Seaweed Diversity Research Articles

Sea Vegetables: An Alternative Food Source: A Review

Seaweeds or sea vegetables are the non-traditional vegetables largely produced and consumed by China, Japan, Korea, Indonesia, Philippines, Malaysia, Vietnam and other island countries. They are rich in essential nutrients, including minerals, vitamins, amino acids etc. making them a valuable addition to a balanced diet. Moreover, they have low caloric content and are free from cholesterol, essential for weight management and heart-healthy diets. Additionally, sea vegetables contain unique bioactive compounds such as polysaccharides, polyphenols and omega-3 fatty acids, which have antioxidant, anti-inflammatory and anti-cancer properties. Globally the demand for seaweed as vegetables along with its several value-added products are increasing day by day. The cultivation of seaweed is cost effective as it does not require seeds, fertilizers, pesticides, no freshwater and arable land. Sea vegetables can serve as bio filters by absorbing excess nutrients from aquatic ecosystems, thus promoting environmental sustainability in coastal aquatic system. To combat hunger, achieve food security and protect the environment, it is crucial to create public awareness on the health benefits and nutritional value of sea vegetables. More in-depth research and developments are required to commercialize, explore the diversity of sea vegetables, develop innovative culinary applications and establishment of quality and safety standards. The present review works highlights a comprehensive overview of seaweed diversity, nutritional composition, health benefits, diverse uses, cultivation methods and potential for developing processed products for food and agricultural industry.

Functional traits of ecosystem engineers as predictors of associated fauna

The ongoing combination of global warming and increased anthropogenic pressure is causing latitudinal shifts in marine species, potentially impacting community composition, local richness, and marine trophic webs. This study investigates the factors influencing the distribution and diversity of intertidal seaweed and associated peracarid communities, including their functional traits, and explores various facets of beta diversity (taxonomic and functional). We hypothesize that: 1) abiotic factors such as temperature and anthropogenic pressure significantly influence seaweed distribution and diversity shifts, and 2) changes in seaweed functional diversity have an impact on the diversity and functioning of its associated peracarid communities. The sampling was conducted along a wide latitudinal gradient in the NE Atlantic (27°N - 65°N), encompassing three distinct ecoregions: Northern European coasts, the Iberian Peninsula, and Macaronesia. The identified seaweed and peracarid species were classified functionally, and taxonomic and functional diversity were analysed on a large geographic scale. The northern region exhibited large brown canopy seaweeds and epibiotic isopods, while Macaronesia featured small red, highly branched, and calcareous crust seaweeds with burrower and tube-building tanaids. The Iberian Peninsula acted as a transitional zone, showcasing a mix of green, red, and brown seaweeds, along with Amphipoda peracarids found across all ecoregions. Our findings underscore the impact of geographic distance on total beta diversity, revealing distinct seaweed and peracarid communities across spatial gradients. Environmental variables, particularly pH and maximum sea surface temperature, emerged as significant factors influencing beta diversity patterns of seaweeds, indicating the potential impact of acidification and heat waves on community composition. In addition, seaweed functional traits were shown to be significant in shaping the diversity and abundance of associated peracarid assemblages, impacting both taxonomic and functional beta diversity. These findings provide crucial insights into the factors influencing the biogeography and biodiversity dynamics of intertidal seaweeds and associated peracarids, offering essential implications for conservation and management strategies amid ongoing environmental changes.

Comparative structure and evolution of the organellar genomes of Padina usoehtunii (Dictyotales) with the brown algal crown radiation clade

