Search Results (105)

Ulva prolifera is the main causative species of marine green tides and exhibits extreme tolerance to intertidal abiotic stress. However, the underlying molecular mechanisms remain largely unclear. In this study, we cloned and characterized an MYB-related transcription factor, UpMYB-PHL, from U. prolifera. Expression analysis showed that UpMYB-PHL is rapidly and significantly induced by high-salt stress. Furthermore, heterologous overexpression of UpMYB-PHL in the model microalga Chlamydomonas reinhardtii significantly improved its salt tolerance and biomass. By yeast one-hybrid and dual-luciferase assays, we demonstrated that UpMYB-PHL directly binds to and activates the promoter of the phosphate transporter gene UpPHT1, which is a typical target gene of phosphate response (PHR) transcription factor and participates in salt stress responses of plants. Interestingly, yeast two-hybrid assays revealed that UpMYB-PHL physically interacts with UpGAPDH, a core enzyme in energy metabolism. Taken together, our findings reveal a novel regulatory network in which UpMYB-PHL coordinates phosphorus transporter and energy metabolism in response to salt stress in U. prolifera. This study provides a vital molecular explanation for the rapid adaptation and massive growth of U. prolifera under severe intertidal salt stress. Full article

The phoD gene encodes alkaline phosphatase, which hydrolyzes organic phosphorus and releases bioavailable phosphorus for direct utilization by marine organisms. phoD-harboring bacteria are reported to be sensitive to environmental changes. As a common ecological disturbance, annual Ulva prolifera green tides in the southern Yellow Sea pose significant ecological challenges, yet the responses and assembly processes of phoD-harboring bacterial communities remain poorly understood. In this study, high-throughput sequencing was used to characterize these communities across the pre-bloom, bloom and post-bloom stages. The results revealed significant stage-specific shifts in community structure, with the bloom and post-bloom stages exhibiting higher similarity to each other than the pre-bloom stage. Abundant taxa were more sensitive to environmental fluctuations across all stages and were characterized by broader niche breadths but reduced phylogenetic diversity during the bloom. In contrast, rare taxa maintained relatively stable diversity but showed marked niche contraction. Neutral community model and βNTI analyses demonstrated that stochastic processes dominated community assembly overall. Green tide drove rare taxa toward heterogeneous selection and drift, while abundant taxa shifted toward homogeneous selection during the post-bloom stage. Co-occurrence network analysis showed increased microbial correlations during the bloom, implying a trend toward greater network stability of phoD-harboring bacterial communities under green tide disturbance. The lagged responses, functional redundancy and divergent ecological strategies of abundant and rare taxa may explain how green tides drive variations in microbes involved in the phosphorus cycle. These findings provide new insights into the microbial regulatory mechanisms of the nutrient cycle in coastal ecosystems affected by large-scale U. prolifera green tides. Full article

Red tide events pose substantial threats to marine ecosystems, aquaculture, and coastal public health. Timely and accurate delineation of red tide extent from satellite imagery is therefore essential for operational monitoring and early warning. However, existing deep learning-based semantic segmentation methods generally treat multispectral bands as homogeneous inputs and do not fully exploit the domain knowledge embodied in spectral indices commonly used in traditional remote sensing analysis. To address this limitation, this study proposes a spectral-index-guided network (SIG-Net) that explicitly incorporates spectral-index priors into deep feature extraction through a dual-branch architecture. SIG-Net comprises three components: a spectral encoder based on a Mix Vision Transformer (MiT-B2) that learns spatial-spectral representations from the original Sentinel-2 bands; a lightweight CNN-based index encoder that extracts discriminative features from four spectral indices, namely the red-green index (RGI), blue-green index (BGI), normalized difference vegetation index (NDVI), and the normalized difference Noctiluca index (NDNI) proposed in this study; and a spectral-index-guided fusion (SIGF) module that adaptively integrates multi-scale features from the two branches using spatial-reduction cross-attention and a gated fusion mechanism. Experiments on a Sentinel-2 red tide dataset show that SIG-Net outperforms single-branch baselines, including U-Net, DeepLabV3+, and SegFormer, as well as naive multi-source fusion strategies. Ablation studies further confirm the contributions of the SIGF module, the gating mechanism, and the proposed NDNI to performance improvements. The proposed method provides an effective framework for integrating domain knowledge with deep learning for red tide remote sensing monitoring. Full article

