Non-indigenous species contribute equally to biofouling communities in international vs local ports in the Biobío region, Chile.

Growing coastal urbanization together with the intensification of maritime traffic are major processes explaining the increasing rate of biological introductions in marine environments. To investigate the link between international maritime traffic and the establishment of non-indigenous species (NIS) in coastal areas, biofouling communities in three international and three nearby local ports along 100 km of coastline in south-central Chile were compared using settlement panels and rapid assessment surveys. A larger number of NIS was observed in international ports, as expected in these 'invasion hubs'. However, despite a few environmental differences between international and local ports, the two port categories did not display significant differences regarding NIS establishment and contribution to community structure over the studied period (1.5 years). In international ports, the free space could be a limiting factor for NIS establishment. The results also suggest that local ports should be considered in NIS surveillance programs in Chile.

Multipurpose Antifouling Coating of Solid Surfaces with the Marine-Derived Polymer Fucoidan.

The control of biofouling, which is the unwanted adsorption of biomolecules and organisms on solid surfaces, is a prerequisite for wider applicability of the functional materials that are currently being used in biomedical industries. One of the frequently used methods for controlling biofouling is the use of surface coatings with antifouling materials. Herein, fucoidan, which is a marine-derived polysaccharide, is reported as a new type of antifouling material that is safe and broadly applicable. Fucoidan is conjugated with catechols, which are known to act as adhesives for grafting functional molecules onto solid substrates. Fucoidan catechol (FD-C) is subsequently utilized for robust fucoidan coatings of solid substrates, and the FD-C-coated surfaces show excellent antifouling capability for fouling organisms, including platelets and bacteria. The FD-C coating is also confirmed to be nonirritating upon skin contact, demonstrating its potential use in public places for inhibiting contagions.

Release of PAHs and heavy metals in coastal environments linked to leisure boats.

Leisure boats are responsible for elevated levels of heavy metals and PAHs in sediments in- and near marinas and natural harbours. As these compounds are released directly into the water column they also pose a threat to organisms in the pelagic environment. Passive samplers were deployed during peak and post tourist season in the water column of natural harbours, leisure boat waterways and small marinas to measure the dissolved fraction of PAHs and metal ions. Differences between seasons indicative of leisure boat activities were found as PAH composition differed between peak and post season for natural harbours and waterways, where heavier PAHs increased during peak season. During peak season, metal samplers were covered by biofouling, which likely affected the uptake. Post season metal concentrations differ between locations, with concentrations exceeding quality standards at near mainland locations where boats are maintained, compared to the sites in the archipelago.

Buzz off! An evaluation of ultrasonic acoustic vibration for the disruption of marine micro-organisms on sensor-housing materials.

Biofouling is a process of ecological succession which begins with the attachment and colonization of micro-organisms to a submerged surface. For marine sensors and their housings, biofouling can be one of the principle limitations to long-term deployment and reliability. Conventional antibiofouling strategies using biocides can be hazardous to the environment, and therefore alternative chemical-free methods are preferred. In this study, custom-made testing assemblies were used to evaluate ultrasonic vibration as an antibiofouling process for marine sensor-housing materials over a 28-day time course. Microbial biofouling was measured based on (i) surface coverage, using fluorescence microscopy and (ii) bacterial 16S rDNA gene copies, using Quantitative polymerase chain reaction (PCR). Ultrasonic vibrations (20 KHz, 200 ms pulses at 2-s intervals; total power 16·08 W) significantly reduced the surface coverage on two plastics, poly(methyl methacrylate) and polyvinyl chloride (PVC) for up to 28 days. Bacterial gene copy number was similarly reduced, but the results were only statistically significant for PVC, which displayed the greatest overall resistance to biofouling, regardless of whether ultrasonic vibration was applied. Copper sheet, which has intrinsic biocidal properties was resistant to biofouling during the early stages of the experiment, but inhibited measurements made by PCR and generated inconsistent results later on. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, ultrasonic acoustic vibration is presented as a chemical-free, ecologically friendly alternative to conventional methods for the perturbation of microbial attachment to submerged surfaces. The results indicate the potential of an ultrasonic antibiofouling method for the disruption of microbial biofilms on marine sensor housings, which is typically a principle limiting factor in their long-term operation in the oceans. With increasing deployment of scientific apparatus in aquatic environments, including further offshore and for longer duration, the identification and evaluation of novel antifouling strategies that do not employ hazardous chemicals are widely sought.

