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The genus Ulva is one of the most commonly commercially cultivated seaweeds both on land in ponds and in the open sea. As a crop, its cultivation is accompanied by three pest groups: (1) diseases caused by pathogenic bacteria, algae, virii, and fungi, which cause perforations, deterioration, and decreased growth of thalli; (2) various grazers, e.g. small crustaceans, gastropods, and non-defined invertebrates, which decrease growth and damage the thalli; and (3) an epiphytic biofilm of microorganisms, which also causes damage to the end-crop decreasing its yield and value. Mitigation categories against Ulva pests may be divided into three categories: (A) pro-active human intervention by washing the infected thalli with acid, fresh water, proprietary chemicals or CO2-saturated seawater, the use of methanolic Ulva extracts, or exudate from the green seaweed, all of which are reported to restrict pest activity; (B) using the beneficial properties of probiotic bacteria thereby eliciting antifouling activity, with selective abilities against pathogens of Ulva spp.; (C) enhancing the effects of environmental changes on pests, i.e. acidification and increased seawater temperature, which mainly decrease the grazer population and thereby their pressure. A summary of these studies is presented as a guide for rapid responses and applied management techniques for the amelioration of cultivation diseases, grazers, and harmful epiphytes affecting the foliose green alga Ulva spp. [ABSTRACT FROM AUTHOR]

The primary aim of this study was to determine if blue cod (Parapercis colias) sub-populations demonstrate increases in abundance and size when protected from fishing. (1) Four South Island, New Zealand no-take marine reserves (MR) (Long Island Kokomohua, LIMR; Hikurangi, HMR; Ulva Island, UIMR; and Five Fingers, FFMR), and areas directly outside these MRs were surveyed using potting surveys. Abundance was higher and mean length larger inside than outside the MRs in thirteen and eleven of the fourteen surveys, respectively. Protection from fishing within three of the four MRs (LIMR, HMR, UIMR), appears to have allowed recovery of blue cod to a lesser or greater extent. (2) Three potting surveys spanned the temporary 2.5 year (2008–2011) closure of the inner Queen Charlotte and Pelorus Sounds to blue cod fishing. Blue cod abundance and mean length increased after closure for two years, and then decreased 30 months after opening as did blue cod presence. Growth alone may be sufficient to account for the observed increases in abundance and size during the closure. Protection from fishing during the temporary inner sounds closures, resulted in a dramatic recovery of blue cod followed by a return to towards pre-closure levels after re-opening. [ABSTRACT FROM AUTHOR]

In order to create new value in biomass production using sterile Ulva with high production efficiency, we selected sterile Ulva with high culture stability from the coast of Imari City in Japan and investigated the conditions for generating high concentrations of dissolved oxygen through photosynthesis using the sterile Ulva. In the cultivation of sterile Ulva, we investigated the conditions for generating high concentrations of dissolved oxygen (DO) by controlling conditions such as aeration, NO3‐N concentration, and population density. As a result, we found that under the cultivation control conditions we found, DO reached about 3.8 times the saturation concentration after 3 h. It was found that this high level of DO can be maintained if the supersaturated DO seawater obtained here is properly sealed. Seawater containing high levels of DO is essential for the cultivation of oysters and shellfish, which also prefer a growth temperature of 20°C−25°C. Therefore, from the perspective of creating new value in biomass production, we developed a new system for simultaneously cultivating sterile Ulva and cultivating oysters. [ABSTRACT FROM AUTHOR]

Recent years have seen the Ulva green tide and Sargassum golden tide become commonplace in the coastal waters of China. However, little is known on how the combination of ocean warming and eutrophication would affect the interaction of green and golden tides. In this study, we cultured the green tide alga Ulva prolifera and the golden tide alga Sargassumhorneri under different temperatures (5, 10, 15, 20, 25, and 30°C) and two nutrient concentrations (Low nutrient, LN: 5 mM-nitrate and 0.5 mM-phosphate; High nutrient, HN: 500 mM-N and 50 mM-P) in both monoculture and coculture systems to investigate the physiological responses and their competitive relationships. In monocultures, the growth of U. prolifera and S. horneri, along with pigment concentrations and photosynthesis, increased with rising temperature, reaching a plateau at 15 - 25°C. However, when the temperature increased to 30°C, the growth of U. prolifera and S. horneri decreased abruptly, with S. horneri even suffering death. In coculture, the growth of both U. prolifera and S. horneri was inhibited compared to the monoculture, with the greatest decline observed in S. horneri at 25°C under two nutrient conditions. Our results show that U. prolifera would outcompete S. horneri under high temperature in coculture, suggesting that ocean warming would enhance the competitive advantage of green tide over golden tide under eutrophication in the future. [ABSTRACT FROM AUTHOR]

Recent years have seen the Ulva green tide and Sargassum golden tide become commonplace in the coastal waters of China. However, little is known on how the combination of ocean warming and eutrophication would affect the interaction of green and golden tides. In this study, we cultured the green tide alga Ulva prolifera and the golden tide alga Sargassumhorneri under different temperatures (5, 10, 15, 20, 25, and 30°C) and two nutrient concentrations (Low nutrient, LN: 5 mM-nitrate and 0.5 mM-phosphate; High nutrient, HN: 500 mM-N and 50 mM-P) in both monoculture and coculture systems to investigate the physiological responses and their competitive relationships. In monocultures, the growth of U. prolifera and S. horneri, along with pigment concentrations and photosynthesis, increased with rising temperature, reaching a plateau at 15 - 25°C. However, when the temperature increased to 30°C, the growth of U. prolifera and S. horneri decreased abruptly, with S. horneri even suffering death. In coculture, the growth of both U. prolifera and S. horneri was inhibited compared to the monoculture, with the greatest decline observed in S. horneri at 25°C under two nutrient conditions. Our results show that U. prolifera would outcompete S. horneri under high temperature in coculture, suggesting that ocean warming would enhance the competitive advantage of green tide over golden tide under eutrophication in the future. [ABSTRACT FROM AUTHOR]

The marine algae Ulva spp. are commonly used as model biofouling organisms. As biofouling studies are primarily conducted using field-collected specimens, factors including species identity, seasonal availability, and physiological status can hinder the replicability of the results. To address these limitations, a protocol was developed for the on-demand laboratory culture and release of Ulva zoospores. The biofouling potential of laboratory-cultured and field-collected Ulva blades was compared using a waterjet. No significant differences were found between field and laboratory-cultured samples in either spore adhesion (before waterjet) or the proportion of spores retained after waterjet exposure. However, there was significant variability within each session type in pre- and post-waterjet exposures, indicating that spore adhesion and retention levels vary significantly among trial runs. In addition, all our laboratory cultures were Ulva Clade C (LPP complex). In contrast, our field samples contained a mix of Ulva Clade C, U. compressa clade I, and U. flexuosa Clade D. This protocol for on-demand production of Ulva spores can improve biofouling research approaches, enables comparison of results across laboratories and regions, and accelerate the development of anti-biofouling strategies. [ABSTRACT FROM AUTHOR]

