Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843-2258, USA.
Ecotoxicology. 2011 Aug;20(6):1467-75. doi: 10.1007/s10646-011-0703-4. Epub 2011 Jun 10.
To examine regional variation in strontium (Sr), which at high concentrations may reduce eggshell quality, increase egg breakage and reproductive failure, we analyzed Sr, and calcium (Ca) concentrations and Sr/Ca ratios in eggshells from 20 avian species from California, Texas, Idaho, Kansas, and Michigan. In addition, we included data previously reported from Arizona to expand the regional comparisons and to better establish patterns of Sr, and Sr/Ca ratios in bird species across the United States. We found Sr concentrations varied significantly among regions, among species, and among foraging guilds; this variability is strongly influenced by the Sr/Ca ratios in surface water from locations close to the region where the eggshells were collected. Sr concentrations and Sr/Ca ratios were significantly higher in bird eggshells from the Volta wildlife region in the San Joaquin Valley, California and in various locales from Arizona. Sr concentrations and Sr/Ca ratios in bird eggshells from other locations in the USA were lower than those detected in these two regions. Among foraging guilds, invertivores had the highest Sr concentrations and Sr/Ca ratios and carnivores had the lowest. In general, the Sr/Ca ratio increased strongly with increasing Sr concentrations (R(2) = 0.99, P < 0.0001). There was a significant correlation (R(2) = 0.58, P < 0.0001) between Sr/Ca ratios in water and the average Sr/Ca ratios in eggshells suggesting that these values could be determined from Sr/Ca ratios in water. Eggshell thickness was poorly correlated with Sr (R(2) = 0.03) but had a significant and positive correlation with Ca and was more properly correlated by a quadratic equation (R(2) = 0.50, Thickness = 2.13 - 0.02Ca - 3.07 * 10(-5)Ca(2)). Our study provides further evidence that Sr accumulates significantly in the avian eggshell, in some regions at concentrations which could be of concern for potential negative effects on reproduction. We suggest that when assessing the effects of metals on avian reproduction in regions with high Sr deposits in rock and soil, Sr concentrations in the eggshell also should be measured to evaluate additional effects on thickness and reproduction.
为了研究锶（Sr）的区域性变化，因为高浓度的锶可能会降低蛋壳质量、增加蛋壳破裂和繁殖失败的风险，我们分析了来自加利福尼亚州、得克萨斯州、爱达荷州、堪萨斯州和密歇根州的 20 种鸟类蛋壳中的锶和钙（Ca）浓度以及锶/钙比值。此外，我们还包括了以前在亚利桑那州报告的数据，以扩大区域比较，并更好地确定美国鸟类物种中锶和锶/钙比值的模式。我们发现，锶浓度在不同地区、不同物种和不同觅食群体之间存在显著差异；这种变异性强烈受采集蛋壳地区附近地表水的锶/钙比值影响。加利福尼亚州圣华金谷沃尔塔野生动物区和亚利桑那州多个地点的鸟类蛋壳中的锶浓度和锶/钙比值明显较高。美国其他地区鸟类蛋壳中的锶浓度和锶/钙比值低于这两个地区。在觅食群体中，食虫动物的锶浓度和锶/钙比值最高，肉食动物的锶浓度和锶/钙比值最低。一般来说，锶/钙比值随锶浓度的增加而强烈增加（R²=0.99，P<0.0001）。水的锶/钙比值与蛋壳中平均锶/钙比值之间存在显著相关性（R²=0.58，P<0.0001），表明这些值可以从水中的锶/钙比值来确定。蛋壳厚度与锶的相关性较差（R²=0.03），但与钙的相关性显著且为正相关，与二次方程的相关性更好（R²=0.50，厚度=2.13-0.02 钙-3.07*10（-5）钙（2））。我们的研究进一步证明，在一些地区，锶在鸟类蛋壳中大量积累，浓度可能对繁殖产生负面影响。我们建议，在评估富含岩石和土壤中的高浓度锶地区金属对鸟类繁殖的影响时，还应测量蛋壳中的锶浓度，以评估其对厚度和繁殖的额外影响。
