Fouling in natural flows: Cylinders and panels as collectors of particles and barnacle larvae (original) (raw)
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Biofouling, 2003
Protection against biofouling is essential for efficient operation of boats and ships. Restrictions on the use of traditional, toxic antifouling coatings call for new less toxic methods. Future antifouling strategies will likely be based on more specific action against dominant foulers and will require more detailed information about spatial and temporal differences in fouling communities on artificial substrates. In this study, the recruitment and succession of fouling organisms was examined on artificial (PMMA) panels exposed to natural flow speeds on the Skagerrak coast (Sweden). The recruitment of foulers on static panels was then compared to fouling allowed to develop on boat hulls in surveys of new nontoxic coatings. The temporal and spatial variation in recruitment was examined on a monthly interval within the boating season, from May-September. Furthermore, the succession of the fouling community was examined during the same interval. A total of 12 sessile invertebrate species was recorded on the static panels with dominant foulers being the barnacle Balanus improvisus (July-September) and the mussel Mytilus edulis (June-August). The mean abundance during peak settlement on panels after 1 month's deployment was 370+134 individuals dm 72 for B. improvisus and 340+415 individuals dm 72 for M. edulis. The succession of foulers on the panels led to a dominance of M. edulis (maximum of 7470+2830 individuals dm 72 ) over B. improvisus (maximum of 2295+680 individuals dm 72 ). This was in contrast to the fouling development on boat hulls, examined after 4 months exposure in 3 successive years, where B. improvisus was the dominant species (mean abundance 222+104 and maximum 713+527 individuals dm 72 ). Some boats were covered to an extent of almost 100% by B. improvisus with only a few M. edulis (mean abundance 20+16). The biomass of fouling on boat hulls varied from average dry weights of 1.3+1 to 13+5 g dm 72 . These results show that extrapolation from static panels (common in evaluation of antifouling performance) to fouling on boat hulls may be problematic.
Journal of Experimental Marine Biology and Ecology, 1994
The effect of four substrata (concrete, plywood, fibreglass and aluminium) on the recruitment of species and development of an intertidal estuarine fouling assemblage was examined in Quibray Bay of Botany Bay, New South Wales, Australia. Many species, including the oyster Saccostrea commercialis (Iredale & Roughley) and the barnacles Hexaminius sp., Balanus amphitrite Darwin and Balanus variegatus Darwin, recruited in greater numbers on concrete or plywood surfaces than on fibreglass or aluminium. As a result, patterns of change in the number of species through time were dependent on the substratum. Multivariate analyses indicated that assemblages on different substrata were significantly different after 1 or 2 months of submersion, but became more similar after longer periods (up to 4-5 months). The reasons for this gradual conformity varied depending on the season of submersion and the composition of the species settling in a particular season. The results of this study indicated that the nature of the substratum can affect both initial colonisation of particular species and the development of the assemblage over time. Because the effect of substratum varies with the period of submersion, comparisons of various studies on fouling assemblages using different natural and artificial substrata and for varying lengths of time are likely to be very difficult.
The Effects of Caging on the Colonization of Fouling Organisms in the Upper Bonny Estuary
2002
The effects of caging on the colonization and development of the fouling community in the upper Bonny estuary was studied. The experimental design was such that sets of wooden panels (20x20 cm) were screened with cages constructed with plastic netting while another set was left uncaged. Both sets of panels were submerged below low tide level and sampled fortnightly for seventy-four days. The species settling on the panels (as well as on the mesh of the cage) were identified and examined for percentage cover. Data obtained were subjected to Analyis of Variance or t-tests after arc-sine transformation. Faunal abundance was found to be significantly higher on the mesh of the cage than on the panels (p<0.001). Differences between the caged and uncaged panels were influenced by time as total cover was found to decline with time on the caged panels. Pennaria distichia, Styela sp. and Sabella sp. achieved significantly higher cover on the mesh of the cage than the panels (p<0.001). Some species that settled on the panels (Balanus sp., Membranipora membranacea, Serpula sp, Halichondria sp, Crassostrea gasar) were not found on the mesh of the cage, and both Balanus and M.