Jeju Island, located in the northern East China Sea, is experiencing a rapid rise in water temperature due to climate change. This has led to the increased activity of subtropical species and extreme fluctuations in coastal ecosystems, such as macroalgal blooms and coral bleaching. Additionally, the region is experiencing more frequent and intense typhoons. This study investigated the green tides caused by Ulva, particularly Ulva ohnoi, a subtropical species, and the effects of typhoons on these blooms through photographic analysis of the Jeju coastline. The study area was consistently covered by Ulva species every August from 2020 to 2022. Super typhoons struck Jeju Island every September during the study period, with wind speeds exceeding 20 m/s. In 2020 and 2022, the green tides largely dissipated following the typhoons. This ironic outcome highlights how climate-driven increases in subtropical Ulva biomass are being mitigated by the increasing frequency of super typhoons. However, despite the impact of super typhoon Chanthu in September 2021, there was no significant reduction in the Ulva bloom area. This anomaly may be attributable to the dominant easterly wind system in 2021, as the study area faces east, preventing the typhoon from influencing the distribution of Ulva blooms. These findings suggest that the wind intensity and direction of annual typhoons play a critical role in determining the resolution of green tide outbreaks. [ABSTRACT FROM AUTHOR]

Sea lettuce (Ulva) is a genus of green macroalgae present along all the coasts of the world's oceans. It represents about 100 species with diverse habitats. Inter- and intra-species natural variation is very large, both in terms of growth characteristics and biomass biochemical composition. As a result, Ulva biomass has a wide range of applications and strain selection can achieve significant increases in yield(s). Establishing solid, long term and cost-effective methodologies for the conservation of Ulva genetic diversity is then required to safeguard and reuse selected strains. Here, we report a cryopreservation-based protocol for the long-term preservation of foliose Ulva strains. Strains from seven different Ulva species were cryopreserved for 15 and/or 120 days in liquid nitrogen, and of the 3 replicates cryopreserved, at least one survived, allowing us to successfully recover all strains. On average, among all specimen cryo-preserved, 82% of them survived and grew post cryo-preservation. [ABSTRACT FROM AUTHOR]

This study set out to provide a preliminary assessment of nutritional profiles of five selected New Zealand macroalgae to investigate the potential of landcultivated Ulva spp. The New Zealand seaweeds species, selected from a limited range, were either collected from the wild (Pyropia plicata from Tauranga and Kaikōura), or were sourced from commercial wild harvest suppliers (Macrocystis pyrifera and Undaria pinnatifida), and were compared to land-based cultivated Ulva species (Ulva ralfsii and Ulva stenophylloides). Species were assessed for their content of crude protein, total lipids, carbohydrates, fibers, amino acids, mineral profiles, heavy metals and antioxidant capacity (Oxygen Radical Absorbance Capacity, ORAC). The two cultivated Ulva spp. had the highest crude protein content of the six seaweeds analyzed (approximately 21% dw, N×6.25), as expected with nutrient supplemented cultivation. They also had the highest total, essential and branched chain amino acid quantities (151, 70, and 29 mg/g for U. stenophylloides and 138, 62, and 27 mg/g for U. ralfsii). Though the two Ulva spp. were grown to the same cultivation specifications, they varied in carbohydrate and total fiber content (U. stenophylloides: 63% and 62%; U. ralfsii: 39% and 40%, respectively). Pyropia plicata collected in Kaikōura had the highest carbohydrate levels (65%) though not the highest total fiber. Both P. plicata had the highest trace minerals (417 mg/kg and 720 mg/kg for Kaikōura and Tauranga P. plicata respectively). All seaweeds analyzed showed no lipophilic antioxidants, though the two Phaeophyceae had the highest hydrophilic antioxidant content at 115 TE and 168 TE for Macrocystis pyrifera and Undaria pinnatifida, respectively. This paper provides a preliminary indication of the relative nutritional attributes of a range of potential New Zealand seaweed aquaculture targets benchmarked against sealettuce (Ulva spp.). [ABSTRACT FROM AUTHOR]

To compare the different effects of petroleum hydrocarbons on intertidal Ulva macroalgae, three dominant Ulva species (U. prolifera, U. linza, and U. lactuca) were exposed to two water-accommodated fractions (WAFs) of 0# diesel oil and crude oil at three concentration levels. The results indicated that two WAFs had significant concentration effects on the physiological characteristics of Ulva, the toxicity of 0# diesel oil was greater than crude oil, and crude oil had hormesis effect. Exposure of high WAFs concentrations, the growth, pigment, carbohydrate, and protein contents of Ulva were inhibited, while the antioxidant system was activated. In addition, the integrated biomarker response (IBR) indicated that U. prolifera had higher resistance to WAFs than U. linza and U. lactuca. Considering that U. prolifera is the main species of green tide in the Yellow Sea (YS) of China, the comparative effects of WAFs on different development stages of U. prolifera were also explored. The results showed that spore was the most sensitive to WAFs, while adult thalli was the most tolerant. The increased resistance of U. prolifera thalli and the hormesis effect triggered by crude oil may influence the outbreak scale of green tides. This study provides a new perspective for understanding the formation of green tides in the YS. [ABSTRACT FROM AUTHOR]

The present study provides information on the effects of BPA on ROS production-related phenomena in the chlorophytes Ulva rigida and U. intestinalis, and on the mechanism they establish against BPA toxicity, at environmentally relevant concentrations (0.1–3 μg L−1). Up-regulated H2O2 generation seems to be a key factor causing oxidative damage. Interspecific differences, in terms of the mechanism and the temporal response to BPA toxicity were observed. BPA effects on U. rigida were more intense and appeared earlier (on 1D at 0.1 μg L−1) compared to U. intestinalis and mostly after 7D (LOEC: 0.3 μg L−1, Terminal time, Tt: 7D). In U. rigida, on 1-5D, the 'mosaic' type effect patterns ('models' 3A/3B) with 'unaffected' and 'affected' areas (dark content, positive H2DCF-DA staining signal/H2O2 production and chlorophyll autofluorescence signal loss) indicated a time-dependent manner. After 7D, only U. rigida cells with dark content formed aggregates, showing positive H2O2 production ('model' 4) or in some cells oxidative damages triggering retrograde signaling in the neighboring 'unaffected' areas ('model' 5). H2O2 overproduction (CTCF ratio) in U. rigida, on 1D at the lowest concentration and after 7D at 0.3–1/3 μg L−1, respectively, seems to stimulate (poly)phenolic production, in a dose- and time-dependent manner. U. intestinalis did not display severe BPA impact (i.e., 'models' 4, 5) at any exposures, although at a later time indicated a lower LOEC (0.1 μg L−1, Tt: 9D) than that in U. rigida. In U. intestinalis, H2O2 production does not appear to stimulate high (poly)phenolic amounts. [ABSTRACT FROM AUTHOR]

Basket height and stocking density are crucial and related factors for successful commercial sea urchin aquaculture, but these factors have not been definitively determined for production of Tripneustes gratilla. This study investigated the effects of varying basket heights (deep 30 cm vs. shallow 15 cm) and stocking densities (4, 6 and 8 kg.m−2 or 13, 19 and 24% coverage of available basket surface area) on aquacultural production of T. gratilla. Contrary to previous suggestions, reduced consumption was identified as the cause of decreased production in deeper baskets. Consumption was significantly higher in shallow baskets than deep baskets for both the fresh seaweed, Ulva lacinulata, (W = 38, p = 0.026) and formulated feed (W = 76.5, p = 0.007). Consequently, baskets of approximately 15 cm deep are recommended to enhance production of T. gratilla and possibly other urchin species. Two subsequent trials assessed production of T. gratilla at different stocking densities. Trial 1 aimed to maximize urchin size over a three-month grow-out period using fresh U. lacinulata, while trial 2 focused on enhancing gonad production over two months using formulated feed. Although greater stocking density significantly reduced the specific growth rates of individual urchin mass in both trials (p < 0.044), there was no significant impact on mortality, net production or gonad size and quality. The variations in growth rates were attributed to spine loss resulting from negative behavioural interactions (F2, 9 = 9.551; p = 0.005). Based on the objectives of both grow-out and gonad-enhancement phases, we recommend a stocking density of approximately 20% coverage. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study used the radio-analytical technique (Neutron Activation Analysis), besides the other advanced chemical technique, which was inductively coupled plasma mass spectroscopy (ICP-MS), in order to evaluate the bioaccumulation factor (BF), of different trace elements inside the collected green macro algal samples. The results showed that BF results were based on the algal selectivity of each analyzed trace element. The study recommended the using of Ulva fasciata, as a bio-filter of nuclear cooling water system (mitigation tool), due to its selective absorption ability for certain trace elements such as; Th, Cs &Sr. [ABSTRACT FROM AUTHOR]

