McCloskey Meagan, Robinson Stacey, Smith Paul A, Forbes Mark
Department of Biology, Carleton University, 1125 Colonel By, Ottawa, ON K1S 5B6 Canada.
Springerplus. 2013 Oct 26;2:567. doi: 10.1186/2193-1801-2-567. eCollection 2013.
Methylmercury is a toxic form of mercury which persists in food webs for long periods of time and biomagnifies up successive trophic levels. Shorebirds breeding in the Arctic are exposed to methylmercury, derived from both natural and anthropogenic sources, when they ingest their invertebrate prey. Populations of many shorebird species are believed to be declining and one hypothesis for these declines is that they are due to detrimental effects of contaminants, including methylmercury. To test this hypothesis, we assessed mercury contamination in eggs of four Canadian Arctic-breeding shorebird species: black-bellied plover (Pluvialis squatarola), ruddy turnstone (Arenaria interpres), semipalmated plover (Charadrius semipalmatus) and white-rumped sandpiper (Calidris fuscicollis). Black-bellied plovers and ruddy turnstones are declining in the western hemisphere, whereas white-rumped sandpipers and semipalmated plovers have stable or slightly increasing populations. We found no relationship between egg mercury concentration and population trend for these four shorebird species. Intraspecific variation in mercury concentration was high. Notably, the mercury concentrations were much higher than levels found in a previous study of eggs of the same shorebird species from this same site, suggesting that mercury contamination may be subject to substantial inter-annual variation in the Canadian Arctic food web.
甲基汞是汞的一种有毒形式，它在食物网中长时间存在，并在连续的营养级中生物放大。在北极繁殖的滨鸟在摄取无脊椎动物猎物时，会接触到来自自然和人为来源的甲基汞。许多滨鸟物种的数量据信正在减少，对于这些减少的一种假设是，它们是由于包括甲基汞在内的污染物的有害影响。为了验证这一假设，我们评估了四种在加拿大北极地区繁殖的滨鸟物种卵中的汞污染情况：黑腹鸻（Pluvialis squatarola）、翻石鹬（Arenaria interpres）、半蹼鸻（Charadrius semipalmatus）和白腰滨鹬（Calidris fuscicollis）。黑腹鸻和翻石鹬在西半球的数量正在减少，而白腰滨鹬和半蹼鸻的数量稳定或略有增加。我们发现这四种滨鸟物种的卵汞浓度与种群趋势之间没有关系。汞浓度的种内变异很大。值得注意的是，汞浓度远高于此前对同一地点相同滨鸟物种卵的研究中所发现的水平，这表明加拿大北极食物网中的汞污染可能存在显著的年际变化。
