Sánchez Marta I, Petit Cathleen, Martínez-Haro Mónica, Taggart Mark A, Green Andy J
Wetland Ecology, Doñana Biological Station, CSIC, Seville, Spain.
Université Pierre et Marie Curie (Paris VI), Paris, France.
PeerJ. 2016 Feb 18;4:e1703. doi: 10.7717/peerj.1703. eCollection 2016.
Limited information exists regarding the complex interactions between biological invasions, pollution, and climate change. Most studies indicate that pollution tends to favor invasive species. Here, we provide evidence that arsenic (As) pollution may have a role in limiting the invasion of the exotic brine shrimp Artemia franciscana. We tested As toxicity in natural populations of Artemia parthenogenetica (a native taxon) and A. franciscana from localities in southern Spain with differing degrees of As contamination. Tests were conducted both under current mean temperature conditions (25 °C), and as per a future climate scenario (i.e., an increase in mean temperature of 4 °C). Acute toxicity was estimated on the basis of the median lethal concentration (at 24 h), and chronic toxicity was evaluated by measuring Artemia survival and growth under sublethal exposures (after 26 days). At 25 °C, native A. parthenogenetica from the highly polluted Odiel and Tinto estuary was much more resistant to acute As stress (LC50-24 h, 24.67 mg L(-1)) than A. franciscana (15.78 mg L(-1)) and A. parthenogenetica from unpolluted sites (12.04 mg L(-1))-suggesting that local adaptation to polluted conditions may occur. At 29 °C, resistance of A. parthenogenetica from Odiel decreased significantly, and there were no statistical differences in sensitivity between the three species/populations, suggesting that climate change may enhance the probability of invasion. Resistance increased with developmental stage from nauplii to adults, and was extremely high in cysts which still hatched at As concentrations of up to 6400 mg L(-1). Under sublethal chronic exposure A. franciscana performed better (survival and growth) than A. parthenogenetica, and both species experienced a faster growth when exposed to As, compared with unexposed (control) individuals, probably due to the hormesis. We discuss the ecological implications of our results.
关于生物入侵、污染和气候变化之间复杂的相互作用，现有信息有限。大多数研究表明，污染往往有利于入侵物种。在此，我们提供证据表明，砷（As）污染可能在限制外来卤虫（Artemia franciscana）的入侵方面发挥作用。我们测试了来自西班牙南部不同砷污染程度地区的孤雌生殖卤虫（Artemia parthenogenetica，一个本地分类群）和旧金山卤虫（A. franciscana）自然种群对砷的毒性。测试在当前平均温度条件（25℃）下以及根据未来气候情景（即平均温度升高4℃）进行。急性毒性根据中位致死浓度（24小时）进行估算，慢性毒性通过测量亚致死暴露（26天后）下卤虫的存活和生长来评估。在25℃时，来自污染严重的奥迪尔河（Odiel）和廷托河（Tinto）河口的本地孤雌生殖卤虫比旧金山卤虫（LC50 - 24小时，15.78毫克/升）和来自未受污染地区的孤雌生殖卤虫（12.04毫克/升）对急性砷胁迫的抵抗力要强得多，这表明可能会出现对污染条件的局部适应。在29℃时，来自奥迪尔河的孤雌生殖卤虫的抵抗力显著下降，并且这三个物种/种群之间在敏感性上没有统计学差异，这表明气候变化可能会增加入侵的可能性。抵抗力随着发育阶段从无节幼体到成体而增加，并且在囊肿中极高，囊肿在砷浓度高达6400毫克/升时仍能孵化。在亚致死慢性暴露下，旧金山卤虫的表现（存活和生长）优于孤雌生殖卤虫，并且与未暴露（对照）个体相比，这两个物种在暴露于砷时生长更快，这可能是由于毒物兴奋效应。我们讨论了我们结果的生态意义。
