Harmful Algal Blooms Research Articles

Epidemiologic and clinical features of cyanobacteria harmful algal bloom exposures reported to the National Poison Data System, United States, 2010–2022: a descriptive analysis

BackgroundHarmful algal bloom occurrences have been increasingly reported globally and over time. Exposure to the variety of toxins and co-contaminants that may be present in harmful algal blooms can cause illness and even death. Poison control data is a valuable public health information source that has been used to characterize many types of toxin exposures, including harmful algal blooms. Prior studies have been limited by location and time, and knowledge gaps remain regarding cyanobacteria harmful algal bloom (cyanoHAB) exposure circumstances, and the breadth and severity of associated clinical effect.MethodsThe objective of this study was to characterize epidemiologic and clinical features of cyanoHAB exposure cases reported to 55 US poison control centers and available in the National Poison Data System (NPDS). We identified 4260 NPDS cyanoHAB exposure cases reported from 2010 to 2022, including symptomatic exposure cases with and without clinical effects related to the exposure and asymptomatic exposure cases. We assessed demographics; exposure routes, locations, chronicity; clinical effects; and medical outcomes. We calculated case rates annually and 13-year case rates by US geographic division.ResultsOver half of cyanoHAB exposure cases were children < 20 years old (n = 2175). Most cyanoHABs exposures occurred in a “public area” (n = 2902, 68.1%); most were acute (≤ 8 h) (n = 3824, 89.8%). Dermal and ingestion routes and gastrointestinal effects predominated. 2% (n = 102) of cases experienced a moderate or major medical outcome; no deaths were reported. National rates increased from 0.4 cases/1 million (1 M) person-years in 2010 to 1.4 cases/1 M person-years in 2022. The Mountain division had the highest 13-year rate (7.8 cases/1 M person-years).ConclusionsCyanoHAB exposure case rates increased 2010–2022, despite a decrease in all-cause exposure cases during the same period. NPDS data provide valuable public health information for characterization of cyanoHAB exposures, an emerging public health challenge.

Cyanobacterial blooms prediction in China’s large hypereutrophic lakes based on MODIS observations and Bayesian theory

Cyanobacterial harmful algal blooms (HABs) pose a significant threat to aquatic ecosystems, water quality, and public health, particularly in large hypereutrophic lakes. Developing accurate short-term prediction models is essential for early warning and effective management of HABs. This study introduces a Bayesian-based model aimed at predicting HABs in three of China’s large hypereutrophic lakes: Lake Taihu, Lake Chaohu, and Lake Hulunhu. By integrating MODIS data from the Terra and Aqua satellites with meteorological data spanning from 2010 to 2018, the model forecasts HABs distributions 1, 4, and 7 days in advance. Validation with meteorological data from 2019 to 2020 showed high accuracy, with 0.83 at the pixel level, 0.74 for zonal predictions, and 0.64 for lake-wide HABs area forecasts. Further evaluation using 2023 weather forecast data yielded similar accuracies of 0.78, 0.57, and 0.62, respectively. In addition to predicting the spatial extent of HABs, the model provides binary HABs maps, outbreak areas, and HABs status within lake zones. This method for building prediction models significantly enhances early warning and management capabilities for HABs, providing a scalable framework that can be adapted to other regions facing similar threats from HABs.

Deep Turbulence as a Novel Main Driver for Multi-Specific Toxic Algal Blooms: The Case of an Anoxic and Heavy Metal-Polluted Submarine Canyon That Harbors Toxic Dinoflagellate Resting Cysts

