Fouling Organisms Research Articles

Quantification of biofouling on nets: a comparison of wet weight measurements and optical (image analysis) methods

Biofouling has been shown to have a number of negative impacts on marine aquaculture. Studies aiming to characterize, inhibit or remove biofouling typically require the quantification of biofouling assemblages on cage nets. Several methods have been used for this whose results are not easily comparable. This study compares three widely used biofouling quantification methods: measurements of (1) wet weight and the (2) analysis of images taken of nets under water and (3) in air to determine percent net aperture occlusion. Comparisons were made for two common types of net biofouling, hydroids and ascidians. Both image analysis methods correlate linearly for both biofouling types, but percent net aperture occlusion calculated from images taken under water (PNOUW) was generally higher in comparison with images taken in air (PNOair). PNOUW was about 50 % larger than PNOair for hydroids, which collapsed when exposed to air and about 10 % larger for ascidians, which retained much of their volume when lifted from the water. Both PNO measures correlate linearly with wet weight for both biofouling types, but for hydroids this study found an upper limit for this correlation at PNOair of around 80 % and a wet weight of about 2 kg m−2. The upper limit for a linear correlation was given by complete net aperture occlusion from wet weight of about 1 kg m−2. Transfer functions were derived between PNOUW, PNOair and wet weight. Such transfer functions may allow the comparison of studies using different quantification methods, but similar fouling organisms.

Temperature, space availability, and species assemblages impact competition in global fouling communities

Competition drives community composition in many ecosystems and can influence the spread of invasive species. Marine fouling communities are excellent study systems for competition because of space limitation and the abundance of invasive species. While many studies have examined individual or site-specific responses to changes in temperature or presence of invasive species, it is difficult to predict ecological impacts without assessing interspecific interactions over a wide geographic range. This study compared interactions between several globally distributed invasive fouling species over a broad geographic range. Weekly examination of photographs of settlement panels in marinas at 18 sites around the world allowed for the quantification of competitive outcomes. In the north Atlantic, experimental panels became covered with fouling organisms exponentially faster at warmer temperatures, while northeast and south Pacific sites did not. An invasive ascidian (Diplosoma listerianum) and bryozoan (Bugula neritina) were strong competitors, but most species displayed a negative response in high competition settings where there was little available space. Two species (Botryllus schlosseri and Botrylloides violaceus) had better competitive outcomes at cooler temperatures, possibly due to fewer strong competitors at these sites. Thus, warmer sites with little open space and multiple strong competitors are likely most resistant to future invasions, while colder sites with more open space and weaker competitors would be more susceptible to invasive species. These results suggest that the establishment and spread of invasive fouling species is likely to be influence by seawater temperature, available space, and the competitive abilities of community members.

Recyclable plastics as substrata for settlement and growth of bryozoans Bugula neritina and barnacles Amphibalanus amphitrite

Plastics are common and pervasive anthropogenic debris in marine environments. Floating plastics provide opportunities to alter the abundance, distribution and invasion potential of sessile organisms that colonize them. We selected plastics from seven recycle categories and quantified settlement of (i) bryozoans Bugula neritina (Linnaeus, 1758) in the lab and in the field, and of (ii) barnacles Amphibalanus (= Balanus) amphitrite (Darwin, 1854) in the field. In the laboratory we cultured barnacles on the plastics for 8 weeks and quantified growth, mortality, and breaking strength of the side plates. In the field all recyclable plastics were settlement substrata for bryozoans and barnacles. Settlement depended on the type of plastic. Fewer barnacles settled on plastic surfaces compared to glass. In the lab and in the field, bryozoan settlement was higher on plastics than on glass. In static laboratory rearing, barnacles growing on plastics were initially significantly smaller than on glass. This suggested juvenile barnacles were adversely impacted by materials leaching from the plastics. Barnacle mortality was not significantly different between plastic and glass surfaces, but breaking strength of side plates of barnacles on polyvinyl chloride (PVC) and polycarbonate (PC) were significantly lower than breakage strength on glass. Plastics impact marine ecosystems directly by providing new surfaces for colonization with fouling organisms and by contaminants shown previously to leach out of plastics and impact biological processes.