Marine Ecology Progress Series, 2000
Tubes constructed of different materials were used to examine the role of hydrodynamics and surface characteristics, as measured by contact angles, on larval attachment of marine polychaetes, bryozoans and barnacles. Tubes (10 mm inner diameter) of 7 different materials, ranging in contact angle from 25°to 113°, were used. Laboratory and field experiments were conducted using a range of flow rates from 1.7 to 84.9 cm s-1. For all 3 taxa of organisms, the results of field experiments were similar to those of the laboratory experiments. Larval settlement of the polychaete Hydroides elegans and the bryozoan Bugula neritina was the highest at a flow rate of ≤ 2.1 cm s-1 , and decreased when the flow rate was increased. H. elegans larvae settled within the narrowest range of flow rates (1.7 to 9.1 cm s-1), B. neritina larvae settled over the widest range of flow rates (1.7 to 53.0 cm s-1), and barnacle larvae (Balanus spp.) settled in an intermediate range of flow rates (4.2 to 21.2 cm s-1). Barnacle larvae did not settle when the flow rate was < 2.1 or > 21.2 cm s-1 , and the highest settlement was recorded at the flow rate of 10.6 cm s-1. Barnacle larvae showed the highest settlement in glass tubes (smallest contact angle) and the lowest in Teflon tubes (largest contact angle), while B. neritina showed the highest larval settlement in Teflon tubes and the lowest settlement in glass tubes. H. elegans also showed the highest larval settlement in Teflon tubes, but the lowest settlement in polyurethane and polyethylene tubes. Biofilm formation changed the contact angles of all the tubes, the degree of change varied among the 7 types of tubes. Bacterial densities of biofilm on the 7 types of tubes were significantly different and were not correlated with the initial contact angles of tubes. The bacterial densities on the Teflon tubes were the same as on glass tubes. Our results suggest a very complex interaction among substratum characteristics, flow rates, and larval settlement behavior and indicate the necessity for considering the interaction when one interprets laboratory bioassay data on larval settlement of marine invertebrates.
Journal of Experimental Marine Biology and Ecology, 1997
During late winter/early spring (1992-1993) a series of 12 tapered channels were placed subtidally in a Long Island, New York (USA) estuary to examine total fouling community development. Rather than relying upon flow-dependent correlations among spatially segregated sites, these channels directly accelerated or decelerated the existing tidal currents 50% (ambient flow speeds ranged from < 2 to > 50 cm/s). In response to experimentally manipulated water flows over five months, the arborescent hydroid Obelia longissima Pallas (1766) accumulated onto Tygon tubing in direct proportion to mean free-stream flow speed, whereas barnacle (Balanus ebumeus Gould) initial settlement and cumulative recruitment along plywood ceilings increased threefold and five-fold, respectively, with a long-term doubling of water speed. These positive flow-dependent results directly contrast those from previous experiments in the same channel apparatus which failed to document any flow enhancement on the growth of suspension-feeding bivalves. 01997 Elsevier Science B.V.
An Effective Mesocosm Design for Studying the Settlement and Recruitment of Fouling Organisms
Marine Technology Society Journal, 2017
Mesocosms are a powerful tool in the scientific community. They bridge the gap between laboratory and field studies by creating a contained test apparatus that allows for greater control over test organisms while still exposing them to natural environmental variations. A new mesocosm was designed to monitor the in-situ settlement patterns of barnacles. This paper focuses on testing the efficacy of the mesocosm to manage potential problems such as biofouling, corrosion, and poor water quality. The mesocosm consisted of a PVC cube, where four of the six sides had windows covered with 100-μm plankton mesh. Every 2 days, the cube was rotated so that one of the mesh sides was held out of the water, preventing biofouling from clogging the mesh. Biofouling on the outside of the mesocosm significantly correlated to the days of immersion in the marine environment; the longer a side was immersed, the greater the biofouling coverage (p < 0.05, R2 > 0.50). Therefore, the design successful...