Over the recent decades, an apparent worldwide rise in Harmful Algae Blooms (HABs) has been observed due to the growing exploitation of the coastal environment, the exponential growth of monitoring programs, and growing global maritime transport. HAB species like Alexandrium catenella—responsible for paralytic shellfish poisoning (PSP)—Protoceratium reticulatum, and Lingulaulax polyedra (yessotoxin producers) are a major public concern due to their negative socioeconomic impacts. The significant northward geographical expansion of A. catenella into more oceanic-influenced waters from the fjords where it is usually observed needs to be studied. Currently, their northern boundary reaches the 36°S in the Biobio region where sparse vegetative cells were recently observed in the water column. Here, we describe the environment of the Biobio submarine canyon using sediment and water column variables and propose how toxic resting cyst abundance and excystment are coupled with deep-water turbulence (10−7 Watt/kg) and intense diapycnal eddy diffusivity (10−4 m2 s−1) processes, which could trigger a mono or multi-specific harmful event. The presence of resting cysts may not constitute an imminent risk, with these resting cysts being subject to resuspension processes, but may represent a potent indicator of the adaptation of HAB species to new environments like the anoxic Biobio canyon.

Robust Natural Light-Absorbable and -Degradable AIE Photosensitizers for Fluorescence Labeling and Efficient Photodynamic Eradication of Algal Pollutants.

Current water pollution caused by the excessive proliferation of harmful algae urges green methods that can efficiently utilize natural light to treat algal pollution. Herein, a series of aggregation-induced emission (AIE) photosensitizers that can efficiently harness sunshine were synthesized for the environmentally friendly and biocompatible treatment of algal pollution. By tuning the number of thiophene units and the electron conjugation degree, the photosensitizers' absorptions were broadened to cover the whole visible light range. The positive charges guided photosensitizers to aggregate on algal cell surfaces, resulting in a turn-on fluorescence signal and robust reactive oxygen species generation under sunshine, thereby achieving fluorescence labeling and photodynamic eradication of algae. The eradication outcomes demonstrated that the AIE photosensitizers significantly outperformed the commercial algaecide ALG. At 20 ppm photosensitizers, 90.4% and 94.2% killing rates were achieved for C. reinhardtii and C. vulgaris, respectively, 2.8- and 3.6-fold higher than those from the same concentration of ALG. Excellent performances in inhibiting algae growth were also verified with efficiency superior to that of ALG. Importantly, the photosensitizers can self-degrade into biocompatible fragments under irradiation to avoid secondary pollution. The developed photosensitizers that possess sunshine convertibility and degradability provide an efficient tool for algal treatment, showing broad research and application prospects.

Expert insights on managing harmful algal blooms

Freshwater harmful algal blooms (HABs) are a global environmental, economic, social, and public health hazard. While there is an increasing understanding of the ecological considerations of HABs, there is limited understanding of human dimensions and management needs. We conducted semi-structured key informant interviews with 28 water managers and researchers to better understand how they perceive current management and to identify future management priorities in regard to HABs. For this study, we interviewed 31 key informants from three regions of the United States (New England, Ohio, and the Mountain West). We solicited insights across aspects of HABs management, including prevention, forecasting, monitoring, response, and communication. Nutrient management was the main consideration for the prevention of HAB events. Key informants noted that forecasting has the potential to be a valuable tool in the future but is not yet accurate enough at a local scale for widespread use. Monitoring was found to be implemented in varying ways across and even within the states and regions, with a need for more funding and standardization. HAB event responses vary greatly from chemical and physical treatments that suppress toxins to no-swim advisories, all with a mix of strengths and weaknesses. Finally, an increase in and improvement of communication efforts was identified as critical for reducing public health risks. These findings provide perceptions of current management practices and future plans while including opportunities to improve current freshwater HAB management efforts.

Chronic microcystin-leucine-arginine exposure induces osteoporosis by breaking the balance of osteoblasts and osteoclasts

