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Plastic waste, especially positively buoyant polymers known as polyolefins, are a major component of floating debris in the marine environment. While plastic colonisation by marine microbes is well documented from environmental samples, the succession of marine microbial community structure over longer time scales (> > 1 month) and across different types and shapes of plastic debris is less certain. We analysed 16S rRNA and 18S rRNA amplicon gene sequences from biofilms on polyolefin debris floating in a flow-through seawater tank in Hawaii to assess differences in microbial succession across the plastic types of polypropylene (PP) and both high-density polyethylene (HDPE) and low-density polyethylene (LDPE) made of different plastic shapes (rod, film and cube) under the same environmental conditions for 1 year. Regardless of type or shape, all plastic debris were dominated by the eukaryotic diatom Nitzschia, and only plastic type was significantly important for bacterial community structure over time (p = 0.005). PE plastics had higher differential abundance when compared to PP for 20 bacterial and eight eukaryotic taxa, including the known plastic degrading bacterial taxon Hyphomonas (p = 0.01). Results from our study provide empirical evidence that plastic type may be more important for bacterial than eukaryotic microbial community succession on polyolefin pollution under similar conditions.

The growing concerns regarding foodborne illnesses related to fresh produce accentuate the necessity for innovative material solutions, particularly on surfaces that come into close contact with foods. This study introduces a sustainable, efficient, and removable antimicrobial and antifouling coating ideally suited for hydrophobic food-contact surfaces such as low-density polyethylene (LDPE). Developed through a crosslinking reaction involving tannic acid, gelatin, and soy protein hydrolysate, these coatings exhibit proper stability in aqueous washing solutions and effectively combat bacterial contamination and prevent biofilm formation. The unique surface architecture promotes the formation of halamine structures, enhancing antimicrobial efficacy with a rapid contact killing effect and reducing microbial contamination by up to 5 log10 cfu·cm-2 against both Escherichia coli (Gram-negative) and Listeria innocua (Gram-positive). Notably, the coatings are designed for at least five recharging cycles under mild conditions (pH6, 20 ppm free active chlorine) and can be easily removed with hot water or steam to refresh the depositions. This removal process not only conveniently aligns with existing sanitation protocols in the fresh produce industry but also facilitates the complete eradication of potential developed biofilms, outperforming uncoated LDPE coupons. Overall, these coatings represent sustainable, cost-effective, and practical advancements in food safety and are promising candidates for widespread adoption in food processing environments.

This study is on fly ash (FA) concrete admixed with TiO2 nanoparticles (FAT), CaCO3 nanoparticles (FAC), and an equal ratio of TiO2 and CaCO3 nanoparticles (FATC) were exposed to seawater for 365 days in order to find the attachment of macrofoulants on their surface. The pH reduction studies were carried out in order to determine concrete deterioration in seawater, the results showed that FA specimens had more pH reduction than FAT, FAC and FATC. Total viable count, epifluorescence microscopy and denaturing gradient gel electrophoresis (DGGE) analysis confirmed the intensity of bacterial attachment and its diversity on FA, FAT, FAC, and FATC specimens. A systematic and comparative analysis predicted the overall relationship in terms of the dominant bacterial species on the different fly ash concrete specimens. To determine the biodeterioration of the fly ash concrete specimens in seawater, we used thermography experiments to evaluate the regions affected by bacteria on mortar specimens and confirmed that FA and FAC had more degradation and that FAT and FATC were the least degraded. Laser Raman Spectroscopy was interesting to find the white micron-sized particles of sulphur on FAC, FAT, and FATC specimens after 365 days immersed in seawater. We used a confocal laser scanning microscope to estimate the thickness of biofilm growth on FAT (13.91 0.38 mm), FATC (21.64 0.22 mm), FAC (33.56 0.26 mm), and FA (43.36 0.10 mm) specimens. The results showed that FAT and FATC specimens were the superior specimens, with enhanced biofouling and biodeterioration resistance in a seawater environment. Practical Applications: Fly ash is a waste material from thermal power plants and is used as a supplementary cementitious material in the construction industry. However, fly ash concrete has a slow hydration process and early strength problems. To overcome these problems, we used TiO2 and CaCO3 nanoparticles to enhance the properties of fly ash concrete. Nanoparticles have a high surface area and unique functional properties such as maintaining concrete pH, reducing porosity, enhancing pozzolanic activity, and so forth. In this study, we used TiO2 and CaCO3 nanoparticles to improve the strength of fly ash concrete and provide it with antibacterial properties. This study is significant in advancing our knowledge of fly ash concrete modified with nanoparticles and exposed to seawater with respect to its mechanical properties, durability, and antibacterial properties. Addition of nanoparticles upgraded the fly ash concrete towards its practical applications. [ABSTRACT FROM AUTHOR]

The antifouling potential of crude organic extracts from five seaweed species collected at the Rameswaram coastal region at Pamban station, Tamil Nadu, has been screened for antifouling activity. Five different species of seaweeds such as two Chlorophyceae (Ulva fasciata and Halimeda tuna), one Rhodophyceae (Portieria hornemanni), and two Phaeophyceae (Padina boergesenii and Turbinaria ornata) did not exhibit fouling inhibition. From the marine macroalgae that displayed antifouling activity, P. hornemanni has shown better results when compared to that of other species. The seaweed extracts were tested in laboratory assays against the marine fouling bacteria's such as B. mycoides, B. fluxes, B. cereus, B. vietnamensis, and P. stutzeri. The GC–MS profile of P. hornemanni suggested the purified fraction is primarily composed of a total of 15 compounds recorded. The maximum byssal thread inhibition of the green mussel Perna viridis was inhibited by the methanol and chloroform extract of P. hornemannii, and the methanol extract of the MIC was found to be 154 8.07 g/ml, followed by EC50 73 ± 3.54 g/ml, respectively. The MIC was determined to be 124 ± 6.54 g/ml in chloroform extract, while the EC50 was determined to be 59 ± 6.74 g/ml. The phytochemical constituents were recorded in methanol extracts except for glycosides and tannins, and the results showed that alkalods, flavnoids, terpenoids, triterpenes, and phenols were found to be 116.6, 72.54, 97.12, 66.34, and 99.78 µg/mg respectively. Which could have a functional role in the chemical defense against marine fouling organisms, and it could be utilized for the improvement of ideal antifoulants in the future. [ABSTRACT FROM AUTHOR]