Background: Nonhealing diabetic wounds are a serious complication associated with extremely lethargic wound closure and a high risk of infection, leading to amputation or limb loss, as well as substantial health care costs and a poor quality of life for the patient. The effects of either eggshell membrane (ESM) and green seaweed (Ulva lactuca) extracts alone or in combination were evaluated for in vivo skin wound healing in a rat model of induced diabetes. Methods: Micronized powders of waste hen ESM, Ulva lactuca, and their 1:1 mixture were prepared using regular procedures. The mechanical, electrical, and surface morphology characteristics of powders were examined using direct compression, LCR-impedancemetry, and scanning electron microscopy. The effect of ESM, Ulva lactuca, and their mixture as compared to standard Dermazin treatments were evaluated on wounds inflicted on male Wistar Albino rats with induced diabetes. Quantitative wound healing rates at baseline and at 3, 7, 14, and 21 days of treatments among all rat groups were conducted using ANOVA. Qualitative histological analysis of epidermal re-epithelization, keratinocytes, basement membrane, infiltrating lymphocytes, collagen fibrines, and blood vessels at day 21 were performed using Image J processing program. Results: Compressive strength measurements of tablets showed a Young's modulus of 44.14 and 27.17 MPa for the ESM and ESM + Ulva lactuca mixture, respectively. Moreover, both samples exhibited relatively low relative permittivity values of 6.62 and 6.95 at 1 MHz, respectively, due to the porous surface morphology of ESM shown by scanning electron microscopy. On day 21, rats treated with ESM had a complete diabetic wound closure, hair regrowth, and a healing rate of 99.49%, compared to 96.79% for Dermazin, 87.05% for Ulva lactuca, 90.23% for the mixture, and only 36.44% for the negative controls. A well-formed basement membrane, well-differentiated epithelial cells, and regular thick keratinocytes lining the surface of the epidermal cells accompanied wound healing in rats treated with ESM, which was significantly better than in control rats. Conclusion: Ground hen ESM powder, a low-cost effective biomaterial, is better than Ulva lactuca or their mixture for preventing tissue damage and promoting diabetic wound healing, in addition to various biomedical applications. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Macroalgae seaweeds such as Ulva lactuca and Gracilaria verrucosa cause problems on the northern coast of the Italian Adriatic Sea because their overabundance hinders the growth of cultivated clams, Rudatapes philippinarum. This study focused on the green synthesis of CuO nanoparticles from U. lactuca and G. verrucosa. The biosynthesized CuO NPs were successfully characterized using FTIR, XRD, HRTEM/EDX, and zeta potential. Nanoparticles from the two different algae species are essentially identical, with the same physical characteristics and almost the same antimicrobial activities. We have not investigated the cause of this identity, but it seems likely to arise from the reaction of Cu with the same algae metabolites in both species. The study demonstrates that it is possible to obtain useful products from these macroalgae through a green synthesis approach and that they should be considered as not just a cause of environmental and economic damage but also as a potential source of income. [ABSTRACT FROM AUTHOR]

To study the effect of ulvans and oligo-ulvans on the stimulation of growth in Arabidopsis thaliana, extracts of Chilean U. lactuca were prepared in water at pH = 7 and pH = 4, and ulvans were purified. The yield of ulvans was 16% of dry weight in both extracts and molecular weights were 115 kDa in extract at pH = 7 and 70 kDa in extract at pH = 4. Purified ulvans were analyzed by FT-IR and H1 RMN showing carboxyl and sulfate groups and they are constituted by rhamnose, rhamnose-3S, xylose and glucuronic acid, but not by iduronic acid. The antioxidant capacities of U. lactuca extracts were determined showing that ulvans are the main contributors to antioxidant capacity whereas ascorbate, glutathione, and phenolic compounds exert a minor contribution. To analyze whether ulvans and oligo-ulvans can stimulate plant growth, oligo-ulvans were prepared by acid hydrolysis and they were sprayed on A. thaliana leaves. Ulvans and oligo-ulvans increased A. thaliana biomass, fresh and dry weight, rosette diameter, number of leaves, and length of the main root, mainly oligo-ulvans. To determine whether the increase in plant growth may involve an enhanced basal metabolism and cell division, the level of transcripts encoding enzymes involved in C, N, and S assimilation, and proteins controlling cell cycle were analyzed. The expression of the latter genes was increased, mainly in response to oligo-ulvans. Thus, ulvans and oligo-ulvans stimulate growth of A. thaliana plants probably by increasing basal metabolism and cell division. [ABSTRACT FROM AUTHOR]

Simple Summary: The spread of large green algae in oceans causes green tides, particularly in the South Yellow Sea of China, where Ulva prolifera has led to the world's largest green tide events. This review looks at how allelopathy, a process where plants release chemicals to affect the growth and development of other plants, influences green tide dynamics. We focus on four main types of these allelochemicals—fatty acids, aldehydes, phenols, and terpenes—explaining how they influence the algae's growth and behavior. We also discuss new methods for quickly detecting these allelochemicals and how these methods can help monitor green tides. By combining allelochemical detection with advanced technologies like satellite observations and environmental DNA analysis, we can better understand and manage green tides. The proliferation of large green macroalgae in marine environments has led to the occurrence of green tides, particularly in the South Yellow Sea region of China, where Ulva prolifera has been identified as the primary species responsible for the world's largest green tide events. Allelopathy among plants is a critical factor influencing the dynamics of green tides. This review synthesizes previous research on allelopathic interactions within green tides, categorizing four extensively studied allelochemicals: fatty acids, aldehydes, phenols, and terpenes. The mechanisms by which these compounds regulate the physiological processes of green tide algae are examined in depth. Additionally, recent advancements in the rapid detection of allelochemicals are summarized, and their potential applications in monitoring green tide events are discussed. The integration of advanced monitoring technologies, such as satellite observation and environmental DNA (eDNA) analysis, with allelopathic substance detection is also explored. This combined approach addresses gaps in understanding the dynamic processes of green tide formation and provides a more comprehensive insight into the mechanisms driving these phenomena. The findings and new perspectives presented in this review aim to offer valuable insights and inspiration for researchers and policymakers. [ABSTRACT FROM AUTHOR]

