Prevention Of Marine Biofouling Research Articles

Biodegradable polymer as controlled release system of organic antifoulant to prevent marine biofouling

Abstract Controlled release of antifoulant is critical for marine antibiofouling. We have prepared polyurethane with degradable polyester segments consisting of poly(ethylene adipate) (PEA), poly(1,4-butylene adipate) (PBA) or poly(1,6-hexamethylene adipate) (PHA) and used it as the release system for organic antifoulants. The degradation rate of the polyurethane increases with the content of the degradable segments. On the other hand, as the segments change from PEA, PBA to PHA, the degradation rate decreases because the crystallinity increases but the ester group density decreases. Such degradable polyurethane allows the antifoulants to release at a constant rate, where the release rate can be regulated by varying the polyester segments. Marine field tests reveal that the polyurethane-antifoulant system has good antifouling performance. Particularly, the degradable polyurethane exhibits excellent adhesion to the substrate ensuring the long duration of the system.

Influences of Zeta Potential, Water Absorption and Surface Roughness of Porous Ceramics on Marine Bio-fouling

The red tide organisms occurring at seashores in Korea damage the marine fish-raising industry every summer. Several methods to prevent the occurrence of red tide organisms, therefore, have been tried; one of them is to filter out red tide organisms using a membrane filled with porous ceramic bodies, allowing only fresh seawater to pass into a fish farm. When this method is used for long period of time, however, the problem of marine bio-fouling can develop on the surfaces of the porous ceramic body, deteriorating the filtering function of the porous bodies. In this paper, the influences of the zeta potential, water absorption and surface roughness of porous ceramics on marine bio-fouling have been inspected. In order to control the above three factors, three kinds of ceramic powders, alumina, titania and zirconia, were coated on the porous bodies. As a result, the water absorption and the surface roughness of the porous ceramics were found to be equally important factors in preventing bio-fouling, while the zeta potential of the specimens did not show a prominent effect. In detail, the water absorption of specimens was an effective factor in the early stages of bio-fouling for about one month; on the other hand, the surface roughness of the specimen was a main factor that could be used to control the amount of bio-fouling after one month. Among the three ceramic powders used as coatings, alumina, by imparting lower water absorption and higher surface roughness to the specimens, proved to be the optimum one to prevent marine bio-fouling.

A new diatom growth inhibition assay using the XTT colorimetric method

Marine biofouling, which leads to significant operational stress and economic damage on marine infrastructures, is a major problem in marine related industries. Currently, the most common way to avoid marine biofouling involves the use of biocidal products in surface coatings. However, the need for environmentally friendly antibiofouling compounds has increased rapidly with the recent global prohibition of harmful antifoulants, such as tributyltin (TBT). In particular, periphytic diatoms have been shown to contribute significantly to biofilms, which play an important role in biofouling. Therefore, inhibiting the proliferation of fouling diatoms is a very important step in the prevention of marine biofouling. In this study, we developed a new, rapid, accurate, and convenient growth inhibition assay using the XTT colorimetric method to prevent the growth of the fouling periphytic diatom, Nitzschia amabilis Hidek. Suzuki (replaced synonym, Nitzschia laevis Hustedt). The feasibility of this method was verified by determining the growth inhibition activities of two standard photosynthetic inhibitors, DCMU and CuSO4. However, neither inhibitor had any cytotoxic activities at the range of concentrations tested. Moreover, this method was applied by screening and purification of herbicidic but non-cytotoxic compounds from cyanobacteria extracts. Our results demonstrate the utility of this newly established growth inhibition assay for the identification of marine anti-biofouling compounds.

Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

Marine biofouling--the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls--is an expensive problem that is currently without an environmentally compatible solution. Biofouling leads to increased hydrodynamic drag, which, in turn, causes increased fuel consumption and greenhouse gas emissions. Tributyltin-free antifouling coatings and paints based on metal complexes or biocides have been shown to efficiently prevent marine biofouling. However, these materials can damage the environment through metal leaching (for example, of copper and zinc) and bacteria resistance. Here, we show that vanadium pentoxide nanowires act like naturally occurring vanadium haloperoxidases to prevent marine biofouling. In the presence of bromide ions and hydrogen peroxide, the nanowires catalyse the oxidation of bromide ions to hypobromous acid (HOBr). Singlet molecular oxygen ((1)O(2)) is formed and this exerts strong antibacterial activity, which prevents marine biofouling without being toxic to marine biota. Vanadium pentoxide nanowires have the potential to be an alternative approach to conventional anti-biofouling agents.

