Ruiz-Ramos Dannise V, Saunders Miles, Fisher Charles R, Baums Iliana B
Biology Department, The Pennsylvania State University, University Park, Pennsylvania, United States of America.
PLoS One. 2015 Oct 21;10(10):e0138989. doi: 10.1371/journal.pone.0138989. eCollection 2015.
Colonial corals occur in a wide range of marine benthic habitats from the shallows to the deep ocean, often defining the structure of their local community. The black coral Leiopathes glaberrima is a long-lived foundation species occurring on carbonate outcrops in the Northern Gulf of Mexico (GoM). Multiple color morphs of L. glaberrima grow sympatrically in the region. Morphological, mitochondrial and nuclear ribosomal markers supported the hypothesis that color morphs constituted a single biological species and that colonies, regardless of color, were somewhat genetically differentiated east and west of the Mississippi Canyon. Ten microsatellite loci were used to determine finer-scale population genetic structure and reproductive characteristics. Gene flow was disrupted between and within two nearby (distance = 36.4 km) hardground sites and two sympatric microsatellite lineages, which might constitute cryptic species, were recovered. Lineage one was outbred and found in all sampled locations (N = 5) across 765.6 km in the Northern Gulf of Mexico. Lineage two was inbred, reproducing predominantly by fragmentation, and restricted to sites around Viosca Knoll. In these sites the lineages and the color phenotypes occurred in different microhabitats, and models of maximum entropy suggested that depth and slope influence the distribution of the color phenotypes within the Vioska Knolls. We conclude that L. glaberrima is phenotypically plastic with a mixed reproductive strategy in the Northern GoM. Such strategy might enable this long-lived species to balance local recruitment with occasional long-distance dispersal to colonize new sites in an environment where habitat is limited.
群体珊瑚出现在从浅海到深海的广泛海洋底栖生境中，常常决定着其当地群落的结构。黑珊瑚光滑异杯珊瑚是一种长寿的基础物种，出现在墨西哥湾北部的碳酸盐露头处。光滑异杯珊瑚的多种颜色形态在该地区同域生长。形态学、线粒体和核糖体标记支持了以下假设：颜色形态构成单一生物物种，且无论颜色如何，群体在密西西比峡谷以东和以西在一定程度上存在遗传分化。使用10个微卫星位点来确定更精细尺度的种群遗传结构和繁殖特征。在两个相邻（距离 = 36.4公里）的硬底质地点之间以及内部，基因流受到干扰，并且恢复了两个同域微卫星谱系，这可能构成隐存种。谱系一为远交，在墨西哥湾北部765.6公里范围内的所有采样地点（N = 5）均有发现。谱系二为近交，主要通过碎片化繁殖，并且局限于维奥斯卡海丘周围的地点。在这些地点，谱系和颜色表型出现在不同的微生境中，最大熵模型表明深度和坡度影响维奥斯卡海丘内颜色表型的分布。我们得出结论，在墨西哥湾北部，光滑异杯珊瑚具有表型可塑性和混合繁殖策略。这种策略可能使这种长寿物种能够在栖息地有限的环境中，平衡本地补充与偶尔的长距离扩散以殖民新地点。