The responses of Ulva species to diurnal temperature difference remain poorly understood. In this present study, we cultured Ulva prolifera under different diurnal temperature treatments with 22°C for photoperiod and 22, 20, 18, 16, 14, and12°C for dark period, respectively (noted as 22-22, 22-20, 22-18, 22-16, 22-14, and 22-12°C treatments). The growth, pigment contents, photosynthesis, superoxide dismutase (SOD) activity, soluble proteins, and sugars were measured. The main results were shown as follows: (1) The growth of U. prolifera was enhanced by the moderate diurnal temperature difference, and the highest growth rate was observed at 22-18°C. (2) Compared with 22-22°C treatment, the thalli grown under 22-18°C condition showed lower chlorophyll a (Chla) content, respiration rate (Rd), the ratio of Rd, and gross photosynthetic rate (Rd/Pg) as well as the net photosynthetic rate (Pn), while the lowest Pn was observed at 22-12°C. (3) The maximum quantum yield (Fv/Fm) was enhanced by diurnal temperature difference, while the effective quantum yield (Fv′/Fm′) decreased with the decreased in temperature in the nighttime. (4) With the increase of the diurnal temperature difference gradient, the SOD activity decreased and then increased, with the lowest value observed at 22-18 °C, and the soluble protein content showed similar trend. Then we cultured this species at 22-22°C and 22-16°C both under 250 and 60 μmol m−2s−1 conditions in order to study the combined effects of diurnal temperature change and light intensities. It was found that under both two light levels, 22-16°C-grown thalli showed higher growth rate, while the SOD activity was lower than that grown under 22-22°C condition. Overall, the suitable range of diurnal temperature difference for the growth of U. prolifera was about 4–6°C and also was mediated by light intensity. [ABSTRACT FROM AUTHOR]

Ulva lactuca is a macroalgae that contains high nutritional values. The heavy metal contaminants in natural Ulva lactuca needs to be eliminated or decreased using natural agent. The aim of this research was to determine the bioaccumulation of Pb, Cd, Hg, and the impact on liver and gastrointestinal function. Parameters of this research were Hepatosomatic Index (HSI), SGPT levels, SGOT levels, bioaccumulation Pb, Cd, Hg, and histological structure of liver and small intestine. Besides that, the progression of body weight was observed. Twelve female Wistar rats (Rattus norvegicus Berkenhout, 1769) were randomly assigned to three groups: Control, NU (treated with natural Ulva lactuca), and DU (treated with heavy metal decontaminated Ulva lactuca using Averrhoa bilimbi juice). Treatment was carried out orally at a dose of 1000 mg/Kg BW/day for 30 days. Histological structure of rat's liver and small intestine were prepared after necropsy at the end of this research. Based on results, it can be concluded that there were no significant differences observed in HSI, SGPT, and SGOT levels among the groups. However, there was a tendency for an increase in total bilirubin levels in the decontaminated Ulva lactuca group. Both natural and heavy metal decontaminated Ulva lactuca showed histological damage on liver and small intestine. Bioaccumulation of Cd and Hg in the liver and gastrointestinal tract of rats after consuming decontaminated Ulva lactuca was lower than the natural Ulva lactuca group, but need more observations. [ABSTRACT FROM AUTHOR]

Marine macroalgae (seaweeds) have been attracting the attention of both consumers and researchers in recent days because of their enormous nutritional and biotechnological properties. Seaweeds are autotrophic plants that are edible in Asia, especially in Indonesia, Philippines, China, and Korea, and recently in Europe, the USA, and Australia. The high rate of lipids, proteins, and fiber-content of seaweeds is an advantageous one. Their bioactive molecules play a major role in the pharmaceutical, nutraceutical, and cosmetics industries. The daily usage of seaweed has been increasing day by day, but their wild harvest rate does not meet their requirements. Hence, on-shore seaweed cultivation was initiated several decades ago in some Asian countries, and subsequently such culture-methods have been followed in some other countries (to encourage seaweed cultivation and its associated products). On-shore cultivation would provide a large algal-quantity at a specific time interval, but when it comes to edible purposes, on-shore cultivation fails to provide contamination free, and nutritionally rich seaweeds. Therefore, the land-based tank cultivation-practise could provide an opportunity to cultivate seaweed (without contamination) and also to make it possible to enhance their nutritional compounds under laboratory conditions initially. Natural calamities may not affect the cultivation of seaweed in tanks. It would ensure the continuous supply of raw material to consumers and industries. This review discusses the world scenario of edible seaweed production especially the green seaweeds, as to why land-based seaweed cultivation is essential, the advantages of tank cultivation, how to select the seaweeds for tank cultivation, the methods of plantlet preparation and the indoor and the outdoor cultivation in tanks, basic applications of tank cultivated seaweeds; and the challenges during tank cultivation. [ABSTRACT FROM AUTHOR]

In this study, we investigated the physiological and biochemical responses of Ulva species to variation in nutrient availability. Sampling was conducted at two sites on Jeju Island, Korea, namely, Handong, which is close to seven intensive land-based fish farms, and Hado, which has no apparent nearby nutrient sources. We examined the water column nutrient concentrations, nitrate reductase (NR) activity, nitrate uptake efficiency, tissue C, N, and P content, and stable isotope ratios of Ulva species. Water column NH4+, NO3− + NO2−, and PO43− concentrations were significantly higher at Handong than at Hado. NR activity and tissue N content of Ulva species were significantly higher at Handong than at Hado. Notably, nitrate uptake efficiency was inversely proportional to NR activity and tissue N content. The physiological and biochemical responses of Ulva species were closely related to dissolved inorganic nitrogen, which stimulates Ulva species to regulate growth. Additionally, the δ15N values of Ulva tissues at both sites were within the previously reported range for fresh groundwater. Therefore, the main nitrogen source for Ulva growth may be submerged groundwater with high nutrient concentrations. Our results provide invaluable information for estimating dissolved inorganic nitrogen levels in water, which may facilitate development of management policies. [ABSTRACT FROM AUTHOR]

Background: The present study aimed to determine the growth, digestibility co-efficient, digestive enzyme activity and disease resistance of juvenile GIF tilapia fed with Ulva seaweed meal supplemented diet. Methods: The study was undertaken with different inclusion levels of Ulva seaweed meal (USM) such as raw (UR) and fermented (UF) Ulva meal (UR-5, UR-10, UR-15, UF-5, UF-10 and UF-15% of diet) and control feed (C) for a period of 60 days. Result: GIFT fed with fermented Ulva meal at a 10% inclusion level in their diet exhibited the highest growth performance (41.43 g) followed by UF5 (41.07±0.43 g), UR5 (39.65±0.36 g), control (39.09±0.20 g), UF15 (38.67±0.26 g), UR10 (38.47±1.47 g) and UR15 (35.77±0.35 g) diet. The highest apparent digestibility coefficient (ADC) with crude protein (85.14±0.91%) was observed in fishes fed with fermented Ulva meal at 10% inclusion rate than that of other treatments group for dry matter, ether extract and gross energy. The digestive enzymatic activities, amylase (0.029±0.00 units/mg protein/min), protease (0.147±0.0 units/mgprotein/min) and Lipase (0.273±0.05 units/mg protein/min), showed higher level in fishes fed with diet containing 10% fermented Ulva meal compared to other treatment groups including control. Moreover, at the end of the trial, increased survival rate (86.66%) was observed with fishes fed with Ulva based diets challenged against Aeromonas hydrophila. The histopathological study showed a lower level of infection in fishes fed with 10% fermented Ulva meal supplementation. The present study concluded that the requirement of Ulva meal in fish diet shows the following trend 10% of Ulva Fermented (UF) and UF-5, Ulva Raw (UR) 5%, control (C), UF-15, UR-10 and UR-15 diet that can improve the health status of the GIF tilapia. [ABSTRACT FROM AUTHOR]