BackgroundOrganellar genomes have become increasingly essential for studying genetic diversity, phylogenetics, and evolutionary histories of seaweeds. The order Dictyotales (Dictyotophycidae), a highly diverse lineage within the Phaeophyceae, is long-term characterized by a scarcity of organellar genome datasets compared to orders of the brown algal crown radiation (Fucophycidae).ResultsWe sequenced the organellar genomes of Padina usoehtunii, a representative of the order Dictyotales, to investigate the structural and evolutionary differences by comparing to five other major brown algal orders. Our results confirmed previously reported findings that the rate of structural rearrangements in chloroplast genomes is higher than that in mitochondria, whereas mitochondrial sequences exhibited a higher substitution rate compared to chloroplasts. Such evolutionary patterns contrast with land plants and green algae. The expansion and contraction of the inverted repeat (IR) region in the chloroplast correlated with the changes in the number of boundary genes. Specifically, the size of the IR region influenced the position of the boundary gene rpl21, with complete rpl21 genes found within the IR region in Dictyotales, Sphacelariales and Ectocarpales, while the rpl21 genes in Desmarestiales, Fucales, and Laminariales span both the IR and short single copy (SSC) regions. The absence of the rbcR gene in the Dictyotales may indicate an endosymbiotic transfer from the chloroplast to the nuclear genome. Inversion of the SSC region occurred at least twice in brown algae. Once in a lineage only represented by the Ectocarpales in the present study and once in a lineage only represented by the Fucales. Photosystem genes in the chloroplasts experienced the strongest signature of purifying selection, while ribosomal protein genes in both chloroplasts and mitochondria underwent a potential weak purifying selection.ConclusionsVariations in chloroplast genome structure among different brown algal orders are evolutionarily linked to their phylogenetic positions in the Phaeophyceae tree. Chloroplast genomes harbor more structural rearrangements than the mitochondria, despite mitochondrial genes exhibiting faster mutation rates. The position and the change in the number of boundary genes likely shaped the IR regions in the chloroplast, and the produced structural variability is important mechanistically to create gene diversity in brown algal chloroplast.

Diversity of seaweeds of the coast of Veracruz, Mexico

Antecedentes y Objetivos: Los primeros registros de algas marinas bentónicas para el litoral de Veracruz datan de 1846; después de 114 años, ficólogos mexicanos reiniciaron su estudio. Actualmente, se tienen registradas 312 especies. Considerando está riqueza específica, las modificaciones y actualizaciones taxonómicas en diversos grupos, el objetivo de este trabajo fue presentar una lista de las algas marinas del litoral veracruzano organizadas por categorías taxonómicas incluyendo datos de distribución, temporalidad y nuevos registros para el área de estudio. Métodos: Se realizaron 92 muestreos durante 18 años, en el nivel intermareal de 11 localidades del litoral, se obtuvieron registros previos desde 1960 a 2020 a través de una revisión bibliográfica y de la colección ficológica del herbario ENCB. El estatus nomenclatural de cada especie y el sistema de clasificación fueron revisados y actualizados. La diversidad α para cada localidad fue calculada con el índice de Shannon-Wiener; también se realizó un análisis de agrupamiento mediante UPGMA con el programa PAST v. 3. Resultados clave: El listado ficoflorístico incluye 316 taxones de algas marinas bentónicas distribuidas en 3 Phyla, 6 clases, 31 órdenes, 60 familias y 130 géneros. Cada especie incluye distribución en el litoral de Veracruz, reproducción, estacionalidad, hábitat, observaciones, bibliografía y número de catálogo del herbario ENCB. Los análisis de diversidad α muestran que la mayor diversidad está en las localidades con sustrato predominantemente rocoso con 180 especies. Las lluvias de verano registraron un elevado número de especies (269); Barra de Cazones alberga 181 especies, además, se encontraron 70 registros nuevos; así, el número de taxones aumentó a 391. Conclusiones: El listado revela una mayor riqueza específica de algas marinas comparada con la registrada en Yucatán, Campeche y Tabasco. La afinidad fitogeográfica de las algas del litoral de Veracruz es mixta, ya que ahí confluyen taxones tropicales y caribeños. Es necesario mantener un monitoreo constante para determinar cambios de la comunidad de algas para establecer programas de conservación y aprovechamiento.