TIDEs (therapeutic peptides, oligonucleotides, and related molecules) represent a rapidly expanding market that has gained significant momentum due to the recent success of Glucagon-like peptide-1 (GLP-1) receptor agonists for the treatment of obesity, diabetes and as cardiovascular and kidney diseases. Chemical synthesis remains the dominant manufacturing route for candidates containing approximately 10–40 amino acids and includes non-proteinogenic amino acids. Consequently, various combinations of solid-phase peptide synthesis (SPPS), liquid-phase peptide synthesis (LPPS), hybrid approaches, or tag-assisted peptide synthesis (TAPS) can be applied to achieve full-sequence assembly. However, identifying the most eco-efficient pathway through experimental trials alone is impractical because of the vast number of possible process combinations and the growing variety of green solvent alternatives. Therefore, process simulation studies—widely established in chemical engineering—must be adapted to the specific physicochemical characteristics of these large, multi-component molecules. This paper provides an overview of the current state of research and illustrates potential process improvements enabled by digital twin technologies as exemplified for the first manufacturing steps of tirzepatide. Full article

Tidal flats are shrinking and eroding due to sea-level rise and human activities. Ecological submerged breakwaters (ESBs) offer a novel solution combining coastal protection and ecological restoration, but their effects on sediment dynamics lack field evidence. This study presents synchronous in situ measurements from an inner tidal flat (WN01) and an outer shallow area (WN02) of a newly built riprap slope-type ESB on the northern coast of the Sheyang River Estuary, Jiangsu, China. Using Acoustic Doppler Velocimeters (ADVs) and wave-tide gauges, we examined hydrodynamics, suspended sediment concentration (SSC), bed shear stress, erosion–accretion, and sediment transport under normal-weather and strong wave events. Within the constraints of a 14-day observation at two stations, our results indicate that: (1) The ESB reduced wave height and weakened currents, shifting dominant bed shear stress from wave-dominated outside to tide-dominated inside. Under normal weather, both sides were accretive. (2) Strong wave events caused sharp increases in bed shear stress, net erosion on both sides, and a 2–3-fold SSC rise, breaking the normal balance. (3) Suspended sediment transport direction remained northwest inside during strong wave events but shifted to northeast/southeast outside, demonstrating effective isolation of wave-driven anomalies. Bedload was trapped inside, resulting in no net sediment loss, in contrast to the unprotected southern tidal flat. (4) We recommend moderately lowering the ESB crest elevation to prevent excessive accretion and implementing “grey-green” restoration (salt marshes or oyster reefs) to enhance coastal resilience against sea-level rise. Full article

Large-scale green tides dominated by Ulva species have recurred annually in the Southern Yellow Sea for nearly two decades, yet early detection remains challenging due to the patchy distribution of incipient floating macroalgae. This study investigated the spatiotemporal dynamics of Ulva micropropagules during the 2020 outbreak using a systematic cultivation assay. Seawater samples were collected from 23 stations across the Subei Shoal and adjacent waters in April, May, and July, and incubated under controlled laboratory conditions to enumerate Ulva germling densities. Results revealed that Ulva micropropagule abundance peaked in April, with high-density foci concentrated in the Subei Shoal region—particularly in aquaculture areas of Neopyropia J. Brodie & L.-E. Yang, 2020—confirming this zone as one of the important sources. Abundance declined progressively through May and July as macroalgae drifted northward under wind and current forcing. This method effectively identified putative source regions and reconstructed initial dispersal patterns prior to satellite-detectable macroalgal aggregation. These findings demonstrate that Ulva micropropagule monitoring provides a cost-effective, sensitive tool for early warning and Ulva source tracking, offering finer-scale propagule distribution data to inform precision management strategies for mitigating green tide impacts on coastal marine ecosystems. Future research should expand investigations into Ulva micropropagule dynamics to elucidate their mechanistic processes and ecological significance in green tide initiation and development. Full article

