Balancing the demands of physiological processes: Decapod crustacean feeding and digestion in hypoxia

平衡生理过程的需求：十足目甲壳类动物在缺氧条件下的摄食和消化

• 批准号: RGPIN-2016-04826
• 负责人: McGaw, Iain
• 金额: $ 2.26万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709106
• 关键词: Balancing; demands; physiological; processes; Decapod

Dissolved oxygen levels in coastal areas have changed more than any other environmental variable during the past few decades, leading to widespread hypoxia. Crustaceans are among the most sensitive organisms to hypoxia and could therefore act as important indicator species of a healthy environment. Knowledge of their behavioural and physiological responses will be invaluable when predicting long-term effects of hypoxia on benthic communities. In general crustaceans respond to a decline in oxygen tension by increasing ventilation rate in an attempt to maintain a stable oxygen (O2) uptake, at a certain level they are unable to maintain O2 uptake and thereafter it drops in line with that of the environment. All organisms must feed in order to survive and the subsequent digestion of a meal leads to a general increase in metabolism termed the specific dynamic action (SDA). Thus current trends in hypoxia will reduce the available dissolved O2 at a time when organisms need to uptake more O2 for digestive processes. This research will investigate how several species of decapod crustaceans (rock crab, green crab, lobster, Dungeness crab) with differing ability to deal with hypoxia balance cardiorespiratory variables (respiration, cardiac function, blood chemistry) when they feed and digest in hypoxia. If animals are unable to maintain O2 uptake during hypoxia we will determine if they can slow or halt digestive processes (mechanical costly” physiological mechanisms. A Loligo shuttlebox® will be used to determine if feeding status alters O2 preference. The apparatus allows animals to choose between two O2 regimes while a computer tracks movement. By monitoring speed of movement, O2 choice and feeding activity we will be able to determine if fed and starved animals have different O2 preferences, or if trade-off occurs whereby with increasing starvation time an animal will be more likely expend energy entering into low O2 in order to obtain a food reward. Ecophysiology has had a renaissance in the last decade and this integrative approach studying the connections between whole animal physiology and behaviour is important when investigating interactions between the animal and its environment. Historically scientists carried out experiments under controlled conditions where feeding was carefully regimented, the results of this research will show how multiple stressors may interact in more natural conditions. In light of climate change and the exponential increase in hypoxia the results of this research will not only be of interest to the scientific community, but will also be important for environmental resource managers in understanding potential responses of communties to environmental change.

在过去的几十年里，沿海地区溶解氧水平的变化比任何其他环境变量都要大，导致广泛的缺氧。甲壳类动物是对缺氧最敏感的生物之一，因此可以作为健康环境的重要指示物种。在预测缺氧对底栖生物群落的长期影响时，了解它们的行为和生理反应将是非常宝贵的。一般来说，甲壳类动物通过增加通气率来应对氧张力的下降，试图保持稳定的氧（O2）摄取，在一定水平下，它们无法保持O2摄取，此后它与环境一致地下降。所有生物体必须进食才能生存，随后的膳食消化导致代谢的普遍增加，称为特定动力作用（SDA）。因此，目前的缺氧趋势将在生物体需要吸收更多O2进行消化过程时减少可用的溶解O2。 本研究将探讨几种具有不同低氧处理能力的十足类甲壳动物（岩蟹、绿色蟹、龙虾、邓杰尼斯蟹）在低氧环境下进食和消化时如何平衡心肺变量（呼吸、心脏功能、血液化学）。如果动物在缺氧期间无法维持O2摄取，我们将确定它们是否可以减缓或停止消化过程（机械昂贵的“生理机制”）。Loligo shuttlebox®将用于确定进食状态是否改变O2偏好。该设备允许动物在两种氧气状态之间进行选择，同时计算机跟踪运动。通过监测运动速度、O2选择和进食活动，我们将能够确定进食和饥饿动物是否具有不同的O2偏好，或者是否发生权衡，从而随着饥饿时间的增加，动物将更有可能消耗能量进入低O2以获得食物奖励。 生态生理学在过去的十年中有了复兴，这种研究整个动物生理和行为之间联系的综合方法在研究动物与环境之间的相互作用时非常重要。从历史上看，科学家们在控制条件下进行了实验，在这些条件下，喂养是经过精心管理的，这项研究的结果将显示多种压力源如何在更自然的条件下相互作用。鉴于气候变化和缺氧指数增加，这项研究的结果不仅会引起科学界的兴趣，而且对环境资源管理人员了解社区对环境变化的潜在反应也很重要。