Attachment Of Organisms Research Articles

Dispersion, fragmentation, abrasion, and organism attachment of drift pumice from the 2021 Fukutoku-Oka-no-Ba eruption in Japan

In August 13, 2021, the submarine volcano Fukutoku-Oka-no-Ba (FOB) erupted and produced massive drift pumice in the western Pacific Ocean off Japan for the first time in ~ 35 years. Although drift pumice plays a crucial role in the dispersion of marine organisms, it can damage infrastructure and disrupt maritime traffic. However, observational data are limited for investigating the dispersion of drift pumice and its temporal changes. In this study, we present a 1-year record of the mass, size, shape, and attached marine organisms of drift pumice from the 2021 FOB eruption. We found that the mass and size of the drift pumice decreased gradually over time. Their shape became rounded after 2 months on the sea surface. Finally, the number and types of attached organisms increased dramatically after 7 months. Based on the changes in these parameters, we divided the 1-year record into three phases that describe the general processes for the dispersion, fragmentation, and abrasion of drift pumice and the transportation of marine organisms. In particular, the degree of pumice concentration in the raft was found to be important for discussing the change of pumice shape at sea and attachment of marine organisms. An additional floating experiment was performed to clarify the very long-term floating of drift pumice from the FOB eruption. Our large dataset offers new findings and quantitative and reproducible data that supplement previous studies and provide insight into the behavior of drift pumice for use in future numerical simulations and to aid in preparing for hazards related to drift pumice.

Amphiphilic Marine Antifouling Coatings Based on Zwitterion-Modified Silicone Polymers.

Silicone coatings are widely employed in marine antifouling applications due to their low surface energy. However, in static marine environments, pure silicone coatings are ineffective in preventing the adhesion of marine biofilms, which consist of proteins, marine bacteria, and extracellular matrices, ultimately promoting the attachment of macrofouling organisms. To address the limitations in antifouling performance under static conditions, this study introduces a silicone-based antifouling coating modified with zwitterionic polymers. Sulfobetaine (SB) zwitterionic segments were grafted onto the side chains of poly(dimethylsiloxane) (PDMS) to synthesize the amphiphilic polymer P(DMS-SB), which was incorporated into the PDMS network to create an interpenetrating network-structured silicone coating. The zwitterionic segments effectively inhibited the adhesion of proteins, bacteria, and algae through hydration effects. Compared to pure PDMS coatings, the adhesion of proteins, bacteria, and algae was reduced by 88%, 98.9%, and 99.3%, respectively. Additionally, the coating demonstrated excellent fouling-release properties, achieving a 91.3% removal rate for settled algae under water flow conditions and reducing the simulated barnacle adhesion strength by 68.4%. This coating presents a promising antifouling solution for ships, offshore structures, and aquaculture facilities in static marine environments with significant potential for widespread application.

Investigation of critical copper release rates for dose optimization of antifouling coatings

Antifouling coatings are applied to ship and boat hulls to prevent the unwanted attachment of marine organisms known as biofouling. Most antifouling coatings do so through toxic means by continuously releasing copper from the paint film to the surrounding water and are thus of environmental concern. Few studies have investigated the minimum dose of copper from an antifouling coating required to inhibit biofouling, commonly referred to as the critical release rate. This study presents a comprehensive investigation into the critical release rates of copper from commercial antifouling coatings in European coastal waters, with study sites in the Atlantic (Arcachon, France), Kattegat (Hundested, Denmark) and Skagerrak (Tjärnö, Sweden). Employing a combination of X-ray Fluorescence (XRF) analysis and visual inspection, this six-month field study has evaluated the efficacy of various antifouling coatings with differing copper contents. The findings of this study indicate that a release rate of 7 μg cm−2 d−1 was sufficient to inhibit macrofoulers at all three sites during static conditions. Results also indicate that the critical release rate is a parameter that coating manufacturers can optimize, as the performance of the coatings was not solely dependent on the copper release rates. The general critical release rate of 7 μg cm−2 d−1 could serve as a benchmark for dose optimization of coatings for both the yacht and ship sectors in the studied waters to reduce their environmental impact. It can also be used as support for decision-makers to phase out coatings with unnecessarily high copper release rates from the market.

