Krång Anna-Sara, Rosenqvist Gunilla
Department of Marine Ecology, Göteborg University, Kristineberg Marine Research Station, S-450 34 Fiskebäckskil, Sweden.
Aquat Toxicol. 2006 Jun 30;78(3):284-91. doi: 10.1016/j.aquatox.2006.04.001. Epub 2006 May 15.
The decapod Norway lobster, Nephrops norvegicus (L.), lives on muddy sediments rich in manganese (Mn). In hypoxic conditions, manganese is reduced and released from the sediment, so increased concentrations of dissolved Mn(2+) become bioavailable. In excess, manganese acts as a neurotoxin and may inhibit vital functions of benthic organisms, such as muscle contraction. We investigated in a laboratory flume experiment, the effect of environmentally realistic concentrations of manganese (0.1 and 0.2mM for 12 days) on the food search behaviour of N. norvegicus. We found that lobsters exposed to manganese had a more than doubled reaction time to food odour stimuli compared to the controls (p<0.05). In addition, manganese exposure reduced the number of N. norvegicus reaching the food stimuli source. Compared to the controls where 86% reached the stimuli source, only about half of the lobsters exposed to 0.1mM Mn and one-third of the lobsters exposed to 0.2mM Mn reached the stimuli source (p<0.05 and 0.001, respectively). There was no significant difference between treatments in the number of lobsters leaving their shelter or in the time from reaction until leaving the shelter and there was no difference in search time for those animals that eventually did locate the stimuli source. This study shows that environmentally realistic manganese concentrations affect parts of the food search behaviour of N. norvegicus, likely due to impaired chemosensory ability or reduced motivation for feeding. Thus, the ability of N. norvegicus to detect and find food can be reduced in areas with high manganese concentrations, with possible consequences on individual and population levels.
十足目动物挪威龙虾（Nephrops norvegicus，L.）生活在富含锰（Mn）的泥泞沉积物中。在缺氧条件下，锰会从沉积物中还原并释放出来，从而使溶解态Mn(2+)的浓度增加并具有生物可利用性。过量的锰会作为一种神经毒素，可能抑制底栖生物的重要功能，如肌肉收缩。我们在实验室水槽实验中研究了环境现实浓度的锰（0.1和0.2 mM，持续12天）对挪威龙虾食物搜索行为的影响。我们发现，与对照组相比，暴露于锰的龙虾对食物气味刺激的反应时间增加了一倍多（p<0.05）。此外，锰暴露减少了到达食物刺激源的挪威龙虾数量。与86%到达刺激源的对照组相比，暴露于0.1 mM Mn的龙虾中只有约一半、暴露于0.2 mM Mn的龙虾中只有三分之一到达了刺激源（分别为p<0.05和0.001）。在离开庇护所的龙虾数量或从反应到离开庇护所的时间方面，各处理组之间没有显著差异，对于最终找到刺激源的动物，其搜索时间也没有差异。这项研究表明，环境现实浓度的锰会影响挪威龙虾食物搜索行为的某些方面，可能是由于化学感应能力受损或进食动机降低。因此，在高锰浓度区域，挪威龙虾检测和寻找食物的能力可能会降低，这可能对个体和种群水平产生影响。
