Genetic Connectivity in Corals on the Flower Garden Banks and Surrounding Oil/Gas Platforms, Gulf of Mexico
Genetic Connectivity in Corals on the Flower Garden Banks and Surrounding Oil/Gas Platforms, Gulf of Mexico
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DOI：
10.1016/j.jembe.2008.07.002
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发表时间：
2008-10-20
影响因子：
2
通讯作者：
Brazeau, Daniel A.
中科院分区：
文献类型：
--
作者：
Atchison, Amy D.;Sammarco, Paul W.;Brazeau, Daniel A.
墨西哥湾北部目前拥有类似的3600个海上石油和天然气生产平台。这些平台充当大陆架上的人工礁石，在它们出现之前，大陆架上很少有浅而硬的底质。这种新的可用底物帮助扩大了GOM中的硬壳珊瑚种群。在这里，我们对花园滩(FGB)珊瑚礁(类似于德克萨斯州加尔维斯顿的180KNN东南)及其周围石油和天然气平台上的成年珊瑚进行了分子遗传学分析。我们试图确定自然种群和周围平台上的种群之间的遗传亲缘程度。采集了3种最丰富的血型硬壳动物：Madracis decacs、Diploria strigosa和Montastraea cavernosa。组织样本来自东部(E-)和西部(W-)FGB以及FGB半径65公里内的7个平台，深度范围为5-37m。利用扩增片段长度多态性(AFLP)分析遗传变异。AFLP产生的大量多态标记允许使用标准遗传分析工具(AMOVA)以及种群分配技术(AFLPOP)。AMOVA分析表明，E-FGB和W-FGB在Madracis decacs和Diploria strigosa种群中具有遗传一致性，而Montastraea cavernosa种群在这两个种群之间存在显著差异。在所有物种中，遗传距离(FST)随着种群间地理距离的增加而显著增加。在孵化物种Madracis decacs中，当人们考虑平台与FGB周长之间的距离时，这种模式甚至更强烈，特别是最近的FGB，这表明FGB可能是平台种群幼虫的来源。AFLPOP分析表明，自分配到主站点的程度也随着站点间距离的增加而增加。在FGB仅一到几公里范围内的所有物种中，地点之间的交叉分配都显着且呈指数级下降。与广播者Diploria strigosa相比，Madracis decacs是一种幼虫释放期较长且具有近即时定居能力的孵化鱼，在距离上对FGB表现出更大的亲和力。这种孵化鱼似乎更有效地在小的、附近的目标地点定居，并在中尺度上扩大其地理范围。所有物种在平台上表现出的低遗传亲和力可能归因于遗传漂移/创始人效应或相对较小的样本量，尽管总体种群是抽样的。总体而言，遗传亲和力随着位点间距离的增加而降低。在群落演替的早期阶段，幼龄珊瑚种群在中尺度上高度分化，这意味着在达到遗传平衡或同质性之前，需要大量时间和在较大潜在幼虫来源周围的斑块栖息地反复定居。(C)2008爱思唯尔B.V.保留所有权利。
The northern Gulf of Mexico (GOM) currently possesses similar to 3,600 offshore oil and gas production platforms. These platforms serve as artificial reefs on the continental shelf, where, until their introduction, shallow hard substrata were rare. This newly available substrate has helped to expand scleractinian coral populations in the GOM. Here, we conduct molecular genetic analyses on adult scleractinian corals on the Flower Garden Banks (FGB) coral reefs (similar to 180 knn SE of Galveston, TX) and on surrounding oil and gas platforms. We have attempted to determine the degree of genetic affinity among the natural populations and those on the surrounding platforms. The three most abundant hermatypic scleractinian species were sampled: Madracis decactis, Diploria strigosa, and Montastraea cavernosa. Tissue samples were collected from the East (E-) and West (W-) FGB, and seven platforms within a 65 km radius of the FGB, at a depth range of 5-37 m. Genetic variation was assessed using Amplified Fragment Length Polymorphisms (AFLPs). The large number of polymorphic markers generated by AFLPs allowed for the use of standard genetic analysis tools (AMOVA) as well as population allocation techniques (AFLPOP). AMOVA analyses indicated that the E- and W-FGB were genetically homogeneous for populations of Madracis decactis and Diploria strigosa; Montastraea cavernosa populations, however, were significantly different there. In all species, genetic distance (FST) increased significantly with geographic distance between populations. In the brooding species Madracis decactis, this pattern was even stronger when one considered distance between the platforms and the perimeters of the FGB, particularly the nearest FGB, suggesting that the FGB may be a source of larvae for platform populations. AFLPOP analyses showed that the degree of self-allocation to home sites also increased with inter-site distance. Cross allocations between sites dropped significantly and exponentially in all species within only one to several kms of the FGB. Madracis decactis, a brooder with extended larval release periods and near-immediate settlement competence, showed greater affinity to the FGB with distance than Diploria strigosa, a broadcaster. This brooder appears to be more effective at colonizing small, nearby target sites and expanding its geographic range at the meso-scale. The low degree of genetic affinity exhibited by all species on the platforms may be attributed to genetic drift/founder effect or relatively small samples sizes, although total populations were sampled. In general, genetic affinity decreased with inter-site distance. Young coral populations are highly differentiated at the meso-scale during early stages of community succession, implying that much time and repeated colonization of patchy habitats around larger potential larval sources will be required before genetic equilibrium or homogeneity is reached. (C) 2008 Elsevier B.V. All rights reserved.