Spatiotemporal analysis in brown seaweed diversity and abundance at selected coastal locations on the Southern coast of Tamil Nadu, India: A way forward for conservation and sustainable utilization

Tamil Nadu and its southern coast are well-known for seaweed diversity and abundant resources in India. Brown seaweeds are primary habitat producers in reef environments. The objective of this study was to assess the spatiotemporal variation in diversity and abundance of brown seaweed species along the intertidal region at selected coastal locations on the southern coast of Tamil Nadu, India. The sampling was performed monthly at six coastal locations, namely Hare Island (HI), Tuticorin Harbour (TH), Chinna Muttom (CM), Arockiapuram (AP), Vedhalai (VD), and Mandapam (MP), along the intertidal region during low tides between January 2021 and December 2021. A total of 36 brown seaweed species were identified at six locations, namely Sargassum (9 species), followed by Padina (5 species), Turbinaria (3 species), Dictyota (3 species) and 16 species each of others. In the context of different locations, the highest species diversity was observed at HI (35) and the lowest at CM (21) during the study period. The highest abundance was recorded at CM (19.80 kg wt m−2), while the lowest was reported at AP (9.51 kg wt m−2). Sargassum and Turbinaria exhibited the highest prevalence across all the locations. Among different seasons, the maximum species diversity was recorded during PoMoN (26), whereas the minimum species diversity was recorded during PrMoN (11). Similarly, the highest abundance was seen during PoMoN, whereas the lowest abundance was reported during PrMoN. These findings offer crucial foundational data for the preservation and exploitation of brown seaweeds.

Gathering and Cooking Seaweeds in Contemporary Ireland: Beyond Plant Foraging and Trendy Gastronomies

Seaweed has historically been essential for coastal communities worldwide. Following a period of decline in the last century, Ireland has seen a recent resurgence in the appreciation and use of seaweed. This research explores the evolution in seaweed foraging practices, with a specific focus on gastronomical uses in two Irish regions: the southwest and the west and midwest. It examines the diversity of seaweed and its present and past uses, comparing abandonment, continuation and revitalisation trajectories. Qualitative data were gathered through semi-structured interviews with 27 individuals who forage seaweed for commercial or personal use. We identified 22 seaweed species across the study areas, predominantly from the Fucaceae, Laminariaceae and Ulvaceae families. There was a fair divergence between the seaweed species used in the two study areas (16 seaweed species in the southwest region and 17 seaweed species in the west and midwest region), with 11 species mentioned in both areas. Different trajectories of resurgence were identified. In the west and midwest region, the revitalisation of local ecological and gastronomic knowledge related to seaweeds seems to be deeply entrenched in the territory’s historical legacy, showing a sort of continuation with the past and having followed a more commercially oriented path. Conversely, in the southwest region, the revival seems to be fostered by new knowledge holders with a contemporary interest in reconnecting with the marine landscape and promoting educational activities centred around seaweed. This research contributes to discussions on sustainable food systems and food heritage promotion, emphasising seaweed’s potential role in Irish coastal communities’ foodscapes.

Optimization of PCR Analysis Based on Start Codon Targeted Markers (SCoT Markers) for Identification of Genetic Variation of Seaweed from Central Sulawesi

Seaweed is a fishery commodity that has high economic value because it contains carrageenan which can be used in the pharmaceutical, food, cosmetics, and industrial fields. Central Sulawesi Province is the second largest seaweed producer in Indonesia after South Sulawesi Province. The genetic diversity of seaweed in Central Sulawesi has not been studied much. Therefore, molecular-based characterization activities to identify the genetic variation of seaweed in the province are urgently needed. The purpose of the study was to optimize PCR techniques based on targeted start codon markers (SCoT markers) to identify the genetic diversity of seaweed accessions from Central Sulawesi Province. The results showed that the parameters for seaweed PCR amplification have been optimized. Of the fifteen SCoT primers, 10 of them can work to amplify seaweed DNA collected from several regions in Central Sulawesi. This is shown by the production of PCR result amplicons. PCR results also indicate polymorphism from the seaweed samples tested, although some seaweed samples have not been successfully amplified. The parameters of the PCR technique still need to be improved, especially the concentration of DNA prints, so that valid PCR results will be obtained for use in identifying seaweed genetic diversity.

Antioxidant activity of crude fucoidan extract from brown seaweeds (Phaeophyceae), Sargassum sp. and Turbinaria sp.

