HADEEP / Life at extreme depth; Fishes and scavenging fauna of the Abyssal to Hadal boundary.

来自阿伯丁大学海洋实验室的一个团队将与日本东京大学和德国图宾根大学联手，对世界上生活在最深的鱼类的分布和行为进行首次定向研究。两辆无人驾驶的自动着陆器将在阿伯丁建造；一个装有摄像机，另一个装有高分辨率数码相机。2007年和2008年，日本和德国的船只将在北太平洋和南太平洋的马里亚纳海沟、汤加海沟和克马德克海沟周围5公里至10公里深的地方发射它们。在海面上，这些海洋区域有清澈的蓝色海水，生产力很低，很可能很少有食物以碎屑和尸体的形式自然沉降到海底，而生活在几公里以下的深海动物完全依赖这些碎屑和尸体。根据着陆器的摄像头，将在海底放置诱饵，模拟从表面到达的自然食物包，并将记录鱼类、深海虾和任何其他被吸引到观察区域的动物。配备深度传感器的着陆器将提供不同物种出现深度的准确信息，这些信息很难通过在世界各地不同博物馆发现的采集死亡标本的设备获得。该小组有可能捕捉到世界上最深的鱼类——加拉泰亚深渊鱼（Abyssobrotula galatheae）的第一张活生生的图像，据信它们生活在8370米深的海底。深海被划分为三个主要的深度区，深海在3000米以下，深海在3000米到6000米之间，深海在6000米以上。在海底，鲨鱼主要局限在海洋边缘、岛屿、海山和洋中脊周围3000米以下的深度。深海区占海洋面积的75%，生活着令人惊讶的各种各样的生物，包括活跃的食腐硬骨鱼，如弹鳗，海鳗，螺鱼和深海鳗鱼，它们被拍摄到在5900米深的深处食用鱼类和海洋哺乳动物的尸体。目前尚不清楚是什么界定了相对丰富的深渊生命和明显稀少的冥带生命之间的界限。Hadal带主要局限于太平洋边缘的海沟，一直延伸到地球上最深的地方，马里亚纳海沟10,896米的挑战者深度。可能有两种主要的解释：首先，随着深度的增加，来自地表的食物供应变得越来越少，达到一定程度时，没有足够的能量来支持活跃的生命形式。其次，压力随着深度的增加而增加，大多数动物都有一个致命的最大压力，在这个压力下，神经、肌肉和重要的过程都停止了功能。深海动物有特殊的适应能力来适应高压环境，但可能有极限，超过了极限，这种适应就不可能了。该项目不会直接回答这些问题，但会与来自较浅深度的信息进行比较。如果鱼类在深达6000米的深海中茁壮成长，并在潜深区开始处有一个恒定的截止点，这将表明存在生理压力极限。然而，如果深海物种在不同地区离潮界的不同距离逐渐消失，这可能表明当地食物供应受到限制。测量动物到达诱饵处的时间、它们的体型、速度、数量和食饵率。将对生活在不同深度的物种进行比较。特别是鱼类，它们显然不能穿透海沟系统的最深处，将与出现在整个海洋深处的片脚类虾进行比较。通过分析，可以对这些深度的流动生物的丰度和生物量进行初步估计。这项研究将扩大所提出的深海生命基本规律可以测试的深度范围。

A team from the University of Aberdeen Oceanlab will join forces with the University of Tokyo, Japan and University of Tuebingen, Germany to undertake the first directed study on the distribution and behaviour of the deepest-living fishes in the world. Two unmanned autonomous lander vehicles will be built in Aberdeen; one equipped with a video camera and a second with a high resolution digital stills camera. They will be launched to depths of 5km to over 10km around the Mariana, Tonga and Kermadec trenches in the North and South Pacific Ocean from Japanese and German ships in 2007 and 2008. At the surface these ocean areas have clear blue water with low productivity and there is likely to be very little natural fall-out of food to the sea floor in the form of detritus and dead carcasses upon which the deep-sea animals living kilometres below are entirely dependent. Baits will be deployed on the sea floor in view of the lander cameras to mimic natural packets of food arriving from the surface and recordings will be made of fish, deep-sea shrimps and any other animals attracted into the observational area. The landers, equipped with depth sensors will provide accurate information on the depth of occurrence of different species, information that was difficult to obtain with equipment used to capture dead specimens that are found in different museums around the world. There is a chance that the team may capture the first living images of the world's deepest fish Abyssobrotula galatheae thought to occur down to 8370m. The deep sea is divided into three main depth zones, Bathyal down to 3000m, Abyssal between 3000 and 6000m and Hadal depths greater than 6000m. On the sea floor sharks are mainly limited to depths less than 3000m around the edges of the oceans, islands, sea mounts and on mid-ocean ridges. The abyssal zone accounts for 75% of ocean area and is populated by a surprising variety of life including active scavenging bony fishes such as grenadiers, cusk-eels, snail fishes and abyssal eels which have been filmed consuming fish and marine mammal carcasses at depths down to 5900m. It is not known what defines the boundary between the relatively rich life of the abyss and evidently sparse life of the hadal zone. The Hadal zone is mainly confined to trenches around the margins of the Pacific Ocean extending down to the deepest point on the planet, the Challenger Deep 10,896m in the Mariana trench. Two main explanations are likely: Firstly with increasing depth, food supply from the surface becomes sparser and a point is reached where there is insufficient energy to support active forms of life. Secondly pressure increases with depth and most animals have a maximum lethal pressure at which nerves, muscles and vital processes cease to function. Deep-sea animals have special adaptations to allow function at high pressures but there may be limits beyond which such adaptations are no longer possible. This project will not answer these questions directly but will make comparisons with information from shallower depths. If fish thrive down to 6000m with a constant cut-off at the start of the hadal region this would suggest a physiological pressure limit. However if the abyssal species peter out at different distances from the hadal boundary in different areas this may suggest limitation by local food availability. The time of arrival of animals at baits, their sizes, speeds, numbers and rate of consumption of bait will be measured. Comparisons will be made between species living at different depths. In particular fishes, which apparently do not penetrate the deepest parts of the trench systems, will be compared with amphipod shrimps that occur down to full ocean depth. Analysis will allow derivation of the first estimates of abundance and biomass of mobile life at these depths. This study will extend the depth range over which proposed fundamental laws of life in the deep sea can be tested.