In contrast to expectations, even buoyant microplastics like polyethylene and polypropylene are found at high concentrations in deep sediment traps and deep-sea sediments. To explain the presence of such buoyant microplastic particles at great ocean depths, several vertical transport mechanisms are under discussion with biofouling as one of the most referred. Biofouling is thought to increase the density of microplastic particles to the point that they sink to the deep sea, but this has mostly been shown on large microplastic particles ≥ 1 mm. However, although microplastics are defined as particles between 1 and 5000 μm, most microplastics are < 100 μm. In the ocean plastic particles continuously fragment, converting each "large" particle into several "small" particles, and particle abundance increases drastically with decreasing size. We argue that biofouling is not a reasonable transport mechanism for small microplastic particles ≤ 100 μm, which form the majority of microplastics. Biofilm density depends on its community and composition. A biofilm matrix of extracellular polymeric substances and bacteria has a lower density than seawater, in contrast to diatoms or large organisms like mussels or barnacles. We suggest that a small microplastic particle cannot host a biofilm community consisting of the heavy organisms required to induce sinking. Furthermore, to reach the deep sea within a reasonable timespan, a microplastic particle needs to sink several meters per day. Therefore, the excess density has to not only exceed that of seawater, but also be large enough to enable rapid sinking. We thus argue that biofouling cannot be an efficient vertical transport mechanism for small microplastic. However, biofouling of small microplastic may promote the likelihood of its incorporation into sinking marine snow and increase the probability of its ingestion, allowing its transport to depth. [ABSTRACT FROM AUTHOR]

Gill disease is a major threat to aquaculture of Atlantic salmon, with an unknown and likely underestimated contribution from cnidarians such as jellyfish and biofouling hydroids. To better understand the risk and thus enable mitigation, technology for the certain identification of cnidarian-related gill damage is needed. We used the hydroid Ectopleura larynx in a case study to determine whether the exposure of salmon to nematocyst-bearing hydrozoans can be deducted via non-destructive PCR-based methods. In a field experiment, we evaluated (i) whether swabbing the inside of the gill operculum in farmed Salmo salar and subsequent PCR analysis can provide quantifiable information about the presence of E. larynx material in the gill chamber and, if so, (ii) whether the screening results correlate with histological assessments of gill damage. The developed PCR methods were able to detect the presence of biofouling hydroids in ambient water. However, despite exposure to suspended hydroid particle concentrations that did result in gill damage in some salmon, quantitative PCR results did not correlate with histological gill assessments. For opercular swabs to serve as a diagnostic tool for detecting biofouling-mediated gill damage in live salmon, increased specificity of genetic markers and improved sampling methods are needed. Animal trial permit no. 24252 (granted 06.07.2020, Norwegian Food Safety Authority). [ABSTRACT FROM AUTHOR]

Biofouling, the accumulation of marine organisms on submerged surfaces, presents significant operational challenges across various marine industries. Traditional detection methods are labor intensive and costly, necessitating the development of automated systems for efficient monitoring. The study presented in this paper focuses on detecting biofouling on tidal stream turbine blades using camera-based monitoring. The process begins with dividing the video into a series of images, which are then annotated to identify and select the bounding boxes containing objects to be detected. These annotated images are used to train YOLO version 8 to detect biofouled and clean blades in the images. The proposed approach is evaluated using metrics that demonstrate the superiority of this YOLO version compared to previous ones. To address the issue of misdetection, a data augmentation approach is proposed and tested across different YOLO versions, showing its effectiveness in improving detection quality and robustness. [ABSTRACT FROM AUTHOR]

To improve the durability of the photobioreactor antibiofouling surface for microalgal cultivation, a series of photoreactive poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) were successfully synthesized and used to modify ethylene-vinyl acetate (EVA) films by a surface coating and UV light grafting method. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy analysis (XPS) and fluorescence microscopy results indicated that PTFEMA were fixed successfully onto the EVA film surface through a covalent bond. During the microalgal adhesion assay, the number of EVA-PTFEMA film-adhered microalgae was 41.4% lower than that of the EVA film. Moreover, the number of microalgae attached to the EVA-PTFEMA film decreased by 61.7% after cleaning, while that of EVA film decreased by only 49.1%. It was found that the contact angle of EVA-PTFEMA film surface increased, and remained stable when immersed in acid and alkali solution for up to 90 days. HIGHLIGHTS: Durable photobioreactor antibiofouling surfaces for microalgal cultivation were prepared successfully. The contact angle of antibiofouling coating surface remained stable in acid and base environment for 90 days. The attached microalgae on antibiofouling surface decreased 41.4% than those of unmodified surface. The attached microalgae on antibiofouling surface could be cleaned by 61.7% through changing the flow velocity of microalgal suspension. [ABSTRACT FROM AUTHOR]

The hormone Neuropeptide Y (NPY) plays critical roles in feeding, satiety, obesity, and weight control. However, its complex peptide structure has hindered the development of fast and biocompatible detection methods. Previous studies utilizing electrochemical techniques with carbon fiber microelectrodes (CFMEs) have targeted the oxidation of amino acid residues like tyrosine to measure peptides. Here, we employ the modified sawhorse waveform (MSW) to enable voltammetric identification of NPY through tyrosine oxidation. Use of MSW improves NPY detection sensitivity and selectivity by reducing interference from catecholamines like dopamine, serotonin, and others compared to the traditional triangle waveform. The technique utilizes a holding potential of −0.2 V and a switching potential of 1.2 V that effectively etches and renews the CFME surface to simultaneously detect NPY and other monoamines with a sensitivity of 5.8 ± 0.94 nA/µM (n = 5). Furthermore, we observed adsorption-controlled, subsecond NPY measurements with CFMEs and MSW. The effective identification of exogenously applied NPY in biological fluids demonstrates the feasibility of this methodology for in vivo and ex vivo studies. These results highlight the potential of MSW voltammetry to enable fast, biocompatible NPY quantification to further elucidate its physiological roles. [ABSTRACT FROM AUTHOR]

Commercial shipping activity plays a crucial role in the unintentional primary and secondary introduction of aquatic Non-Indigenous species (NIS), with ballast water (BW) and hull biofouling being the two major vectors of NIS transportation. The aim of this study is to identify potential high-risk donor port areas that may act as pools for NIS introduction in Saronikos Gulf, Greece. For the purpose of the study, we conducted a regional risk assessment and produced a NIS watch list based on the commercial vessel arrivals at the major ports of the Saronikos Gulf (Piraeus and Elefsis) for the period 2020–2022. In our risk analysis, we used the two most important factors for ship-mediated species introductions identified in the literature: salinity and biogeographic region of the voyage last origin ports. Then, combined with data on vessel arrivals, based on marine traffic data collected from the Marine Traffic online platform, we produced a NIS watch list for the study area. The most highrisk ports for primary introductions were found to be in the Temperate Northern Atlantic (e.g. Gemlik, Ambarli, Asyaport and Derince in Türkiye, Sines in Portugal), Western Indo-Pacific (e.g. Jeddah in Saudi Arabia, Aqaba in Jordan) and the Central Indo-Pacific (e.g. Singapore). For secondary introduction, the most high-risk voyage origin ports are located in the Levantine Sea (e.g. Limassol in Cyprus, Alexandria and Port Said in Egypt, Haifa and Ashdod in Israel, Iskenderun, Mersin and Nemrut in Türkiye), the Aegean Sea (e.g. Izmir in Türkiye) and the Ionian Sea (e.g. Marsaxlokk in Malta). Our watch list included 44 high risk and 13 medium risk NIS to be transferred to Saronikos Gulf. Of these, 38 high-risk species are already present in the Mediterranean, 6 high-risk species are absent from the Mediterranean and 18 species pose a high risk for both primary and secondary introduction. [ABSTRACT FROM AUTHOR]