Seaweed is one of the highly commercial aquatic commodities, accounting for 51.3% of total marine and coastal aquaculture production. As much as 99.5% of seaweed production is concentrated in Asia, especially in East and Southeast Asian countries, one of which is Indonesia. The wide diversity of seaweeds has not been fully optimizing their potential to provide maximum economic benefits. This study aimed to determine the characteristics of crude extracts of fucoidan using two different solvents and to analyze the antioxidant activity of crude extracts of fucoidan using different solvents. The research method included the preparation of raw materials, extraction with distilled water and 2% CaCl2 at 85 °C for 4 h, followed by quality analyses. Total sugar using the phenol-sulphate method obtained higher results in distilled water (67.88%). The total sulphate analysis showed higher results with 2% CaCl2 (19.60%). The total phenol analysis yielded higher results with 2% CaCl2 (978.20%). The antioxidant activity of the crude fucoidan were 312.01 ppm (distilled water), 193.52 ppm (distilled water), 54.653 μg/mL ascorbic acid/g extract (CaCl2 2%, 128.38 mol Fe2+/g (CaCl2 2%).

Species diversity of the brown alga Lobophora (Dictyotales) in the Con Co Island Marine Protected Area, Vietnam

Abstract We reevaluated species diversity of the brown alga Lobophora in Vietnam’s Con Co Marine Protected Area (MPA), where only one species had previously been reported. Integrating morphological, ecological, and molecular analyses, we redefined the genus diversity, identifying nine species including two new ones: L. asiatica, L. boussoleae, L. lamourouxii, L. obscura1, L. pachyventera3, L. thailandensis, L. quangtriensis sp. nov., L. vietnamensis sp. nov., and Lobophora sp.1VNA. Lobophora variegata, the sole species previously reported, was absent. This study expands the number of Vietnam’s documented Lobophora species to 11. This work reevaluated Lobophora diversity in Vietnam based on a small island, contributing valuable seaweed diversity reference data for Con Co MPA management. Notably, within the MPA, Lobophora species exhibited no coral-aggressiveness, potentially serving as a health indicator for coral reef communities.

Phycoremediation potential and agar yield of red macroalgae (Gracilaria corticata) against HEDP (hydroxyethylidene diphosphonic acid) and CAPB (cocoamidopropyl betaine) detergents and the heavy metal pollutants.

The discharge of raw industrial, agricultural, and domestic wastes leads to an increase in heavy metal (HM) burden and detergents in aquatic environs, which can have destructive effects on aquatic organisms. Agarophyte Gracilaria corticata, a major component of seaweed flora of the southern coast of Iran (Bushehr) that contains agar and red pigments, is one of the economically valuable red marine algae. Agar is one of the important polysaccharides with high economic value, widely used in pharmaceutical, medicinal, and cosmetic product manufacturing industries. The aim of this work was to investigate the effect of 5 HMs and two common surfactants in household and industrial detergents on the agar yield, appearance color, and the red algae's phycoremediation potential against HMs. The metal ions were Zn(II), Cu(II), Ni(II), Mn(II), and Cr(VI), and the surfactants were HEDP and CAPB. The analysis results of samples cultured for 60 days in seawater and polluted environments showed that G. corticata can accumulate copper and nickel. In the presence of detergents without HMs, the amount of extracted agar significantly increased compared to the control sample with no change in algae color. But with increasing concentration of HMs, the amount of agar in seaweed samples decreased significantly, and the algae discolored from red to dark green or yellowish-green color (signs of death in the algae). These results show that increasing of HM pollution and detergents can lead to toxicological effects and reduce the species diversity of red seaweeds in the future.

AlgaeTraits: a trait database for (European) seaweeds

Abstract. The analysis of biological and ecological traits has a long history in evolutionary and ecological research. However, trait data are often scattered and standardised terminology that transcends taxonomic and biogeographical context are generally missing. As part of the development of a global trait database of marine species, we collated trait information for European seaweeds and structured the data within the standardised framework of the World Register of Marine Species (WoRMS). We collected 45 175 trait records for 21 biologically and ecologically relevant traits of seaweeds. This resulted in a trait database for 1745 European seaweed species of which more than half (56 %) of the records were documented at the species level, while the remaining 44 % were documented at a higher taxonomic level and subsequently inherited at lower levels. The trait database for European seaweeds will serve as a foundation for future research on diversity and evolution of seaweeds and their responses to global changes. The data will contribute to developing detailed trait-based ecosystem models and will be an important tool to inform marine conservation policies. The data are publicly accessible through the AlgaeTraits portal, https://doi.org/10.14284/574 (AlgaeTraits, 2022).