The lipopeptide 6-2 produced by Bacillus amyloliquefaciens anti-CA has potent activity against the biofilm-forming organisms

Both the whole cells and protoplasts of Pseudomonas aeruginosa PAO1 and Bacillus cereus, two biofilm-forming bacteria, were disrupted by the lipopeptide 6-2 produced by Bacillus amyloliquefaciens anti-CA. The lipopeptide 6-2 could also effectively inhibit the formation of biofilms and disperse pre-formed biofilms. Live/dead staining of the biofilms grown in the absence or presence of the lipopeptide 6-2 showed that more dead bacterial cells in the presence of the lipopeptide than those in the absence of the lipopeptide and biofilm formation was greatly reduced by the lipopeptide 6-2. Expression of the PslC gene related to exopolysaccharides in P. aeruginosa PAO1 was also inhibited. All these results demonstrated that the lipopeptide 6-2 produced by B. amyloliquefaciens anti-CA had a high activity against biofilm-forming bacteria. The lipopeptide 6-2 also killed the larvae of Balanus amphitrite and inhibit the germination of Laminaria japonica spore and growth of protozoa, all of which were the fouling organisms in marine environments.

Chlorination-induced genotoxicity in the mussel Perna viridis: assessment by single cell gel electrophoresis (comet) assay

Mussels are important fouling organisms in the cooling water systems of coastal power plants. Continuous low-dose chlorination (CLDC) is being practiced as an effective method to control mussel biofouling in power plant cooling water systems. CLDC effectively controls mussel fouling by discouraging larval settlement rather than by killing the larvae or adults. Mussels are an integral part of the natural benthic community in the receiving water body where the coolant water is discharged. Hence, from a toxicological point of view, they can serve as both target and non-target organisms. Previous researchers have indicated that chlorine residual, rather than elevated temperature, can be the major stress factor in the effluents released from coastal power plants. However, very little data are available on the sub-lethal effects of low level chlorination on representative benthic fauna. In this study, we used native and transplanted mussels (Perna viridis) to study lethal and sub-lethal effects of chlorination in the cooling water circuit of an operating power plant. Experiments involving comet assay suggested that CLDC can cause DNA damage in treated mussels. However, activation of DNA repair appeared to get initiated after the accrued damage reached a threshold. The results indicate that, at chlorine residual levels observed at the discharge point, exposure to chlorinated effluents is unlikely to cause significant genetic damage to mussels in the recipient water body.

Preliminary Assessment of Biofouling on Offshore Mussel Farms

AbstractBiofouling is a significant operational problem for the aquaculture industry globally; however, options for on‐farm management are limited. In New Zealand, the green‐lipped mussel,Perna canaliculus, has historically been cultivated at inshore locations, but increased competition for space has led the industry to develop offshore farming sites several kilometers from the coast. We hypothesize that the distance to these farm sites from coastal locations, and their placement over extensive soft‐sediment habitats, may provide a barrier to colonization by biofouling species with limited natural dispersal abilities. A study of two offshore mussel farms revealed that they supported relatively impoverished biofouling communities by comparison with inshore mussel farms and other artificial structures. Offshore sites had a relatively low number of taxa and a low prevalence of short‐dispersing organisms such as ascidians, which are a problematic group of fouling organisms in aquaculture. We suggest that newly established offshore marine farms have the potential to be kept free of a range of problematic fouling organisms, provided the introduction of such species via human transport pathways can be mitigated.

The invasive sun coral Tubastraea coccinea hosting a native Christmas tree worm at Cura\xe7ao, Dutch Caribbean

Interspecific relationships of invasive species hosting a native associated species are noteworthy, particularly if the invasive does not have a similar relationship in its native range. The azooxanthellate Indo-Pacific coral Tubastraea coccinea (Dendrophylliidae) has become a widespread invasive in the tropical western Atlantic, where it was probably introduced as a fouling organism in the 1930s. During recent coral reef surveys this invader has been observed as host for a native tube worm, Spirobranchus giganteus (Serpulidae), at Curaçao, where this association was most commonly found on a shipwreck. Although Spirobranchus species are known to live in association with various shallow-water corals in the Atlantic and the Indo-Pacific, none of them has been recorded as an associate of a dendrophylliid or of an azooxanthellate coral before. This new association may be possible because of the generalist host selection of S. giganteus, which could have been facilitated by the availability of shipwrecks and other man-made substrates.

