Aquatic metabolism and ecosystem health assessment using dissolved O2 stable isotope diel curves.
Aquatic metabolism and ecosystem health assessment using dissolved O2 stable isotope diel curves.
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使用溶解 O2 稳定同位素昼夜曲线进行水生代谢和生态系统健康评估。
DOI：
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发表时间：
2008
影响因子：
5
通讯作者：
L. Wassenaar
中科院分区：
文献类型：
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作者：
J. Venkiteswaran;S. Schiff;L. Wassenaar
溶解O2浓度和delta 18 O-O2日变化曲线可以结合起来评估水生光合作用，呼吸作用和代谢平衡，并解开一些与传统O2浓度曲线解释相关的混淆因素。一个动态模型被用来说明如何6个关键的环境和生物参数相互作用，影响昼夜O2饱和度和delta 18 O-O2曲线，从而提供了一个基本框架使用delta 18 O-O2在生态系统生产力的研究。Delta 18 O-O2提供了仅从浓度无法获得的信息，因为Delta 18 O-O2和饱和曲线不对称，并且可以通过消除许多常见假设来约束气体交换和同位素分馏。主要参数的变化对昼夜O2饱和度和δ 18 O-O2曲线的影响如下：（1）初级生产力和呼吸速率的增加使O2饱和度和δ 18 O-O2的昼夜变幅增大，δ 18 O-O2的平均值减小：（2）初级生产力与呼吸速率之比（P：R）的降低使O2饱和度降低，δ 18 O-O2值增大;（3）气体交换率的增加使O_2饱和度和δ ~（18）O-O_2值的昼夜变化范围减小，使平均O_2饱和度和δ ~（18）O-O_2值向大气平衡方向移动;（4）呼吸同位素分馏强度降低（5）δ 18 O的增加对O2饱和度没有影响，但增加了最小（白天）δ 18 O-O2值;和（6）温度的升高降低了O2的溶解度，从而增加了O2饱和度的diel范围和δ 18 O-O2值。了解这些关键参数之间的相互作用，可以更容易地破译O2和delta 18 O-O2的控制，比较水生生态系统，并对生态系统代谢进行定量估计。光合作用呼吸气体交换比（P：R：G）是更好地描述和评估各种环境压力下的水生态系统的脆弱性，通过提供更好的生态系统代谢和气体交换的约束估计比P：R比。
Dissolved O2 concentration and delta18O-O2 diel curves can be combined to assess aquatic photosynthesis, respiration, and metabolic balance, and to disentangle some of the confounding factors associated with interpretation of traditional O2 concentration curves. A dynamic model is used to illustrate how six key environmental and biological parameters interact to affect diel O2 saturation and delta18O-O2 curves, thereby providing a fundamental framework for the use of delta18O-O2 in ecosystem productivity studies. delta18O-O2 provides information unavailable from concentration alone because delta18O-O2 and saturation curves are not symmetrical and can be used to constrain gas exchange and isotopic fractionation by eliminating many common assumptions. Changes in key parameters affect diel O2 saturation and delta18O-O2 curves as follows: (1) an increase in primary production and respiration rates increases the diel range of O2 saturation and delta18O-O2 and decreases the mean delta18O-O2 value; (2) a decrease in the primary production to respiration ratio (P:R) decreases the level of O2 saturation and increases the delta18O-O2 values; (3) an increase in the gas exchange rate decreases the diel range of O2 saturation and delta18O-O2 values and moves the mean O2 saturation and delta18O-O2 values toward atmospheric equilibrium; (4) a decrease in strength of the respiratory isotopic fractionation (alphaR closer to 1) has no effect on O2 saturation and decreases the delta18O-O2 values; (5) an increase in the delta18O of water has no effect on O2 saturation and increases the minimum (daytime) delta18O-O2 value; and (6) an increase in temperature reduces O2 solubility and thus increases the diel range of O2 saturation and delta18O-O2 values. Understanding the interplay between these key parameters makes it easier to decipher the controls on O2 and delta18O-O2, compare aquatic ecosystems, and make quantitative estimates of ecosystem metabolism. The photosynthesis to respiration to gas exchange ratio (P:R:G) is better than the P:R ratio at describing and assessing the vulnerability of aquatic ecosystems under various environmental stressors by providing better constrained estimates of ecosystem metabolism and gas exchange.