Antifouling paint was introduced and utilized as a control to prevent the problem of biofouling. The Methanolic Crude Extract (MCE) and the Essential Oil (EO) were extracted from Melaleuca cajuputi. Gas Chromatography-Mass Spectrometry (GC-MS) was used to determine the metabolite profiles. An antibacterial assay was conducted via the disc diffusion technique and an antifouling assay of MCE and EO of M. cajuputi was investigated using a crystal violet assay and painted steel panels incorporating MCE and EO. Painted steel panels were immersed in the aquarium to measure the antibiofilm activity and in the natural sea environment to observe the settlement of foulers. The MCE exhibits antibacterial activity against Gram-negative bacteria, indicating narrow-spectrum activity, while EO has broad-spectrum activity against Gram-positive and −negative bacteria. The GC-MS profile showed the presence of cycloheptasiloxane, tetradecamethyl-, cyclotrisiloxane, hexamethyl-, terpinene-4-ol, caryophyllene, and 1,8-cineole in both MCE and EO of M. cajuputi. Crystal violet assay revealed that both samples reduced the attachment of biofilm form by Pseudomonas aeruginosa at 61% and 60%. Panel painted with paint incorporated 5% MCE inhibits bacteria growth in natural seawater, followed by 10% MCE, 5% EO, and 10% EO in aquarium testing. Referring to photographic observation, all the panels coated with paint incorporated with samples successfully reduced the attachment of foulers compared to Blank Paint (BP). In conclusion, these findings indicated that the MCE and EO of M. cajuputi could potentially be used as a substitute for toxic antifoulants to prevent the formation of microfoulers. [ABSTRACT FROM AUTHOR]

Hull fouling by marine organisms is a known major pathway for introducing non-indigenous species, but information on this process is very limited. This study aimed to investigate variations in species diversity and distribution patterns based on navigation type (domestic–international and international) and attachment area. This study investigated the attached macroinvertebrates on six ships in 2021 and 2022. Quadrat sampling (15 × 15 cm) was conducted by scuba divers at eight ship attachment areas. Forty species from seven phyla were identified through qualitative and quantitative surveys, with 17 attached species, including 10 non-indigenous species (NIS). Dominant species included Balanus trigonus, Amphibalanus amphitrite, and Bugula neritina. Cluster and non-metric multidimensional scaling analyses (nMDS) revealed four distinct groups based on species density, with significant differences between domestic–international and international ships. Statistical analyses indicated significant differences in species number, density, richness, and diversity index among groups, with Group D showing the highest values. The study emphasized international ships as primary introducers of NIS. Unique findings included differences in biofouling based on ship shape, antifouling paint conditions, and speed, highlighting the need for tailored management strategies based on navigation type and attachment area. This study urges further research to explore differences in attachment areas and emphasizes the importance of obtaining more information about ships for effective management. [ABSTRACT FROM AUTHOR]

For the marine industry biofouling has a negative reputation. On ship hulls, the accumulation of these unwanted plants and animals can lead to increased drag, fuel consumption, and greenhouse gas emissions. Offshore platforms are also subject to biofouling which can result in corrosion and hydrodynamic loading, thus shortening their lifespan. While the harmful impacts of biofouling are commonly reported throughout the literature, biofouling can also benefit both aquatic and human populations. Common biofouling organisms act as natural filtration systems, thus improving water quality. Many of the same flora and fauna serve as a food source, and structures could be designed to lessen the impacts of fouling on hydrodynamic forces. In addition, microfouling species commonly found in biofilms have the potential to be harnessed as biofuel sources and can be a component of the carbon cycle. The following review discusses the benefits of biofouling and why ecological engineering initiatives may aid in ecosystem restoration versus the use of antifouling techniques for preventative growth. [ABSTRACT FROM AUTHOR]

The current scenario of antifouling (AF) strategies to prevent the natural process of marine biofouling is based in the use of antifouling paints containing different active ingredients, believed to be harmful to the marine environment. Compounds called booster biocides are being used with copper as an alternative to the traditionally used tributyltin (TBT); however, some of them were recently found to accumulate in coastal waters at levels that are deleterious for marine organisms. More ecological alternatives were pursued, some of them based on the marine organism mechanisms' production of specialized metabolites with AF activity. However, despite the investment in research on AF natural products and their synthetic analogues, many studies showed that natural AF alternatives do not perform as well as the traditional metal-based ones. In the search for AF agents with better performance and to understand which molecular motifs were responsible for the AF activity of natural compounds, synthetic analogues were produced and investigated for structure–AF activity relationship studies. This review is a comprehensive compilation of AF compounds synthesized in the last two decades with highlights on the data concerning their structure–activity relationship, providing a chemical toolbox for researchers to develop efficient nature-inspired AF agents. [ABSTRACT FROM AUTHOR]

Abstract This study investigated the modification of polyethersulfone (PES) ultrafiltration membranes with TiO2 and Fe2O3–TiO2 nanoparticles to enhance their hydrophilicity and biofouling resistance against the marine microalgae Chlorella vulgaris. It is a common freshwater and marine microalga that readily forms biofilms on membrane surfaces, leading to significant flux decline and increased operational costs in ultrafiltration processes. The microalgae cells and their extracellular polymeric substances (EPS) adhere to the membrane surface, creating a dense fouling layer that impedes water permeation. The modified membranes were characterized using contact angle measurements, scanning electron microscopy, and pure water flux/resistance tests. Short-term ultrafiltration experiments evaluated the membranes’ antifouling performance by measuring flux decline, flux recovery ratio, and relative flux reduction during C. vulgaris filtration. The TiO2 membrane showed improved hydrophilicity and antifouling over the pristine PES membrane, while the Fe2O3–TiO2 nanocomposite membrane exhibited the best performance. It reduced the water contact angle and showed only a 5% relative flux reduction compared to 60% for the pristine membrane. SEM images confirmed reduced microalgal deposition on the nanocomposite surface. Long-term tests with microalgal cells under dark and visible light conditions in saline water further assessed the membranes’ biofouling resistance. The Fe2O3–TiO2 membrane maintained 59 L/m2 h water flux under visible light after immersion in the microalgal solution, outperforming the pristine (38 L/m2 h) and TiO2 (52 L/m2 h) membranes. This superior antifouling was attributed to photocatalytic generation of reactive oxygen species inhibiting microalgal adhesion. This study demonstrates a promising strategy for mitigating biofouling in membrane-based water treatment and desalination processes.

