Effects of tissue decomposition on stable isotope ratios and implications for use of stranded animals in research
Effects of tissue decomposition on stable isotope ratios and implications for use of stranded animals in research
复制标题
DOI：
10.1002/ecs2.4385
复制
发表时间：
2023-02-01
期刊：
影响因子：
2.7
通讯作者：
Carmichael, Ruth H.
中科院分区：
文献类型：
--
作者：
Cloyed, Carl S.;Johnson, Che'Isha;Carmichael, Ruth H.
稳定同位素分析（SIA）提供了可以安全有效地收集濒危、受威胁和隐种的生态数据。海洋哺乳动物是一个生态上重要的群体，经济和后勤限制可能使数据收集具有挑战性。搁浅的海洋哺乳动物经常被用于研究，但搁浅的原因和随后的组织分解可能会影响SIA。我们进行了一项由三部分组成的研究，以测试从搁浅的宽吻海豚（Tursiops truncatus）和西印度海牛（trichecchus manatus）的组织中提取δ C-13和δ N-15值用于生态研究的有效性。首先，基于95%的数据，我们使用椭圆来量化同位素重叠，以比较搁浅动物和活捕获动物皮肤中的同位素值。其次，我们比较了搁浅动物的肝脏、皮肤和肌肉的稳定同位素值，并在不同的分解阶段取样。第三，我们通过实验将每个组织暴露在环境条件下，并在组织分解时取样。对于海豚和海牛来说，搁浅的尸体皮肤上的同位素椭圆与活捕获的个体相似。在不同分解阶段恢复的个体中，较晚期的分解对海豚肝脏和皮肤的δ C-13值有影响，而对海牛组织的δ N-15值没有影响。在实验操作中，分解导致两种物种肝脏中δ C-13值减少，δ N-15值增加，C:N增加。搁浅海豚和海牛的皮肤和肌肉是其相应活种群的代表，可在适当谨慎的情况下用于SIA。为方便使用搁浅动物的组织，取样后应尽快将组织干燥或冷冻保存。我们建议，只有当研究人员需要周转时间短的组织并且可以获得新鲜样本时，才能将搁浅动物的肝脏用于SIA。如果不考虑分解对同位素值的影响，生态学家可能会对栖息地利用、饮食和群落结构做出不准确的推断。在搁浅动物的组织上仔细使用SIA可以帮助研究人员为管理者和决策者提供更高质量的信息。
Stable isotope analysis (SIA) provides ecological data that can be safely and efficiently collected on endangered, threatened, and cryptic species. Marine mammals are an ecologically important group for which economical and logistical constraints can make data collection challenging. Stranded marine mammals are often used in research, but the causes of strandings and subsequent tissue decomposition could affect SIA. We conducted a three-part study to test the validity of using delta C-13 and delta N-15 values from tissues of stranded bottlenose dolphins (Tursiops truncatus) and West Indian manatees (Trichechus manatus) for ecological studies. First, we quantified isotopic overlap using ellipses based on 95% of the data to compare isotope values in skin between stranded and live-captured animals. Second, we compared stable isotope values from liver, skin, and muscle of animals that had stranded and were sampled at different decomposition stages. Third, we experimentally exposed each tissue to environmental conditions and sampled tissues as they decomposed. For both dolphins and manatees, isotopic ellipses from skin of stranded carcasses were similar to live-captured individuals. Among individuals recovered at different decomposition stages, more advanced decomposition affected delta C-13 values in dolphin liver and skin but not in manatee tissues and had no effect on delta N-15 values in any tissue for either species. In the experimental manipulation, decomposition resulted in depleted delta C-13 values, enriched delta N-15 values, and increased C:N in liver for both species. Skin and muscle from stranded dolphins and manatees are representative of their corresponding live populations and can be used for SIA with appropriate caution. To facilitate the use of tissues from stranded animals, tissues should be dried or frozen for storage as soon as possible after sampling. We recommend liver from stranded animals only be used for SIA when researchers need tissues with short turnover times and can access fresh samples. Without consideration of decomposition effects on isotope values, ecologists may make inaccurate inferences about habitat use, diet, and community structure. Careful use of SIA on tissues from stranded animals can help researchers provide better quality information for managers and policy makers.