their own negligence and to offer possible solutions to these problems. New, reliable, viable, cheap, and sustainable technologies must be developed to improve drinking water quality. One such technology that can be developed and implemented is using the biological method of biosorption. Stranded seaweed on the Romanian Black Sea coast is currently treated as waste, but it could be exploited as biomass in the biosorption process. The research aimed to investigate the possibility of valorification of macrophyte seaweed species in this direction. Five different species of stranded macrophyte seaweed were collected and used to remove selected metallic ions (Cr, Fe, Zn, Cu) from a source of wastewater resulted from the metallurgical industry processes. The wastewater samples were analyzed before and after the application of the biosorption technique using the spectrophotometric method.

Effect of different seedling weights on Kappaphycus alvarezii growth

Seaweed K. alvarezii is one of leading commodities in aquaculture because this seaweed species produces carrageenan which has high economic value. This study aimed to determine effect of different seedling weights on the growth of seaweed K. alvarezii, and to determine which seedling weight had the best effect on seaweed growth. Planting process was carried out using longline method. Size of longline construction used was 10 m x 20 m, with a length of 20 m and a distance of 1 m between each ropes. Each rope line contained about 66 clumps of seedlings with a distance between clumps of 15 cm. Thallus weight used was 30 gr, 50 gr, 70 gr for each treatment. The highest mean value of absolute weight growth of seaweed K. alvarezii was found in treatment C (thallus weight 70 gr) with an average value of 99.27 gr, followed by treatment A (thallus weight 30 gr) of 51.95 gr and the lowest value found in treatment B (thallus weight 50 gr) of 51.65 gr.

Spectral Discrimination of Six Dominant Seaweed Species in the Intertidal Zone of GouQi Island

Probing the coverage and biomass of seaweed is the basis for achieving sustainable utilization of nearshore seaweed resources. Unlike traditional sample surveys, remote sensing technology can realize dynamic monitoring on a large scale and for a long time. In this paper, we measured the spectral data of six dominant seaweed species in different dry and wet conditions in the intertidal zone of Gouqi Island: Ulva pertusa, Sargassum thunbergii, Chondrus ocellatus, Chondria crassiaulis Harv., Grateloupia filicina C. Ag., and Hizikia fusifarme. The different seaweed species were identified and analyzed by a combination of ANOVA and support vector machine (SVM). Fourteen common spectral parameters were used as input variables, and the input parameters were filtered by ANOVA. The samples were divided into a training set (266 samples) and a test set (116 samples) at a 3:1 ratio for input into the SVM model. The results showed that when the input parameters were NDVI (Rg,Rr), RVI (Rg,Rr), Vre, Abe, Lbe, Lg, Lre, and Rr and the model parameters g=1.30 and c=2.85, the maximum discrimination rate of the six different wet and dry states of seaweed was 74.96%, and the highest accuracy was 93.94% when distinguishing different phyla of seaweed (g=6.85 and c=2.55). In addition, SVM is fused with XGBoost (eXtreme Gradient Boosting) by vote and further classified in combination with the selected parameters. The accuracy of the six seaweeds was 73.98% (vote mean score = 0.972). In this study, the spectral data of intertidal seaweed in different dry and wet states were classified for the first time to provide technical support for remote sensing monitoring of coastal zones and seaweed resource statistics.

Study on using fatty acid data in the botanical chemotaxonomy for Vietnamese seaweed species

Vietnam's sea is assessed to be very diverse and rich in seaweed species. It is about 1000 different species of seaweed, of which more than 800 species have been identified, classify into genus, families, classes, phylums, and continuously updated from the 1950s to the present. Previous studies by Vietnamese and international scientists have shown that lipids from seaweed contain many valuable active ingredients such as acids C20: 4n-6 (AA), C20:5n-3 (EPA), C22:6n-3 (DHA), prostaglandin E2… In this study, fatty acids were converted to methyl esters and identified by gas chromatography using flame ionization detector (GC-FID) with column Cap Mao Equity 5 (Merck, L×ID 30m×0.25 mm, df 0.25 µm). From the total lipid of 50 of Vietnamese seaweed, we have identified 30 fatty acids, in which, C16:0, C18:1n-9, C20:4n-6 (AA) fatty acids have the high content, and C20:5n-3 (EPA), C22:6n-3 (DHA), C22:5n-3 (DPA) fatty acids have the high bioactivities. By the method of PCA main component analysis, from the dataset of fatty acids, we have identified 8 main fatty acids with high correlation and used to represent the distribution of seaweed species on the two-way plane. Three phylums were classified by different fatty acid groups with the high reliability. In the detail, the distribution of the phylum Phaeophyta depends on the content of 3 fatty acids including C16:1n-7, C18:1n-9 và C20:4n-6, the phylum Rhodophyta depends on C15:0, C16:0, C18:0 fatty acids, and the phylum Chlorophyta depends on C18:1n-7, C18:3n-6 fatty acids. This method can may help provides more chemical data in the taxonomy of Vietnamese seaweed species.

POTENSI BEBERAPA JENIS RUMPUT LAUT DI ACEH (STUDI KASUS: SKRINING FITOKIMIA DAN AKTIVITAS ANTIOKSIDAN)

One of the sea potentials in Aceh is seaweed. Seaweed contains secondary metabolites and antioxidants that are very well consumed because it can act as an antidote/protector from the free radicals. This study aimed to determine the secondary metabolite content and antioxidant activity of seaweed in Aceh.The seaweed that has been macerated then screened for phytochemicals and tested for antioxidant activity by using the DPPH method. The seaweed species found were Gracillaria verrucosa, Sargassum sp., and Chaetomorpha antennina. The results of this study indicated that Gracillaria verrucosa, Sargassum sp., and Chaetomorpha antennina seaweeds were contained by alkaloids and steroids. Flavonoid and saponins were only detected in the types of seaweed Gracillaria verrucosa and Sargassum sp. It was also found that the higher the concentration of the extract, the higher the percentage of IC50 against free radicals. The Sargassum sp. has a stable percentage of inhibition at a 2-10 ppm concentration, so it is recommended in this study to be considered cultivated in Aceh.

A global dataset of seaweed net primary productivity

Net primary productivity (NPP) plays a pivotal role in the global carbon balance, but estimating the NPP of underwater habitats remains a challenging task. Seaweeds (marine macroalgae) form the largest and most productive underwater vegetated habitat on Earth. Yet, little is known about the distribution of their NPP at large spatial scales, despite more than 70 years of local-scale studies being scattered throughout the literature. We present a global dataset containing NPP records for 242 seaweed species at 419 individual sites distributed on all continents from the intertidal to 55 m depth. All records are standardized to annual aerial carbon production (g C m-2 yr-1) and are accompanied by detailed taxonomical and methodological information. The dataset presented here provides a basis for local, regional and global comparative studies of the NPP of underwater vegetation, and is pivotal for achieving a better understanding of the role seaweeds play in the global coastal carbon cycle.