Abstract In contrast to expectations, even buoyant microplastics like polyethylene and polypropylene are found at high concentrations in deep sediment traps and deep-sea sediments. To explain the presence of such buoyant microplastic particles at great ocean depths, several vertical transport mechanisms are under discussion with biofouling as one of the most referred. Biofouling is thought to increase the density of microplastic particles to the point that they sink to the deep sea, but this has mostly been shown on large microplastic particles ≥ 1 mm. However, although microplastics are defined as particles between 1 and 5000 μm, most microplastics are

For the marine industry biofouling has a negative reputation. On ship hulls, the accumulation of these unwanted plants and animals can lead to increased drag, fuel consumption, and greenhouse gas emissions. Offshore platforms are also subject to biofouling which can result in corrosion and hydrodynamic loading, thus shortening their lifespan. While the harmful impacts of biofouling are commonly reported throughout the literature, biofouling can also benefit both aquatic and human populations. Common biofouling organisms act as natural filtration systems, thus improving water quality. Many of the same flora and fauna serve as a food source, and structures could be designed to lessen the impacts of fouling on hydrodynamic forces. In addition, microfouling species commonly found in biofilms have the potential to be harnessed as biofuel sources and can be a component of the carbon cycle. The following review discusses the benefits of biofouling and why ecological engineering initiatives may aid in ecosystem restoration versus the use of antifouling techniques for preventative growth.

Biofouling constitutes one of the main obstacles in the sector of shellfish farming. Under this perspective, it is of highly importance to critically combine the updated information regarding the invasive potential of ascidian species, together with the factors contributing toward these events. The biological features of each species in relation to the gathering of the main non-indigenous species in the Mediterranean basin represent the first step toward mitigation of negative effects of the phenomenon. Further, there are limited studies investigating the physiological changes of bivalves caused by biofouling while leading to an increase in stress biomarkers. In the present review, the major ascidian species negatively affecting bivalve culture in the Mediterranean Sea are presented, alongside monitoring of ascidians from four Greek mussel farming locations as typical mussel culture cases. Among the main ascidian species, Styela plicata, Clavelina oblonga, Ciona robusta, Aplidium sp., Didemnum sp., Botryllus schlosseri, and Didemnum drachi are included, with the last three being the most harmful for this aquaculture sector. Based on the existing literature and research conducted so far, future research directions are proposed, in an effort to effectively control or efficiently manage ascidian biofouling organisms. Overall, perspectives toward the way we manage the biofouling phenomenon, such as the use of ascidian’s by-products in feedstuffs, chemical and pharmaceutical industry, or their incorporation in bivalve co-culture and integrated multi-trophic aquaculture systems represent promising alternative approaches.

Abstract A comprehensive multi-analytical investigation was conducted on a piece of Longquan celadon excavated from the Shengbeiyu shipwreck site in the East China Sea. This study focused on a representative type of tubular bio-concretions attached to the submerged celadon, believed to have been formed through the construction activities of a marine tubeworm belonging to the benthic phylum of Polychaeta Annelids. The research examined the microstructure, composition and adhesion form of these tubular bio-concretions, aiming to elucidate their developmental and attachment patterns from a biomineralization and biofouling perspective. The tubular bio-concretions were found to have a bimineralic composition, with notably higher content of aragonite than calcite, and display diverse yet highly ordered microstructures. The presence of organic matter within the bio-concretions indicates an organic matrix-controlled crystallization model, commonly observed in the construction of benthic calcareous tubes. Microscopic analyses revealed the primary degradation microstructures and corresponding phases of the glaze to which calcareous tubes attached. These findings closely resembled the corrosion characteristics observed in submerged ceramic glaze without bio-concretion attachments, as documented in earlier studies. OM and SEM observations also indicated that the calcareous tubes intricately intermeshed with the cracked glaze layer of the celadon. Additionally, Raman spectroscopic analysis detected the presence of proteins at the interface, likely residual adhesives secreted by fouling organisms to cement themselves to the settlement substrata, suggesting the occurrence of organic-mediated bio-adhesion mechanisms. These results shed new light on the formation process of bio-concretions and their interaction with attached underwater ceramics. A simplified formation mechanism of this biologically-induced degradation has been discussed.

Low‐input proteomics, also referred to as micro‐ or nanoproteomics, has become increasingly popular as it allows one to elucidate molecular processes in rare biological materials. A major prerequisite for the analytics of minute protein amounts, e.g., derived from low cell numbers, down to single cells, is the availability of efficient sample preparation methods. Digital microfluidics (DMF), a technology allowing the handling and manipulation of low liquid volumes, has recently been shown to be a powerful and versatile tool to address the challenges in low‐input proteomics. Here, an overview is provided on recent advances in proteomics sample preparation using DMF. In particular, the capability of DMF to isolate proteomes from cells and small model organisms, and to perform all necessary chemical sample preparation steps, such as protein denaturation and proteolytic digestion on‐chip, are highlighted. Additionally, major prerequisites to making these steps compatible with follow‐up analytical methods such as liquid chromatography‐mass spectrometry will be discussed. [ABSTRACT FROM AUTHOR]

The International Maritime Organization has adopted a revision to the 2023 International Maritime Organization biofouling guidelines and has been discussing the development of guidelines for evaluating the efficacy of inwater cleaning systems. In hull cleaning, which involves aquatic invasive species removal, capture is considered very important in preventing the release of by-products. However, capture efficacy is difficult to evaluate due to the absence of unified evaluation guidelines or standardized methods. Here, we describe a new test method for evaluating the capture efficacy of in-water cleaning systems, using artificial barnacles that simulate the physical characteristics of actual barnacles. The test was designed to evaluate the impact of in-water cleaning on biocide release and biofouling organisms in the marine environment. We used a test plate with artificial barnacles attached to evaluate the capture efficacy with respect to the fouling rating. This test overcomes limitations in the evaluation of the capture efficacy of in-water cleaning systems and provides a reference for the development of more comprehensive tests and in-water cleaning regulation in the future. [ABSTRACT FROM AUTHOR]