Diversity, distribution and seasonal variation of seaweeds in Southwest coast of Peninsular India

Six different research locations around the southwest coasts of Tamil Nadu and Kerala were used for the current investigations on the diversity, distribution, and seasonal fluctuation of seaweeds (India). A total of 73 Chlorophyta, Ochrophyta and Rhodophyta were recorded under 23 families and 38 genera. The study site Rasthakaadu (53) was with the maximum number of seaweeds followed by Kanniyakumari (51). Out of six study sites, four study sites (Rasthakaadu, Kanniyakumari, Muttom, Kurumpanai) were dominant with Rhodophyta in contrast to the other two study sites (Vallavilai, Vizhinjam) in which Chlorophyta was dominant. Chlorophyta such as Chaetomorpha antannina, C. indica, C. media, Ulva fasciata, U. lactuca, brown seaweeds Sargassum ilicifolium and red seaweed Gracilariopsis longissima were commonly seen in the study area. Chaetomorpha indica (Chlorophyceae) was recorded as the most dominant species in season I, whereas Sargassum ilicifolium (Phaeophyaceae) was considered as the most dominant seaweed taxon in seasons II and III. The seasonal variation in physicochemical parameters of seawater had much influence on the growth of seaweeds. Comparing the eastern Coromandel Coast of peninsular India to the western Malabar Coast, it has been found from the current study that the eastern Coromandel Coast was rich in seaweed. Moreover, the study shows that the topography and seasonal change of the physicochemical characteristics of seawater at a given site were the key determinants of seaweed richness. Anthropogenic activities, like Nuclear power plants (Koodankulam), sand mining, construction works, dumping of plastics etc., also affected the potential growth of seaweeds thereby reducing the sustainability of the natural resource.

Seaweed diversity and community structure on the west coast of Aceh, Indonesia

Abstract. Erniati, Erlangga, Andika Y, Muliani. 2023. Seaweed diversity and community structure on the west coast of Aceh, Indonesia. Biodiversitas 24: 2189-2200. One of the commodities that continues to be developed by the Indonesian government in fisheries is seaweed. The potential of seaweed as a food ingredient in Aceh is very abundant. However, diversity and community structure of seaweeds on the west coast of Aceh have not been studied much. Therefore, this study has been carried out to assess the diversity and community structure of seaweeds on the west coast of Aceh based on transect method. Sampling has been carried out in all districts/cities (6 districts and 1 city) of west coast of Aceh. Altogether, a total of 50 species have been identified; of which, maximum number of species belongs to Phaeophyta (21 species) followed by Chlorophyta (16 species) and Rhodophyta (13 species). The estimated value of diversity (H'), uniformity (E), and dominance (D) index is 1.02, 0.50 and 0.51 respectively. Based on the univariate diversity indices analysis, it has been found that seaweed on the west coast of Aceh is in the moderate category. Furthermore, the water quality parameters revealed the existence of conducive environmental conditions for the growth and life of seaweed. So, it is proposed that use of appropriate seaweed culture techniques can be carried out on the west coast of Aceh to able to make Aceh a seaweed center in Indonesia.

Molecular analyses of turf algae reveal a new species and an undetected introduction in the Pterosiphonieae (Rhodomelaceae, Rhodophyta).