Cellulose was successfully extracted from green algae (Ulva ohnoi) by chemical treatments. The contents of holocellulose and α‐cellulose significantly increased from 37.6% and 3.3% to 82.5% and 63.3%, respectively, after whole extraction treatments. The extracted cellulose (EC) was mixed to polyvinyl alcohol (PVA) to prepare EC/PVA composite films with polyethylene glycol (PEG) or glycerol (GLY) as a plasticizer. The EC/3%PVA composite film showed the highest tensile strength of 54.42 MPa because of the high PVA content. Adding GLY steeply increased the elongation of the EC/3%PVA film from 3.12% to 126.76%, but adding PEG slightly decreased to 2.63%. The EC/1%PVA/PEG composite film showed the highest visible light transmittance of 84.47%, while the addition of zinc oxide nanoparticles (ZnO‐NPs) significantly improved UV‐blocking properties. In addition, the incorporation of ZnO‐NPs on the EC/PVA‐based composite films showed excellent antibacterial activity against six Gram‐positive and Gram‐negative bacteria. [ABSTRACT FROM AUTHOR]

Ulva rigida green macroalgae contain a variety of polysaccharides. A recent study investigated the optimum concentration and yield of polysaccharide extraction from oven-dried U. rigida biomass using a water-soluble polysaccharide extraction method that adhered to safety standards. This study utilised complete factorial experiments to examine the effects of varying factors on polysaccharide extraction. Results showed a positive correlation between increased levels of all factors and higher polysaccharide extraction yield. This study also found that the main factors and their interaction had a significant impact on the extracted polysaccharides from U. rigida. The highest polysaccharide content and yield were 9.5 mg/mL and 189 mg/g, respectively. Water-soluble polysaccharides demonstrated the presence of reducing sugar (8 mg/g), phenolics (0.69 mg/g) and flavonoids (1.42 mg/g) and exhibited antioxidant properties. Results revealed that freeze-dried polysaccharide powders were primarily composed of the monosaccharide rhamnose. Preliminary results on the effect of these powders on probiotics demonstrated that supplementation of polysaccharides from U. rigida promoted viable Lactobacillus rhamnosus ATCC 53103 growth during cultivation. This discovery has the potential to revolutionise the human food industry and promote the development of functional ingredients for novel and future food products, with numerous applications in the nutraceutical and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The bacterial communities related to seaweed can vary considerably across different locations, and these variations influence the seaweed's nutrition, growth, and development. To study this further, we evaluated the bacteria found on the green marine seaweed Ulva prolifera from Garorim Bay and Muan Bay, two key locations on Republic of Korea's west coast. Our analysis found notable differences in the bacterial communities between the two locations. Garorim Bay hosted a more diverse bacterial population, with the highest number of ASVs (871) compared to Muan Bay's 156 ASVs. In Muan Bay, more than 50% of the bacterial community was dominated by Pseudomonadota. On the other hand, Garorim Bay had a more balanced distribution between Bacteroidota and Pseudomonadota (37% and 35.5%, respectively). Additionally, Cyanobacteria, particularly Cyanothece aeruginosa, were found in significant numbers in Garorim Bay, making up 8% of the community. Mineral analysis indicated that Garorim Bay had higher levels of S, Na, Mg, Ca, and Fe. Function-wise, both locations exhibited bacterial enrichment in amino acid production, nucleosides, and nucleotide pathways. In conclusion, this study broadens our understanding of the bacterial communities associated with Ulva prolifera in Korean waters and provides a foundation for future research on the relationships between U. prolifera and its bacteria. [ABSTRACT FROM AUTHOR]

This study was conducted to determine whether the macroalgae Ulva papenfussi and Ulva nematoidea could be alternatives for preventing Litopenaeus vannamei vibriosis caused by the bacterium Vibrio parahaemolyticus. Phytochemical screening was performed on methanolic extracts to qualitatively determine the main groups of bioactive compounds, previous to an in vitro antibacterial test against V. parahaemolitycus. Phenols, polyphenols, flavonoids, and the high presence of carbohydrates were found in both macroalgae. U. papenfussi showed more presence of lipids and alkaloids than U. nematoidea. Macroalgae extracts prepared (v:v) with a 1:1 methanol: dichloromethane solvent was used for the in vitro test using the disc diffusion method (MDD). Filter paper discs impregnated with 1.0, 1.5, 2.0, 3.0, and 4.0 mg of the extracts showed antibacterial activity against V. Parahaemolitycus in a dose-dependent manner in both macroalgae. The inhibition zone varied significantly (p < 0.05) from 8.33 ± 0.12 to 11.41 ± 0.73 mm for 1 to 3 mg of extract levels, respectively. In conclusion, both macroalgae have antibacterial activity in their crude extracts against this bacteria. It is suggested to evaluate it as a feed additive for L. vannamei. This study is the first report on a phytochemical screening and antibacterial activity of these macroalgae against V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

Different fertilization regimes in biofloc systems influence the predominance of distinct bacterial populations, impacting water quality and organism performance. This study evaluates the growth and nutrient absorption of the macroalgae Ulva lactuca when cultivated in an integrated system with Penaeus vannamei and Oreochromis niloticus in chemoautotrophic and heterotrophic systems. The experiment lasted 45 days and comprised two treatments, each with three replicates: chemoautotrophic—utilizing chemical fertilizers; heterotrophic—employing inoculum from mature biofloc shrimp cultivation, supplemented with organic fertilizers. Each treatment consisted of three systems, each containing a 4 m3 tank for shrimp, 0.7 m3 for tilapia, and 0.35 m3 for macroalgae, with continuous water circulation between tanks and constant aeration. Water quality analyses were carried out during the experiment, as were the performances of the macroalgae and animals. The data were subjected to a statistical analysis. Results revealed an increase in macroalgae biomass and the removal of nitrate (57%) and phosphate (47%) during cultivation, with a higher specific growth rate observed in the chemoautotrophic treatment. Nonetheless, the heterotrophic treatment exhibited higher levels of protein in the macroalgae (18% dry matter) and phosphate removal rates (56%), along with superior maintenance of water quality parameters. Tilapia performance varied across treatments, with a higher final weight and weight gain recorded in the heterotrophic treatment. The recycling of water from an ongoing biofloc cultivation with organic fertilization demonstrated viability for macroalgae cultivation within an integrated system involving shrimp and fish. [ABSTRACT FROM AUTHOR]

Algae are photosynthetic organisms which can be cultivated and produced in photo-bioreactors; therefore, choosing the design parameters and conditions are critical in order to achieve high efficiency and maximum productivity. Algae are of interest to biochemical industries because of their diverse species. This project seeks to build a photo-bioreactor tank to maximize Ulva lactuca non-seasonal survival to produce biodiesel from its biomass. The chosen design was because of the ease of monitoring, and the tank design effectively kept Ulva lactuca alive and fresh. Biodiesel was accomplished using an alkaline esterification for 50 g of dry mass of Ulva lactuca giving a relatively limited yield of approximate 13% of Ulva lactuca oil (4 ml) that was converted to (0.5 ml) biodiesel, compared with other oils such as soybean (42%), corn oil (60%) and cooked corn oil (40%). The yield of Ulva lactuca oil was statistically significantly lower than the other three types of oil (p-value = 0.0032). However, this project still aids in the economics of Jordan, as Ulva lactuca is grown locally in the Gulf of Aqaba. Ulva lactuca investment is worth considering because of its natural exposure, high yield, low cost, reduced algae contamination risk, and space requirements. [ABSTRACT FROM AUTHOR]