Passive sampling is a crucial method for evaluating concentrations of hydrophilic organic compounds in the aquatic environment, but it is insufficiently understood to what extent passive samplers capture the intermittent emissions that frequently occur for this group of compounds. In the present study, silicone sheets and styrene-divinyl benzene-reversed phase sulfonated extraction disks with and without a polyethersulfone membrane were exposed under semi-field conditions in a 31 m3 flume at three different flow velocities. Natural processes and spiking/dilution measures caused aqueous concentrations to vary strongly with time. The data were analyzed using two analytical models that account for these time-variable concentrations: a sampling rate model and a diffusion model. The diffusion model generally gave a better fit of the data than the sampling rate model, but the difference in residual errors was quite small (median errors of 19 vs. 25% for silicone and 22 vs. 25% for SDB-RPS samplers). The sampling rate model was therefore adequate enough to evaluate the time-integrative capabilities of the samplers. Sampler performance was best for SDB-RPS samplers with a polyethersulfone membrane, despite the occurrence of lag times for some compounds (0.1 to 0.4 days). Sampling rates for this design also spanned a narrower range (80 to 110 mL/day) than SDB-RPS samplers without a membrane (100 to 660 mL/day). The effect of biofouling was similar for all compounds and was consistent with a biofouling layer thickness of 150 µm. [ABSTRACT FROM AUTHOR]

Introduction: Net biofouling has a significant impact for the global salmon industry in the seawater grow-out stage in terms of its management. Current mitigation strategies occur primarily through the regular removal of biofouling using in situ cleaning. While in situ net cleaning is effective there is uncertainty as to whether the equipment or dispersed material has an impact upon the fish in the cages. Through direct contact with the environment, the significant surface area of the gill including its microbiome is directly exposed to the acute environmental changes generated by net cleaning. This study aimed to provide a detailed understanding of the impact of in situ net cleaning on Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) gill health. Methods: Three field trials were conducted on commercial fish farms in western Norway. Fouling organisms on net pens and flushed particles during in situ cleaning were identified and screened for major fish pathogens. Hydrographic profile measurements were performed to measure the impact on water quality. Gill samples were examined for histopathological changes, immune gene expression, and the prevalence of major pathogens. 16S rRNA amplicon sequencing was employed to explore the impact of net cleaning on gill microbiome. Results and discussion: Data obtained from these trials identified a diversity of fouling species including hydroids, algae, skeleton shrimps, and filter feeders on net pens, a direct impact on measured water quality indicators, a moderate change in gill inflammatory and antigen presentation activity at the level of mRNA, and a large significant change in gillmicrobiome. Observed changes in gill microbial community involved a decrease in bacterial richness coupled to an increase in identified bacterial genera related to negative health consequences. Parallel analyses for pathogens load in biofouling organisms and flushed particles highlighted the presence of several fish bacteria and parasites. However, minor changes were detected in salmon gill pathogen diversity and loading. Our results suggest that biofouling organisms may actas transient reservoirs for somefishpathogensbutnotvirusesandthatgillmicrobial dysbiosis could be related to the host stress response during and post net cleaning. [ABSTRACT FROM AUTHOR]

Freshwater invaders threaten both natural ecosystems and human activities. An invasive freshwater sponge Heterorotula multidentata (Weltner, 1895) has been found for the first time in continental waters of Europe (Spain). It is a species native to Australia and New Zealand, from which it spread to Japan, being considered invasive. The species has been found in water intake grids of irrigation and drinking water systems in the basins of the Guadalquivir and Tajo rivers, affecting their hydrological functions. It has also been found growing on the invasive mussel Dreissena polymorpha in the Guadalquivir River. To assess the risks associated with invasive alien organisms, a detailed knowledge of their taxonomic status and distribution is necessary. A morphological and molecular evaluation confirmed that the specimens found in Spain belong to the Japanese type. A full morphological description and the fouling problems caused by the species are also provided. It is not yet clear how H. multidentata arrived at Spain, but indirect transport by other invasive freshwater species cannot be ruled out either, as H. multidentata has been found fouling the invasive species zebra mussel. [ABSTRACT FROM AUTHOR]

Balanomorph (acorn) barnacles are found throughout the world's coastal oceans, and their success is dependent on a hard, mineralized, outer shell. Although macro-scale morphology of barnacle shells has been studied extensively, relatively little is known about shell properties at the micron-scale and if such properties vary among species. We assessed shell structure, mechanics, and composition in seven species of balanomorph barnacles from five genera. Three species, Amphibalanus amphitrite, Amphibalanus improvisus, and Austrominius modestus, were laboratory-reared, enabling direct comparison of shell properties of barnacles grown under the same conditions for the same duration. Four other species, Semibalanus balanoides, Amphibalanus eburneus, Chthamalus stellatus, and Tetraclita rubescens, were field-collected. At the macro- and meso-scales, shell properties varied markedly among species, with differences in the number of shell plates, the presence of canals within the plates, mineralization of the base, and shell plate thickness. At the micron-scale, however, structure was remarkably similar among species. Plates of all species were constructed of irregular micron-scale crystallites, with a broad range of crystallite dimensions observed within the same shell. Similarly, micromechanical properties did not vary among species, regardless of testing orientation. Calcium carbonate was identified as calcite in all species assessed with no other mineral phases present, and calcium content did not vary among species. Hence, despite variation in the overall macro- and meso-scale morphology of barnacles, all appear to be built using the same, evolutionarily conserved, mineralization pathway. [ABSTRACT FROM AUTHOR]

Marine biofouling poses a major challenge to ship navigation and hinders the development of the shipping industry. Urgent action is required to tackle this problem through the implementation of innovative strategies. Antimicrobial peptides have garnered considerable attention due to their outstanding effectiveness, wide range of activity, and eco‐friendly characteristics. This study involved grafting the antibacterial peptide andricin 01 (AIGHCLGATL) onto the surface of an aluminum alloy, thereby creating a modified surface with antibacterial properties. In summary, amino groups were introduced onto the surface of aluminum alloys through the silanization process using (3‐aminopropyl) triethoxysilane (APTES), and then the peptides were covalently immobilized on the treated surface using glutaraldehyde as a cross‐linking agent. The successful modification of the peptide was confirmed by Fourier transform‐infrared spectroscopy (FT‐IR) and X‐ray photoelectron spectroscopy (XPS) analysis. The antimicrobial peptide‐modified aluminum alloy surfaces exhibited significant bactericidal activity, killing 75.3% of Bacillus sp. and 85.5% of Escherichia coli, while achieving antifouling efficiencies of 88.6% and 90.7% against Bacillus sp. and E. coli, respectively. Furthermore, molecular dynamics simulations showed that the inserted of the peptides into the phospholipid membrane caused a change in the local membrane curvature, which eventually led to membrane rupture. These results provide valuable information for the application of antimicrobial peptides in the field of antifouling and the elucidation of antifouling mechanisms. [ABSTRACT FROM AUTHOR]

Ultrasound waves have been employed to control marine biofouling but their effects on fouling organisms remain poorly understood. This study investigated the influence of ultrasound waves on barnacle (Tetraclita stalactifera cyprid larvae) pre-settlement behavior. Substrate inspection constituted most of the larval time budget, with a focus on the bottom surface rather than lateral or air–water interfaces. The frequency of substrate inspection decreased at 10 kPa when compared to higher acoustic pressures, while the time spent in the water column had an opposite trend. Various larval swimming modes were observed, including rotating, sinking, walking, and cruising, with rotating being dominant. Barnacle larvae exhibited higher speeds and less complex trajectories when subjected to ultrasound in comparison to controls. The impact of ultrasound waves on barnacle cyprid larvae behavior had a non-linear pattern, with lower acoustic pressure (10 kPa) inducing more effective substrate rejection than higher (15 and 20 kPa) intensities. [ABSTRACT FROM AUTHOR]