Introduced seaweeds and undescribed species often remain undetected because marine regional floras are as yet poorly understood. DNA sequencing facilitates their detection, but databases are incomplete, so their improvement will continue to lead the discovery of these species. Here we aim to clarify the taxonomy of two turf-forming red algal Australian species that morphologically resemble the European Aphanocladia stichidiosa. We also aim to elucidate whether either of these species could have been introduced in Europe or Australia. We studied their morphology, analyzed 17 rbcL sequences of European and Australian specimens, examined their generic assignment using a phylogeny based on 24 plastid genomes, and investigated their biogeography using a taxon-rich phylogeny including 52 rbcL sequences of species in the Pterosiphonieae. The rbcL sequences of one of the Australian species were identical to A. stichidiosa from Europe, considerably expanding its known distribution. Unexpectedly, our phylogenetic analyses resolved this species in the Lophurella clade rather than in Aphanocladia and the new combination L. stichidiosa is proposed. The other Australian species is described as L. pseudocorticata sp. nov. Although L. stichidiosa was originally described in the Mediterranean ca. 70 years ago, our phylogenetic analyses placed it in a lineage restricted to the southern hemisphere, showing that it is native to Australia and introduced to Europe. This study confirms that further work using molecular tools is needed to characterize seaweed diversity, especially among the poorly explored algal turfs, and showcases the usefulness of phylogenetic approaches to uncover introduced species and to determine their native ranges.

Nutrients content of four tropical seaweed species from Kelapa Beach, Tuban, Indonesia and their potential as ruminant feed

Abstract. Kustantinah, Hidayah N, Noviandi CT, Astuti A, Paradhipta DHV. 2022. Nutrients content of four tropical seaweed species from Kelapa Beach, Tuban, Indonesia and their potential as ruminant feed. Biodiversitas 23: 6191-6197. Indonesia is one of the tropical countries with the largest diversity of seaweed, but studies on identifying the nutrients content of numerous seaweed species from tropical oceans and their potential as ruminant feed have not been widely reported. This study was designed to evaluate the nutrient, macro and micromineral content of brown (Laminaria sp. and Padina australis) and red seaweed (Eucheuma cottonii and Gracilaria sp.) from Kelapa Beach, Tuban, East Java. All tests were carried out in duplicate from individual seaweed and data were analyzed descriptively by calculating the average of data obtained. The result showed that all of the seaweed species in this experiment had a high content of water (69.41-86.33%) and ash/mineral (23.42-65.63%). The brown seaweed Padina australis had the highest dry matter (30.59%) and crude protein (12.57%). The red seaweed of Gracilaria sp. had the highest ash (65.63%) and the lowest organic matter (34.37%), ether extract (0.21%), crude fiber (2.49%), nitrogen-free extract (19.95%), neutral detergent fiber (21.74%), acid detergent fiber (5.46%), and gross energy (1,083 Cal/g); however, in contrast, Eucheuma cottonii had the highest organic matter (76.58%), ether extract (2.85%), crude fiber (8.80%), nitrogen-free extract (56.38%), neutral detergent fiber (56.93%), acid detergent fiber (11.44%), and gross energy (2,911 Cal/g) but the lowest dry matter (13.67%) and crude protein (8.55%). The brown seaweed Padina australis had the highest Na (0.89%), Mg (4.90%), and Cd (3.73 ppm) contents. The red seaweed of Gracilaria sp. had the highest K (2.18%), Ca (5.80%), Fe (7,596 ppm), Mn (818 ppm), Cu (5 ppm), Zn (52 ppm), and Pb (60.38%); however, in contrast, Eucheuma cottonii had the lowest P (0.01%), K (2.02%), Ca (0.64%), Mg (1.09%), Fe (400 ppm), Mn (38 ppm), Pb (17.31 ppm), and Cd (1.53 ppm) but the highest S (0.46%). Based on this study, brown seaweed (Laminaria sp and Padina australis) and red seaweed (Eucheuma cottonii and Gracilaria sp.) from Tuban Regency, East Java, Indonesia have the potential as ruminant feed, especially as soluble carbohydrates and an organic mineral source that requires attention for heavy metals to prevent toxicity to ruminants.

