• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Experimental Marine Biology and Ecology >Cardiac responses of the bay scallop Argopecten irradians to diel-cycling hypoxia
【24h】

Cardiac responses of the bay scallop Argopecten irradians to diel-cycling hypoxia

机译：海湾扇贝Argopecten irradians对diel循环缺氧的心脏反应

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Bottom water oxygen concentrations in coastal environments can oscillate between fully oxygenated and hypoxic conditions on a daily basis. How benthic organisms respond to such drastic changes in oxygen availability is not well understood. Specifically, we do not know the magnitude, duration, and frequency at which diel-cycling hypoxic conditions become stressful. Here we have used non-invasive, infrared sensors to measure the cardiac activity of the Atlantic bay scallop, Argopecten irradians, in response to diel-cycling hypoxia in-situ over one-month periods as well as in controlled laboratory incubations using animals conditioned to contrasting field conditions. In the field, heartbeat rates at a well-oxygenated site were 23.0 +/- 1.8 beats minute(-1) with 12.7 +/- 2.1% variance while heartbeat rates at sites with pronounced diel-cycling hypoxia were higher and more variable (site 1: 34.5 +/- 3.1 beats minute(-1) with 20.8 +/- 3.2% variance; site 2: 48.4 and 45.8 beats minute 1 with 16% variance). Maximal heartbeat rates were commonly recorded around dawn when oxygen concentrations fell below 5 mg O-2 L-1 suggesting this was a threshold concentration or critical P-o2 (P-C) that induced a switch to oxyconformity and onset of anaerobic metabolic pathways. In-situ cardiac activity at locations with diel-cycling hypoxia indicate that A. irradians spent nearly 40% of each day in sub-optimal conditions during which metabolic activity was reduced and/or at least partially sustained by anaerobic metabolism. During laboratory experiments, an increase in heartbeat rate in response to initial declines below 5 mg o(2) L-1 from fully oxygenated conditions suggests a regulatory response in which cardiac activity was enhanced to maintain oxygen supply. At DO below 2 mg O-2 L-1, however, heartbeat rates declined reaching a state of bradycardia and acardia during anoxia, suggesting a conformer response to severe hypoxia. Heartbeat frequency was a suitable proxy for respiration under normoxia, but heartbeat and respiration rates decoupled during severe hypoxia ( 2.0 mg O-2 L-1). A. irradians were able to survive anoxic periods between 12 and 14 h and cardiac activity rapidly returned to basal rates once full oxygen saturation was re-established. Mortality occurred after 23-32 h in anoxia regardless of prior conditioning. We speculate that repetitive exposure to periods of DO oscillations with exposure below 5 mg O-2 L-1 in the field can cause sub-lethal effects to A. irradians affecting fitness, growth, and reproductive success.
机译：沿海环境中的底水中氧气浓度每天都会在完全充氧和低氧条件之间振荡。底栖生物如何对氧气供应的这种急剧变化做出反应尚不清楚。具体来说，我们不知道Diel循环低氧条件变得紧张的程度，持续时间和频率。在这里，我们使用非侵入性的红外传感器来测量大西洋湾扇贝（Argopecten irradians）的心脏活动，以应对一个月内Diel循环低氧的原位循环，以及在受控的实验室温育中使用条件为对比现场条件。在野外，氧合良好的部位的心跳速率为23.0 +/- 1.8次/分（-1），方差为12.7 +/- 2.1％，而明显的diel循环缺氧部位的心跳速率更高且变化更大（部位1：1分34.5 +/- 3.1节拍分钟（-1），方差20.8 +/- 3.2％;位置2：1分48.4和45.8节拍1分钟，方差16％）。当氧浓度低于5 mg O-2 L-1时，通常会在黎明左右记录最大心跳率，这表明这是阈值浓度或临界P-o2（P-C），会导致转换为氧顺应性和厌氧代谢途径的发作。在存在diel循环低氧的地方进行的原位心脏活动表明，irradians每天花费近40％的时间处于次优状态，在此期间，代谢活性降低和/或至少部分由厌氧代谢维持。在实验室实验期间，响应于从完全充氧条件下降至低于5 mg o（2）L-1的初始下降，心跳速率增加表明调节反应可增强心脏活动以维持氧气供应。但是，在DO低于2 mg O-2 L-1时，缺氧时心跳率下降，达到心动过缓和无心跳的状态，表明对严重缺氧的顺应性反应。心跳频率是常氧下呼吸的合适代表，但在严重缺氧（<2.0 mg O-2 L-1）期间，心跳和呼吸频率解耦。一旦完全恢复了氧饱和度，A。irradians能够在缺氧的12至14 h期间生存，并且心脏活动迅速恢复至基础速率。不论是否预先调节，缺氧症均在23-32小时后发生。我们推测，田间重复暴露于溶解氧低于5 mg O-2 L-1的溶解氧振荡时期，可能对拟南芥产生亚致死作用，从而影响其适应性，生长和繁殖成功。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号