Heritable pollution tolerance in a marine invader

The University of New South Wales, Sydney, Australia.
Environmental Research (Impact Factor: 4.37). 02/2011; 111(7):926-32. DOI: 10.1016/j.envres.2010.12.007
Source: PubMed


The global spread of fouling invasive species is continuing despite the use of antifouling biocides. Furthermore, previous evidence suggests that non-indigenous species introduced via hull fouling may be capable of adapting to metal-polluted environments. Using a laboratory based toxicity assay, we investigated tolerance to copper in the non-indigenous bryozoan Watersipora subtorquata from four source populations. Individual colonies were collected from four sites within Port Hacking (Sydney, Australia) and their offspring exposed to a range of copper concentrations. This approach, using a full-sib, split-family design, tests for a genotype by environment (G×E) interaction. Settlement and complete metamorphosis (recruitment) were measured as ecologically relevant endpoints. Larval sizes were also measured for each colony. Successful recruitment was significantly reduced by the highest copper concentration of 80μgL(-1). While there was no difference in pollution tolerance between sites, there was a significant G×E interaction, with large variation in the response of colony offspring within sites. Larval size differed significantly both between sites and between colonies and was positively correlated with tolerance. The high level of variation in copper tolerance between colonies suggests that there is considerable potential within populations to adapt to elevated copper levels, as tolerance is a heritable trait. Also, colonies that produce large larvae are more tolerant to copper, suggesting that tolerance may be a direct consequence of larger size.

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Available from: Emma L Johnston, Oct 04, 2015
    • "This is likely due to marine invertebrate species having varied tolerances to metal toxicity where some species are less sensitive than others (Bellas et al. 2001; Brown et al. 2004; Rivera-Duarte et al. 2005; Brooks & Waldock 2009; Pineda et al. 2012). Tolerance to metal toxicity can also differ within species and even within individuals of the same population depending on the tolerance coping mechanism being employed (McKenzie et al. 2011). Copper and its alloys are effective against a variety of marine fouling invertebrates including barnacles (Johnston & Keough 2000), bryozoans (Piola & Johnston 2006), mussels (Dormon et al. 1996) and ascidians (Bellas et al. 2001; Agell et al. 2004; Pineda et al. 2012), while copper-tolerant species include polychaetes (Johnston & Keough 2000; Bao et al. 2010) and bryozoans (Piola & Johnston 2006). "
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    ABSTRACT: Particles of copper, bronze and zinc were embedded into a polymer using cold-spray technology to produce loading density gradients of metal particles. The gradients were used to identify the species with the highest tolerance to the release of copper and zinc ions. The gradients also established the minimum effective release rates (MERRs) of copper and zinc ions needed to prevent the recruitment of fouling under field conditions. Watersipora sp. and Simplaria pseudomilitaris had the highest tolerances to the release of metal ions. Copper and bronze gradient tubes were similar in their MERRs of copper ions against Watersipora sp. (0.058 g m(-2) h(-1) and 0.054 g m(-2) h(-1), respectively) and against S. pseudomilitaris (0.030 g m(-2) h(-1) and 0.025 g m(-2) h(-1), respectively). Zinc was not an effective antifoulant, with failure within two weeks. In conclusion, cold-spray gradients were effective in determining MERRs and these outcomes provide the basis for the development of cold-spray surfaces with pre-determined life-spans using controlled MERRs.
    No preview · Article · Apr 2014 · Biofouling
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    • "Differential sensitivity to metals in particular (Luoma & Rainbow 2005) can lead to shifts in the overall composition of a sessile community. Some species of solitary ascidian are adversely affected by increased Cu, while the bryozoan Watersipora subtorquata is largely Cu-tolerant (Johnston & Keough 2003; Dafforn et al. 2008; McKenzie et al. 2011). In this study, barnacles and ascidians were absent from the recruitment plates located within the marina, while bryozoans and hydroids occupied more space in the marina than in the outer channel sites. "
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    ABSTRACT: Anthropogenic modifications to waterways are common and their ecological consequences must be understood to effectively conserve local biodiversity. The facilitation of recreational boating activities often requires substantial alteration of natural areas, however the environmental and ecological consequences of such alterations are rarely described in the scientific literature. In this study, ecological and physico-chemical conditions were investigated in a recreational boating marina, located inside a marine park on the south-east coast of Australia. Recruitment panels were deployed for 8 weeks both inside and outside the marina, and differences in the composition of the developing fouling communities were observed. The recruitment of taxa, which often have short-lived larvae, was increased inside the marina (bryozoans, spirorbids and sponges) while the recruitment of taxa, which often have longer-lived larvae, was reduced or absent (barnacles, solitary ascidians and non-spirorbid polychaetes). Differences were also observed in environmental conditions inside the marina cf. directly outside. The marina environment had higher turbidity, temperature and pH along with higher concentrations of lead and copper in suspended sediments, while flow rates and trapped sediment loads were reduced inside the marina. The differences observed in the study suggest that there may be marked environmental changes associated with marina developments. The potential ecological consequences of these changes should be a primary consideration during the planning process, particularly for developments in locations of notable ecological value.
    Full-text · Article · Jul 2013 · Biofouling
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    • "Among these, embryogenesis, settlement and metamorphosis are critical life-history phases for many organisms (e.g. [13], [14]), especially when exposed to anthropogenic stressors [15]–[17]. For sessile marine organisms, where adults are unable to escape unfavourable abiotic conditions, the importance of successful early stages is even more striking as it determines the viability of local adult populations [18]–[20]. "
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    ABSTRACT: All ontogenetic stages of a life cycle are exposed to environmental conditions so that population persistence depends on the performance of both adults and offspring. Most studies analysing the influence of abiotic conditions on species performance have focussed on adults, while studies covering early life-history stages remain rare. We investigated the responses of early stages of two widely introduced ascidians, Styela plicata and Microcosmus squamiger, to different abiotic conditions. Stressors mimicked conditions in the habitats where both species can be found in their distributional ranges and responses were related to the selection potential of their populations by analysing their genetic diversity. Four developmental stages (egg fertilisation, larval development, settlement, metamorphosis) were studied after exposure to high temperature (30°C), low salinities (26 and 22‰) and high copper concentrations (25, 50 and 100 µg/L). Although most stressors effectively led to failure of complete development (fertilisation through metamorphosis), fertilisation and larval development were the most sensitive stages. All the studied stressors affected the development of both species, though responses differed with stage and stressor. S. plicata was overall more resistant to copper, and some stages of M. squamiger to low salinities. No relationship was found between parental genetic composition and responses to stressors. We conclude that successful development can be prevented at several life-history stages, and therefore, it is essential to consider multiple stages when assessing species' abilities to tolerate stress. Moreover, we found that early development of these species cannot be completed under conditions prevailing where adults live. These populations must therefore recruit from elsewhere or reproduce during temporal windows of more benign conditions. Alternatively, novel strategies or behaviours that increase overall reproductive success might be responsible for ensuring population survival.
    Full-text · Article · Oct 2012 · PLoS ONE
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