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Life stage-specific effects of the fungicide pyrimethanil and temperature on the snail Physella acuta (Draparnaud, 1805) disclose the pitfalls for the aquatic risk assessment under global climate change
2013
Seeland, Anne | Albrand, Jennifer | Oehlmann, Jörg | Müller, Ruth
It can be suggested that the combined stress of pesticide pollution and suboptimal temperature influences the sensitivity of life stages of aquatic invertebrates differently.The embryo, juvenile, half- and full-life-cycle toxicity tests performed with the snail Physella acuta at different concentrations (0.06–0.5 or 1.0 mg L−1) of the model fungicide pyrimethanil at 15, 20 and 25 °C revealed, that pyrimethanil caused concentration-dependent effects at all test temperatures. Interestingly, the ecotoxicity of pyrimethanil was higher at lower (suboptimal) temperature for embryo hatching and F1 reproduction, but its ecotoxicity for juvenile growth and F0 reproduction increased with increasing temperature.The life-stage specific temperature-dependent ecotoxicity of pyrimethanil and the high fungicide susceptibility of the invasive snail clearly demonstrate the complexity of pesticide–temperature interactions and the challenge to draw conclusions for the risk of pesticides under the impact of global climate change.
Показать больше [+] Меньше [-]The regrowth of phytoplankton cultures after UV disinfection
2013
Martínez, Lucía F. | Mahamud, Manuel M. | Lavín, Antonio G. | Bueno, Julio L.
This study addresses how cultures of three phytoplankton species –Chaetoceros calcitrans, Chlorella autotrophica and Phaeocystis globosa – can recover from the effects of UV-C exposure if the cells are placed in a rich medium. Flow cytometry and pulse amplitude modulation (PAM) were used to determine cell recovery after UV treatment. The recovery of C. calcitrans was complete 9days after treatment. For C. autotrophica, the recovery was noticeable 5days after treatment. P. globosa only recovered if the UV dose did not exceed 7.3×105μWs/cm2. The recovery of the UV-treated cultures introduced to a regrowth medium, compared with the recovery of the irradiated cultures kept in their original environment, had two main characteristics: cell recovery was slower but was more efficient. This pattern of recovery has very important implications for real ballast water management systems because such systems discharge treated water into the environment.
Показать больше [+] Меньше [-]Promoting invasive species control and eradication in the sea: Options for managing the tunicate invader Didemnum vexillum in Sitka, Alaska
2013
McCann, Linda D. | Holzer, Kimberly K. | Davidson, Ian C. | Ashton, Gail V. | Chapman, Marnie D. | Ruiz, Gregory M.
Bioinvasions are a significant force of change – and economic and ecological threat – in marine ecosystems. The threat now encroaches on Alaska, which has had relatively few invasions compared to other global regions, prompting need to develop new incursion response tools. We appraised five ‘eco-friendly’ immersion treatment options (dilute acetic acid, dilute bleach, freshwater, brine and hypoxia) at either minute- or hour-scale exposures to kill the invasive tunicate Didemnum vexillum. Data revealed 100% treatment efficacy after two minutes in acetic acid, ten minutes in bleach, four hours in freshwater and over four hours in brine solution. We also demonstrated the importance of monitoring D. vexillum recovery for at least three weeks, since seemingly destroyed colonies rebounded during this timeframe. Combined, these findings provide insights towards a bay-scale eradication and post-border management plan applicable to the recent D. vexillum incursion in Whiting Harbor, Alaska and other shallow, inshore invasion sites.
Показать больше [+] Меньше [-]High cyst concentrations of the potentially toxic dinoflagellate Alexandrium tamarense species complex in Bedford Basin, Halifax, Nova Scotia, Canada
2013
Lacasse, Olivia | Rochon, André | Roy, Suzanne
We report a large cyst bed of the potentially toxic and bloom-forming dinoflagellate Alexandrium tamarense species complex in bottom sediments from the port of Halifax, Nova Scotia, Canada. The average cyst concentrations of that species ranged from 4033±2647 to 220872±148086cystsg−1 of dry sediments and the highest concentrations were found near ship terminals in Bedford Basin. Although this species is endemic to this region, our work strongly suggests that some of the cysts of A. tamarense species complex found in the port of Halifax were introduced through discharged ballast water and sediments.
Показать больше [+] Меньше [-]Polybrominated diphenyl ethers do not affect metamorphosis but alter the proteome of the invasive slipper limpet Crepidula onyx
2013
Mukerji, Joy | Po, Beverly H.K. | Chiu, Jill M.Y. | Wu, Rudolf S.S. | Qian, Pei-Yuan | Thiyagarajan, Vengatesen
Man-made polybrominated diphenyl ethers (PBDEs) used as flame retardants in various consumer products may be harmful to marine organisms. Larvae of some marine invertebrates, especially invasive species, can develop resistance to PBDEs through altered protein expression patterns or proteome plasticity. This is the first report of a proteomics approach to study BDE-47 induced molecular changes in the invasive limpet Crepidula onyx. Larvae of C. onyx were cultured for 5days (hatching to metamorphosis) in the presence of BDE-47 (1μgL−1). Using a 2-DE proteomics approach with triple quadrupole and high-resolution TOF-MS, we showed that BDE-47 altered the proteome structure but not the growth or metamorphosis of C. onyx larvae. We found eight significant differentially expressed proteins in response to BDE-47, deemed the protein expression signature, consisting of cytoskeletal, stress tolerance, metabolism and energy production related proteins. Our data suggest C. onyx larvae have adequate proteome plasticity to tolerate BDE-47 toxicity.
Показать больше [+] Меньше [-]Optimizing early detection of non-indigenous species: Estimating the scale of dispersal of a nascent population of the invasive tunicate Ciona intestinalis (L.)
2013
Collin, Samuel B. | Edwards, Paul K. | Leung, Brian | Johnson, Ladd E.
Knowledge of dispersal and establishment during the early stages of invasion is essential for allocating monitoring effort, detecting nascent populations and predicting spread. The scarcity of these data, however, provides little guidance for monitoring programs. Here we present data on the adult distribution and the subsequent pattern of larval recruitment from a nascent population of the invasive tunicate Ciona intestinalis in Prince Edward Island, Canada. Existing niche models indicate the entire study site is suitable for recruitment, suggesting an equal probability of detection throughout the site. In contrast, we found a heterogeneous pattern of larval recruitment, including areas of zero recruitment. By fitting a dispersal kernel, we show Ciona is not capable of naturally dispersing between bays, restricting further spread, and provide guidance for future monitoring. Our results also highlight how large-scale models, although important, lack the small-scale patterns essential for monitoring and early detection of invasive species.
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