Prevention of marine biofouling on nylon mesh doped with silver iodide

Many textiles have been often used in marine environments for a wide variety of purposes. Consequently, effective and clean methods to prevent biofouling in these textiles are needed. In this study, a nylon mesh doped with AgI was examined for its antifouling performance. The nylon mesh was iodinated with an iodine–potassium iodide aqueous solution and subsequently immersed in silver nitrate solution to form AgI particles in the fiber. SEM-EDX analysis indicated that the AgI crystals were highly incorporated into the nylon 6,6 polymer (173wt% gain). The bactericidal activity of AgI-doped nylon mesh was more than 200 times higher than that of silver-coated nylon mesh. Furthermore, continuous prevention of biofouling in the coastal marine environment was attained for 437days by using the AgI-doped nylon mesh. Since the concentration of the released silver ions from the nylon mesh was estimated to be less than 1ppb, the proposed nylon mesh is useful as an effective and clean method for prevention of biofouling in polymer textiles.

Real-Time Quantification of Microscale Bioadhesion Events In situ Using Imaging Surface Plasmon Resonance (iSPR)

From macro- to nanoscales, adhesion phenomena are all-pervasive in nature yet remain poorly understood. In recent years, studies of biological adhesion mechanisms, terrestrial and marine, have provided inspiration for "biomimetic" adhesion strategies and important insights for the development of fouling-resistant materials. Although the focus of most contemporary bioadhesion research is on large organisms such as marine mussels, insects and geckos, adhesion events on the micro/nanoscale are critical to our understanding of important underlying mechanisms. Observing and quantifying adhesion at this scale is particularly relevant for the development of biomedical implants and in the prevention of marine biofouling. However, such characterization has so far been restricted by insufficient quantities of material for biochemical analysis and the limitations of contemporary imaging techniques. Here, we introduce a recently developed optical method that allows precise determination of adhesive deposition by microscale organisms in situ and in real time; a capability not before demonstrated. In this extended study we used the cypris larvae of barnacles and a combination of conventional and imaging surface plasmon resonance techniques to observe and quantify adhesive deposition onto a range of model surfaces (CH(3)-, COOH-, NH(3)-, and mPEG-terminated SAMs and a PEGMA/HEMA hydrogel). We then correlated this deposition to passive adsorption of a putatively adhesive protein from barnacles. In this way, we were able to rank surfaces in order of effectiveness for preventing barnacle cyprid exploration and demonstrate the importance of observing the natural process of adhesion, rather than predicting surface effects from a model system. As well as contributing fundamentally to the knowledge on the adhesion and adhesives of barnacle larvae, a potential target for future biomimetic glues, this method also provides a versatile technique for laboratory testing of fouling-resistant chemistries.

Use of hydrolytic enzymes to prevent marine biofouling

Use of hydrolytic enzymes to prevent marine biofouling

Synthesis and antibiofouling properties of novel crosslinkable terpolymers containing semifluoroalkyl substituted aromatic side chains

AbstractSynthesis, contact angle analysis, surface properties and biofouling characteristics of novel crosslinkable terpolymers with semifluoroalkyl substituted aromatic side chains have been described. These polymers are targeted for use as coatings to prevent marine biofouling. The marine antifouling properties of these materials were evaluated by laboratory assays employing the fouling diatom Nitzschia and ubiquitous Staphylococcus aureusi. Results indicated that the experimental coatings exhibited better antibiofouling performance than that of a standard Poly(dimethyl siloxane) (PDMS) coating. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

A passive apparatus for controlled-flux delivery of biocides: hydrogen peroxide as an example

A new test method has been developed to estimate the required release rate of hydrogen peroxide (H2O2) to prevent marine biofouling. The technique exploits a well-defined concentration gradient of biocide across a cellulose acetate membrane. A controlled flux of H2O2, an environmentally friendly biocide, was obtained. Larvae of the barnacle, Balanus improvisus, were subjected to known release rates of H2O2 from a surface, under laboratory conditions. It was found that the distribution of settled larvae was not significantly different from the controls when H2O2 fluxes of 5–8 μg cm−2 day−1 were applied. However, release rates of 40 μg cm−2 day−1 significantly displaced the distribution of settled larvae towards the area of the chamber farthest away from the membrane. Membrane tests in seawater (Jyllinge Harbour, Denmark) for over 16 weeks showed that release rates of H2O2 of approximately 2800 μg cm−2 day−1 deterred biofouling efficiently. A H2O2 release rate of about 224 μg cm−2 day−1 resulted in some slime formation, but it was less than that on the H2O2-free control. It appears that to obtain efficient resistance to biofouling in natural seawater requires much higher membrane release rates of H2O2 (factor of between 5 and 50) than laboratory membrane exposure assays using barnacle larvae.

