Ultrafiltration (UF) is widely employed for harmful algae rejection, whereas severe membrane fouling hampers its long-term operation. Herein, calcium peroxide (CaO2) and ferrate (Fe(VI)) were innovatively coupled for low-damage removal of algal contaminants and fouling control in the UF process. As a result, the terminal J/J0 increased from 0.13 to 0.66, with Rr and Rir respectively decreased by 96.74 % and 48.47 %. The cake layer filtration was significantly postponed, and pore blocking was reduced. The ζ-potential of algal foulants was weakened from -34.4 mV to -18.7 mV, and algal cells of 86.15 % were removed with flocs of 300 µm generated. The cell integrity was better remained in comparison to the Fe(VI) treatment, and Fe(IV)/Fe(V) was verified to be the dominant reactive species. The membrane fouling alleviation mechanisms could be attributed to the reduction of the fouling loads and the changes in the interfacial free energies. A membrane fouling prediction model was built based on a long short-term memory deep learning network, which predicted that the filtration volume at J/J0= 0.2 increased from 288 to 1400 mL. The results provide a new routine for controlling algal membrane fouling from the perspective of promoting the generation of Fe(IV)/Fe(V) intermediates.

Lakes play a crucial role in the nitrogen (N) cycle, and eutrophication disrupts the balance of the nitrogen cycle within lakes, including both the N removal process and the N supplement process. However, the mechanisms by which different nutrient levels affect seasonal nitrogen variations in the water columns are not clear, especially for long-term and large- scale studies. In this study, we used 206 independent spatial samples from a total of 108 subtropical shallow lakes from four surveys in the middle and lower reaches of the Yangtze River, as well as time-case study data from Lake Taihu and Lake Donghu of up to 23 and 14 years, respectively, to analyze the changes in summer TN compared to spring (delta TN). Delta TN was significantly negatively correlated with initial spring TN concentrations, with similar trends observed in both space and time. Furthermore, the slopes of spring TN vs. delta TN varied little across lakes in both time and space, suggesting a consistent relationship between initial spring TN and summer TN changes. When initial TN or TN: TP ratio was low, N fixation by algae played a significant role in compensating for summer N removal, thus mitigating summer N reductions; when TN was high or TN: TP ratio was high, ammonia stress reduced the compensatory effect of algae and denitrification played a significant role in summer N removal, thus increasing summer N reductions. Our study suggested that no matter what the initial conditions are, lakes tend to evolve towards a common nutrient status through biological regulation.

Parabens, bisphenols (BPs), and triclosan (TCS) are common environmental phenols widely applied in industrial products, pharmaceuticals, and personal care products. They are endocrine disruptors and pervade the natural environment, causing significant detrimental impacts on ecosystems, including marine habitats. Therefore, in this study, 40 samples comprising coral polyps, algae, and sediments were collected from Sanya, Hainan Province, China, in which the presence and compositional profiles of parabens, BPs, and TCS were examined to identify their fate in the oceans. The results unveiled the ubiquitous occurrence of at least one paraben or bisphenol in all samples, with TCS detected in over 80% of cases. Notably, coral samples contained the most contaminants (median concentration: 9.42 ng/g dry weight-dw), followed by sediment samples (5.95 ng/g dw) and algal samples (3.58 ng/g dw). Attributed to their broadest application, methylparaben (MeP) and propylparaben (PrP) emerged as the primary paraben constituents. MeP displayed the highest median concentration in coral samples (4.42 ng/g dw), probably related to its high-water solubility and the filtration mechanism employed by the coral polyps during seawater intake. Intriguingly, bisphenol P (BPP) superseded bisphenol A (BPA) as the dominant bisphenol, especially in the algal samples, probably owing to the lipophilic character of BPP and the enhanced biodegradability of BPA within aquatic environments. The highest concentration of TCS (3.44 ng/g dw) was found in the sediment samples, associated with its long half-life in the sediments. Furthermore, the correlation between multiple parabens and TCS implies their co-use to augment antimicrobial efficacy. Future research should prioritize the examination of these phenols in diverse marine environmental media. Corresponding toxicological experiments should be conducted to visualize their transport dynamics, degradation byproducts, and toxicity to marine biota to gain insights into the risks they pose to the marine ecosystem.

The process of oxygenic photosynthesis is primarily driven by two multiprotein complexes known as photosystem II (PSII) and photosystem I (PSI). PSII facilitates the light-induced reactions of water-splitting and plastoquinone reduction, while PSI functions as the light-driven plastocyanin-ferredoxin oxidoreductase. In contrast to the highly conserved structure of PSII among all oxygen-evolving photosynthetic organisms, the structures of PSI exhibit remarkable variations, especially for photosynthetic organisms that grow in special environments. In this review, we make a concise overview of the recent investigations of PSI from photosynthetic microorganisms including prokaryotic cyanobacteria and eukaryotic algae from the perspective of structural biology. All known PSI complexes contain a highly conserved heterodimeric core; however, their pigment compositions and peripheral light-harvesting proteins are substantially flexible. This structural plasticity of PSI reveals the dynamic adaptation to environmental changes for photosynthetic organisms.