Microcystin-leucine-arginine (MC-LR) produced by cyanobacterial harmful algal blooms are hazardous materials. However, the toxicity and mechanisms of continuous exposure to MC-LR on the occurrence of osteoporosis remains poorly documented. In this study, to mimic the chronic influences of MC-LR on the bone tissues in humans, an animal model was constructed in which mice were treated with MC-LR through drinking water at an environmentally relevant level (1–30 μg/L) for 6 months. MC-LR was enriched in the skeletal system, leading to the destruction of bone microstructure, the decrease of bone trabecular number, the reduction of osteoblasts, the enhanced content of lipid droplets, and the activation of osteoclasts, which is the characteristic of osteoporosis. Herein, we revealed ferroptosis is a vital mechanism of osteoblast death in mouse models of MC-LR. MC-LR exposure activates AMPK/ULK1 signaling, further promotes ferritin selective autophagy, causes free iron release and lipid peroxidation deposition, and eventually leads to ferroptosis of osteoblasts. Importantly, the use of AMPK or ferroptosis inhibitors in vivo markedly reduced MC-LR-induced osteoblast death and impaired osteogenic differentiation. Interestingly, MC-LR exposure promotes iron uptake in bone marrow macrophages through the TF-TFR1 pathway, leading to its transformation to TRAP-positive pre-osteoclast cells, thereby promoting bone resorption. Overall, our data innovatively revealed the core mechanism of MC-LR-induced osteoporosis, providing the bi-directional regulation of MC-LR on osteoblast-osteoclast from the perspective of iron homeostasis imbalance.

Ocean warming enhances the competitive advantage of Ulva prolifera over a golden tide alga, Sargassum horneri under eutrophication

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 Sargassum horneri under different temperatures (5, 10, 15, 20, 25, and 30°C) and two nutrient concentrations (Low nutrient, LN: 5 μM-nitrate and 0.5 μM-phosphate; High nutrient, HN: 500 μM-N and 50 μM-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.

Teleconnection Between Early Winter Monsoon System and Harmful Algal Blooms in Shallow Lake Taihu

AbstractThere is a long history of observation and monitoring at local scales with a focus on meteorological modulation of lakes, however, the features at the local scale are heavily influenced by large‐scale atmospheric circulation. Harmful algal blooms (HABs) in large shallow eutrophic lakes are susceptible to local meteorological conditions, but their response to climate system variability is rarely considered. This study reveals that HABs in Lake Taihu, the third largest freshwater lake in subtropical China, are promoted by the weakened East Asian monsoon system in precursory early winter, but show no response in late winter with the low temperature unfavorable for algal metabolism. The weak early winter monsoon system is characterized as the northward‐shifted polar front jet and eastward‐tilted East Asian Trough. The accompanied anomalous descending motion decelerates surface winds over the middle to lower reaches of the Yangtze River including Taihu basin by strengthening atmospheric stratification and decreasing turbulent activity in the lower troposphere. The weakened surface winds reduce sediment resuspension and improve underwater light availability in Lake Taihu, providing favorable light condition for phytoplankton growth. It is indicated that the early‐winter surface winds rather than simultaneous nutrient supply, play a dominant role on the interannual variability of algal biomass in Lake Taihu. The positive algal biomass anomaly in early winter tends to persist and promote HABs in the following warmer seasons. Our finding validates the interannual teleconnection between climate system and HAB variation in Lake Taihu, and provides insights on predicting HABs in subtropical East Asian shallow lakes.

Understanding the fouling characteristics in ultrafiltration membrane for marine algae-laden seawater pretreatment: Focus on the role of algal extracellular organic matter

The increasing frequency and extent of harmful algal blooms (HABs) due to global warming and environmental pollution pose significant challenges to the ultrafiltration (UF)-seawater reverse osmosis (SWRO) desalination process. The UF process is a dominant pretreatment method to reduce HAB fouling potential in subsequent SWRO processes. Herein, we systematically evaluate the UF membrane fouling characteristics at different growth phases of HAB algae in terms of reversible/irreversible fouling and pinpoint the fouling mechanisms on UF membranes in the real seawater matrix. We employed Prorocentrum donghaiense as a model marine HAB specie to characterize algal derivatives, including extracellular organic matter (EOM) and granule particles. LC-OCD, MFIs, 3D-EEM, and GPC were used to analyze algae-derived matters. Results from the multiple fouling model revealed that algal solution in both stationary and decline phases exhibit severe membrane fouling, characterized by rapid cake layer formation, swift flux decline, and high membrane resistance. Soluble EOM (S-EOM) was the primary contributor to membrane fouling, linked to its elevated concentrations of dissolved organic matters, polysaccharides, proteins, and humic substances, which are predominantly hydrophobic. Additionally, granule particles mitigated organic membrane fouling, as evidenced by the smaller permeate volume required for S-EOM cake layer formation (<5 mL), resulting in a faster initial flux decline. These results revealed a shift in released organic matter from protein-centric to humic substance-centric during the transition from exponential growth to the decline phase, with correlation analysis further underscoring the substantial contribution of humic substances to membrane resistance. This research highlights the distinct UF membrane fouling characteristics at different marine algal growth stages, offering theoretical support for predicting and managing HABs.

