见于北美大西洋沿岸的海洋入侵物种岩藻（Fucus serratus）和欧洲玉黍螺（Littorina littorea）很可能是在19世纪跟随英国和爱尔兰船只而来到这里的。那时候，跨大西洋的船只通常使用岩石作为压舱物，这些压舱物在港口或沿岸浅水区被抛弃。
Susan Brawley及其同事提出，这种倾泻压舱物的方式很可能也把这两种海洋物种引入了加拿大的沿岸地区。岩藻持续在加拿大沿岸扩散，而欧洲玉黍螺已经向南推进到了特拉华州的沿岸。这组科学家对来自新斯科舍省Pictou 港的当代岩藻和欧洲玉黍螺样本进行了一次遗传分析，，结果显示它们和来自苏格兰和爱尔兰的岩本相匹配，这两个地区与Pictou有频繁的货运联系。
这组作者发现，岩藻表现显出的自主扩散的本领有限，它们分别从爱尔兰的Galway和苏格兰的Greenock到达了新斯科舍，而且这组作者把新斯科舍的欧洲玉黍螺和见于爱尔兰和苏格兰的物种的遗传指纹联系了起来。这组作者认为岩藻和欧洲玉黍螺在北美的引入是“入侵的冰山一角”，并且提出这类入侵物种新的到来可以对海洋生态系统产生广泛的影响。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS May 4, 2009, doi: 10.1073/pnas.0812300106
Historical invasions of the intertidal zone of Atlantic North America associated with distinctive patterns of trade and emigration
Susan H. Brawleya,1, James A. Coyerb, April M. H. Blakesleec, Galice Hoaraub, Ladd E. Johnsond, James E. Byerse, Wytze T. Stamb and Jeanine L. Olsenb
aSchool of Marine Sciences, University of Maine, Orono, ME 04469;
bDepartment of Marine Benthic Ecology and Evolution, Center for Ecological and Evolutionary Studies, University of Groningen, 9750 AA Haren, The Netherlands;
cMarine Invasion Laboratory, Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, MD 21037;
dDepartment of Biology, Université Laval, Québec, QC, Canada G1V 0A6; and
eOdum School of Ecology, University of Georgia, Athens, GA 30602
Abstract
Early invasions of the North American shore occurred mainly via deposition of ballast rock, which effectively transported pieces of the intertidal zone across the Atlantic. From 1773–1861, >880 European ships entered Pictou Harbor, Nova Scotia, as a result of emigration and trade from Europe. The rockweed Fucus serratus (1868) and the snail Littorina littorea (≈1840) were found in Pictou during this same period. With shipping records (a proxy for propagule pressure) to guide sampling, we used F. serratus as a model to examine the introductions because of its relatively low genetic diversity and dispersal capability. Microsatellite markers and assignment tests revealed 2 introductions of the rockweed into Nova Scotia: 1 from Galway (Ireland) to Pictou and the other from Greenock (Scotland) to western Cape Breton Island. To examine whether a high-diversity, high-dispersing species might have similar pathways of introduction, we analyzed L. littorea, using cytochrome b haplotypes. Eight of the 9 Pictou haplotypes were found in snails collected from Ireland and Scotland. Our results contribute to a broader understanding of marine communities, because these 2 conspicuous species are likely to be the tip of an “invasion iceberg” to the NW Atlantic from Great Britain and Ireland in the 19th Century.