Steel monopile support structures for offshore wind turbines require protection from corrosion and consideration with respect to biofouling on their external and internal surfaces. Cathodic protection (CP) works effectively to protect the external surfaces of monopiles, but internally, byproducts from aluminum sacrificial anode CP (SACP) and impressed current CP (ICCP) induce acidification that accelerates steel corrosion. Through an 8-week sea water deployment of four steel pipes, this project investigated the effect of perforations on internal CP systems. Additionally, marine growth on the internal and external surfaces of the pipes was assessed. SACP and ICCP systems inside perforated pipes performed similarly to external systems at a lower current demand relative to internal systems in sealed pipes. The organisms that grew inside of the perforated SACP and ICCP pipes were similar, suggesting that the CP systems did not affect organism recruitment. The results of this study demonstrate the potential benefits of designing perforated monopiles to enable corrosion control while providing an artificial reef structure for marine organisms to develop healthy ecosystems. [ABSTRACT FROM AUTHOR]

Introduction: Global shipping has accelerated the spread of non-native species. Factors such as environmental filtering and interactions with local biota can affect invasion likelihood, yet their relative contribution to predicting invasion risk remains unresolved. To test how abiotic filters and an experimentally-derived measure of biotic resistance interact with propagule pressure, we developed an integratedmodel to evaluate their relative effects on invasion risk of marine biofouling organisms to different focal port regions. We predicted that environmental filtering impacts invasion risk when fewer but stronger connections are part of the network. Further, predation is a mechanism of biotic resistance, which can reduce invasion risk, with most pronounced effects predicted in the tropics that decline at higher latitudes. Methods: We examined shipping traffic and predation impact at three coastal bioregions spanning 47-degrees of latitude al range in the Northeast Pacific (Alaska, California, and Panama). We used vessel traffic databases to characterize propagule pressure and construct a worldwide port network of marine shipping routes and ports. Environmental resistance was estimated using temperature and salinity data from donor and recipient regions. We further used standardized predator exposure experiments to quantify predation impact on fouling community biomass as an estimate of potential for biotic resistance. We then expanded on existing models of relative invasion risk to incorporate the probability that propagules will survive predation by local predators and overcome environmental filtering to generate a predicted invasion risk for each port. Results: Environmental filtering in all regions and predation pressure in the tropics worked to reduce the invasion risk, resulting in markedly different cumulative risk profiles over time among regions. Discussion: In an increasingly connected world withmore vessel traffic, our results highlight thatwhile the number and distribution of shipping routes are important to understand risk, abiotic and biotic filters can modify model predictions. [ABSTRACT FROM AUTHOR]

The damage caused by corrosion in metallic materials is a problem that produces substantial economic and environmental costs. According to the World Bank, the global annual GDP (Gross Domestic Product) in corrosion costs was approximately 96.1 trillion US dollars for 2021, about 20% are due to the corrosion produced by the presence of bacteria, however there are no statistics related to environmental damages produced by this problem [1]. Microbial corrosion activity on metallic surfaces, cannot be classified as a corrosion type, but a process or mechanisms that can influence, accelerate and even initiate it, regardless the type of corrosion generated. The only necessary condition to initiate or accelerate the microbial corrosion on a metallic surface is the growth of biofilms. Biofilms are very complex systems, due to the large amount and types of microorganisms that can grow in it, the metabolic activities that can be developed, and the chemical products, which can attack the metallic materials, causing great deterioration. Due to the complex nature of these processes, specifics norms, procedures and methodologies of operation, patented or established to study, evaluate or fight the action of biofilms are scarce [2,3]. However, some industrial methods have being reported to mitigate their effects [4-7]. In this work it is presented an information review compiled by bibliographic search related to some relevant aspects about biofilms and microbial corrosion, electrochemistry, microscopic studies and preventive actions. [ABSTRACT FROM AUTHOR]

Recreational vessels are an important pathway for spreading marine non‐indigenous species (NIS) around coastal environments globally. However, most vessels are not tracked, limiting our ability to map their movements and identify locations at greater risk of NIS introductions.Using New Zealand as a case study, we quantified spread and risk patterns of recreational vessel movements, using a web‐based survey allowing the more than 1,800 respondents to map significant trips with over 12,000 visits. These vessel routes were used to build a network model representing nationwide recreational vessel movements. Two proxies were used to quantify the risk of introduction of marine NIS: (i) incoming hull length and (ii) cumulative residency periods at sites.There was significant variation in the distances travelled, the destinations they visited and the duration of their stays. New Zealand's recreational boating network contained 317 destinations with over 4,000 unique connections, concentrated within two distinct areas of the country. Network‐based metrics and risk proxies quantified the relative importance of domestic locations as incursion or spreading hubs for NIS. This approach highlighted several areas that pose high relative biosecurity risk within the national network, but are underrepresented within current surveillance programmes.Synthesis and applications. Our study demonstrates how the movement dynamics of recreational vessels can be quantified at a regional scale to inform proactive management. The identification of spreading hubs and locations at particular risk of NIS introductions, enables managers to design risk‐based and effective surveillance and monitoring programmes. Our network‐based approach to determine the biosecurity implications posed by recreational vessels is transferable to other parts of the world. It enables managers to understand the distribution of risk within an area of interest (e.g. a jurisdiction) and develop optimised approaches for mitigating impact. [ABSTRACT FROM AUTHOR]

Understanding the magnitude of biosecurity risks in aquatic environments is increasingly complex and urgent because increasing volumes of international shipping, rising demand for aquaculture products, and growth in the global aquarium trade, are accelerating invasive alien species spread worldwide. These threats are especially pressing amid climate and biodiversity crises. However, global and national biosecurity systems are poorly prepared to respond because of fragmented research and policy environments, that often fail to account for risks across sectors or across stakeholder needs and fail to recognize similarities in the processes underpinning biological invasions. In the present article, we illustrate the complex network of links between biosecurity threats across human, animal, plant, and environment sectors and propose a universal approach to risk assessment. One Biosecurity is a holistic, interdisciplinary approach that minimizes biosecurity risks across human, animal, plant, algal, and ecosystem health and is critical to reduce redundancy and increase cross-sectoral cohesion to improve policy, management, and research in aquatic biosecurity. [ABSTRACT FROM AUTHOR]