Temperature dependent sensitivity of the harpacticoid copepod Nitokra spinipes to marine algal toxins

Harmful algal blooms (HABs) – proliferated algae densities, often producing toxins – have increasingly been found in ocean and coastal areas. Recent studies show that rising temperatures contribute to HAB occurrence, but the broader influence of climate change on these outbreaks is less quantified. Of particular concern is the limited research on HAB toxin effects under varying temperatures, especially regarding primary consumers such as copepods, a crucial component of aquatic ecosystems. Therefore, we examined the impact of marine toxins on the harpacticoid copepod Nitokra spinipes, a model organism for marine ecotoxicology, in the context of climate change. We evaluated the toxicity of four purified, commonly occurring algal toxins, at three different temperatures in the laboratory. First, adult females were exposed to a concentration series of toxins at 15, 20, and 25 °C for 48 hours. EC50 values of domoic acid ranged from 8.79 ± 1.93 μg L-1 to 25.97 ± 11.96 μg L-1. Nauplii, aged 48 to 72 hours, were exposed at 18, 20 and 22 °C for the same duration. Less sensitive compared to adults, the EC50 of domoic acid in this case varied from 57.26 ± 6.82 μg L-1 to 97.24 ± 6.45 μg L-1. Both results indicated a temperature-dependent EC50. For the chronic toxicity tests, larval development ratio (LDR), brood size and inter-brood time of domoic acid (DA), yessotoxin (YTX), saxitoxin (STX), and microcystin-LR (MC-LR) were examined at 18, 20 and 22 °C. We observed that with increasing temperatures, LDR increased, whereas brood size significantly decreased as DA, YTX or STX concentrations rose. No interaction between temperature and algal toxins was found but a temperature dependent sensitivity of copepods towards DA, YTX and STX was revealed. Our research provides insights into the effects of long-term exposure to algal toxins on marine copepods and the potential impacts of climate warming.

Morphological and molecular characterization of two potentially toxigenic species of the genus Pseudo-nitzschia (Bacillariophyceae) in Luzon Island, Philippines

Harmful algal blooms are a major concern for the environment and industries like fisheries, healthcare, and tourism in coastal countries such as the Philippines. Blooms of diatoms (Bacillariophyceae) seldom cause harm, but half of the species in the cosmopolitan genus Pseudo-nitzschia produce the neurotoxin domoic acid. Only two published Pseudo-nitzschia surveys in the Philippines carried out morphology-based species identification. Molecular taxonomy has revealed a high level of cryptic diversity corresponding to minute morphological differences. This study sought to explore the diversity of and characterize the genus Pseudo-nitzschia in mariculture zones around Luzon Island using morphological and molecular information. Ten culture strains of Pseudo-nitzschia isolated from shellfish farms were used for morphological and molecular species identification. The secondary structure of the internal transcribed spacer 2 region revealed five strains from Pagbilao Bay to be most similar to P. brasiliana, the first record of this species in Luzon. Meanwhile, four Bacoor isolates and one from Pagbilao clustered within a monophyletic clade representing P. pungens, previously found in Manila Bay. Three single nucleotide polymorphisms and one hemi-compensatory base change were found among the P. pungens strains. Morphological characters, specifically cell shape, apex shape, and poroid density confirmed both species identities. Based on band striae, all P. pungens strains were of the nominal variety, P. pungens var. pungens. This study is among the first culture-based taxonomic studies of diatoms in the Philippines, in this case confirming the presence of harmful microalgae in the coastal ecosystems of the country.

