Deep-Sea Biodiversity: A Morphological Dimension

对深海软沉积物栖息地生物多样性的研究主要集中在一个？多样性，即在涉及干扰、生物相互作用和环境异质性的传统解释的背景下估计当地物种多样性及其地理变异。对物种本身的自然历史和分布模式知之甚少，而这些信息对于理解物种在群落组织中扮演的角色以及当地多样性与最终调节物种多样性的区域尺度过程之间的关系至关重要。本文提出了将物种的生物地理和生活史特征与深海物种多样性联系起来的两种研究途径。首先，将腹足类动物壳结构的形态变异作为生物多样性的一个新维度。二是探讨体表大小与体表深度的关系。两者都增加了对深海群落结构的理解，这是通过简单的a-多样性分析无法获得的。建议的研究直接涉及美国国家科学基金会海洋系统生物多样性的生物海洋学主题，特别是深海生态系统海洋生物的分布、丰度和生活史领域；海洋生物的适应；以及它们的种群生态。形态变化。本文对北大西洋西部腹足类深海和深海组合的水深范围和壳结构变化进行了初步分析。深海动物群被发现仅仅是深海动物群的一个子集，这些动物群组成的物种将它们的活动范围延伸到更深的深渊上。腹足类动物的壳结构反映了摄食类型、发育模式、捕食者防御机制、运动和碳酸钙的保存。我们利用壳几何的特征形分析和劳普斯模型构造了壳形的经验和理论形态空间。两种方法都会产生相同的结果。就基本贝壳类型的范围而言，深海动物群似乎是丰富的深海动物群的随机子集。然而，深海动物群在数量上主要是一些深海起源的岩心沉积物食性物种，它们的壳预先适应了CaCO3补偿深度以下的碳酸盐保护。结合形态变异、水深范围、摄食类型和扩散能力，提出了一种与现行理论的生态决定论截然不同的深海生物多样性新假说。我们认为深海环境和深海环境组成了一个源-汇系统，其中深海动物群在很大程度上代表了一种质量效应。深海动物群似乎是深海动物群的衰减，只有少数丰富的物种，而大多数极稀有的物种可能代表着通过分散维持的非繁殖种群。我们将通过将分析扩展到其他四个深海盆地，并通过确定同一物种的深海和深海种群的繁殖状态来验证这一假设。由于深海平原是一个巨大的生态系统，本研究对于多样性的发生和维持以及估计全球深海生物多样性水平具有重要意义。身体的大小。体型是生物学中一个具有基础性意义的问题，对丰度、分布、宏观生态和生物多样性有着重要的影响。先前NSF支持的结果（OCE-9301687）表明，与主流观点相反，腹足动物个体的大小随着深度的增加而增加。随着深度和水深范围的扩大，坡度的尺寸-深度曲线减小。我们提出了一个概念模型，该模型结合了物种内部这种非常一致的趋势，以及物种之间的平均尺寸似乎随着深度而减小的观察结果。我们建议测量模型的平均尺寸分量。这项研究有可能解决深海生态学中一个非常基本的悖论，并将提供迄今为止最大、控制最完善的深海底栖生物规模数据库。

Research on the biodiversity of deep-sea soft sediment habitats has centered largely on a?diversity, that is estimating local species diversity and its geographic variation in the ontext of traditional explanations involving disturbance, biological interactions and environmental heterogeneity. Little is known about the natural history and distributional patterns of the species themselves - information that is vital to understanding the roles species play in community organization, and the relationship between local diversity and the regional-scale processes that ultimately regulate it. Here we propose two avenues of research to relate biogeographic and life-history characteristics of species to deep-sea species diversity. The first is to introduce morphological variation in shell architecture of gastropods as a new dimension of biodiversity. The second is to explore the relationship of body size to depth within and among species of prosobranch snails. Both add a new level of understanding about how deep-sea communities are structured that could not be attained by analyses of simple a-diversity. The proposed research directly addresses the NSF Biological Oceanography theme of Biological Diversity in Marine Systems, particularly the areas of distribution, abundance, and life history of marine organisms from deep-sea ecosystems; adaptations of marine organisms; and their population ecology.1. Morphological Variation. We present a preliminary analysis of bathymetric ranges and variation in shell architecture in lower bathyal and abyssal assemblages of gastropods from the western North Atlantic. The abyssal fauna is revealed to be merely a subset of the bathyal fauna consisting of species that extend their ranges deeper and out onto the abyss. In gastropods, shell architecture reflects feeding type, mode of development, predator defense mechanisms, locomotion and calcium carbonate conservation. We construct both empirical and theoretical morphospaces of shell form by using an eigenshape analysis and Raups model of shell geometry. Both approaches yield the same result. In terms of the range of basic shell types, the abyssal fauna appears to be a random subset of the richer bathyal fauna. However, the abyssal fauna is dominated numerically by a few core deposit-feeding species of bathyal origin with shells that are preadapted for carbonate conservation below the CaCO3 compensation depth. The combination of morphological variation, bathymetric range, feeding type and dispersal ability suggests a new hypothesis for abyssal biodiversity that is radically different from the ecological determinism of current theories. We propose that bathyal and abyssal environments comprise a source-sink system in which the abyssal fauna largely represents a mass effect. The abyssal fauna appears to be an attenuation of the bathyal fauna with a small minority of abundant species, and a majority of extremely rare species that may represent nonreproducing populations maintained by dispersal. We will test this hypothesis by extending the analysis to four other deep-sea basins, and by determining the reproductive state of bathyal and abyssal populations of the same species. Since the great abyssal plains represent such a huge ecosystem, this research has very significant implications for the genesis and maintenance of diversity, and for estimating the level of global deep-sea biodiversity.2. Body Size. Body size is an issue of fundamental significance in biology, and one that has an important bearing on abundance, distribution, macroecology and biodiversity.Results from prior NSF support (OCE-9301687) showed that, in contrast to the prevailing view, individual gastropod species increase in size with depth. Size-depth clines decrease in slope with depth and bathymetric ranges expand. We present a conceptual model that integrates this very consistent trend within species with the observation that average size among species appears to decrease with depth. We propose measuring the average size component of the model. This research has the potential to reconcile a very basic paradox in deep-sea ecology, and will provide, by far, the largest and most well-controlled database on size in the deep-sea benthos.