Degradation of a Sauce-Glazed Ware from the Song Dynasty Salvaged Out of Water at the Dalian Island Wharf: Part II—The Effect of Surface-Attached Marine Organism Remains

Dalian Island, located in the northwest of Pingtan County, Fujian Province, China, has been an important junction on the Maritime Silk Road since the Tang dynasty. This study focuses on sauce-glazed ceramic ware from the Song dynasty salvaged from the waters near Dalian Island Wharf. The composition, phase attributes, and microstructures of the marine organism remains attached to the ceramic ware were analyzed using an optical microscope, scanning electron microscope, and micro-Raman spectrometer to investigate the influence of marine organisms on the degradation of the ceramic ware. Long-term abrasion by sea wave-borne debris led to the increased surface roughness and wettability of the ceramic ware, facilitating the attachment of marine organisms. Differences in surface roughness between the inner and outer walls led to varying levels of biomass. Coralline algae secreted inducers to attract the larvae of macrofoulers. The attachment of different types of marine organisms had varying effects on the degradation of the ceramic ware. Firmly attached unitary organisms could alleviate the scouring of sea wave-borne debris and hinder the intrusion of foreign pollutants, thereby playing a ‘bio-protective’ role. In contrast, the group skeletons of modular organisms could reinforce the mechanically damaged surface but failed to block the intrusion of iron rust and other pollutants, resulting in chemical alterations of the glaze. Therefore, the specific species of the attached marine organisms should be considered in subsequent conservation efforts.

Application of Self-Polishing Copolymer and Tin-Free Nanotechnology Paint for Ships

During a ship’s voyage, it is difficult to maintain its hull, and prolonged exposure to seawater can lead to the attachment of marine organisms, which can negatively impact the ship’s speed. The original self-polishing copolymer was a tributyltin-containing paint used for applying two layers of protective coating onto a ship’s bottom plate. According to International Maritime Organization (abbreviated as IMO) regulations, users are no longer allowed to use paints containing tributyltin. Therefore, manufacturers have developed a tributyltin-free paint, known as tin-free nanotechnology paint, which can be used as a replacement for the base coat on ship bottom plates. This study involves the use of a self-polishing copolymer spray and tin-free nanotechnology paint. A model coated with these two types of paint will be observed underwater to study the growth of marine organisms. Additionally, fuel consumption will be analyzed through underwater inspections and sea trials. Based on the experimental data, it is known that tin-free nanotechnology paint can significantly reduce the need for repairs in factories and greatly decrease maintenance costs when compared to self-polishing copolymers.

Self-growing composite photocatalytic materials for surface self-renewal of marine antifouling coatings

The attachment of marine organisms leads to the problem of marine biofouling. Biofouling can be prevented by using antifouling coatings this provided a low surface energy surface to inhibit the attachment of marine organisms. However, microorganisms inevitably attach during their use, leading to failure of the fouling release coating. To address this problem, we report an innovative strategy of doping photocatalytic materials into silicone coatings. This approach enables the degradation of bacterial carcasses and their secretions, leading to surface self-renewal and extended fouling protection. In this work, we report the controlled crystallisation of Ag-TiO2 nanomaterials (APTES-Ag@TiO2) using various methods influenced by aminopropylsilane. This strategy ensures the full utilisation of sunlight and strong interfacial adhesion, thereby preventing the degradation of photocatalytic performance. APTES-Ag@TiO2 not only has a self-growth effect and excellent photocatalytic performance but also facilitates the degradation of bacterial carcasses, thereby renewing the surface in organosilicon coatings.

Comparative assessment of the quantitative and qualitative composition of zooperiphyton on the surface of duckweed (<i>Lemna minor</i>) grown in a recirculating water supply system

Relevance. The quantitative and qualitative composition of organisms settling on floating macrophytes depends on the presence in the water of nutrients necessary for their life, such as fish waste products, food residues and excrement.Methods. The roots and leaves of duckweed (Lemna minor) act as a substrate for the attachment and development of aquatic organisms. And they, in turn, consume organic substances as food sources, thereby reducing the amount of pollutants in the water. In this regard, it seems relevant to study the faunal composition, frequency of occurrence and density of various taxonomic groups of organisms settling on duckweed leaves during the integrated cultivation of aquatic plants and aquaculture objects.Results. The results of the study showed that the zooperiphyton of duckweed is characterized by a high diversity of the faunal complex. On the surface of aquatic macrophytes (Lemna minor), grown by the integrated method together with carps, the number of hydrobionts is twice as large as on duckweed grown in a control installation of a closed water supply, in which there were no fish. Fish excrement and washed-out food residues created a nutrient substrate for the development of aquatic organisms.A total of 22 species of organisms were found inhabiting duckweed in the experimental variant, among which barnacle crustaceans dominated, rotifers were subdominants, and chironomids, copepods, and nematodes were also found. The zooperiphyton of duckweed in the control version consisted of 12 taxa of hydrobionts, most often there were protozoa and barnacles, there were protists, paddlefoot crayfish and oligochaetes. The greatest faunal diversity was recorded on duckweed in the experimental version.