Marine Ecology Progress Series
We report the results of 2 types of field experiment done to examine the influence of the interaction between small-scale flow disruptions and chemical cues associated with conspecific individuals on the settlement of larvae of 2 congeneric barnacle species, Elminius modestus and E. covertus. One series of experiments (ridge experiments) examined the effects of the chemical component of barnacle presence and flow disruptions at the scale of settlement plates (<l0 cm). Cypnds could contact surfaces containing chemical cues from conspecific adults on either ridged or flat plates. Settlement was greatest on plates with cues but was not affected by flow disruptions. The other experiment (mimic experiment) used settlement plates with either live barnacles or casts of adult barnacles attached, as well as flat control plates, to test the influence of conspechc presence and flow disruption at the scale of individual barnacles (< l cm) on the settlement of cyprids. Settlement was affected by both live barnacles and barnacle mimics, indicating that a combination of flow and conspecific-derived cues influence settlement. Hence, the importance of flow disruption to the settlement of cyprids is dependent on the scale of the disruption. The survival of barnacles for up to 2 mo after settlement was also followed in the ridge experiments. The settlement patterns larvae showed early in these experiments were not evident after periods of heavy recruitment; we discuss possible causes. KEY MTORDS: Settlement. Recruitment. Larval behaviour. Chemical cues. Hydrodynamics-Barnacles. Elminius modestus Elminius covertus
2014
Background Mid-Atlantic shallow coastal bays have experienced progressive eutrophication, and environmental degradation, as evidenced by increased macroalgal growth, harmful algal blooms (brown tide), proliferation of gelatinous zooplankton, and loss of bottom habitat (e.g. submerged aquatic vegetation, SAV). These effects may result in shifts in food web structure, loss of fisheries, serious decline in ecosystem services, and declining human uses of estuaries. The Barnegat Bay-Little Egg Harbor (BB-LEH) estuary, NJ, has experienced a historical decline in stocks of the suspension-feeding hard clam (=quahog), Mercenaria mercenaria, (Gastrich and Celestino 2003; reviewed by Bricelj et al. 2012), and in SAV, especially eelgrass Zostera marina (Kennish et al. 2010, 2012). Hard clam populations have also experienced a dramatic decline in other Atlantic coastal lagoonal ecosystems, such as Long Island's south shore estuaries (SSE), NY, and inland MD bays (Chincoteague and Assawoman Bay, MD). The precipitous decline of hard clams in SSE in the 1980s was clearly attributed to overfishing (Kraeuter et al. 2008), but continued decline of this population, despite markedly reduced fishing pressure in recent decades, has led to postulate other potential contributing factors, which could also be operating in BB-LEH. These include potential changes in the food supply that may lead to poor recruitment, growth and compromised reproductive success of hard clams (Bricelj 2009). Therefore, characterization of food quantity and quality of suspended particulates and their relationship to bivalve somatic and reproductive growth is required. This characterization has often required measurement of multiple parameters (Newell et al. 2009; Powell et al. 2012), as single metrics are often inadequate. Total Chlorophyll a concentrations alone tend to underestimate the food supply for suspension-feeding bivalves. Recent short-term studies indicate that there are strong spatial gradients in food quality/quantity across Long Island SSE, NY, and Sandy Hook Bay, NJ, during years of no or low brown tide, that are associated with marked differences in hard clam production (Newell et al. 2009; reviewed by Bricelj 2009). Empirical data have shown that the food supply for benthic suspension-feeders such as M. mercenaria remains ill-defined, and larval model simulations showed that variation in food quality had much greater effects on hard clam larval metamorphic success than changes in temperature and food quantity (Bricelj 2009). Specific algal species, classes and/or size groups are known to play a role in limiting the production of suspension-feeding bivalves. The BB-LEH estuary has experienced toxic brown