Lichens are dual organisms, with one major mycobiont and one major photobiont in each lichen symbiosis, which can survive extreme environmental conditions in the Arctic. However, the diversity and distribution of lichen photobionts in the Arctic remain poorly understood compared to their mycobiont partners. This study explored the diversity of lichen mycobionts and photobionts in 197 lichen samples collected from the Ny-Ålesund region (Svalbard, High Arctic). The nuclear ribosomal internal transcribed spacer (ITS) regions were sequenced and phylogenetic analyses were performed. The relationships between mycobionts and photobionts, as well as the association patterns, were also investigated. A total of 48 species of lichen mycobionts (16 families, nine orders) and 31 species/lineages of photobionts were identified. These 31 photobiont species belonged to one class (Trebouxiophyceae) and five genera, including 22 species of Trebouxia, five species of Asterochloris, two species of Chloroidium, one species of Symbiochloris, and one species of Coccomyxa. The results indicated that most analyzed lichen mycobionts could associate with multiple photobiont species, and the photobionts also exhibited a similar pattern. The results provided an important reference dataset for characterizing the diversity of lichen mycobionts and photobionts in the High Arctic region.

Algae and its extracts, widely consumed as functional foods, offer numerous health benefits; however, a comprehensive systematic summary of clinical evidence is currently lacking. The study was to assess the available evidence and provide an accurate estimate of the overall effects of algae and its extracts supplementation on various health outcomes. The comprehensive searches in PubMed, Scopus, Embase, Web of Science, and the Cochrane Library until December 22, 2023 were implemented. The random-effects model was employed to pool the overall effect sizes (ESs) and the corresponding 95% confidence intervals (CIs) using Stata software. Moreover, detecting the methodological quality and evidence level of the eligible studies were employed by A Measurement Tool to Assess Systematic Review 2 (AMSTAR2) and the Grading of Recommendations Assessment Development and Evaluation. Ultimately, 25 articles covering 133 health outcomes were included in this umbrella review. The pooled results demonstrated that the algae and its extracts could significantly decrease body weight (ES = -1.65; 95% CI: -1.97, -1.34; p < 0.001), body mass index (BMI) (ES = -0.42; 95% CI: -0.78, -0.07; p = 0.020), waist circumference (WC) (ES = -1.40; 95% CI: -1.40, -1.39; p < 0.001), triglyceride (TG) (ES = -1.38; 95% CI: -2.15, -0.62; p < 0.001), total cholesterol (TC) (ES: -1.40; 95% CI: -2.09, -0.72; p < 0.001), very low-density lipoprotein cholesterol (VLDL-C) (ES = -7.85; 95% CI: -8.55, -7.15; p < 0.001), fasting blood glucose (ES = -2.68; 95% CI: -4.57, -0.79; p = 0.005), glycated hemoglobin (HbA1c) (ES = -0.15; 95% CI: -0.24, -0.07; p < 0.001), systolic blood pressure (ES = -3.21; 95% CI: -5.25, -1.17; p = 0.002), diastolic blood pressure (ES = -3.84; 95% CI: -7.02, -0.65; p = 0.018), alanine transaminase (ES = -0.42; 95% CI: -0.70, -0.14; p = 0.003), and alkaline phosphatase (ES = -0.54; 95% CI: -0.99, -0.10; p = 0.017). Due to the limited number of studies, no benefit was displayed on markers of inflammation and oxidative stress. Considering the suboptimal quality of studies and the insufficient articles pertaining to certain outcomes, further well-designed research is imperative to substantiate the observed findings.

As an important emerging pollutant, the fate of microplastics (MPs) in ecosystems is of growing global concern. In addition to hydrodynamics and animals, algae can also affect the transport of MPs in aquatic environments, which could potentially remove MPs from the water column. Although researchers have conducted many studies on the sink of MPs regulated by algae in both marine and freshwater environments, there is still a lack of comprehensive understanding coupled with the increasingly scattered study contents and findings. This review aims to provide a systematic discussion of the processes, mechanisms, and influencing factors, which are coupled with the sink of MPs changes by algae. The main processes identified include retention, flocculation, deposition, and degradation. The retention of MPs is achieved by adhesion of MPs to algae or embedment/encrustation of MPs within the epibiont matrix of algae, thereby preventing MPs from migrating with water currents. The extracellular polymeric substances (EPS) and enzymes produced by algal metabolic activities can lead not only to the formation of aggregates containing MPs but also to the biodegradation of MPs. The processes that algae alter the fate of MPs in aquatic environments are very complex and can be influenced by various factors such as algal attributes, microplastic characteristics and environmental conditions. This review provides insights into recent advances in the fate of aquatic MPs and highlights the need for further research on MPs-algae interactions, potentially shortening the knowledge gap in the sink of MPs in aquatic ecosystems.