Since 2007, green tides have recurrently occurred in the Yellow Sea during spring and summer, with a massive outbreak recorded in 2021. Given the critical significance of green tide monitoring and prediction for marine ecological security and sustainable development, this study developed a satellite remote sensing-validated coupled simulation system for green tide drift and growth, by integrating multi-source satellite remote sensing data and oceanographic reanalysis datasets. Leveraging this system, we systematically analyzed the spatiotemporal evolution characteristics and underlying driving mechanisms of both routine green tide processes in 2014–2015 and the extreme 2021 event. Satellite images with low cloud cover and extensive green tide distribution were screened to confirm the accuracy of green tide drift trajectories and distribution ranges for validating the model’s reliability, and the results demonstrated the spatial consistency between simulation results and satellite observations. The validated model was used to track the drift and growth–decline processes of green tides and investigate the underlying cause of high-biomass appearance in 2021. Combined with environmental parameters, our analyses revealed that variations in attachment substrates alter wind resistance coefficients, thereby potentially accelerating the northward drift velocity of green tides. Furthermore, substrate properties may exert a significant regulatory effect on the attachment, germination, and biomass accumulation of Ulva prolifera spores, which could be a leading factor driving the massive green tide outbreak. Full article

The Ulva prolifera green tide in the South Yellow Sea has erupted annually for many years, posing significant threats to coastal ecology, the economy, and society. While environmental factors are widely acknowledged as prerequisites for these outbreaks, the asynchrony and complex coupling between their variations and disaster events have challenged traditional studies that rely on instantaneous correlations to uncover the underlying dynamic mechanisms. This study focuses on the Ulva prolifera disaster in the South Yellow Sea, systematically analyzing its spatiotemporal distribution patterns, the temporal accumulation and lag effects of environmental factors, and the coupled driving mechanisms using the Floating Algae Index (FAI). The results indicate that: (1) The disaster shows significant interannual variability, with 2019 experiencing the most severe outbreak. Monthly, the disaster begins offshore of Jiangsu in May, moves northward and peaks in June, expands northward with reduced scale in July, and largely dissipates in August. Years with large-scale outbreaks exhibit higher distribution frequency and broader spatial extent. (2) Environmental factors demonstrate significant accumulation and lag effects on Ulva prolifera disasters, with a mixed temporal mode of both accumulation and lag effects being dominant. Temporal parameters vary across different factors—nutrients generally have longer lag times, while light and temperature factors show longer accumulation times. These parameters change dynamically across disaster stages and display a clear inshore–offshore gradient, with shorter effects in coastal areas and longer durations in offshore waters, revealing significant spatiotemporal heterogeneity in temporal response patterns. (3) The driving mechanism of Ulva prolifera disasters follows a “nutrient-dominated, temporally relayed” pattern. Nutrient accumulation (PO₄, NO₃, SI) from the previous autumn and winter serves as the decisive factor, explaining 86.8% of interannual variation in disaster scale and 56.1% of the variation in first outbreak timing. Light and heat conditions play a secondary modulating role. A clear temporal relay occurs through three distinct stages: the initial outbreak triggered by nutrients, the peak outbreak governed by light–temperature–nutrient synergy, and the system decline characterized by the dissipation of all driving forces. These findings provide a mechanistic basis for developing predictive models and targeted control strategies. Full article