Influence of intertidal Manila clam Venerupis philippinarum aquaculture on biogeochemical fluxes

Bivalve aquaculture introduces high densities of farmed organisms to the natural environment with potential consequences on a number of ecosystem processes, including modifi- cation of nutrient fluxes (e.g. NH4, NOX, PO4, and Si(OH)4) and benthic respiration, and may impact benthic communities. Infaunal clam culture may influence the environment due to the clams themselves (their metabolic processes (e.g. feeding, respiration), production of faeces/ pseudo faeces, and/or trapping of organic matter), the farm structures, or the fouling on these structures. This study examined how farmed Manila clams Venerupis philippinarum, the nets placed on beaches to protect them from predators, and the fouling organisms growing on these nets modify nutrient fluxes, benthic respiration, and benthic community structure in coastal British Columbia, Canada. In 2012, a manipulative experiment involving sixty 2.25 m 2 plots and 6 treat- ments was conducted on an intertidal farmed beach to evaluate the effect of clams (presence/ absence) and net status (fouled, cleaned, and absent). Percentage organic matter in the first cen- timetre of sediment was significantly greater with the presence of clams than without. The abun- dance and taxonomic richness of organisms in sediments were significantly affected by net status. Nutrient fluxes and oxygen consumption increased significantly with the presence of clams, the latter also increasing with the presence of nets and fouling on nets (incubated under dark condi- tions). These results show that farmed clams and the structures used to culture them influence several environmental parameters, and provide a better understanding of the role of these factors in modulating the benthic environment.

Rapid treatment of vessels fouled with an invasive polychaete, Sabella spallanzanii, using a floating dock and chlorine as a biocide

Chlorine solution was added to the water encapsulated within a proprietary ‘floating dock’ to treat a vessel infested with the invasive polychaete Sabella spallanzanii. The chlorine was added as sodium dichloroisocyanurate (‘dichlor’) at an initial concentration of 200 mg l−1 of free available chlorine (FAC). This concentration killed 99% of S. spallanzanii in their tubes during a 4-h exposure in laboratory tests (EC99 160 mg FAC l−1). The concentration of FAC in the floating dock declined to ~50 mg l−1 after 4 h and < 10 mg l–1 after 16 h. Residual FAC was neutralised with thiosulphate at completion of exposure. A sample of 30 S. spallanzanii individuals collected from the hull after treatment all showed morphological damage and 28 showed no response to touch. Re-examination of the hull after 6 d found no live worms or other fouling organisms. This method provides a cost-effective, rapid means of treating hull fouling.

Anti-fouling behavior of polymer brush immobilized surfaces

Nature-inspired material design concepts and recent progress on anti-fouling polymer materials are reviewed, and our recent researches on anti-fouling studies with polymer brushes are summarized. Zwitterionic polyelectrolyte brush immobilized surfaces represent significant anti-fouling for bio-macromolecules, oil foulants, marine fouling organisms and pipeline foulants. The anti-fouling mechanism was considered on the basis of the wetting, lubrication, hydrated chain dimension and hydrogen-bonding structure of hydrated water in the polyelectrolyte brushes.

Design and development of a data management system for marine fouling organisms

Biofouling, the unwanted assemblage of marine organisms colonizing submerged parts of ships and artificial facilities, has a negative impact on human activities related to the sea. The development of fouling communities is closely related to a variety of factors such as temperature, salinity, depth, season, immersion time, geographic location, distance from shore and substratum type. To facilitate systematic analysis and processing of data on marine fouling and clarify the intrinsic relationship between the various elements mentioned above, it is necessary to build a technical platform to integrate scattered and sporadic information and to share this data through a network. By means of internet technology, the ASP.NET framework and MySQL database, the MS Visual Studio 2013 software was used to devise a data management system for marine fouling organisms under the Windows 7 or Windows Server 2008 R2 (recommended) operating system. From the system, data integration, storage and management of fouling organisms are implemented via the network. Query and retrieval of data can be conducted under single or multiple search conditions and the results are exported in several formats according to the user’s requirements. The data management system for marine fouling organisms provides a useful and effective way to help data analysis and decision-making for research, industry and administration. ·研究报告· 第 7 期 冯华等: 海洋污损生物数据管理系统的设计与构建 839