Prevention of marine biofouling for ocean instruments:

現在, むつ研究所では, 海洋表層の二酸化炭素分圧の高密度観測を可能にする漂流型二酸化炭素分圧観測装置 (小型漂流ブイ) の開発を行なっている. 一般に, ブイなどを用いた中・長期の海洋観測では, 観測期間中に機器に生物付着が発生し, 装置の機能や能力を低下させる. 海洋では生物付着防止効果に優れた塗料の防汚剤として有機スズ (トリブチルスズ) が長く利用されてきたが, 海洋環境への負荷が明らかとなり, その使用が禁止された. 本報では, 防汚剤を使用せず塗膜表面物性を利用したシリコーン系防汚塗料が, 海洋観測機器にも利用出来るかを検討するため, 各種防汚塗料とともに防汚効果の比較試験を行なった. 試験開始から500日後, シリコーン系防汚塗料を塗布したプレートが, 試験した塗料の中で最も付着物が少なく (被覆率 : 25%), 優れた防汚効果を示した. この結果より, 開発中の小型漂流ブイの生物付着防止に, シリコーン系防汚塗料を利用した.

Field Study on New Aeration Techniques for Water Environment Restoration in the Amagasaki Canal

The Amagasaki Canal is an enclosed waters located in innermost recesses of Osaka Bay. In this areas, we confirmed that the canal have been polluted and increased the sedimentation of organic matter because the canal is sheltered waters with artificial vertical structures and is affected by waste water from factories. According to theconsumption of oxygen by the organic mud, there is anoxic water in the bottom of the canal. In this study, a field experiment for clarification on the adjustability of the new aeration technique was executed. A basic performance of the diffused aeration based on microscopic bubble was evaluated. Consequently, the control methods of the aeration system and the prevention of marine biofouling in fall were clarified.

Contact Angle Analysis, Surface Dynamics, and Biofouling Characteristics of Cross-Linkable, Random Perfluoropolyether-Based Graft Terpolymers

The conventional approach to prevention of marine biofouling has been the use of antifouling paints and coatings which function through the release of toxins in the immediate vicinity of the ship. Such technology, while admittedly effective, has proven to be responsible for an alarming increase in the levels of organotin and other toxic materials in and around dry docks, harbors, and shipping lanes which experience significant commercial and tourist traffic. Therefore, our objective is the rational design of minimally adhesive, mechanically stable, nontoxic fouling release coatings as responsible and practical alternatives to antifouling technologies. Herein we report on the synthesis and characterization of a series of cross-linkable perfluoropolyether (PFPE) graft terpolymers containing various alkyl (meth)acrylate monomers with glycidal methacrylate as the cure-site monomer. These materials were targeted for use as coatings to prevent marine biofouling. A series of terpolymers were prepared through application of the macromonomer approach, allowing for control of cross-link density, Tg, and modulus. Structure/property relationships were established through compositional variation with regard to the three classes of monomers. The first monomer class was an alkyl (meth)acrylate used to create the continuous phase of the microphase-separated graft terpolymers. Variation between methyl methacrylate (MMA) and n-butyl acrylate (BA) provided materials with a low (−10 °C) and a high (95 °C) Tg for the continuous phase. This was a means of isolating the effect of modulus and Tg on surface properties, while the basic chemical nature of the monomer remained unchanged. The second monomer class contained a curable functional group. Through incorporation of glycidyl methacrylate (GMA) in the monomer feed and manipulation of curing conditions, the relative effect of cross-link density on surface dynamics has been evaluated. The third monomer class was the PFPE macromonomer itself. The incorporation of this macromonomer was used to enhance the release properties of the resulting materials which relied on surface enrichment of the low surface energy PFPE component. Dynamic surface properties of these materials have been evaluated through dynamic surface tensiometry (DST). Herein, it has been demonstrated that contact angle hystersis can be significantly mitigated (i.e., θr is maximized) by as much as 50° through variation in bulk polymer composition, the chemical nature of monomers, cross-link density, modulus, and environmental conditions at the time of cure. The antifouling and fouling-release potential of the experimental coatings were also evaluated by laboratory assays employing the green fouling macroalga Ulva. The results from these initial studies suggest promising antifouling properties, especially with regard to spore settlement which was strongly inhibited on the experimental surfaces. Additionally, those that did settle were only weakly attached with one sample set exhibiting fairly moderate release of the young Ulva plants.

Prevention of marine biofouling using natural compounds from marine organisms

All surfaces that are submerged in the sea rapidly become covered by a biofilm. This process, called biofouling, has substantial economic consequences. Paints containing tri-butyl-tin (TBT) and copper compounds are used to protect marine structures by reducing biofouling. However, these compounds have damaging effects on the marine environment, as they are not biodegradable. It has been noted that many seaweeds and invertebrates found in the sea are not covered by a mature biofilm. This is due to the release of compounds into the surrounding seawater that deter the settlement of fouling organisms. In addition, seaweeds and invertebrates have bacteria on their surfaces that produce compounds to deter settling organisms. The production of compounds by bacteria and their living hosts work in concert to protect the hosts' surfaces. All of these compounds can be collected so they may be natural alternatives to TBT and copper compounds. However, the benefits associated with the use of bacteria as sources of these compounds means that bacteria are the organisms of choice for obtaining natural products for antifouling coatings.