Acidification effects on biofouling communities: winners and losers.

How ocean acidification affects marine life is a major concern for science and society. However, its impacts on encrusting biofouling communities, that are both the initial colonizers of hard substrata and of great economic importance, are almost unknown. We showed that community composition changed significantly, from 92% spirorbids, 3% ascidians and 4% sponges initially to 47% spirorbids, 23% ascidians and 29% sponges after 100 days in acidified conditions (pH 7.7). In low pH, numbers of the spirorbid Neodexiospira pseudocorrugata were reduced ×5 compared to controls. The two ascidians present behaved differently with Aplidium sp. decreasing ×10 in pH 7.7, whereas Molgula sp. numbers were ×4 higher in low pH than controls. Calcareous sponge (Leucosolenia sp.) numbers increased ×2.5 in pH 7.7 over controls. The diatom and filamentous algal community was also more poorly developed in the low pH treatments compared to controls. Colonization of new surfaces likewise showed large decreases in spirorbid numbers, but numbers of sponges and Molgula sp. increased. Spirorbid losses appeared due to both recruitment failure and loss of existing tubes. Spirorbid tubes are comprised of a loose prismatic fabric of calcite crystals. Loss of tube materials appeared due to changes in the binding matrix and not crystal dissolution, as SEM analyses showed crystal surfaces were not pitted or dissolved in low pH conditions. Biofouling communities face dramatic future changes with reductions in groups with hard exposed exoskeletons and domination by soft-bodied ascidians and sponges.

Biofouling of reverse-osmosis membranes under different shear rates during tertiary wastewater desalination: microbial community composition.

We investigated the influence of feed-water shear rate during reverse-osmosis (RO) desalination on biofouling with respect to microbial community composition developed on the membrane surface. The RO membrane biofilm's microbial community profile was elucidated during desalination of tertiary wastewater effluent in a flat-sheet lab-scale system operated under high (555.6 s(-1)), medium (370.4 s(-1)), or low (185.2 s(-1)) shear rates, corresponding to average velocities of 27.8, 18.5, and 9.3 cm s(-1), respectively. Bacterial diversity was highest when medium shear was applied (Shannon-Weaver diversity index H' = 4.30 ± 0.04) compared to RO-membrane biofilm developed under lower and higher shear rates (H' = 3.80 ± 0.26 and H' = 3.42 ± 0.38, respectively). At the medium shear rate, RO-membrane biofilms were dominated by Betaproteobacteria, whereas under lower and higher shear rates, the biofilms were dominated by Alpha- and Gamma- Proteobacteria, and the latter biofilms also contained Deltaproteobacteria. Bacterial abundance on the RO membrane was higher at low and medium shear rates compared to the high shear rate: 8.97 × 10(8) ± 1.03 × 10(3), 4.70 × 10(8) ± 1.70 × 10(3) and 5.72 × 10(6) ± 2.09 × 10(3) copy number per cm(2), respectively. Interestingly, at the high shear rate, the RO-membrane biofilm's bacterial community consisted mainly of populations known to excrete high amounts of extracellular polymeric substances. Our results suggest that the RO-membrane biofilm's community composition, structure and abundance differ in accordance with applied shear rate. These results shed new light on the biofouling phenomenon and are important for further development of antibiofouling strategies for RO membranes.

[Mechanism of membrane fouling and filtration characteristics in a membrane bioreactor for industrial wastewater treatment].

