Influence of population connectivity on depth-dependent diversity of deep-sea marine benthic biota

物种种群通过成虫的运动(迁徙)和卵、幼虫和幼虫的运动(扩散)相互联系。如果种群变得彼此孤立(即不再相连)，那么通过基因突变、漂移和自然选择，它们可能会变得如此不同，以至于它们进化成新的生物物种。了解种群是如何变得孤立的，对于理解物种形成过程至关重要。在海洋环境中，许多物种不会作为成体活动(例如珊瑚)或移动非常缓慢(海胆)。这意味着不同的成年种群要保持联系，他们依赖于早期生活史阶段的分散。大多数海洋物种都有一个幼虫阶段，在浮游生物中生活一段时间，随着水流移动，然后在一个新的区域定居。正是幼虫的扩散将遥远的种群联系在一起。因此，了解幼虫的扩散模式对于了解连通性很重要。在深海(200米)，大陆坡的半深海区域被确定为支持高物种丰富度的区域，也是新物种起源率高的区域。原因尚不清楚，但鉴于连通性对种群隔离和物种形成的重要性，因此，理解该区域物种多样性格局的关键在于理解连通性。新的研究表明，由于携带幼虫的水流速度随着你走得更深而降低，幼虫可能无法传播到更远的地方，从而导致半深海深处的种群在给定距离内更容易被隔离，从而增加物种形成的机会。这项研究旨在通过调查连接模式如何随深度变化来验证这一理论。这将通过三种方式完成：1)使用遗传分析(类似于DNA指纹)来比较遥远的种群之间的亲缘关系，以及它们是否随着你的深入而变得不那么密切；2)使用洋流模型来模拟幼虫在不同地点之间的移动；以及3)观察出现在遥远地点的物种的范围和丰度，看看是否浅层的物种比半深海的物种更相似。这项研究对海洋环境的可持续管理具有重要的意义。人类越来越依赖海洋环境来为我们提供食物、建材、燃料，并吸收碳，减缓人类引起的气候变化的进程。然而，我们越来越多地使用这种环境，开始影响到它的“正常”功能，影响到它为我们提供食物、燃料等的过程。为了努力保护和维持这些“生态系统功能”，世界各国政府都在建立海洋保护区网络，以确保不受过度开发造成的严重生态系统干扰和最终损害生态系统功能的级联影响。在尝试建立MPA网络时有许多问题需要回答，但一个重要的问题是将它们放在哪里，以确保生活在其中的人口不是彼此孤立的，而是相互联系的。这项研究将有助于回答深海中的这个问题，从而帮助管理者、政府和社会确保海洋的长期健康。

Species populations are connected to each other through both movement of adults (migration) and eggs, larvae and juveniles (dispersal). If populations become isolated from one another (i.e. are no longer connected), then through genetic mutation, drift and natural selection, they may become so different that they evolve into new biological species. Understanding how populations become isolated is critical to understanding the process of speciation. In the marine environment many species do not move as adults (e.g. corals) or move very slowly (sea urchins). This means that for different adult populations to remain connected they rely on dispersal of early life history stages. Most marine species have a larval stage that lives in the plankton for a period of time, moving with the currents, before settling in a new area. It is larval dispersal that keeps distant populations connected. So understanding patterns of larval dispersal is important to understanding connectivity. In the deep-sea (>200m) the bathyal region of the continental slope has been identified as supporting high species richness and being an area where the rate of origination of new species may also be high. The reasons for this are not clear, but given the importance of connectivity to population isolation and speciation, it follows that the key to understanding patterns of species diversity in this region lies in understanding connectivity. New research has suggested that because the speed of the currents that carry larvae decreases as you go deeper, larvae might not be able to travel as far, leading to a greater tendency for populations at bathyal depths to become isolated over a given distance, and thus increasing the chances of speciation. This study aims to test this theory by investigating how patterns of connectivity vary with depth. This will be done in 3 ways: 1) using genetic analysis (similar to DNA fingerprinting) to compare how related distant populations are and if they become less closely related as you go deeper, 2) using a model of ocean currents to simulate the movement of larvae between sites, and 3) to look at the range and abundance of species present at distant locations to see if those at shallower depths are more similar to each-other than those at bathyal depths.This research has important implications for the sustainable management of the marine environment. Humans increasingly rely on the marine environment to supply us with food, building materials, fuel, and to soak up carbon slowing the progress of human induced climate change. However, our increasing use of this environment is starting to affect is 'normal' functioning, affecting the processes that allow it to provide us with food, fuel, etc. To try to help protect and sustain these 'ecosystem functions', Governments all over the world are setting up networks of Marine Protected Areas (MPAs) to ensure against serious ecosystem disturbance and cascade effects resulting from overexploitation that ultimately impair ecosystem function. There are many questions to be answered when trying to set up an MPA network, but one important question is where to put them to make sure that the populations that live within them are not isolated from each other but are connected. This research will help answer this question in the deep sea, and thus help managers, governments and society ensure the long term health of the ocean.