Artificial structures act as points of entry for non-indigenous species (NIS) in port areas and may support higher abundance and richness of them. The studies about NIS are increasing, but studies focusing on the variations in temporal recruitment and ecological mechanisms are still scarce. Thus, the aim of this work was to determine the colonization and development of non-indigenous sessile fouling species over two types of substrates (electrolytic carbonated and steel) during 12 months of immersion in the Alicante harbor. The biofouling communities of both substrates were analyzed in terms of abundance and species richness by status (native, cryptogenic, and NIS), and NIS assemblages of both substrates were studied by means of multivariate analyses. In total, 53 different species were identified, 38 in steel (six NIS and six cryptogenic) and 50 in the carbonated substrate (six NIS and 10 cryptogenic). Most NIS were more abundant and diverse after 9 months of immersion and had a preference for carbonated substrates. Furthermore, most of them were positively correlated in both substrates (mainly in steel) and it is noted that the number of NIS in the port of Alicante is increasing as new records have been detected. [ABSTRACT FROM AUTHOR]

Biofouling of air cathode surface decreases the electricity generation performance of membrane‐free microbial fuel cells (MFCs). Ag@Co/Zn N‐doped carbon (Ag@Co/Zn‐NC) is designed as an antibacterial oxygen reduction reaction (ORR) catalyst to inhibit biofouling on the cathode surface. The Co/Zn‐NC active component promotes ORR catalytic activity through the advantages of well‐distributed Co nanoparticles and numerous active sites. Superficial Ag nanoparticles act as antibacterial active species to inhibit bacterial proliferation and suppress biofilm growth. Ag@Co/Zn‐NC catalyst prevents bacterial adhesion and biofilm formation, effectively preventing excessive biofouling on the cathode surface. The antibacterial catalyst maintains a high catalytic activity and good ion diffusion properties without the adverse effects of biofouling, resulting in enhanced ORR durability of the air cathode. The assembled MFCs achieve high electricity generation during long‐term cyclic operation. The maximum power density retention percentage (82.6%) is higher than that of Co/Zn‐NC MFC (65.3%) and Pt/C MFC (52.4%) after continuous operation for 1200 h. Excellent operational durability is revealed for the air‐cathode MFCs assembled with the antibacterial ORR catalyst during the cyclic process. The novelty of this study is that the design of antibacterial catalysts inhibits the excessive growth of the cathode biofilm to improve the cyclic electricity generation performance of MFCs. [ABSTRACT FROM AUTHOR]

Limnoperna fortunei (L. fortunei) (Dunker, 1857), the golden mussel, is an invasive species possessing exceptional environmental adaptability and a destructive impact on water systems and artificial structures. To better conservation of freshwater ecosystems by controlling this mussel, it is essential to study its distribution, potential for invasion, environmental tolerance and biological traits.This paper outlines the distribution of L. fortunei in Asia and South America, as well as its potential for future invasion in freshwater habitats, along with the research methods employed.We find that the mussel had a temperature tolerance range of 8–35 °C and a pH range was 5–10, with some individuals surviving in extreme conditions for extended periods.We find that temperature was a decisive factor for success at reproductive stages, larval development and adult growth.The biological traits of L. fortunei are discussed, focusing on feeding habits, attachment characteristics and locomotion, with an emphasis on byssus structure, foot proteins and adhesion mechanisms. The study elucidates the impact of flow velocity, light exposure and substrate material on their attachment, with the optimal attachment being identified at a flow velocity of 0.3–0.9 m/s. Additionally, the mussel exhibits strong light avoidance performances and a preference for rough surfaces.Extensively‐researched control strategies are classified and summarized, primarily categorized into physical, chemical and biological control, with an outline of their respective strengths and limitations. [ABSTRACT FROM AUTHOR]

Surfaces that combine low-toxicity antifouling effects with fouling-release properties are an intriguing possibility for developing effective measures against marine biofouling. This study field tested siloxane-based fouling-release surfaces enhanced by adding biodegradable surfactants. Two different surfactants were added to a standard polydimethylsiloxane (PDMS) surface, as well as to PDMS soaked in silicone oil, and compared to controls without surfactant augmentation. Antifouling and fouling-release performance was assessed over 11 to 13 weeks against the most prominent fouling species at three locations in Cape Breton, Nova Scotia, Canada. Using nonlinear mixed effect analysis, surfactants were found to have little impact on the progression of biofouling on PDMS without silicone oil in all three sites and had no additional impact on the progression of biofouling on PDMS augmented with silicone oil. (Silicone oil was found to delay biofouling in PDMS without other additives.) Given the known toxicity of some surfactants to invertebrate larvae, future efforts should consider either higher concentrations or alternative varieties for incorporation into fouling-release surfaces. [ABSTRACT FROM AUTHOR]

Fouling and biofouling remain significant challenges in seawater desalination plants. One practical approach to address these issues is to develop anti-biofouling membranes. Therefore, novel hybrid zinc phthalocyanine/polyvinylidene fluoride-co-hexafluoropropylene (Zn(4-PPOx)4Pc/PVDF-HFP) membranes were prepared by electrospinning to evaluate their properties against biofouling. The hybrid nanofiber membrane was characterized by atomic force microscopy (AFM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and contact angle measurements. The theoretical calculations of PVDF-HFP, Zn(4-PPOx)4Pc), and Zn(4-PPOx)4Pc/PVDF-HFP nanofibers were performed using a hybrid functional RB3LYP and the 6-31 G (d,p) basis set, employing Gaussian 09. DFT calculations illustrated that the calculated physical and electronic parameters ensured the feasibility of the interaction of PVDF-HFP with Zn(4-PPOx)4Pc via a halogen–hydrogen bond, resulting in a highly stable and remarkably reactive structure. Moreover, molecular electrostatic potential (MEP) maps were drawn to identify the reactive regions of the Zn(4-PPOx)4Pc and PVDF-HFP/Zn(4-PPOx)4Pc nanofibers. Molecular docking analysis revealed that Zn(4-PPOx)4Pc has highest binding affinity (−8.56 kcal/mol) with protein from S. aureus (1N67) mainly with ten amino acids (ASP405, LYS374, GLU446, ASN406, ALA441, TYR372, LYS371, TYR448, LYS374, and ALA442). These findings highlight the promising potential of Zn(4-PPOx) 4Pc/PVDF-HFP nanocomposite membranes in improving the efficiency of water desalination by reducing biofouling and providing antibacterial properties. [ABSTRACT FROM AUTHOR]

