Yasuhara Moriaki, Huang Huai-Hsuan May, Chong Raine Wing Ki, Hong Yuanyuan, Iwatani Hokuto, Zhang Jingwen, Kimoto Katsunori, Ikehara Minoru
School of Biological Sciences, Area of Ecology and Biodiversity, Swire Institute of Marine Science, Institute for Climate and Carbon Neutrality and Musketeers Foundation Institute of Data Science, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Pokfulam, Hong Kong SAR, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
Department of Geosciences, Princeton University, Princeton, NJ 08544, USA.
Curr Biol. 2025 Jan 20;35(2):347-353.e1. doi: 10.1016/j.cub.2024.11.026. Epub 2024 Dec 19.
The deep-time development of the Southern Ocean's deep-sea ecosystem remains poorly understood, despite being a key region in global ecological, climatological, and oceanographic systems, where deep water forms and biodiversity is unexpectedly high. Here, we present an ∼500,000-year fossil record of the deep-sea Southern Ocean ecosystem in the subantarctic zone. The results indicate that changes in surface productivity and the resulting food supply to the deep sea, driven by eolian dust input and iron fertilization, along with changes in bottom-water temperature influenced by deep-water circulation, have controlled the deep-sea ecosystem in the Southern Ocean on orbital (10-10 years) timescales following the Mid-Brunhes event (MBE), a major climatic transition ∼430,000 years ago. However, before the MBE, the deep-sea Southern Ocean ecosystem was distinct from the present-day, post-MBE one. The present-day form of the deep-sea Southern Ocean ecosystem was established following the MBE, likely because of a stronger incursion of the warm North Atlantic deep water into the Southern Ocean after the MBE. Before that, the deep-sea Southern Ocean ecosystem lacked typical deep-sea faunal components and resembled deep, marginal sea fauna, likely because of the stronger thermal isolation of the Southern Ocean from the Atlantic Ocean. This result suggests that if future human-induced climatic warming weakens global deep-water circulation from the Atlantic through the Southern Ocean to the Pacific, a deep-sea biodiversity hotspot in the Southern Ocean may diminish or even vanish.
尽管南大洋是全球生态、气候和海洋系统的关键区域，深水在此形成，生物多样性出奇地高，但人们对其深海生态系统的长期发展仍知之甚少。在此，我们展示了亚南极区南大洋深海生态系统约50万年的化石记录。结果表明，在约43万年前的一次重大气候转变——布容正向极性时带事件（MBE）之后，由风尘输入和铁施肥驱动的表层生产力变化以及由此产生的向深海的食物供应，再加上受深水环流影响的底层水温变化，在轨道（10⁴ - 10⁵年）时间尺度上控制了南大洋的深海生态系统。然而，在MBE之前，南大洋深海生态系统与现今MBE之后的生态系统不同。南大洋深海生态系统的现今形态是在MBE之后形成的，可能是因为MBE之后温暖的北大西洋深水更强地侵入了南大洋。在此之前，南大洋深海生态系统缺乏典型的深海动物群落组成部分，类似于深海边缘海的动物群，可能是因为南大洋与大西洋的热隔离更强。这一结果表明，如果未来人为导致的气候变暖削弱了从大西洋经南大洋到太平洋的全球深水环流，南大洋的一个深海生物多样性热点可能会减少甚至消失。
