Distribution patterns of decapod crustaceans in polar areas:: a result of magnesium regulation?
Distribution patterns of decapod crustaceans in polar areas:: a result of magnesium regulation?
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DOI：
10.1007/s003000100270
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发表时间：
2001-10-01
期刊：
影响因子：
1.7
通讯作者：
Pörtner, HO
中科院分区：
文献类型：
--
作者：
Frederich, M;Sartoris, FJ;Pörtner, HO
在南极汇流以南的南极水域中发现的几乎所有十足类甲壳类动物都是加勒比对虾(游泳亚目)，而在这一地区基本上没有Reptantia类群。报道了一种生理假说的发展进展，该假说解释了这种分布模式，这种分布模式是基于血淋巴中镁水平调节的差异以及低于阈值温度的镁离子依赖性，低于该阈值温度会发生冷诱导的心脏和呼吸功能衰竭。以前的研究表明，在不同的爬行动物十足类物种中，通过实验降低[Mg2+](HL)可以导致寒冷中耗氧量和活动水平的增加。在本研究中，我们测试了这些实验结果预测自然界低[Mg2+](HL)影响的可能性，并研究了来自智利南部的两种低[Mg2+](HL)的物种([Mg2+](HL)分别为10.7和21.6 mmol1(-1))的耗氧量随温度的变化。根据以前的研究结果，低[Mg2+](HL)水平与降低热敏感性和在寒冷条件下较高的代谢率有关。建立了一个模型，描述了[Mg~(2+)](HL)还原如何导致阈值温度(Pejus温度，TP)下降，这是冷诱导的组织氧供应失败的开始。对这一阈值温度的解释，不仅是为了表明耐寒性的界限，也是为了说明地理分布。TP在Natantia向较低的温度移动，后者是有效的[Mg2+](HL)调节器。相比之下，Reptantia[Mg2+](HL)调节器较差，由于心脏功能能力不足，似乎无法在南极永久冷水中定居，因此大大减少了高[Mg2+](HL)的活动范围。
Nearly all decapod crustaceans found in Antarctic waters south of the Antarctic Convergence are caridean shrimps (Natantia) while the group of Reptantia is largely absent in this area. Progress in the development of a physiological hypothesis is reported, which explains this distribution pattern based on differences in the regulation of magnesium levels in the haemolymph ([Mg2+](HL)) and on the Mg2+ dependence of threshold temperatures below which cold-induced failure of cardiac and ventilatory performance occurs. Previous studies had shown that an increase in oxygen consumption and activity levels in the cold can be induced by experimental reduction of [Mg2+](HL) in different reptant decapod species. In the present study, we tested the potential of these experimental findings for predicting the effect of low [Mg2+](HL) in nature, and investigated temperature-induced changes in oxygen consumption in two species with low but different [Mg2+](HL) from southern Chile, Halicarcinus planatus and Acanthocyclus albatrossis ([Mg2+](HL)= 10.7 and 21.6 mmol 1(-1), respectively). In accordance with previous findings, low [Mg2+](HL) levels were associated with a reduction of thermal sensitivity and a higher metabolic rate in the cold. A model is developed which describes how [Mg2+](HL) reduction caused a threshold temperature (pejus temperature, Tp) to fall, which characterises the onset of cold-induced failure in oxygen supply to tissues. This threshold temperature is interpreted, not only to indicate the limits of cold tolerance, but also of geographical distribution. Tp is shifted towards lower temperatures in Natantia, which are efficient [Mg2+](HL) regulators. In contrast, Reptantia, which are poor [Mg2+](HL) regulators, appear unable to colonise the permanently cold water of the Antarctic due to insufficient capacity of cardiac performance and, therefore, largely reduced scope for activity at high [Mg2+](HL).