鸟类在湿地汞循环和汞监测中的作用

The Role of Birds in Mercury Cycle and Monitoring in Wetlands

湿地被称为汞的活性库,鸟类在汞的生物富集和搬运过程中发挥了重要作用。鸟类汞富集程度与营养级及年龄呈正相关,在其组织器官中,羽毛、肝和肾中的汞富集含量高。食鱼鸟类是湿地生态系统的顶级消费者,汞富集程度最高,鸥类、鹭类等常见食鱼鸟是推荐的指示生物。在极地等偏远地区,生物富集和生物搬运的协同作用对汞迁移的影响大于大气沉降,粪便、羽毛是鸟体排出汞的主要方式。由于鸟类的周期性迁徙,以及对不同生境的利用强度不同,鸟类对汞的生物搬运呈现出明显的规律性和方向性,影响其生物搬运汞的因素主要有新陈代谢、迁徙、栖息地景观特征和气候变化等。鸟类的组织器官乃至种群参数已经被广泛用于汞污染监测中,鸟的羽毛和卵因具有汞富集程度高、易于获取、无损伤性、可以长期保存等优点,所以是推荐的可以采集的样品材料。未来加强鸟类食物链结构分析、室内控制毒理实验、鸟类迁徙生态等基础研究,可提高鸟类作为汞污染指示生物的科学性和准确性。

Wetlands are called active pools of mercury in general and the birds play an important role in bioaccumulation and transportation of mercury. The degree of mercury biomagnification of the birds with the trophic level and age are positively correlated. In all the tissues and organs of these birds, mercury biomagnification of feather, liver and kidney are relatively higher. As the top consumers of wetland ecosystem, the degree of mercury accumulation of piscivorous birds is the highest, especially Laridae and umbrette which are recommended as indicator organism. In the remote areas such as polar region, the influence on the migration of mercury of the synergy between bioaccumulation and biological transportation is bigger than that of atmospheric deposition, and droppings and feathers of the birds are the main ways to get rid of mercury. Because of the cyclical migration of the birds and the difference of the intensity of using different habitats, birds have obvious regularity and direction to the biological transportation of mercury. The main factors of mercury biological transportation are metabolism, migrating, landscape features of habitat, climatic variation and so on. The tissues and organs even the population parameters of the birds have been widely used in monitoring of mercury pollution. Because of some advantages such as the high degree of mercury enrichment, easy access, no damage and long-term keeping, feathers and eggs of the birds are always recommended as samples. In order to improve the scientificity and accuracy of the birds as the indicator organism of mercury pollution, the analysis of food chain structure, control experiments of toxicology and ecological study of the birds migrating should be further strengthened.