1. The American brine shrimp Artemia franciscana is important in aquaculture and has become invasive in other continents, aided by dispersal via waterbirds. However, little is known about processes underlying its genetic diversity and population structure in its natural habitat in North America. These processes, including dispersal and local adaptation, are pivotal drivers of species distribution and community structure, and therefore central to aquatic biodiversity.
2. We studied 15 populations in natural saline lakes of Saskatchewan, Canada to determine the influence of variation in geological history, water chemistry, lake size, and location. We aimed to determine the relative importance of isolation by distance and isolation by environment using the cytochrome c oxidase subunit 1 gene (CO1) as a mitochondrial marker and five nuclear microsatellite markers.
3. Geographic patterns for CO1 and microsatellites differed, with lakes clustering in different groups based on genetic distances according to the marker used. CO1 better indicated historical colonisation processes, suggesting potential routes of initial colonisation when lakes were formed after deglaciation 11,000–15,000 years ago.
4. Differentiation between lakes based on nuclear markers was strongly related to variation in hydrochemistry, suggested by distance-based redundancy analysis, but there was no indication of isolation by distance. The ratio between alkalinity and the sum of Ca and Mg concentrations was particularly important, although a lake with a high Cl concentration caused by potash mining also had a unique Artemia population.
5. Geochemistry is important in the adaptive radiation of anostracan crustaceans. Our study suggests that it also underlies intraspecific genetic variation between populations, promoting isolation by environment, and making dispersal ineffective when cysts are moved by birds between lakes with different hydrochemistry.

中文翻译：

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盐水化学很重要：通过环境和距离的隔离解释了盐湖中卤虫种群的遗传结构

1. 美国丰年虾Artemia franciscana在水产养殖中很重要，并且在水鸟传播的帮助下已侵入其他大陆。然而，对其在北美自然栖息地的遗传多样性和种群结构的潜在过程知之甚少。这些过程，包括扩散和局部适应，是物种分布和群落结构的关键驱动因素，因此对水生生物多样性至关重要。
2. 我们研究了加拿大萨斯喀彻温省天然盐湖中的 15 个种群，以确定地质历史、水化学、湖泊大小和位置变化的影响。我们旨在使用细胞色素c氧化酶亚基 1 基因 (CO1) 作为线粒体标记和五个核微卫星标记来确定按距离隔离和按环境隔离的相对重要性。
3. CO1 和微卫星的地理模式不同，根据所用标记的遗传距离，湖泊聚集在不同的组中。CO1 更好地表明了历史殖民过程，表明在 11,000-15,000 年前冰川消退后形成湖泊时，初始殖民的潜在途径。
4. 基于距离的冗余分析表明，基于核标记的湖泊之间的区分与水化学的变化密切相关，但没有迹象表明距离隔离。碱度与 Ca 和 Mg 浓度总和之间的比率特别重要，尽管由钾盐开采引起的高 Cl 浓度的湖泊也有独特的卤虫种群。
5. 地球化学对于甲壳类动物的适应性辐射很重要。我们的研究表明，它也是种群之间种内遗传变异的基础，促进了环境的隔离，并且当包囊被鸟类在具有不同水化学的湖泊之间移动时，传播无效。