As the global environment continues to deteriorate, water blooms and red tides occur more frequently, making it increasingly important to control eutrophication in water bodies. This study focuses on optimizing an adjustable vortex well alga extractor for deep-well alga removal to reduce the risks associated with algal blooms and red tides. Numerical simulation was employed to model the working process of the vortex well alga extractor and to determine its most efficient structural parameters. The optimal dimensions of the adjustable vortex well alga collector optimized by the PSO-GP model are as follows: during the experiment, the water depth at the suction inlet is 200 mm, the diameter of the suction inlet is 480 mm, the distance of the fence is 2000 mm, and the average flow velocity of the water area is 0.12 m/s. Under these conditions, the working flow rate of the pressurizer can reach up to 18,400 cubic meters per hour at a maximum. Under these conditions, the collection efficiency for blue-green algae can reach 92%. The proposed optimization method can assist project managers in improving the design and operation of deep-well alga removal systems, achieving higher accuracy and efficiency, conserving energy, and enhancing overall alga removal performance. Full article

The bloom-forming dinoflagellates and euglenophyceae were observed in the coastal waters of Hammam-Lif (Southern Mediterranean), during a green tide event on 3 June 2023. The bloom was dominated by Lepidodinium chlorophorum, identified through ribotyping with densities reaching 2.3 × 10⁷ cells·L⁻¹. Euglena spp. and Eutrepsiella spp. contributed to the discoloration, with abundances up to 2.9 × 10⁷ cells·L⁻¹. Environmental data revealed significant depletion of nitrite and nitrate, coinciding with a rapid increase in sunlight duration, likely promoting the proliferation of L. chlorophorum and euglenophyceae. By 5 June, two days after the bloom, nutrient stocks were exhausted. Diatoms appeared limited by low silicate concentrations (<0.05 µmol·L⁻¹), while dissolved inorganic phosphate and Nitrogen-ammonia were elevated during the bloom (0.88 and 4.8 µmol·L⁻¹, respectively), then decreased significantly afterward (0.23 and 1.06 µmol·L⁻¹, respectively). Low salinity (34.0) indicated substantial freshwater input from the Meliane River, likely contributing to nutrient enrichment and bloom initiation. After the event, phytoplankton abundance and chlorophyll levels declined, with a shift from dinoflagellates to diatoms. The accumulation of pigments (chlorophyll b and carotenoids) and the presence of Mycosporine-like amino acids (MAAs) during and after the bloom suggest that UV radiation and Nitrogen-ammonia were key drivers of this green tide. Full article

For nearly two decades, the Yellow Sea has experienced recurrent green tides, which are now considered the largest of their kind globally; the mechanism behind these outbreaks remains highly complex and not fully understood. This study investigates the pre-outbreak distribution, abundance, and species composition of suspended macroalgae in the Southern Yellow Sea (SYS) during 2023–2024, along with environmental parameters. The results indicate that suspended macroalgae were predominantly distributed in the nearshore waters, particularly along the shallow beaches of northern Jiangsu. Furthermore, their abundance in the surface water layer significantly exceeded that in the bottom water. A total of 1353 and 493 algal filament samples were collected in 2023 and 2024, respectively. Dominant species included Ulva prolifera, Ulva linza, Ulva flexuosa, and Blidingia sp. Nutrient levels positively correlated with filament abundance. As a primary means of rapid proliferation for U. prolifera, suspended macroalgae contribute significantly to the initial expansion of green tides. Furthermore, their abundance holds promise as a biological indicator for forecasting the scale and extent of impending blooms, thereby providing a critical foundation for elucidating the underlying outbreak mechanisms. Full article

Since 2007, the Yellow Sea has experienced the world’s largest green tides, with Ulva prolifera O.F. Müller as the dominant species. Those blooms severely impacted the local tourism and aquaculture, resulting in significant economic losses, as well as negative social and ecological consequences. Unlike other global green tides, those in the Yellow Sea are characterized by long-distance drifting and an astonishing scale. These destructive events display significant temporal and spatial variability, which is largely driven by dynamic environmental conditions and human activities. In this review, we summarize recent advancements in understanding the spatiotemporal patterns of long-distance transport, the interannual variability in bloom size, and the underlying mechanisms driving these fluctuations. Additionally, we highlight important knowledge gaps that need further investigation to support the development of effective management strategies for mitigating the impacts of green tides in the Yellow Sea. Full article

