Do sediment-dwelling species have large ranges along a continental slope?

沉积物覆盖的深海海底可以说是地球上最大的栖息地。尽管有极端的条件，在给定的位置上，一些分类群的物种数量可以与地球上物种最丰富的栖息地中物种最丰富的群体相媲美（例如，雨林中的昆虫）。 这种丰富性的本质是有争议的。 一些研究报告说，少数物种的范围为100到1,000公里，但许多物种只在一个地方被发现。 在其他工作中，据报告有更多的物种分布范围很大。 更糟糕的是，现有的数据可能并不完全提供信息，因为关于将个体分配到物种的决定是基于形态学做出的，这可能无法区分生物学上分离的物种，通常被称为神秘物种。 深海沉积物中物种范围有多大的问题需要解决，因为这对深海沉积物生态学的概念模型有着深远的影响。 如果大多数物种的活动范围都很小，那么研究深海的学生就会想了解，例如，在一个似乎没有什么物理障碍的环境中，物种的活动范围是如何界定的。 或者，如果大多数物种都有很大的分布范围，研究人员将希望研究与100到1,000公里的物种遗传连接有关的问题。 该项目的主要目标是评估某些深海沉积物栖息物种分布广泛的可能性。 为此，这些调查人员将在美国西海岸外大陆坡四个纬度（北纬47.6度、北纬42.6度、北纬36.5度和北纬32.6度）各从一个2 700米深的站和一个3 700米深的站收集沉积物样本。 非常常见的桡足类将是这项研究的目标群体。 根据传统的形态特征，每个样本中的每个成虫都将被分配到一个物种。 然后将这些成年硬足类桡足类动物切成两半;后部将用于DNA序列分析，前部将作为凭证样本保留。 DNA序列分析将用于确定基于形态学被视为相同种属的个体是否形成基于分子数据的支持良好的种属组。 这些物种群在各站之间的分布将使调查人员知道，其范围至少与发现它们的站之间的距离一样大。拟议的研究可以帮助决策者评估人类对深海海底的干扰所造成的环境代价，从而造福社会（例如，海洋倾倒1）开始澄清物种范围和人类干扰之间的关系。 调查人员还将通过在科学会议上和出版物上的介绍与同事分享他们的成果，并通过公开讲座和网站向更广泛的受众分享他们的成果。 该项目还将促进代表性不足的群体参与海洋学。

The sediment-covered deep-sea floor is arguably the largest habitat on Earth. Despite the extreme conditions, the number of species present at a given location for some taxa can rival that of the most species-rich groups in the most species-rich habitats on Earth (e.g., insects in rain forests). The nature of this richness is controversial. Some studies have reported that a few species had ranges of 100's to 1,000's of kilometers, but many species were found at only a single location. In other work, many more species were reported to have large ranges. Worse, the existing data may not be completely informative because the decisions about the assignment of individuals to species were made on the basis of morphology, which can fail to distinguish species that are biologically separate, and commonly known as cryptic species. The question of how big is a species range in deep-sea sediments needs to be resolved because it matters profoundly to conceptual models of the ecology of deep-sea sediments. If most species have small ranges, students of the deep sea will want to understand, for example, how species' ranges are bounded in an environment that appears to have few physical barriers. Alternatively, if most species have large ranges, investigators will want to study issues related to the genetic connectivity of species over 100's to 1,000's of kilometers. The primary objective of this project is to evaluate the possibility that some sediment-dwelling deep-sea species have large ranges. To do that these investigators will collect sediment samples from one station at 2,700 m and one at 3,700 m depth at each of four latitudes (47.6° N, 42.6° N, 36.5° N, and 32.6° N) on the continental slope off the west coast of the United States. The very common harpacticoid copepods will be the target group for this study. Each adult harpacticoid from each sample will be assigned to a species on the basis of traditional morphological characters. Each of these adult harpacticoid copepods will then be cut in two; the posterior portion will be used for DNA-sequence analysis, and the anterior will be retained as a voucher sample. The DNA-sequence analysis will be used to determine whether the individuals deemed to be the same species on the basis of morphology form a well-supported species group based on molecular data. The distribution of these species groups among stations will allow the investigators to know that its range is at least as large as the distance between the stations where they were found. The proposed research could benefit society by helping policy makers evaluate the environmental cost of human disturbance of the deep-sea floor (e.g., ocean dumpingl) by beginning to clarify the relationship between species ranges and human disturbances. The investigators will also share their results with colleagues through presentations at scientific meetings and in publications and to a wider audience by means of public lectures and a web site. The project will also foster the participation of underrepresented groups in oceanography.