Cyanophage-encoded auxiliary metabolic genes in modulating cyanobacterial metabolism and algal bloom dynamics

Cyanophages play a pivotal role in controlling cyanobacterial populations in aquatic environments. These dsDNA viruses harbor auxiliary metabolic genes (AMGs) that modulate the key metabolic processes of their cyanobacterial hosts, such as Photosynthesis, nutrient uptake for the optimization of viral replication. Recently, pan1~pan5 and pam1~pam5 cyanophages have been isolated from the fifth largest water resource in China; Lake Chaohu. Detailed genomic analysis of these phages revealed that these isolated cyanophages especially Pan1, Pam2 and Pam3 possess unique AMGs that significantly enhance the metabolic activities of their hosts, potentially leading to the suppression of bloom formation and stabilization of the ecological dynamics of Lake Chaohu. Our findings provide concrete evidence that cyanophages encoding AMGs could serve as effective biocontrol agents against harmful algal blooms, offering a targeted approach to manage these environmental threats. The integration of cyanophage-based management therapies with traditional methods could advance the efficiency and sustainability of controlling cyanobacterial outbreaks, paving the way for novel applications in water resource management. This review emphasizes the importance and critical need for further exploration of phage-host dynamics to fully harness the potential of cyanophages in ecosystem regulation.

Deep-learning and data-resampling: A novel approach to predict cyanobacterial alert levels in a reservoir

The proliferation of harmful algal blooms results in adverse impacts on aquatic ecosystems and public health. Early warning system monitors algal bloom occurrences and provides management strategies for promptly addressing high-concentration algal blooms following their occurrence. In this study, we aimed to develop a proactive prediction model for cyanobacterial alert levels to enable efficient decision-making in management practices. We utilized 11 years of water quality, hydrodynamic, and meteorological data from a reservoir that experiences frequent harmful cyanobacterial blooms in summer. We used these data to construct a deep-learning model, specifically a 1D convolution neural network (1D-CNN) model, to predict cyanobacterial alert levels one week in advance. However, the collected distribution of algal alert levels was imbalanced, leading to the biased training of data-driven models and performance degradation in model predictions. Therefore, an adaptive synthetic sampling method was applied to address the imbalance in the minority class data and improve the predictive performance of the 1D-CNN. The adaptive synthetic sampling method resolved the imbalance in the data during the training phase by incorporating an additional 156 and 196 data points for the caution and warning levels, respectively. The selected optimal 1D-CNN model with a filter size of 5 and comprising 16 filters achieved training and testing prediction accuracies of 97.3% and 85.0%, respectively. During the test phase, the prediction accuracies for each algal alert level (L-0, L-1, and L-2) were 89.9%, 79.2%, and 71.4%, respectively, indicating reasonably consistent predictive results for all three alert levels. Therefore, the use of synthetic data addressed data imbalances and enhanced the predictive performance of the data-driven model. The reliable forecasts produced by the improved model can support the development of management strategies to mitigate harmful algal blooms in reservoirs and can aid in building an early warning system to facilitate effective responses.

Harmful Microalgae Exhibit Broad Environmental Adaptability in High-Salinity Area Across the Dafengjiang River Estuary.

Harmful algal blooms (HABs) often occur in estuaries due to their unique environmental heterogeneity, posing significant environmental and human health risks. However, there is limited understanding of the community composition and community-level change points (thresholds) of harmful microalgae in subtropical estuaries. This study explored harmful microalgae community structure and thresholds in the Dafengjiang River estuary using a metabarcoding approach. The results revealed 63 harmful microalgae species, and major species included Guinardia flaccida, Prorocentrum cordatum, Thalassiosira punctigera, Pseudo-nitzschia galaxiae and T. gravida. Nonparametric change-point analysis and threshold indicator taxa analysis (TITAN) showed threshold responses of harmful microalgae community structure to ammonium (57.5-60 μg·L-1), total phosphorus (27.8-28.5 μg·L-1) and dissolved inorganic phosphorus (14.5-28 μg·L-1) along the salinity gradient. Wider environmental thresholds were also found in hypersaline areas. Additionally, Pyrodinium bahamense, Pfiesteria piscicida, Skeletonema tropicum and T. punctigera were sensitive to environmental changes and thus could be used as bioindicators. Overall, our study unveiled diverse abrupt transitions of harmful microalgal communities, providing a risk assessment for human health and ecological safety in subtropical estuary ecosystems.