This study developed a microelectrolysis-integrated constructed wetland with pyrite filler around the cathode (e-PCW) to treat eutrophic water. Results indicated that e-PCW effectively enhanced pyrite dissolution, converting solid-phase electron donors into bioavailable forms, thereby facilitating the enrichment of various denitrifying bacteria on pyrite surfaces. Importantly, iron-reducing and sulfur-reducing bacteria attached to the pyrite surfaces enhanced the conversion of ferric iron and sulfate, thereby driving iron and sulfur cycles and promoting electron transfer. Therefore, synergistic effects of pyrite and microelectrolysis made e-PCW achieve higher total nitrogen (TN) and total phosphorus (TP) removal efficiencies. With a hydraulic retention time of 24 h, the highest removal efficiencies of TN and TP achieved 78% and 75%, respectively. Furthermore, when eutrophic water containing high concentration of algae was fed into e-PCW, it consistently demonstrated superior TN and TP removal capabilities. This work provides a valuable approach to optimizing constructed wetland technology for treating eutrophic water.

Microbial manganese (Mn) oxidation, predominantly occurs within the anaerobic-aerobic interfaces, plays an important role in environmental pollution remediation. The anaerobic-aerobic transition zones, notably riparian and lakeside zones, are hotspots for algae-bacteria interactions. Here, we adopted a Mn(II)-oxidizing bacterium Pseudomonas sp. QJX-1 to investigate the impact of algae on microbial Mn(II) oxidation and verify the underlying mechanisms. Interestingly, we achieved a remarkable enhancement in bacterial Mn(II)-oxidizing activity within the algae-bacteria co-culture, despite the inability to oxidize Mn(II) for the algae used in this study. In addition, the bacterial density almost remains constant in the presence of algal cells. Therefore, the increased Mn(II) oxidation by QJX-1 in the presence of algae cannot be due to the increased biomass. Within this co-culture system, the Mn(II) oxidation rate surged to an impressive 0.23 mg/L/h, in stark contrast to 0.02 mg/L/h recorded within pure QJX-1 system. The presence of algae could inhibit the Fe-S cluster activity of QJX-1 by the produced active substance in co-culture, and result in the acceleration of extracellular superoxide production due to the impairment of electron transfer functions located in QJX-1 cell membranes. Moreover, elevated peroxidase gene expression and heightened extracellular catalase activity not only expedited Mn(II) ions oxidation but also facilitated conversion of intermediate Mn(III) ions into microbial Mn oxides, achieved through the degradation of hydrogen peroxide. Therefore, the acceleration of extracellular superoxide production and the decomposition of hydrogen peroxide are identified as the principal mechanisms behind the observed enhancement in Mn(II) oxidation within algae-bacteria co-cultures. Our findings highlight the need to consider the effect of algae on microbial Mn(II) oxidation, which plays an important role in the environmental pollution remediation.

Microplastics (MPs) and pharmaceuticals and personal care products (PPCPs) are ubiquitous in aquatic environments. Algae play an important role in aquatic environments. Thus, it is important to study the response of algae to combined exposure of MPs and PPCPs. Here, we review the effects of MPs and PPCPs on algae. First, the individual effects of MPs and PPCPs on algae were summarized. Second, the combined effects of MPs and PPCPs on algae were systematically analyzed. (1) Antagonism: ① when the MPs are too large to enter the algal cells, the adsorption of PPCPs onto MPs results in decreased the contact of MPs and PPCPs with algae; ② PPCPs and MPs have opposing actions on the same biological target; ③ MPs increase the activity of metabolic enzymes in algae, thus promoting the PPCP degradation. (2) Synergy: ① when the MPs are small enough to enter algal cells, the adsorption of PPCPs on MPs promotes the entry of PPCPs; ② when MPs are negatively charged, the adsorption of positively charged PPCPs by MPs decreases the electrostatic repulsion, increasing the interaction between algae and MPs; ③ complementary modes of action between MPs and PPCPs show combined effects on the same biological target. Third, the relative importance of the factors that impact the combined effects are evaluated using the random forest model decreased in the following order: PPCP types > algal species > MP size > MP concentration > MP types > exposure time. Finally, future directions for the combined effects of MPs and PPCPs are proposed, which will facilitate a better understanding of the environmental fate and risks of both MPs and PPCPs.