First record of the non-native bryozoan Amathia (= Zoobotryon) verticillata (delle Chiaje, 1822) (Ctenostomata) in the Galápagos Islands

The warm water marine bryozoan Amathia (= Zoobotryon) verticillata (delle Chiaje, 1822) is reported for the first time in the Galapagos Islands based upon collections in 2015. Elsewhere, this species is a major fouling organism that can have significant negative ecological and economic effects. Comprehensive studies will be necessary to determine the extent of the distribution of A. verticillata in the Galapagos and its effects on native species. The establishment of A. verticillata emphasizes the need for regular monitoring of those vectors that could bring additional non-native species to the Archipelago.

Comparison of Substrates for Eastern Oyster (Crassostrea virginica) Spat Settlement in the Loxahatchee River Estuary, Florida

The eastern oyster [Crassostrea virginica (Gmelin, 1791)] is an important epibenthic species in estuarine and coastal marine ecosystems, providing habitat for commercially valuable species and enhancing ecosystem function. One way to assess oyster population structure and the potential suitability of oyster restoration sites is through deployment of adult oyster shells or other substrates, and quantifying oyster spat settlement. The suitability of travertine tiles versus axenic adult oyster shells for C. virginica settlement was compared by deploying shellstrings with tiles and shells in four different locations across two seasons (fall or spring) in the subtropical, Loxahatchee River estuary, FL. There was no significant difference in spat densities on oyster shells compared with tile tops and bottoms, although there was significant spatial and temporal variation in spat settlement. Spat were slightly more abundant on the top of deployed tiles compared with the bottom, which differs from typical C. virginica settlement behavior. One possible explanation may be the presence of other fouling organisms on the bottom of tiles which decrease oyster settlement rates. Results show that oyster spat settlement was indistinguishable between travertine tiles and oyster shells and thus suggest that travertine tiles are preferable to axenic oyster shells because spat settlement can be precisely quantified per unit area.

Sensitivity of veliger larvae of Mytilus edulis and mussel of various sizes to chlorination

The blue mussel Mytilus edulis is one of the dominant fouling organisms in cooling water systems. In this work, how veliger larvae and different size groups of the mussels responded against chlorine dosage was examined. Veliger larvae mortality was studied at different residual chlorine concentrations (0.05–0.5 mg L−1), and it was found that a chlorine dose of 0.5 mg L−1 is 4 times as effective as 0.05 mg L−1 and twice as effective as 0.1 mg L−1. Mortality of 100% for three size groups (1.4, 14, and 25 mm) and relative physiological activities of two size groups (14 and 25 mm) were observed. The exposure duration for 100% mortality of mussels decreased with the increasing residual chlorine concentration (0.1–4.0 mg L−1). Mussel size was also found to be an important factor, considering that the continuation times for mussel mortality were 28 h for the 1.4 mm and 410 h for the 25 mm size groups. All size groups showed progressive reduction in physiological activities, such as oxygen consumption, foot activity, and byssus thread production with increasing chlorine dose (0.05–1.0 mg L−1); the two data-sets were strongly correlated with each other. The results of this study should be of significance for optimizing the chlorine content, and minimize the environmental threat to industries where mussels are the dominant fouling organisms.