The epipelagic macroalgae of Ulva prolifera and Sargassum are the primary contributors to widespread seaweed tides globally. Both ocean plants release large amounts of chromophoric dissolved organic matter (CDOM) into the surrounding seawater. The photochemical reactivity of this CDOM, however, has not been adequately addressed. In this study, we extracted CDOM from Ulva prolifera and Sargassum, examined their ultraviolet (UV)-visible absorption characteristics, and quantified their broadband apparent quantum yields (AQY) of absorbance photobleaching and photomineralization (in terms of CO2, CO, and CH4 photoproduction). On a per-unit-weight basis, Sargassum leached 3.5 times more CDOM than did Ulva prolifera in terms of the absorption coefficient averaged over 254-500 nm. Both Ulva prolifera and Sargassum CDOM were characterized by quasi-exponential decay absorption spectra, with Sargassum CDOM exhibiting a distinct shoulder over 310-350 nm suggestive of mycosporine amino acids. The Sargassum CDOM had a higher photobleaching AQY but lower photomineralization AQYs compared to Ulva prolifera CDOM. The photobleaching and photomineralization AQYs of both macroalgal CDOM are, however, orders of magnitude higher than those of CDOM in various natural waters. Potential photoproduction rates of CO2 and CO from the Ulva prolifera CDOM and Sargassum CDOM during the bloom periods are several times to orders of magnitude higher than the air-sea fluxes of these gases in the absence of the macroalgae. This study demonstrates that CDOM released by Ulva prolifera and Sargassum is extremely prone to photobleaching and photomineralization, rendering floating mats of these plants in oceans as potential "hotspots" of greenhouse gas emissions to the atmosphere. This photochemical feedback should be considered when assessing ocean afforestation as a CO2 removal approach to mitigate climate warming. [ABSTRACT FROM AUTHOR]

The present investigation explores the efficacy of green algae Ulva lactuca biochar-sulfur (GABS) modified with H2SO4 and NaHCO3 in adsorbing methylene blue (MB) dye from aqueous solutions. The impact of solution pH, contact duration, GABS dosage, and initial MB dye concentration on the adsorption process are all methodically investigated in this work. To obtain a thorough understanding of the adsorption dynamics, the study makes use of several kinetic models, including pseudo-first order and pseudo-second order models, in addition to isotherm models like Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich. The findings of the study reveal that the adsorption capacity at equilibrium (qe) reaches 303.78 mg/g for a GABS dose of 0.5 g/L and an initial MB dye concentration of 200 mg/L. Notably, the Langmuir isotherm model consistently fits the experimental data across different GABS doses, suggesting homogeneous adsorption onto a monolayer surface. The potential of GABS as an efficient adsorbent for the extraction of MB dye from aqueous solutions is highlighted by this discovery. The study's use of kinetic and isotherm models provides a robust framework for understanding the intricacies of MB adsorption onto GABS. By elucidating the impact of various variables on the adsorption process, the research contributes valuable insights that can inform the design of efficient wastewater treatment solutions. The comprehensive analysis presented in this study serves as a solid foundation for further research and development in the field of adsorption-based water treatment technologies. [ABSTRACT FROM AUTHOR]

Macroalgae are considered healthy food ingredients due to their content in numerous bioactive compounds, and the traditional use of whole macroalgae in Asian cuisine suggests a contribution to longevity. Although much information is available about the bioactivity of pure algal compounds, such as different polyphenols and polysaccharides, documentation of potential effects of whole macroalgae as part of Western diets is limited. Lifestyle- and age-related diseases, which have a high impact on population health, are closely connected to underlying chronic inflammation. Therefore, we have studied crude extracts of green (Ulva fenestrata) and brown (Saccharina latissima) macroalgae, as two of the most promising food macroalgae in the Nordic countries for their effect on inflammation in vitro. Human macrophage-like reporter THP-1 cells were treated with macroalgae extracts and stimulated with lipopolysaccharide (LPS) to induce inflammatory signalling. Effects of the macroalgae extracts were assessed on transcription factor activity of NF-κB and IRF as well as secretion and/or expression of the cytokines TNF-α and IFN-β and chemokines IL-8 and CXCL10. The crude macroalgae extracts were further separated into polyphenol-enriched and polysaccharide-enriched fractions, which were also tested for their effect on transcription factor activity. Interestingly, we observed a selective activation of NF-κB, when cells were treated with macroalgae extracts. On the other hand, pretreatment with macroalgae extracts selectively repressed IRF activation when inflammatory signaling was subsequently induced by LPS. This effect was consistent for both tested species as well as for polyphenol- and polysaccharide-enriched fractions, of which the latter had more pronounced effects. Overall, this is the first indication of how macroalgae could modulate inflammatory signaling by selective activation and subsequent repression of different pathways. Further in vitro and in vivo studies of this mechanism would be needed to understand how macroalgae consumption could influence the prevention of noncommunicable, lifestyle- and age-related diseases that are highly related to unbalanced inflammatory processes. [ABSTRACT FROM AUTHOR]

Main Conclusion: The combined photoinhibitory and PSII-reaction centre quenching against light stress is an important mechanism that allows the green macroalga Ulva rigida to proliferate and form green tides in coastal ecosystems. Eutrophication of coastal ecosystems often stimulates massive and uncontrolled growth of green macroalgae, causing serious ecological problems. These green tides are frequently exposed to light intensities that can reduce their growth via the production of reactive oxygen species (ROS). To understand the physiological and biochemical mechanisms leading to the formation and maintenance of green tides, the interaction between inorganic nitrogen (Ni) and light was studied. In a bi-factorial physiological experiment simulating eutrophication under different light levels, the bloom-forming green macroalga Ulva rigida was exposed to a combination of ecologically relevant nitrate concentrations (3.8–44.7 µM) and light intensities (50–1100 µmol photons m−2 s−1) over three days. Although artificial eutrophication (≥ 21.7 µM) stimulated nitrate reductase activity, which regulated both nitrate uptake and vacuolar storage by a feedback mechanism, nitrogen assimilation remained constant. Growth was solely controlled by the light intensity because U. rigida was Ni-replete under oligotrophic conditions (3.8 µM), which requires an effective photoprotective mechanism. Fast declining Fv/Fm and non-photochemical quenching (NPQ) under excess light indicate that the combined photoinhibitory and PSII-reaction centre quenching avoided ROS production effectively. Thus, these mechanisms seem to be key to maintaining high photosynthetic activities and growth rates without producing ROS. Nevertheless, these photoprotective mechanisms allowed U. rigida to thrive under the contrasting experimental conditions with high daily growth rates (12–20%). This study helps understand the physiological mechanisms facilitating the formation and persistence of ecologically problematic green tides in coastal areas. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study the correlation between different topographies and the reaction of Ulva Linza fouling species. Design/methodology/approach: In this research, topographies with a different method, such as hot embossing and hot pulling, were achieved, and biological analyses were done with macroalgae Ulva Linza cells. The effect of topography via local binding geometry (honeycomb size gradients) and Wenzel roughness on the settling of Ulva microorganisms was tested. Findings: As a result, Ulva spores confirmed different reactions to a similar set of tapered microstructures that was in agreement with the results on distinct honeycombs. The local binding geometry and the Wenzel roughness factor "r" were dominant on settling of Ulva Linza spores. Research limitations/implications: The reaction of an organism at the interface of vehicles' substrate is powerfully affected by surface topographies. Practical implications: The best embedment occurred on structures with bigger sizes than Ulva Linza's spores. The density of settled spores was proportional to Wenzel roughness and the spores favour to attach to "kink sites" positions. Social implications: Unfortunately, unpleasant aggregation of marine biofouling on marine vehicles' surfaces, generate terrific difficulties in the relevant industry. Originality/value: There was a sharp relationship between Wenzel roughness and settle of Ulva Linza spores. The local binding geometry and the Wenzel roughness factor "r" were dominant on settling of Ulva Linza spores. [ABSTRACT FROM AUTHOR]