The influence of mixed liquor suspended solids (MLSS), soluble microbial product (SMP), extracellular polymeric substance (EPS), colloidal particles and other factors contributed to membrane fouling was analyzed in this pilot test by membrane bioreactor (MBR) process for the leather printing and dyeing industrial park mixed wastewater treatment. The results showed that slight membrane fouling occurred after 120-day experiment with an observable increase in membrane resistance R20 from 1.5 x 10(12) m(-1) to 1.8 x 10(12) m(-1). Also, a linear correlation was found between the proportion of colloidal particles concentration in TOC of MBR former solution and membrane filtration resistance change. However, the change of MLSS, SMP, EPS and other factors was not correlated with the membrane filtration resistance change. Therefore, the colloidal particle was considered to be the main factor causing membrane fouling, which attached to the membrane surface and deposited to block the membrane pore.

Thermal treatment as a method to control transfers of invasive biofouling species via vessel sea chests.

This study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. In laboratory trials, three temperature regimes (37.5°C for 60 min, 40°C for 30min and 42.5°C for 20 min) were tested on a range of temperate taxa commonly found in sea chests. Field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. During laboratory trials, 100% mortality was achieved across all three treatments for the majority of taxa; the exceptions being the barnacle Elminius modestus and the oyster Crassostrea gigas. Temperature tolerance limits observed in the laboratory were successfully replicated under simulated sea chest conditions; however, a failure to achieve even heat distribution was an obstacle to achieving uniform mortality. This study provides guidance on the temperature/exposure parameters required for vessels plying temperate latitudes, and demonstrates that heated seawater has potential for controlling biofouling in vessel sea chests.

Biosecurity risks associated with in-water and shore-based marine vessel hull cleaning operations.

The removal of biofouling from vessels during hull cleaning can pose a biosecurity threat if viable, non-indigenous organisms are released into the aquatic environment. However, the effect of cleaning on biofouling organism viability in different types of cleaning operations has been poorly studied. We compared the effects of hull cleaning on biofouling organisms removed from 36 marine vessels during in-water (without capture of cleaning waste) and shore-based (with capture, and treatment of cleaning waste) cleaning. In-water cleaning resulted in higher proportions of viable biofouling organisms surviving cleaning (62.3 ± 7.1% of all organisms examined) compared to dry dock (37.8 ± 8.6%) and haul-out (20.1 ± 5.3%) operations. For shore-based facilities with effluent treatment systems, concentrations of organisms and/or their propagules in cleaning effluent was reduced by ≥ 98.5% compared to initial hydro-blast effluent concentrations. These results can be used in guidance for hull cleaning operations to minimize associated biosecurity risk.

[A novel approach of using fouling index to evaluate NOM fouling behavior during low pressure ultrafiltration process].

In this study, fouling index (FI) was introduced as a novel approach to investigate NOM fouling behavior during low pressure membrane ultrafiltration process. Three kinds of typical NOMs, humic acid (HA), bovine serum albumin (BSA) and sodium alginate (NaAlg), were used in the experiments. The results indicated that the fouling caused by NOM can be considered as two steps with different FI values. One is the fast fouling phase, and the other is the slow phase. Apparently, the total fouling index of the fast phase (TFI(F)) was much greater than that of the slow phase (TFI(S)), which means the initial interaction between NOM and membrane would play a significant role in the whole fouling process. A higher TFI(F) could lead to a faster fouling and the flux would decline more rapidly. After hydraulic washing, the flux was recovered and the resistance was reduced, indicating that physical cleaning could remove a part of foulants. Additionally, the results also represented that the sequences of NOM causing irreversible fouling and chemical clean irreversible fouling were BSA > HA > NaAlg and NaAlg > BSA > HA, respectively. Humic acid and protein tended to cause irreversible fouling and were easily removed by alkaline cleaning, while irreversible fouling caused by polysaccharide was difficult to remove by alkaline. The main cause of membrane fouling may be the interaction between foulants and membrane, which needs further research. Generally speaking, FI with a simple expression would play a significant role to describe the membrane fouling.