In Australasian countries such as New Zealand, algae consumption is gaining in popularity within consumer markets. Beverages containing macro-algae, like kelp, and those containing micro-algae, such as spirulina, are considered novel products. While consumer preferences for algae-based products are well explored, less attention has been given to beverages, despite their importance for consumers, specifically those interested in health and well-being. The present study is dedicated to this research gap and investigates the key factors driving and hindering New Zealand consumers’ willingness to drink, pay a price premium, and spread word of mouth about micro-algae-based beverages, such as tea, smoothies, and cuppa soups. Theoretically, the present study is grounded in a seminal Australasian driver and barrier model of seaweed consumption. The current research design both confirms and extends the consumer behaviours previously examined. An online consumer study was distributed and collected via an opt-in panel provider, resulting in 437 responses. Consumers mirroring the NZ population in age, gender, and household income were the target sample, and descriptive statistics and a quantitative analysis via a partial least squares structural analysis served as the methodological foundation for the study. Food neophilia and involvement with algae were significant drivers for all three behavioural intentions investigated. Food neophobia was a significant inhibitor to the willingness to drink but not significantly related to the willingness to pay a price premium or spread word of mouth. Consumer perceptions of product attributes were a significant driver of New Zealand consumers’ willingness to spread word of mouth. The study provides best practice recommendations for marketers in Australasian beverage industries. In terms of its theoretical merit, two aspects stand out. Micro-algae beverages are an emerging beverage product category in Australasian markets, requiring wider exploration and complementary consumer research dedicated to algae-based food items. The focus on food neophobia and neophilia is original, as it helps to understand the barriers and drivers essential to beverages. In contrast to food items, beverages cannot hide novel ingredients such as micro-algae, making them simultaneously more appealing to food neophilic consumers and extremely challenging to food neophobic consumers. Full article

This article documents the widespread absence of sessile species in bedrock intertidal habitats at the head of the St. Lawrence Estuary, a large macrotidal estuary located in eastern Canada. Extensive observations revealed that no seaweeds or sessile invertebrates occurred anywhere (including cracks and crevices) on substrate areas that become exposed to the air during low tides. Only one sessile species, a green filamentous alga, was found submerged in tidepools. The lack of truly marine sessile species is likely explained by the very low water salinity of this coast, while the absence of sessile freshwater species on intertidal substrates outside of tidepools likely responds to a combination of oligohaline conditions during high tides and daily exposures to the air during low tides, which freshwater species are typically not adapted to. Influences of winter ice scour and coastal suspended sediments are likely secondary. Experimental research could unravel the interactive effects of these abiotic stressors. Overall, this “intertidal desert” could be a useful model system to further explore the boundaries of life on our planet. Full article

This review examines sustainable cascading biorefinery strategies for the green alga Ulva, which is globally prevalent in eutrophic marine waters and often forms extensive “green tides.” These blooms cause substantial environmental and economic damage to coastal communities. The primary target products within an Ulva biorefinery typically encompass salts, lipids, proteins, cellulose, and ulvan. Each of these components possesses unique properties and diverse applications, contributing to the economic robustness of the biorefinery. Salts can be repurposed for agricultural or even human consumption. Lipids offer high-value applications in nutraceuticals and animal feed. Proteins present significant potential as plant-based nutritional supplements. Cellulose can be transformed into various advanced materials. Finally, ulvan, a polyanionic oligosaccharide unique to Ulva, holds promise due to its distinct properties, particularly in the biomedical field. Furthermore, state-of-the-art chemical modifications of ulvan are presented with the aim of tailoring its properties and broadening its potential applications. Future research should prioritize optimizing these integrated extraction and fractionation processes. Furthermore, a multi-product biorefining approach, integrated with robust Life Cycle Assessment studies, is vital for transforming this environmental challenge into a significant opportunity for sustainable resource valorization and economic growth. Full article