On biomimetic surface texturing and its impact on turbulent flow and hydrodynamic forces acting on an early-stage bio-fouling organism

Recent marine anti-fouling research efforts have sought inspiration from bio-mimetic strategies to develop nontoxic solutions. Surface modifications have shown promising results in their ability to disrupt attachment and growth of early-stage organisms under static immersion conditions but very limited research has attempted to explore the interaction between surface textures and flow under turbulent conditions. The study presented in this article focuses on a simple texture, inspired by the growth rings of the Brill fish Scophthalmus rhombus and developed for applications on the blades of tidal stream turbine. A series of Large Eddy Simulations of fully developed turbulent channel flow were performed to assess the influence of the spacing between the texture elements on turbulent stresses. The aim is to characterize the impact of the texture on turbulent stresses by comparison to a smooth surface and identify whether shelters may form within the gaps between textures. The study clarifies the role of dispersive and Reynolds stresses in terms of their impact on hydrodynamic forces acting on a simplified model of a marine diatom. Reynolds shear stresses predominantly govern the intensity of forces, while dispersive shear stress affects the mean hydrodynamic forces acting on the organism at the early stage of settlement.

BIOFOULING IN THE MARINE ENVIRONMENT: MECHANISMS, IMPACTS, AND MODERN SOLUTIONS. A BRIEF REVIEW

Biofouling in the marine environment is a complex biological process that leads to serious economic and ecological effects for the marine industry and ecosystems. It begins with the adhesion of microorganisms and the formation of a biofilm, which facilitates the attachment of larger organisms and leads to an increase in the weight and hydrodynamic resistance of the vessels. These changes cause significant costs related to fuel, maintenance and operation of marine facilities. In addition, biofouling increases environmental risks, including contamination from biocides and carrying invasive species, which poses a threat to local ecosystems. This article examines the mechanisms of biofouling, economic and ecological impact, as well as global technologies to combat it, including innovations in biocidal and non-biocidal coatings. Achieving efficient and environmentally sound solutions remains a key challenge for the future of the maritime industry.

Phosphate and amphiphilic-functionalized luffa with anti-biofouling property for efficient uranium extraction from seawater

The attachment of marine organisms is the main problem of extracting uranium from seawater. In this article, phosphate groups were grafted to the surface of luffa (LUP), and an antifouling material for uranium extraction from seawater (LUPPC) was prepared by ionic initiated free radical polymerization with amphiphilic polymers. The LUPPC expressed great uranium adsorption and antifouling property. After soaking in small crescent diamond algae for 10 days, the LUPPC surface had almost no seaweed attachment compared with luffa and LUP. According to the DFT theory, the P-U bond length is 2.44 Å and the adsorption energy with uranium is −219.63 kcal mol−1. The short bond length and high binding energy indicate the excellent adsorption properties of the LUPPC.

Antifouling Coatings from Glassy Polyelectrolyte Complex Films.

Coatings that prevent or decrease fouling are sought for many applications, including those that inhibit the attachment of organisms in aquatic environments. To date, antifouling coatings have mostly followed design criteria assembled over decades: surfaces should be well/strongly hydrated, possess low net charge, and maintain a hydrophilic character when exposed to the location of use. Thus, polymers based on ethylene glycol or zwitterionic repeat units have been shown to be highly effective. Unfortunately, hydrated materials can be quite soft, limiting their use in some environments. In a major paradigm shift, this work describes glassy antifouling films made from certain complexes of positive and negative polyelectrolytes. The dense network of electrostatic interactions yields tough materials below the glass transition temperature, Tg, in normal use, while the highly ionic character of these polyelectrolyte complexes ensures strong hydration. The proximity of equal numbers of opposite charges within these complexes mimics zwitterionic structures. Films, assembled layer-by-layer from aqueous solutions, contained sulfonated poly(ether ether ketone), SPEEK, a rigid polyelectrolyte that binds strongly to a selection of quaternary ammonium polycations. Layer-by-layer buildup of SPEEK and polycations was linear, indicating strong complexes between polyelectrolytes. Calorimetry also showed that complex formation was exothermic. Surfaces coated with these films in the 100 nm thickness range completely resisted adhesion of the common flagellate green algae, Chlamydomonas reinhardtii, which were removed from surfaces at a minimum applied flow rate of 0.8 cm s-1. The total surface charge density of adsorbed cations, determined with a sensitive radioisotopic label, was very low, around 10% of a monolayer, which minimized adsorption driven by counterion release from the surface. The viscoelastic properties of the complexes, which were stable even in concentrated salt solutions, were explored using rheology of bulk samples. When fully hydrated, their Tg values were observed to be above 75 °C.