White rot fungi as a multifaceted biocontrol agent: Metabolic disruption and algal inhibition in Microcystis aeruginosa

Microcystis aeruginosa is a prevalent cyanobacterium linked to water eutrophication and harmful algal blooms. While bacterial control strategies are well-studied, the effects of white rot fungi on Microcystis aeruginosa are less understood. This study examines the impact of whole fungal liquid, its centrifuged supernatant, and sterilized solutions on the algae’s physiological and biochemical traits. Metabolomics and multivariate analysis identified significant changes in 47 metabolic markers, including carbohydrates, amino acids, and fatty acids, across treatments. The complete fungal liquid exhibited the strongest algicidal effect, likely due to synergistic solubilization mechanisms mediated by extracellular enzymes such as manganese peroxidase, catalase, and laccase. Notably, algicidal activity persisted even after sterilization, suggesting the presence of non-proteinaceous compounds like polysaccharides or lipids. The metabolic disturbances included downregulation of the TCA cycle and reduced fatty acid synthesis, leading to inhibited photosynthesis and compromised nucleic acid integrity in the algal cells. This research enhances our understanding of how white rot fungi disrupt Microcystis aeruginosa metabolism, providing a theoretical basis for their potential use in bioremediation of eutrophic aquatic environments.

Climate warming effects on temperature structure in lentic waters: A bibliometric analysis from the recent 20 years

Global climate warming and intensified summer heatwaves have exacerbated thermal stratification in inland lakes and reservoirs, leading to increased issues of deep-water hypoxia and harmful algae blooms. This study aims to systematically review the developments, barriers, and future directions of thermal phenology in freshwaters under warming conditions through a visualized meta-analysis. According to the Web of Science Core Collection database, we retrieved 3262 articles published between January 1, 2000, and December 31, 2023, using an advanced search query that included terms related to global warming, temperature stratification, and freshwater bodies. The data was then analyzed via bibliometric visualization tools to create comprehensive visual maps, highlighting research hotspots and development trends. Key findings include a significant upward trend on this topic, in the annual number of published articles post-2015, in which China and the USA are leading in the publication output. Keyword co-occurrence analysis identified climate change, global warming, and temperature as central themes, with specific environmental issues linking to lake eutrophication and runoff being prominent as well. The study also delves into the collaboration networks among researchers, institutions, and countries, revealing strong international partnerships primarily between China, the USA, and European nations. Based on the analysis, we recommend future research should focus on integrating machine learning and advanced modeling techniques to better predict and mitigate the impacts of climate warming on thermal dynamics of inland waters. By upscaling the research from traditionally local (or regional) to global perspective, our work is vital, not just for science, but also for management of the aquatic systems under rapidly changing climate conditions.

Nanobubble-enabled foam fractionation to remove algogenic odorous micropollutants

Due to climate change and environmental pollution, natural lakes and reservoir water suffer increasingly serious algal blooms and associated water quality problems due to the presence of algal or algogenic organic matter (AOM) such as algal odour and toxins. Effective removal of these micropollutants, especially in the event of algal blooms, is critical to aesthetic values of water bodies, drinking water security and human health. The study investigated the removal efficiency of two common odorous compounds, trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-Methylisoborneol (2-MIB), using foam fractionation enabled by air nanobubbles with addition of two common cationic and anionic surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), to enhance foaming ability and stability. The results showed that the cationic surfactant (i.e., CTAB), a low pH, and high ionic strength significantly promoted the removal of geosmin and 2-MIB. For example, the removal tests using the synthetic water determined that the conditions of pH = 7, [CTAB] = 20 mg·L−1 and IS = 10 mM as NaCl resulted in both the highest geosmin removal rate of 91.81% and highest 2-MIB removal rate of 85.0%. The removal of two odorous compounds in real lake water was evaluated, which yielded removal rates of 83.2% for geosmin and 48.1% for 2-MIB, highlighting the minor inhibition from water matrixes on the removal performances. Compared to microbubbles, nanobubbles enabled greater surface areas of foam and higher removal efficiencies. The study provided new insights into the use of foam fractionation with air nanobubbles to enhance the removal of odorous compounds from impaired water and mitigate the negative environmental and health impacts of harmful algal blooms (HABs).