Antifouling strategies: history and regulation, ecological impacts and mitigation.

Biofouling increases drag on marine vessels resulting in higher fuel consumption and can also facilitate the transport of harmful non-indigenous species (NIS). Antifouling technologies incorporating biocides (e.g., copper and tributyltin) have been developed to prevent settlement of organisms on vessels, but their widespread use has introduced high levels of contamination into the environment and raised concerns about their toxic effects on marine communities. The recent global ban on tributyltin (1 January 2008) and increasing regulation of copper have prompted research and development of non-toxic paints. This review synthesises existing information regarding the ecological impact of biocides in a wide range of organisms and highlights directions for the management of antifouling paints. We focus particularly on representatives of the recent past (copper and tributyltin) and present (copper and 'booster') biocides. We identify knowledge gaps in antifouling research and provide recommendations relating to the regulation and phasing-out of copper.

Vessel biofouling as an inadvertent vector of benthic invertebrates occurring in Brazil.

This article reviews the literature involving benthic invertebrates that are cited in association with hull fouling, reporting the species that occur on the Brazilian coast and evaluating the importance of this vector for the introduction of nonindigenous and cryptogenic invertebrates in Brazil. It discusses some of the strategies that were used by the species that allowed for their overseas transport and made it easier to cross natural barriers that otherwise would have been obstacles to their dispersion. The compiled data list 343 species (65% nonindigenous and 35% cryptogenic), mainly from the northwestern Atlantic Ocean. The traveling fauna, composed mostly of cosmopolitan species (70.3%), is primarily euryhaline and marine stenohaline, with sessile and sedentary habits. After delineating the shipborne species' ecological profiles and traveling strategies and evaluating their overlapping vectors, we concluded that hull vessels were the main vector of introduction to the Brazilian coast for 89.8% of the compiled species.

Quality of drinking-water at source and point-of-consumption--drinking cup as a high potential recontamination risk: a field study in Bolivia.

In-house contamination of drinking-water is a persistent problem in developing countries. This study aimed at identifying critical points of contamination and determining the extent of recontamination after water treatment. In total, 81 households were visited, and 347 water samples from their current sources of water, transport vessels, treated water, and drinking vessels were analyzed. The quality of water was assessed using Escherichia coli as an indicator for faecal contamination. The concentration of E. coli increased significantly from the water source [median=0 colony-forming unit (CFU)/100 mL, interquartile range (IQR: 0-13)] to the drinking cup (median=8 CFU/100 mL; IQR: 0-550; n=81, z=-3.7, p<0.001). About two-thirds (34/52) of drinking vessels were contaminated with E. coli. Although boiling and solar disinfection of water (SODIS) improved the quality of drinking-water (median=0 CFU/100 mL; IQR: 0-0.05), recontamination at the point-of-consumption significantly reduced the quality of water in the cups (median=8, IQR: 0-500; n=45, z=-2.4, p=0.015). Home-based interventions in disinfection of water may not guarantee health benefits without complementary hygiene education due to the risk of posttreatment contamination.

Imposex levels and tributyltin pollution in Ria de Aveiro (NW Portugal) between 1997 and 2007: evaluation of legislation effectiveness.

Nucella lapillus imposex levels and organotin (OT) concentrations in water and female tissues were measured in samples collected from the Ria de Aveiro (NW Portugal) between 1997 and 2007. Vas deferens sequence index (VDSI), relative penis size index (RPSI), mean female penis length (FPL) and percentage of imposex affected females (%I) were used to determine imposex levels at each site. A significant temporal decline in imposex intensity was observed during the assessed period. Imposex decrease was evident after 2003 although improvements were most notable from 2005 to 2007, probably due to the implementation of the EU Council Regulation no.782/2003 forbidding further application of tributyltin (TBT) antifouling on vessels carrying EU flags. Despite these improvements, OT analysis in N. lapillus female tissues and water indicate there are still recent TBT inputs into the study area.