Prevention of marine biofouling using a conductive paint electrode

Conductive paint electrode was used for marine biofouling on fishing nets by electrochemical disinfection. When a potential of 1.2 V vs. a saturated calomel electrode (SCE) was applied to the conductive paint electrode, Vibrio alginolyticus cells attached on the electrode were completely killed. By applying a negative potential, the attached cells were removed from the surface of the electrode. Changes in pH and chlorine concentration were not observed at potentials in the range -0.6 approximately 1.2 V vs. SCE. In a field experiment, accumulation of the bacterial cells and formation of biofilms on the electrode were prevented by application of an alternating potential, and 94% of attachment of the biofouling organisms was inhibited electrically on yarn used for fishing net coated with conductive paint. Copyright 1998 John Wiley & Sons, Inc.

Prevention of marine biofouling using a conductive paint electrode

Conductive paint electrode was used for marine biofouling on fishing nets by electrochemical disinfection. When a potential of 1.2 V vs. a saturated calomel electrode (SCE) was applied to the conductive paint electrode, Vibrio alginolyticus cells attached on the electrode were completely killed. By applying a negative potential, the attached cells were removed from the surface of the electrode. Changes in pH and chlorine concentration were not observed at potentials in the range −0.6 ∼1.2 V vs. SCE. In a field experiment, accumulation of the bacterial cells and formation of biofilms on the electrode were prevented by application of an alternating potential, and 94% of attachment of the biofouling organisms was inhibited electrically on yarn used for fishing net coated with conductive paint. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:374–378, 1998.

Tributyltin: case study of a chronic contaminant in the coastal environment

As early as 1975, significant and repeated disturbances were observed to occur in the Crassostrea gigas oyster farms of the Arcachon Bay along the French Atlantic Coastline. TBT contamination of the local breeding waters was found to be responsible for failure to reproduce and for anomalies occurring in the shell calcification of adult oysters leading to stunted growth. On 17 January 1982, the French Ministry of the Environment issued a 3 month ban on the sale of marine anti-fouling paints with an organotin compound content exceeding 3%. The Ministerial ban was subsequently renewed and reinforced and ultimately converted into an enforcement decree transcribing an European Union directive into French law, in October 1992. The ban was the first official action in response to a growing awareness to the TBT-related pollution of some coastal areas and to its unacceptable impact on shellfish farming. These measures were adopted as soon as the first scientific evidence of a causal relationship was established between tributyltin and oyster shell anomalies. Since then numerous research studies have been conducted on the geochemical behavior of tributyltin, its ecotoxicity and on TBT-related risks presented by antifouling paints. The knowledge gained on this topic since 1982 reveals in particular that: • TBT is extremely toxic to aquatic organisms in general and to molluscs in particular for which the NOELs are below 1 ng l -1(imposex, calcification anomalies), • Contamination levels can reach very high values in port areas, and even exceed no effect levels beyond which mollusc reproduction and growth are affected, in estuaries or semi-enclosed areas, • Contamination of breeding waters has a significant economic impact, jeopardizing the sustainable development of some highly exposed marine activities, • The ban on TBT use in antifouling paints for crafts under 25 m represents an efficient way of reducing TBT inputs in coastal areas and restoring proper water quality, • The regulations adopted by many countries to ban or restrict TBT use on ships sailing along the coastline, have prompted manufacturers to develop less toxic paints. Fifteen years after TBT was first implicated as a major cause of coastal contamination, the issue no longer lies in finding out under which conditions TBT could still be used in antifouling paints, but rather in developing environmentally-harmless formulations. While the ban on TBT-based paints may be justified due to their harmful impact on coastal ecosystems, substitutes based on the release of biocides (copper oxide, pesticides …) also give rise to major concerns. Prevention of marine biofouling is not motivated merely by esthetics: it responds to economic needs and to navigation safety requirements. Protection of the ships while preserving the coastal ecosystems remains a major challenge for future research.

Prevention of Marine Biofouling by Ozonation Using Plate-Type Heat Exchanger.

The prevention of marine biofouling by ozonation is investigated experimentally. A plate-type heat exchanger made of titanium is used. The length of the plate is 880 mm, the width 300 mm, and the thickness 0.5 mm. The total number of plates is 6 and the total heat transfer area is 0.8m2. The ozonation of the sea water is performed for 5 minutes per day for about one month. The prevention of marine biofouling is evaluated from the measured value of overall heat transfer coefficient. In this experiment, the mean concentration of ozone is 2 mg/l, and the sea water velocity in the heat exchanger is 0.5m/s. It is clearly shown that an effective prevention of marine biofouling is attained by ozonation.