Chemical diversity and therapeutic potentialities of seaweeds and marine sponges collected from the Red Sea: An update

Chemical diversity and therapeutic potentialities of seaweeds and marine sponges collected from the Red Sea: An update

Diversity and Carbon Sequestration of Seaweed in the Ma’an Archipelago, China

Seaweed communities perform a variety of ecological services, including primary productivity supply, biological habitat construction, water purification, and acting as marine carbon sinks. The abundance of seaweed is the basis for the assessment of ecological services in communities. The Ma’an Archipelago, adjacent to the Yangtze River estuary in China, is an important and typical island group. In this study, the abundance of seaweed in the typical coastal islands of the Ma’an Archipelago, Zhejiang Province, was evaluated by means of sonar detection and scuba diving sampling methods. The organic carbon content of six dominant seaweed species was measured to estimate the carbon sequestration capacity of the dominant species in the Ma’an Archipelago. The results show that 27 species of Rhodophyta, 10 species of Ochrophyta, and two species of Chlorophyta were found in the Ma’an Archipelago. Seaweed was distributed in the coastal areas of the islands, with a distribution width of 2–60 m. Gouqi Island had the longest shoreline, and there, the distribution depth of the seaweed reached 15 m and the area of the seaweed community was the largest. The slope of the rocks in the Sanheng survey area was large and the width of the seaweed community was small. The distribution area of seaweed in the Ma’an Archipelago was 6.51–13.43 km2 and the organic carbon content of the seaweed was 33.16 ± 3.26%. The biomass of Ochrophyta in the Ma’an Archipelago was the largest, followed by Chlorophyta and Rhodophyta. Among the six dominant species, the carbon sequestration of Sargassum thunbergii was the largest, at 277.91–848.74 t per year, and that of Undaria pinnatifida was the smallest. This study provides scientific guidance for the assessment of the primary productivity supply, carbon sink, and conservation capacity of seaweeds in China.

Diversity and Distribution of Seaweeds in the West Bengal Coast, India

Diversity and Distribution of Seaweeds in the West Bengal Coast, India

Seaweed (macroalgae) diversity on the Dikwella coast, Southern Sri Lanka

Seaweeds are photosynthetic and macroscopic eukaryotic organisms found in marine and brackish water environments. They are one of the major primary producers in marine ecosystems. They are also important in maintaining coastal biodiversity by interacting with other organisms. In addition to their biological and ecological importance, seaweeds are economically significant. Data from the Food and Agriculture Organization (FAO) shows that a total of 35 million tonnes of seaweed were produced through cultivation in 2019 and 97% of this was from East Asia. China was ranked as the top producer. In contrast to all the positives, there are a few negative impacts of seaweeds; including biofouling, habitat invasion, and unwanted beach drift.

Valorization of the chemical diversity of the tropical red seaweeds Acanthophora and Kappaphycus and their applications in aquaculture: A review

The role that seaweeds play as primary producers and ecosystems engineers in marine coastal ecosystems is widely acknowledged. Seaweeds, however, are also important drivers in the development of the blue bioeconomy due to their vast diversity of unique chemicals with a broad range of industrial and biotechnological applications. In tropical regions, seaweed production has been focused on a few species only, because of their hydrocolloids used in the food industry. There is a strong need to identify new applications of red seaweed species in other sectors such as aquaculture. Therefore, to diversify the culture of red seaweeds, more tropical species need to be investigated for their chemical composition and potential application in aquaculture, and then, to develop a method for a sustainable cultivation of new seaweed candidates and enhance their economic potential. Based on this context, we analyze the potential value of the red edible seaweed Acanthophora spp., an under-valued seaweed species which is naturally abundant in tropical countries, and Kappaphycus spp., a commercially valuable seaweed commonly used for polysaccharide extraction. The vast chemical diversity of seaweeds (polysaccharides, phytohormones, amino acids, and pigments) has led to research on a wide range of applications in aquaculture, including pathogen control, immunostimulant, antioxidant, bioremediation, feed, UV protectants, increase in seafood shelf life, animal colorant, and growth regulator for microalga culture. This review hopes to stimulate the interest among seaweed researchers to investigate other local seaweed species and seek greater added value of their biomass and chemical compounds and their applications in the aquaculture sector. Additionally, this information will help stakeholders to benefit from these two red seaweeds by contributing to the diversification of the blue bioeconomy in tropical countries.