Acute and Chronic Effects of the Antifouling Booster Biocide Diuron on the Harpacticoid Copepod Tigriopus japonicus Revealed through Multi-Biomarker Determination

Diuron, an additive biocide in antifouling paints, is widely employed to curtail the attachment of organisms on submerged surfaces in aquatic structures. Despite the detection of diuron in aquatic ecosystems, information regarding its acute and chronic impacts on aquatic invertebrates, particularly planktonic crustaceans, remains limited. In this study, we analyzed the acute (24 h) and chronic (12 days exposure across three generations) effects of different concentrations of diuron (1/10 of the no observed effect concentration (NOEC), the NOEC, and 1/10 of the lethal concentration 50% (LC50), derived from the 24 h acute toxicity value of 1152 μg L−1) on the harpacticoid copepod Tigriopus japonicus. The acute exposure experiment indicated that the 1/10 LC50 value of diuron significantly reduced the copepod’s feeding rate and acetylcholinesterase activity. In response to the 1/10 LC50 value, the intracellular reactive oxygen species were elevated alongside increased malondialdehyde levels, while the glutathione content was depleted. The enzymatic activities of glutathione S-transferase, catalase, and superoxide dismutase were significantly enhanced by the 1/10 LC50 value, suggesting a proactive role of the antioxidant defense system against oxidative stress. Conversely, the activities of glutathione peroxidase and glutathione reductase enzymes were increased at the NOEC value, while their values were reduced by the 1/10 LC50 value. Chronic exposure to 1/10 NOEC and NOEC values revealed the adverse multigenerational effects of diuron. The second generation exhibited the most sensitivity to diuron, with the NOEC value notably reducing survival rate, body length, nauplius-to-adult development, neonates per brood count, and extending the reproduction period. Taken together, our findings underscore that even sublethal diuron levels can adversely impact copepod populations across generations through intergenerational toxicity.

Effects of Different Fouling Organisms on Corrosion Behavior of Carbon Steel in Dalian Seawater

Carbon steels are widely used in ocean engineering due to their cost effectiveness, ease of manufacture, and excellent weldability. However, the attachment of macro-fouling organisms in seawater poses a serious threat to the integrity of carbon steel structures. In this experiment, carbon steel plates were immersed in the Dalian Sea area from January to October to investigate the effects of macro-fouling on corrosion propagation. The electrochemical measurement indicated that the propensity for the corrosion of Q235B is ranked as ascidians > mussels > barnacles. The characterization results indicated that various marine organisms significantly influenced the corrosion behavior of Q235B carbon steel immersed in natural seawater. The colonization of barnacles inhibited corrosion at the barnacle central area, and the presence of barnacle covering caused crevice corrosion at the edges of the barnacle due to oxygen concentration cells. The presence of ascidians resulted in general corrosion due to the locally high conductivity and ion diffusion rate. A relatively compact rust layer, which exhibited localized defects, was observed beneath the mussels. Seawater had the ability to penetrate the rust layer through these defects, leading to the formation of pitting corrosion on the metal substrate.

COMPARISON OF THE INHIBITORY EFFECT BETWEEN ULIN (Eusideroxylon zwageri) BARK EXTRACT AND Chlorhexidine gluconate 0.2% AGAINST Streptococcus sanguinis