Simple Summary: Marine biofouling is the undesirable accumulation of marine organisms onto man-made surfaces, which causes severe economical and environmental consequences. In recent years, using natural products as environmentally friendly antifouling agents to combat foulers has been a promising approach. However, the search for effective antifouling agents is hampered by the lack of well-defined conserved molecular targets responsible for regulating the larval settlement in fouling organisms. In this study, an in silico approach was used to screen the natural compounds' libraries against silk gland factor 1 (SGF1), which is responsible for the larval settlement of the fouling mussel Mytilopsis sallei. It was found that the targeted binding compounds against SGF1 could significantly affect the larval settlement, foot proteins' gene expression, and byssus secretion of adults in M. sallei. The laboratory bioassay results are promising, even though field trials are necessary to confirm the in silico results. Hence, this study paves the way for new experimental studies to be carried out for finding environmentally friendly antifouling agents by using SGF1-targeted compounds. Most fouling organisms have planktonic larval and benthic adult stages. Larval settlement, the planktonic–benthic transition, is the critical point when biofouling begins. However, our understanding of the molecular mechanisms of larval settlement is limited. In our previous studies, we identified that the AMP-activated protein kinase-silk gland factor 1 (AMPK-SGF1) pathway was involved in triggering the larval settlement in the fouling mussel M. sallei. In this study, to further confirm the pivotal role of SGF1, multiple targeted binding compounds of SGF1 were obtained using high-throughput virtual screening. It was found that the targeted binding compounds, such as NAD+ and atorvastatin, could significantly induce and inhibit the larval settlement, respectively. Furthermore, the qRT-PCR showed that the expression of the foot proteins' genes was significantly increased after the exposure to 10 μM NAD+, while the gene expression was significantly suppressed after the exposure to 10 μM atorvastatin. Additionally, the production of the byssus threads of the adults was significantly increased after the exposure to 10–20 μM of NAD+, while the production of the byssus threads was significantly decreased after the exposure to 10–50 μM of atorvastatin. This work will deepen our understanding of SGF1 in triggering the larval settlement in mussels and will provide insights into the potential targets for developing novel antifouling agents. [ABSTRACT FROM AUTHOR]

This work investigated the trade-off among cavitation erosion resistance, corrosion resistance, and antifouling properties in HVOF-sprayed WC-10Co4Cr coatings. By adding 316L stainless steel (316L) and copper to WC-10Co4Cr coatings, this work aimed to enhance their antifouling ability while maintaining their cavitation erosion and corrosion resistances, presenting a comprehensive evaluation of the modified coatings, including their microstructure, hardness, fracture toughness, and resistance to cavitation erosion, corrosion, and biofouling. The results revealed that Cu addition significantly improved the antifouling property but at a cost of the compromised cavitation erosion and corrosion resistances. In contrast, 316L enhanced the cavitation erosion and corrosion resistances but did not effectively improve the antifouling property. The dual addition of Cu and 316L demonstrated a balanced performance in all three aspects. This research contributed to the development of HVOF-sprayed WC-CoCr coatings suitable for marine environments, suggesting further optimization possibilities by altering Cu and 316L contents. [ABSTRACT FROM AUTHOR]

A biofilm is a layer of microbes that have aggregated to form a colony. The colony attaches to a surface with a slime layer which protects the microorganisms, promoting their growth and survival. Biofilms occur in various environments such as soils, sediments, wastewater, water pipelines, water purifying systems, cooling water systems, medical devices, archaeological monuments, marine vessels, and hospitals. Biofilms may induce adverse effects such as fostering drug-resistant strains. Here, we review biofilms with focus on their formation, occurrence in water systems, impact, microbial interactions, and characterization methods. Communication includes cell-to-cell interactions by quorum sensing, interactions mediated by flagella, gene, and signaling molecules, and interactions mediated by extracellular polymeric substances. Characterization methods comprise surface-enhanced Raman scattering spectroscopy, confocal laser scanning microscopy, scanning electron microscopy, fluorescence microscopy, sensors, and metagenomics analysis. [ABSTRACT FROM AUTHOR]

Despite the development of numerous coating techniques and materials, today’s anti-biofouling applications require coatings that are facile and mechanically robust in nature. Studies on the hydrophobicity of rare-earth oxides have risen due to their unusual chemical properties; ytterbium oxide is one such oxide substance. In this study, spray combustion was used to create a hydrophobic coating of ytterbium oxide (Yb2O3) on a stainless steel (SS) substrate, which was then vacuum-treated. GI-XRD analysis confirmed the sesquioxide cubic crystalline structure of Yb2O3. FESEM images displayed an underneath wavy morphological coating with discrete particles on the surface. The thickness and roughness were ~12 and ~0.17 µm, respectively. When 5 and 10 N loads were applied, the coating showed better scratch hardness than uncoated SS. Water contact angle (WCA) <10° indicated superhydrophilicity in the fabricated coating. After vacuum treatment, it became hydrophobic, and the WCA was 128°; because of the increment in the relative area fraction of the C–H bond. The proportion of area covered by blue–green algae (Phormidium sp.) on vacuum-treated Yb2O3 coating was only 3% compared to uncoated SS samples, 80%. [ABSTRACT FROM AUTHOR]

Discovering macromolecules and understanding the associated mechanisms involved in underwater adhesion are essential for both studying the fundamental ecology of benthos in aquatic ecosystems and developing biomimetic adhesive materials in industries. Here, we employed quantitative proteomics to assess protein expression variations during the development of the distinct adhesive structure - stolon in the model fouling ascidian, Ciona robusta. We found 16 adhesive protein candidates with increased expression in the stolon, with ascidian adhesive protein 1 (AAP1) being particularly rich in adhesion-related signal peptides, amino acids, and functional domains. Western blot and immunolocalization analyses confirmed the prominent AAP1 signals in the mantle, tunic, stolon, and adhesive footprints, indicating the interfacial role of this protein. Surface coating and atomic force microscopy experiments verified AAP1′s adhesion to diverse materials, likely through the specific electrostatic and hydrophobic amino acid interactions with various substrates. In addition, molecular docking calculations indicated the AAP1′s potential for cross-linking via hydrogen bonds and salt bridges among Von Willebrand factor type A domains, enhancing its adhesion capability. Altogether, the newly discovered interfacial protein responsible for permanent underwater adhesion, along with the elucidated adhesion mechanisms, are expected to contribute to the development of biomimetic adhesive materials and anti-fouling strategies. Discovering macromolecules and studying their associated mechanisms involved in underwater adhesion are essential for understanding the fundamental ecology of benthos in aquatic ecosystems and developing innovative bionic adhesive materials in various industries. Using multidisciplinary analytical methods, we identified an interfacial protein - Ascidian Adhesive Protein 1 (AAP1) from the model marine fouling ascidian, Ciona robusta. The interfacial functions of AAP1 are achieved by electrostatic and hydrophobic interactions, and the Von Willebrand factor type A domain-based cross-linking likely enhances AAP1's interfacial adhesion. The identification and validation of the interfacial functions of AAP1, combined with the elucidation of adhesion mechanisms, present a promising target for the development of biomimetic adhesive materials and the formulation of effective anti-fouling strategies. [Display omitted] [ABSTRACT FROM AUTHOR]