Embryonic and larval development of the invasive biofoulerMytilopsis sallei(Récluz, 1849) (Bivalvia: Dreissenidae)

The marine dreissenid bivalve Mytilopsis sallei is a fouling organism that has invaded habitats outside its original range. Understanding its early development will be useful for early detection in the environment, for species identification in ballast water and for development of control strategies targeted at early life stages, which will help us better manage this important invader. The processes of embryogenesis, shell formation and larval development of M. sallei are described here for the first time by using light and scanning electron microscopy. Released oocytes are 64 mm in diameter. Fertilized eggs were incubated at 27+ 1 8C. The trochophore, with an apical tuft and a prototroch, developed by 6.0+ 2.3 h postfertilization (hpf). At 16.5+ 4.2 hpf, D-shaped veligers with shell length (SL, mean+ SD) of 87.3+ 8.2 mm appeared, each possessing a velum and a calcified shell. At 2–3 d postfertilization (dpf ), the D-shaped veligers developed into umbonate larvae (SL ¼ 111.9+ 10.7 mm), the last obligate freeswimming veliger stage. Pediveligers (SL ¼ 232.8+ 37.1 mm) observed at 6–8 dpf could either swim using their velum or crawl with their foot. Pediveligers settled by secreting byssal threads and metamorphosed to plantigrades (SL ¼ 298.7+ 45.2 mm) 8–10 dpf. It is noteworthy that the larvae of this invasive bivalve are capable of settlement within 10 d. This is the first detailed study of early shell formation of a species of the family Dreissenidae. Shell field invagination appeared during gastrulation, secreting shell material by expanding over both sides in a saddle-shape during the trochophore stage.

Drag of Clean and Fouled Net Panels--Measurements and Parameterization of Fouling.

Biofouling is a serious problem in marine aquaculture and it has a number of negative impacts including increased forces on aquaculture structures and reduced water exchange across nets. This in turn affects the behavior of fish cages in waves and currents and has an impact on the water volume and quality inside net pens. Even though these negative effects are acknowledged by the research community and governmental institutions, there is limited knowledge about fouling related effects on the flow past nets, and more detailed investigations distinguishing between different fouling types have been called for. This study evaluates the effect of hydroids, an important fouling organism in Norwegian aquaculture, on the forces acting on net panels. Drag forces on clean and fouled nets were measured in a flume tank, and net solidity including effect of fouling were determined using image analysis. The relationship between net solidity and drag was assessed, and it was found that a solidity increase due to hydroids caused less additional drag than a similar increase caused by change in clean net parameters. For solidities tested in this study, the difference in drag force increase could be as high as 43% between fouled and clean nets with same solidity. The relationship between solidity and drag force is well described by exponential functions for clean as well as for fouled nets. A method is proposed to parameterize the effect of fouling in terms of an increase in net solidity. This allows existing numerical methods developed for clean nets to be used to model the effects of biofouling on nets. Measurements with other types of fouling can be added to build a database on effects of the accumulation of different fouling organisms on aquaculture nets.

In situ measurements of diatom adhesion to silicone-based ship hull coatings

Diatoms are tenacious fouling organisms and have been observed to remain on ship hull coatings at speeds in excess of 30 knots. This study was designed to investigate the adhesion of diatoms to three fouling release ship hull coatings, Intersleek 700 (IS 700), Intersleek 900 (IS 900), and Hempasil X3 (HX3) and one reference coating Dow Corning 3140 (DC 3140), that were exposed at a static immersion test site. The coatings were subjected to water jet testing to determine biofilm adhesion and the subsequent pressures needed to remove specific diatom species. Differences in community composition were observed among coatings in the pre and post water jet evaluation. All diatoms were removed from HX3 after 0.08 MPa; however, the pressure required to completely remove biofilm and diatoms on DC 3140, IS 700, and IS 900 varied. Biofilm removal pressure ranged from 0.08 to 0.40 MPa on DC 3140, 0.16 to 0.40 MPa on IS 700, and 0.08 to 0.40 MPa on IS 900. Significant differences were observed among coatings for removal pressure, as well as initial diatom abundance; however, differences were dependent on the sampling date. The diatom genera which required the highest pressure for removal from the fouling release coatings were Achnanthes, Amphora, Cocconeis, Navicula, and Synedra. The results show differences in the adhesion strength of diatoms to different fouling release coatings and highlight those species, which have the potential to contribute to biofilms remaining on ship hulls once a vessel is underway.