Research has been carried out on the effect of pH, fermentation time and yeast concentration on bioethanol production through hydrolysis using a CEM (Ceramic Elekctromagnetic Microwave) synthesizer and bioethanol production from Ulva reticulata seaweed. Ulva reticulata seaweed contains carbohydrates in the form of heteropolysaccharides such as glucose, arabinose, ramnose and xylose which are very abundant and suitable for conversion into bioethanol because the people of Timor Island do not use them as food. The carbohydrate content of Ulva reticulata seaweed can be converted into hexose and pentose sugars (glucose, arabinose, ramnose and xylose) through hydrolysis using 3 types of acid catalysts, namely hydrochloric acid (HCl), sulfuric acid (H2SO4) and nitric acid (HNO3). Fermentation was carried out with S. cerevisiae concentration variation of 6; 8; 10; 12 % (v/v) and fermentation time variation of 3; 5; 7; 9 days and a pH variation of 4; 4.5; 5; 5.5 at a temperature of 30 °C. Reducing sugar characterization used the Dinitrosalicylic acid (DNS) reagent, sample surface texture analysis was carried out using Scanning Electron Microscopy (SEM) and ethanol characterization used Gas Chromatography-Flame Ionization Detector (GC-FID). The results of surface texture analysis before and after hydrolysis experienced significant changes. Optimal conditions for hydrolysis of Ulva reticulata seaweed using sulfuric acid (H2SO4) combined with a CEM synthesizer at an acid concentration of 3 % (v/v) with irradiation power of 200 watts for 50 min at a temperature of 150 °C, produced reducing sugar of 97.06 g/L. The results of GC-FID analysis indicated that bioethanol concentration obtained at optimal conditions of pH 4.5 was 42.32 %, S. cerevisiae concentration was 12 % with a bioethanol content of 42.53 % at a fermentation time of 5 days. This research is expected to provide information for researchers and industry to overcome world energy problems and environmental pollution through Ulva reticulata waste. [ABSTRACT FROM AUTHOR]

Green algae blooms of the genus Ulva are occurring globally and are primarily attributed to anthropogenic factors. At Los Tubos beach in Algarrobo Bay along the central Chilean coast, there have been blooms of these algae that persist almost year-round over the past 20 years, leading to environmental, economic, and social issues that affect the local government and communities. The objective of this study was to characterize the species that form these green tides based on a combination of ecological, morpho-anatomical, and molecular information. For this purpose, seasonal surveys of beached algal fronds were conducted between 2021 and 2022. Subsequently, the sampled algae were analyzed morphologically and phylogenetically using the molecular markers ITS1 and tufA, allowing for the identification of at least five taxa. Of these five taxa, three (U. stenophylloides, U. uncialis, U. australis) have laminar, foliose, and distromatic morphology, while the other two (U. compressa, U. aragoensis) have tubular, filamentous, and monostromatic fronds. Intertidal surveys showed that U. stenophylloides showed the highest relative coverage throughout the seasons and all intertidal levels, followed by U. uncialis. Therefore, we can establish that the green tides on the coast of Algarrobo in Chile are multispecific, with differences in relative abundance during different seasons and across the intertidal zone, opening opportunities for diverse future studies, ranging from ecology to algal biotechnology. [ABSTRACT FROM AUTHOR]

In 2022, Yellow Sea green tide caused by Ulva prolifera reached a historic minimum and the coastal areas of Shandong Peninsula were less affected. However, the largest amount of seaweed biomass has been washed ashore on Lianyungang and Rizhao coasts since 2015. We studied the development pattern of Yellow Sea green tide in 2022, and analyzed the key environmental factors on the growth and drifting, then discussed the possible reasons that resulted in the massive stranding of green tide biomass in Lianyungang and Rizhao. Results show under the combined influence of the east to southeast winds and currents with shoreward anomalies, green tide drifted to the coastal waters between Shandong and Jiangsu provinces and the distribution areas located westward compared with previous years (2008–2021). Floating U. prolifera rafts from the coastal waters of Binhai and Sheyang drifted continuously into the coastal waters of Lianyungang and Rizhao, providing important supplements for Yellow Sea green tide. Because green tide in 2022 distributed close to the coastal waters, the abundant nutrients might support their continuous high growth rate. In addition, the amount of rainfall around Shandong Peninsula from late June to early July were significantly higher than in previous years, which might promote the development of green tide to some extent. [ABSTRACT FROM AUTHOR]

Aims Macroalgae harbor a rich epiphytic microbiota that plays a crucial role in algal morphogenesis and defense mechanisms. This study aims to isolate epiphytic cultivable microbiota from Ulva sp. surfaces. Various culture media were employed to evaluate a wide range of cultivable microbiota. Our objective was to assess the antibacterial and biofilm-modulating activities of supernatants from isolated bacteria. Methods and results Sixty-nine bacterial isolates from Ulva sp. were identified based on 16S rRNA gene sequencing. Their antibacterial activity and biofilm modulation potential were screened against three target marine bacteria: 45%, mostly affiliated with Gammaproteobacteria and mainly grown on diluted R2A medium (R2Ad), showed strong antibacterial activity, while 18% had a significant impact on biofilm modulation. Molecular network analysis was carried out on four bioactive bacterial supernatants, revealing new molecules potentially responsible for their activities. Conclusion R2Ad offered the greatest diversity and proportion of active isolates. The molecular network approach holds promise for both identifying bacterial isolates based on their molecular production and characterizing antibacterial and biofilm-modulating activities. [ABSTRACT FROM AUTHOR]

Featured Application: Firstly, it is an extensive review of one of the most talked about "hot topics" today. Subsequently, it could be a complete guide to the cultivation and use for aquaculture of one of the most cosmopolitan species ever, as well as a guide to controlling "green tides". Green algae, phylum Chlorophyta, due to their green appearance as higher plants, are seen as one of the raw materials to be widely used by humanity for different purposes. How can these different purposes achieve ONU Sustainable Development Goals? The genus Ulva sp. is widely distributed through all continents, tolerating different ecosystems (freshwater and marine), different intensities of light, temperature, and salinity. The Ulva sp. life cycle is isomorphic and biphasic type, also affected by biotic factors such as thallus age, phytohormones, microbiome, sporulation inhibitors and metabolomic. Due to that, types of farming can be implemented depending on the cultivation method and it is final biomass exploitation. Thus, this critical review analyzes the laminar Ulva species from the ecology and demonstrates that the seaweed biomass application, may make significant contributions to marine ecosystems, humans, aquaculture, and biotechnological innovation, indicating its importance in both environmental and socioeconomic contexts based on experiments across the world, time and critical thinking. This means that explaining the actual road and future roads of laminar Ulva into a multi-tool development from humankind welfare. With right management of resources and human empowerment, Ulva sp. products can be produced facing climate change and support different industries. However, responsible management of Ulva populations and farming is essential to prevent overgrowth, green floods, and maintain environmental equilibrium. [ABSTRACT FROM AUTHOR]

