小柯机器人

海洋动物昼夜垂直迁移
2019-11-28 14:10

美国俄勒冈州立大学Michael J. Behrenfeld研究小组,利用全球卫星观测了海洋动物昼夜垂直迁移。11月27日,国际学术期刊《自然》在线发表了这一成果。

研究人员使用来自安装在卫星上的光探测与测距(激光)仪器的观测值来描述DVM动物光信号的全球分布,这些动物在晚上到达海面。研究人员的发现表明,这些动物通常在亚热带回旋流中占总浮游生物丰度的很大一部分,这符合避免该地区视觉掠食者的生活策略。另一方面,diel垂直迁移(DVM)的总生物量在生产力高的区域中较高,在这些区域内,食物的供应量增加。此外,十年的卫星记录揭示了DVM生物量显著的时间变化以及DVM生物量与地表生产力的相关变化。这些结果为全球DVM活动提供了详细视图,以及完善了其在生物地球化学的重要性作用。

研究人员介绍,在全球海域范围内,每天晚上无数海洋动物在向上迁移数百米后到达海洋表面,获取浮游生物为食。在日出之前,这种迁移被逆转,这些动物回到了它们白天的住所-黑暗的海洋中层区域(200-1,000 m的深度)。这种日常旅行被称为diel垂直迁移,主要是为了躲避日光照射下的表层中的视觉掠食者,是在约200年前首次使用船网运输观察到的。如今,DVM通常由船载声学系统(例如,声学多普勒电流分析仪)记录。这些数据表明,夜间到达和离开的时间在整个海洋地区都是高度保守的,并且海洋动物白天下降的深度随水的净度而增加,这表明动物在较清澈的水中游速更快。

然而,虽然已进行了数十年的声学测量,但仍未对更广阔的海洋区域进行采样,并且可获得数据的海域通常只能提供几个月的信息,这导致对DVM理解的不完整。这个问题亟待解决,因为DVM在全球海洋生物地球化学中具有至关重要的作用。海洋动物这种夜间进食和日间深度新陈代谢为碳和养分的输出提供了有效的途径

附:英文原文

Title: Global satellite-observed daily vertical migrations of ocean animals

Author: Michael J. Behrenfeld, Peter Gaube, Alice Della Penna, Robert T. OMalley, William J. Burt, Yongxiang Hu, Paula S. Bontempi, Deborah K. Steinberg, Emmanuel S. Boss, David A. Siegel, Chris A. Hostetler, Philippe D. Tortell, Scott C. Doney

Issue&Volume: 2019-11-27

Abstract: Every night across the world’s oceans, numerous marine animals arrive at the surface of the ocean to feed on plankton after an upward migration of hundreds of metres. Just before sunrise, this migration is reversed and the animals return to their daytime residence in the dark mesopelagic zone (at a depth of 200–1,000 m). This daily excursion, referred to as diel vertical migration (DVM), is thought of primarily as an adaptation to avoid visual predators in the sunlit surface layer1,2 and was first recorded using ship-net hauls nearly 200 years ago3. Nowadays, DVMs are routinely recorded by ship-mounted acoustic systems (for example, acoustic Doppler current profilers). These data show that night-time arrival and departure times are highly conserved across ocean regions4 and that daytime descent depths increase with water clarity4,5, indicating that animals have faster swimming speeds in clearer waters4. However, after decades of acoustic measurements, vast ocean areas remain unsampled and places for which data are available typically provide information for only a few months, resulting in an incomplete understanding of DVMs. Addressing this issue is important, because DVMs have a crucial role in global ocean biogeochemistry. Night-time feeding at the surface and daytime metabolism of this food at depth provide an efficient pathway for carbon and nutrient export6,7,8. Here we use observations from a satellite-mounted light-detection-and-ranging (lidar) instrument to describe global distributions of an optical signal from DVM animals that arrive in the surface ocean at night. Our findings reveal that these animals generally constitute a greater fraction of total plankton abundance in the clear subtropical gyres, consistent with the idea that the avoidance of visual predators is an important life strategy in these regions. Total DVM biomass, on the other hand, is higher in more productive regions in which the availability of food is increased. Furthermore, the 10-year satellite record reveals significant temporal trends in DVM biomass and correlated variations in DVM biomass and surface productivity. These results provide a detailed view of DVM activities globally and a path for refining the quantification of their biogeochemical importance.

DOI: 10.1038/s41586-019-1796-9

Source: https://www.nature.com/articles/s41586-019-1796-9

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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