Comparative research on inorganic carbon acquisition by the macroalgae Ulva prolifera (Chlorophyta) and Pyropia yezoensis (Rhodophyta)

The red macroalga Pyropia/Porphyra is one of the most important marine crops in the world; Pyropia cultivation is severely affected by the green macroalga Ulva spp., a fouling organism. In this study, growth competition and acquisition of dissolved inorganic carbon (Ci) by Ulva prolifera and Pyropia yezoensis were investigated to understand the physiological characteristics of the two species. Competition experimental results showed that the relative growth rate of U. prolifera was not affected, whereas the growth rate of P. yezoensis was significantly inhibited. U. prolifera exhibited a competitive advantage when these two species were cultured together. The two algal species displayed high pH compensation points, suggesting that U. prolifera and P. yezoensis can photosynthesize by using HCO3 −; the utilization ability of U. prolifera is stronger than that of P. yezoensis. The net photosynthetic rates of P. yezoensis and U. prolifera were significantly inhibited by the carbonic anhydrase (CA) inhibitors acetazolamide and 6-ethoxyzolamide indicating that CA is implicated in carbon-concentrating mechanisms (CCM). 4,4′-diisothiocyano-stilbene-2,2′-disulfonate (DIDS), another inhibitor that prevents direct HCO3 − uptake, did not significantly affect U. prolifera. Conversely, DIDS can sharply decrease the photosynthetic rate of P. yezoensis, particularly at high pH. U. prolifera and P. yezoensis also showed CO2-limited photosynthesis by which the half-saturating concentration of Ci exceeds that of seawater. U. prolifera did not show active HCO3 − uptake; instead, U. prolifera used HCO3 − via extracellular CA for photosynthetic carbon fixation. U. prolifera also utilizes extracellular CA-mediated HCO3 − absorption to a higher extent than P. yezoensis. By contrast, P. yezoensis shows active HCO3 − uptake and extracellular CCMs for photosynthetic carbon fixation. Therefore, these two algal species can survive in changing environments with high pH and low Ci concentration because of the action of CCMs.

From broad-spectrum biocides to quorum sensing disruptors and mussel repellents: antifouling profile of alkyl triphenylphosphonium salts.

‘Onium’ compounds, including ammonium and phosphonium salts, have been employed as antiseptics and disinfectants. These cationic biocides have been incorporated into multiple materials, principally to avoid bacterial attachment. In this work, we selected 20 alkyl-triphenylphosphonium salts, differing mainly in the length and functionalization of their alkyl chains, in fulfilment of two main objectives: 1) to provide a comprehensive evaluation of the antifouling profile of these molecules with relevant marine fouling organisms; and 2) to shed new light on their potential applications, beyond their classic use as broad-spectrum biocides. In this regard, we demonstrate for the first time that these compounds are also able to act as non-toxic quorum sensing disruptors in two different bacterial models (Chromobacterium violaceum and Vibrio harveyi) as well as repellents in the mussel Mytilus galloprovincialis. In addition, their inhibitory activity on a fouling-relevant enzymatic model (tyrosinase) is characterized. An analysis of the structure-activity relationships of these compounds for antifouling purposes is provided, which may result useful in the design of targeted antifouling solutions with these molecules. Altogether, the findings reported herein provide a different perspective on the biological activities of phosphonium compounds that is particularly focused on, but, as the reader will realize, is not limited to their use as antifouling agents.

Grooming using rotating brushes as a proactive method to control ship hull fouling

Grooming may be defined as the frequent and gentle cleaning of a ship hull coating, when it is in port or idle, to prevent the establishment of fouling. This study assessed the effectiveness of grooming with a five-headed rotating brush system on epoxy, ablative copper and two silicone fouling release (FR) coatings. These coatings were placed under static immersion at Port Canaveral, FL on a weekly and biweekly frequency. The results showed that grooming reduced fouling on all surfaces and was able to prevent fouling on the ablative copper and FR coatings when performed weekly. It was concluded that the grooming tool used for these tests was sufficient to remove biofilm and most hard fouling. However, when fouling pressure increased or when grooming was performed less frequently, insufficient forces were imparted by the brush to remove all of the established hard fouling organisms.