Defining algal bloom phenology in Lake Erie

Elucidating the impact of global climate change on aquatic ecosystems, particularly through phenological shifts in primary producers, is critical for understanding ecological resilience. Here, we focus on the phenological shifts in chlorophyll as a proxy for algae biomass and primary production in aquatic ecosystems, specifically in Lake Erie as well as concentrations of the toxin microcystin. By tracking temporal changes in each, we identified key phenological phases important to estimate duration, magnitude, and intensity of harmful algal blooms (HABs). Determining which influential biotic and abiotic factors such as temperature, wind speed, nutrient availability, and climate change is most important, is a long-term management need for Lake Erie, which can be explored using our methodology. Our novel statistical framework employing Bayesian generalized additive mixed models described seasonal chlorophyll and particulate microcystin concentration from Lake Erie and our simple geometric method identified the start, peak, and end of algal blooms. This research enhances our understanding of the ecological effects of nutrient pollution on aquatic ecosystems and provides a repeatable method for determining phenological events without the need for user defined cutoffs which aids in the management and mitigation of HABs, safeguarding water quality in regions dependent on lakes for drinking water.

Water-soluble polysaccharides extracted from Enteromorpha prolifera/PVA composite film functionalized as ε-polylysine with improved mechanical and antibacterial properties

The issue of environmental protection has received sustained and widespread attention. In order to reduce environmental pollution related to traditional plastics, it is an incessant demand to design novel environment-friendly food packaging materials with excellent performance. Sulfated polysaccharide extracted from the “green tide” marine pollution Enteromorpha prolifera (SPE) has been innovatively transformed into a film-forming material for better utilization. The insufficient mechanical properties and limited functionalities, however, hinder its wide application. In this study, polyvinyl alcohol (PVA) was blended to enhance its mechanical properties and ε-polylysine (ε-PL) was incorporated to endow it with antimicrobial performance. A novel and biodegradable film composed of SPE, PVA, and ε-PL was fabricated by casting method. We further determined the physicochemical properties of composited films. Mechanical performance test revealed the tensile strength of SPE-PVA-PL films increased from 5.56 MPa to 6.65 MPa and the E% increased from 128.8 % to 246.9 % compared with that of SPE-PVA films. Antimicrobial tests showed the excellent antibacterial activity of SPE-PVA-PL films against representative microbial species, Staphylococcus aureus and Escherichia coli. The results of this study suggested that the SPE-based composite film has the potential to be used as a potential food packaging and wound dressing materials.

Re-thinking human interactions with the oceans.

Earth's marine ecosystems are changing rapidly, in large part owing to the damaging effects of human activities. Unless humans find better ways of interacting with the seas and oceans, the marine resources upon which we rely will diminish as more ecosystems collapse. The consequences for human health and wellbeing will be severe. The meta-discipline of Oceans and Human Health has catalogued how the oceans and their constituents benefit human lives. Examples include access to seafood, pharmaceuticals and physical and mental health benefits. This interdisciplinary research effort has also revealed how the integrated impact of anthropogenic activities has disrupted ocean processes resulting in extensive losses of marine biodiversity, increasing chemical and microbial pollution, proliferation of harmful algal blooms and increased coastal inundation, all of which threaten human populations. In response, non-governmental organizations and national governments have established various agreements and treaties to prevent further damage, restore what has been lost and grasp new economic opportunities. Nevertheless, ocean-related risks continue to escalate rapidly in the absence of political commitment. New thinking regarding the interconnectedness of all human/ocean interactions is required to remove the barriers and impediments that hamper tackling the wicked problem of fostering health and wellbeing while achieving ocean sustainability.