Background: Gingivitis is caused by a build up of plaque bacteria, one of which is Streptococcus sanguinis. Streptococcus sanguinis act as an anchor for the attachment of oral organisms that colonize the surface of the teeth, forming plaque so that it becomes the development of gingivitis. Currently, many natural ingredients, as alternatives, have antibacterial effects. One of which is Eusideroxylon zwageri, because it contains flavonoids, tannins, phenolics, saponins, alkaloids, and terpenoids. Purpose: to compare the inhibitory effect between ulin bark extract and Chlorhexidine gluconate 0.2% against Streptococcus sanguinis. Method: True experimental research with post test only with control group design using ulin bark extract concentrations of 20%, 40%, 60%, 80%, and 100% and Chlorhexidine gluconate 0.2% as the K(+). The maceration method was used to extract ulin bark while the inhibitory test was using the diffusion method with 6 treatment groups and 4 replications, so that there were 24 samples. All treatment groups were incubated 24 hours at 37oC then measurement of inhibition zones was using callipers. Results: The results of the test showed that ulin bark extract concentrations of 20%, 40%, 60%, 80%, 100%, and Chlorhexidine gluconate 0.2% obtained an average inhibition zone with diameter of 7.18 mm, 9.06 mm, 11.08 mm, 13 mm, 15.09 mm, and 18.14 mm. Analysis of One Way ANOVA and Post Hoc Games-Howell data showed a significant difference between treatment groups. Conclusion: Ulin bark extract can inhibit the growth of Streptococcus sanguinis but has not been able to equal to Chlorhexidine gluconate 0.2%. Keywords: Chlorhexidine gluconate 0,2%, gingivitis, inhibitory activity, ulin bark extract, Streptococcus sanguinis.

Nacre‐Inspired Metal‐Organic Framework Coatings Reinforced by Multiscale Hierarchical Cross‐linking for Integrated Antifouling and Anti‐Microbial Corrosion

AbstractA long‐standing quest in marine materials science has been the development of tough and effective antifouling coatings for diverse surface protection. However, most commercial coatings are severely limited by poor mechanical behavior and unsustainable passive biocidal effect, leading to irreversible marine biofouling and even microbiologically influenced corrosion (MIC). Herein, inspired by the amorphous/crystalline feature within nacreous platelets, a mechanically robust antifouling coating composed of biopolymer‐based hydrogel and dense metal‐organic frameworks (MOFs) is developed. Tailoring the cross‐linked networks across multiscale interfaces can furnish strength, dissipate strain, and improve toughness of the building blocks, resulting in a firm and scalable configuration on various substrates regardless of material category and surface topology. The resultant coating as a suitable reservoir exhibits a unique active defensive behavior of intelligent MOF degradation or drug release, enabling a groundbreaking performance for broad‐spectrum biofouling and corrosion control. Notably, neither attachment of marine organisms nor MIC of metal substrates is observed and aggravated during the prolonged testing process in complex biological environments. This study provides distinctive insights into the underlying multimechanisms of comprehensive anti‐fouling‐corrosion and pioneer a rational strategy to design next‐generation reliable MOFs‐derived coatings in marine environments.

Estuarine copper concentrations following boat-wash down and subsequent accumulation in blue mussels

Antifouling paints may contain copper which prevents the attachment and growth of organisms on vessel hulls. In the study, estuarine copper concentrations and its dispersal are determined as well as whole-body copper burden of Mytilus edulis deployed at 8 sites in the estuary, following boat wash-down in Lymington estuary, United Kingdom. The copper concentrations half a meter away from a boat wash-down was quickly diluted within 4 h. But 24 h following a wash down, copper levels remained 10- to 20-fold elevated above the levels 30 m away from the source. Copper concentrations in the sediment half a meter from the point source were about 100-fold greater than within the marina but the marina sediment concentrations were still above the effect range low. Mortality of M. edulis was not observed, but copper body burden 24 h following a wash down event was up to tenfold elevated for 5 d before returning to normal within 21 d.

Study of the Interaction between Regular Waves and a Wind-Fish Combined Structure

The combination of a wind turbine and fish cage (wind-fish) is able to solve the complex issue of power supply for deep-sea aquaculture. Nevertheless, the hydrodynamic coupling between the fish cage and the wind turbine foundation is increasingly complex, and there is little research on the related hydrodynamics. In this paper, the hydrodynamic research on the wind turbine foundation and fish cage structure is carried out using numerical simulation, in which the porous medium model is adopted to simulate the effects of the fish cage on the flow field. By analyzing the hydrodynamic characteristics of the combined structure of an offshore wind turbine and aquaculture cage under the action of regular waves, the load on both the cage in the combined structure and the wind turbine foundation, and the overall load on the combined structure of offshore wind turbine and cage are obtained. The effects of wave parameters, structural dimensions, cage submergence depth, and biological attachment on cage load, wind turbine foundation load, and overall load of the combined structure are analyzed. The results demonstrate that the wind turbine foundation is persistently the central part of the combined structure. The wave height, water depth, and degree of attachment of marine organisms all have different effects on the amplitude of the structural load. In contrast, the wave period, cage geometry, and cage submergence depth have no significant effects on the amplitude of the structural load. In addition to the water depth, other factors will affect the proportion of the load on the wind turbine foundation and the total load as well.