Benefits of integrated shrimp/seaweed culture systems have been investigated; nevertheless, knowledge of the importance of microorganisms in the systems is limited. In the present study, we evaluated shrimp Litopenaeus vannamei under four experimental conditions: fed pelleted diet in the presence of Ulva lactuca with (UPE) and without water exchange (UPN) and fed only a pelleted diet with (PE) and without water exchange (PN). Bacterial communities present in shrimp, seaweed, and water were analyzed after 4 weeks of an experimental trial. Our results showed significantly lower shrimp final weight, weight gain, specific growth rate (SGR), and higher feed conversion ratio (FCR) with PN treatment compared to the rest of the treatments (P < 0.05). Seaweed resulted in lower relative abundance of Vibrio in the presence of shrimp (UPE and UPN) compared to monoculture (Ulv). Shrimp intestine presented lower Vibrio and significantly increased Sagittula and Lutimonas in treatments without water exchange. In the case of shrimp fed only pellet with water exchange (PE), a significantly higher relative abundance of Lucibacterium and Planctomicrobium genera was found compared to PN, UPE, and UPN treatments. The results suggest that the seaweed in a system with no water exchange is advantageous to promote water bacterial diversity, and that reduces the relative abundance of Vibrio in shrimp gut. Additionally, PERMANOVA analyses revealed that both seaweed presence and water exchange are significant factors in structuring the culture system microbiota (P < 0.001). The present study contributes to understanding the importance of microbial communities in shrimp/seaweed integrated aquaculture systems. [ABSTRACT FROM AUTHOR]

When emersed, intertidal seaweeds experience rapid changes in environmental conditions. On warm sunny days, seaweeds can desiccate soon after emersion. On rainy days or in areas with freshwater inputs, they may experience rapid drops in salinity. To determine whether one low tide's exposure to environmental stress alters seaweed growth, palatability to herbivores, and dimethylsulfoniopropionate (DMSP) concentrations, we exposed Ulva fenestrata to desiccation and hyposaline conditions for 3 h in summer and winter. Two days later, summer desiccation decreased growth, consumption by Lacuna vincta, and DMSP by 71%, 83%, and 67%, relative to controls. Winter desiccation reduced DMSP by 19% and did not affect growth or L. vincta feeding. Summer hyposaline conditions increased growth by 75% but did not affect L. vincta grazing or DMSP, whereas winter hyposaline conditions reduced growth by 37%. After 2 days of exposure to L. vincta, seaweeds were allowed to recover for 7 days, then DMSP was measured. U. fenestrata desiccated in the summer did not survive. Average DMSP concentrations were 127% higher in grazed than ungrazed seaweed in the summer salinity experiment, providing evidence that grazing induces DMSP. No DMSP induction occurred in winter, possibly because grazing rates were much lower. In a follow-up summer desiccation experiment, maximum quantum yields (MQYs) and DMSP decreased to 12% and 14% of controls within an hour. After 7 days, MQY and DMSP concentrations recovered, but growth was 81–97% lower in seaweeds desiccated for 30–60 min, relative to controls. These results provide the first evidence for grazer-induced DMSP increases. [ABSTRACT FROM AUTHOR]

Annual outbreaks of floating Ulva prolifera blooms in the Yellow Sea have caused serious local environmental and economic problems. Rapid and effective monitoring of Ulva blooms from satellite observations with wide spatial-temporal coverage can greatly enhance disaster response efforts. Various satellite sensors and remote sensing methods have been employed for Ulva detection, yet automatic and rapid Ulva detection remains challenging mainly due to complex observation scenarios present in different satellite images, and even within a single satellite image. Here, a reliable and fully automatic method was proposed for the rapid extraction of Ulva features using the Tasseled-Cap Greenness (TCG) index from satellite top-of-atmosphere reflectance (RTOA) data. Based on the TCG characteristics of Ulva and Ulva-free targets, a local adaptive threshold (LAT) approach was utilized to automatically select a TCG threshold for moving pixel windows. When tested on HY1C/D-Coastal Zone Imager (CZI) images, the proposed method, termed the TCG-LAT method, achieved over 95% Ulva detection accuracy though cross-comparison with the TCG and VBFAH indexes with a visually determined threshold. It exhibited robust performance even against complex water backgrounds and under non-optimal observing conditions with sun glint and cloud cover. The TCG-LAT method was further applied to multiple HY1C/D-CZI images for automatic Ulva bloom monitoring in the Yellow Sea in 2023. Moreover, promising results were obtained by applying the TCG-LAT method to multiple optical satellite sensors, including GF-Wide Field View Camera (GF-WFV), HJ-Charge Coupled Device (HJ-CCD), Sentinel2B-Multispectral Imager (S2B-MSI), and the Geostationary Ocean Color Imager (GOCI-II). The TCG-LAT method is poised for integration into operational systems for disaster monitoring to enable the rapid monitoring of Ulva blooms in nearshore waters, facilitated by the availability of near-real-time satellite images. [ABSTRACT FROM AUTHOR]

Ulva prolifera (U. prolifera) green tide outbreaks have occurred in the Yellow Sea of China for many years, causing serious losses to marine ecology and the marine economy. The monitoring and tracking of U. prolifera green tide is a crucial aspect of marine ecological disaster prevention and control management. This paper aims to investigate the spatiotemporal distribution changes in U. prolifera green tide in the Yellow Sea throughout its life cycle. A survey of the Yellow Sea from 2008 to 2023 was conducted using multi-source remote sensing images. Long-term monitoring and analysis of U. prolifera revealed the evolution process of the green tide, including the early development, outbreak, decline, and extinction stages, considering time, space, and frequency of occurrence. Additionally, this study examined peak coverage change patterns over the past 16 years and analyzed the influence of environmental factors such as sea surface temperature and sea surface wind field on the development of U. prolifera. The research results serve as a valuable reference for the monitoring, early warning, and scientific prevention and control of U. prolifera green tide in the Yellow Sea, as well as other similar marine disaster areas. [ABSTRACT FROM AUTHOR]

Edible green algal species are the most widely distributed and diverse macroalgae in the world and are considered as an important source of bioactive molecules which serve as multi-product sources for nutritional and pharmaceutical applications. The present investigations were carried out concerning biochemical constituents from three species of green marine algae Ulva conglobata, Caulerpa racemosa, and Bryopsis plumosa collected from the coast of Veraval Chowpati, Gujarat India. The biochemical composition was analysed using uv-spectrophotometer to evaluate its food value and find out variations in composition during the investigation period. The reducing sugar, proline, and starch contents were high in Bryopsis plumosa followed by Caule rpa racemosa and Ulva conglobata. Proline content is higher than the total amino acids in three algal species. The protein contents following by Lowry method Caulerpa racemosa have a high amount with 1667.32 ± 18.42 (µgg-1 dry wt.) followed by Bryopsis plumosa 1394.98 ± 18.78 (µgg-1 dry wt.) and Ulva conglobata 292.72 ± 17.85 (µgg-1 dry wt.). The protein content was recorded maximum in Bryopsis plusmosa and Caulerpa racemosa than in the Ulva conglobata. All the assays carried out in the present work showed that all selected green algae are good sources of biochemical. According to the biochemical composition values of the studied algae, they have the potential to be a source of constituents with high nutritional value and use in the food, dietary, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue of the journal Botanica Marina focused on the green seaweed Ulva. The collection of articles explores various aspects of Ulva, including its ecology, phylogeny, and practical applications in aquaculture. The articles cover topics such as taxonomy, cross-kingdom interactions with bacteria and fungi, and the cultivation of Ulva for sustainable alternatives to essential fatty acids. The special issue aims to advance our understanding of Ulva and its potential in sustainable aquaculture and ecological contexts. The collection is dedicated to the late Prof. Dr. Klaus Lüning, a renowned marine botanist who made significant contributions to the study of Ulva. The special issue is also supported by the EU-funded COST Action SeaWheat, which aims to integrate Ulva into various industries and daily life. [Extracted from the article]