The elemental (C/N) and stable isotopic (δ¹³C, δ¹⁵N) compositions and compound-specific δ¹⁵N values of amino acids (δ¹⁵N_AA) were evaluated for coral holobionts as diagnostic tools to detect spatiotemporal environmental heterogeneity and its effects on coral health. Hermatypic coral samples of eight species were collected at 12 reef sites with differing levels of pollution stress. The C/N ratios, δ¹³C values, and δ¹⁵N values of coral tissues and endosymbiotic algae were determined for 193 coral holobionts, and the amino acid composition and δ¹⁵N_AA values of selected samples were analyzed. δ¹⁵N values were influenced most by pollution stress, while C/N ratios and δ¹³C values depended most strongly on species. The results imply that δ¹³C and δ¹⁵N values are useful indicators for distinguishing the ecological niches of sympatric coral species based on microhabitat preference and resource selectivity. Using δ¹⁵N_AA values, the trophic level (TL) of the examined coral samples was estimated to be 0.71 to 1.53, i.e., purely autotrophic to partially heterotrophic. Significant portions of the variation in bulk δ¹⁵N and δ¹³C values could be explained by the influence of heterotrophy. The TL of symbionts covaried with that of their hosts, implying that amino acids acquired through host heterotrophy are translocated to symbionts. Dependence on heterotrophy was stronger at polluted sites, indicating that the ecological role of corals changes in response to eutrophication.

中文翻译：

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珊瑚和藻类共生体的有机碳和氮等值线：环境梯度和异养作用的相对影响。

元素（C / N）和稳定同位素（δ ¹³ C，δ ¹⁵ N）的组合物和化合物的特定δ ^15个氨基酸（δ的N个值¹⁵ Ñ _AA）为珊瑚holobionts用作诊断工具，以检测时空环境异质进行评价及其对珊瑚健康的影响。在十二个珊瑚礁地点收集了八种物种的珊瑚珊瑚标本，它们的污染压力程度不同。的C / N比，δ ^13个C值，和δ ^15个珊瑚组织和内共生藻类的N个值进行了测定为193个珊瑚holobionts，和氨基酸组成和δ ^15个Ñ _AA所选样本的值进行分析。δ ¹⁵N个值分别影响由污染应力最多，而C / N比和δ ^13个C值取决于最强烈物种。该结果意味着，δ ¹³ C和δ ^15个N个值是用于区分基于微生偏好和资源选择性同域珊瑚物种的生态位有用的指标。使用δ ^15个Ñ _AA值，的营养级（TL）检查样品珊瑚估计为0.71〜1.53，即，纯粹自养，以部分地异。δ散装的变化显著部分¹⁵ N和δ ¹³C值可以通过异养性的影响来解释。共生体的TL与其宿主的TL协变，这意味着通过宿主异养而获得的氨基酸易位至共生体。受污染的地方对异养的依赖性更强，表明珊瑚的生态作用随着富营养化而变化。