Degradation Mechanism of a Sauce-Glazed Ware of the Song Dynasty Salvaged out of the Water at Dalian Island Wharf: Part I-The Effect of the Surface-Attached Composite Coagula.

Dalian Island is located in the sea area near Pingtan County, Fujian, Southeast China. The sea area used to be the junction of the eastern and western ship routes on the Maritime Silk Road, and is also an important region for underwater archaeology in China. This study focused on a sauce-glazed ware of the Song Dynasty, with serious degradation, which was salvaged out of the water at the Dalian Island Wharf. Optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and micro-Raman spectroscopy were used to comprehensively analyze the composition, phase attributes and microstructure of the ware and the surface-attached coagula. The findings revealed that the sea wave-borne debris scoured the surface of the ware, causing mechanical damage to varying degrees and a significant decrease in its degradation resistance. This was the primary factor accounting for the poor preservation state of the salvaged ceramic ware, and the precondition for the subsequent attachment of marine organisms and the deposition of inorganic pollutants. The calcareous skeletons formed on the surface induced by the bio-mineralization of coralline algae (a type of marine plant) could resist the mechanical action caused by the motion of sea waves, thereby slowing down the ware's degradation process. In other words, the calcareous skeletons played a 'bio-protective' role to a certain degree. In addition, inorganic pollutants represented by iron rusts also participated in the corrosion of the glaze. Some pollutants were directly deposited on the pits and cracks on the surface of the ware, which brought stress to the glaze and glaze/body interface, causing the glaze to further crack and spall. Moreover, iron rusts reacted with the glaze, leading to chemical alteration, accompanied by the formation of iron silicate as the alteration product. Anorthite crystals in the interlayer did not participate in the reaction but remained at the original position. The alteration product gradually replaced the original glass phase of the glaze and entered into the body via pores and cracks. In conclusion, the complex degradation morphology of the salvaged sauce-glazed ware could be attributed to the combined action of mechanical damage, marine bio-fouling, and chemical alteration.

A comparison study of crevice corrosion on typical stainless steels under biofouling and artificial configurations

In this work, the crevice corrosion behavior and biofouling coverage of 316L stainless steel (316L SS), 2205 duplex stainless steel (2205 DSS), and 2507 super duplex stainless steel (2507 SDSS) in natural seawater were investigated through long-term field exposure tests. The results revealed that both artificial crevice corrosion and biofouling-induced crevice corrosion occurred on the surface of three stainless steels. The corrosion rate was ranked as 316L SS » 2205 DSS＞2507 SDSS. The deepest area of the artificial corrosion pit was at the edge of the crevice, which was related to the IR drop and acidification of the localized solution. The highest biofouling coverage and the most severe biofouling-induced corrosion occurred on the surface of 316L SS. The attachment of large organisms to the metal surface formed a fouling barrier layer, further blocking the flow of material over the crevices, and the artificial crevice corrosion was accelerated. The initiation of barnacle-induced corrosion was due to the formation of a crevice between the barnacle and the substrate, resulting in the entry of seawater. The acidification of the solution caused by catalytic-occluded cells was responsible for the continuous development of barnacle-induced corrosion, which was similar to the propagation of the artificial crevice corrosion.

Methods studies for attached marine organisms detecting based on convolutional neural network

The use of neural networks to detect marine targets has been an important research direction in the field of target detection. Traditional detection models are generally only for fish, coral, large plants and animals and other easy to detect targets, for the attached marine species that are not easy to detect there are problems such as lower detection accuracy, slower speed, and large interference in the sea environment. With the increasing problems caused by the attachment of marine organisms, the identification methods for marine attached organisms are also receiving more and more attention. In this paper, the original YOLO v5 is improved in terms of activation function, optimized image information extraction method, and balanced positive and negative samples. Finally, an improved YOLO v5 target detection algorithm is proposed and tested on a self-built dataset. The experimental results show that the values of mAP and F1 of the improved YOLO v5 target detection algorithm are 72.1% and 0.722, respectively, which are better than other target detection algorithms in terms of accuracy and reliability.