在广袤无垠的海洋中，除了我们熟知的盐分、鱼类和珊瑚，还蕴藏着许多含量极低却至关重要的“痕量金属”。它们如同海洋中的“维生素”，虽然微量，却几乎参与了海洋生命的方方面面，从细胞结构的构建到蛋白质的合成，无不留下它们的踪迹。一些痕量金属，如铁（Fe）、锌（Zn）、锰（Mn）等，是海洋生物生长所必需的痕量营养盐；而一些痕量金属，如铜（Cu）、镉（Cd）、铅（Pb）等，在浓度过高时会表现出潜在毒性。此外，还有一些金属元素，如稀土元素（REEs），可作为示踪剂，帮助我们识别水团来源、追踪大洋环流。揭示这些痕量金属在海洋中的循环过程，对于理解现代海洋生态系统、应对气候变化乃至解读地球历史环境变迁都具有至关重要的意义。
张衎博士对于海洋生物地球化学循环的探索，始于她对地球早期生命与环境协同演化的研究。研究生时期，她认识到沉积岩是古海洋信息的重要载体，为此，她建立了碳酸盐岩全岩稀土元素的精确定量溶解法，使得从古老岩石中读取更准确的环境信息成为可能。基于这一方法，张衎博士选取我国中上元古界标准剖面——天津蓟县剖面作为研究对象，首次发现了距今约15.7亿年前的一次古海洋氧化事件，并提出该事件与地球上最早的大型多细胞真核生物的出现密切相关，从而打破了“18–8亿年前地表环境相对稳定（Boring Billion）”的传统认识。相关成果发表在国际知名期刊Nature Geoscience（Zhang et al. 2018）和Chemical Geology（Zhang et al. 2015），其中Nature Geoscience期刊在同期News & Views版块刊发了评论文章（Hammarlund. 2018），高度评价了这一突破性发现的重要意义。
图1. 海洋颗粒物的洁净采样与样品前处理过程
在博士后阶段，张衎博士将研究视野从远古拓展至现代，以其擅长的元素地球化学为基础，重点探究海洋颗粒物中铁、锌、锰、镉、铜、钴、铅及稀土元素等痕量金属的生物地球化学循环。她率先搭建了国内首套面向开阔大洋颗粒态痕量金属研究的洁净采样与分析系统，并多次参与综合性海洋调查航次，包括我国第一个自主实施的GEOTRACES断面调查航次（国际海洋化学调查计划，聚焦全球海洋痕量元素及其同位素生物地球化学循环）、国家自然科学基金重大项目“Carbon-FE（海洋荒漠生物泵固碳机理及增汇潜力）”的夏季和冬季航次、国家自然科学基金共享航次计划的“黑潮延伸体”航次，以及国家重点研发计划重点专项的“PIN-Pump（西北太平洋生物碳泵的氮磷铁调控及演变趋势）”航次等。这些航次经历为她的研究提供了宝贵的第一手观测资料。依托在西北太平洋获取的数据，她不仅深化了对该海域痕量营养盐来源及其生物地球化学循环过程的定性与定量认识，也为古海洋地球化学指标的适用性与局限性提供了新的启示(2024 Limnol Oceanogr, 2025 Global Planet. Change)。
图2. 张衎博士在“嘉庚”号科考船采集海水样品
未来，她的研究将围绕“元素与同位素海洋生物地球化学”展开，具体研究方向包括但不限于：
（1）海洋痕量金属的生物地球化学循环
（2）海洋浮游植物的多元素化学计量学
（3）元素及其稳定同位素在古海洋学研究中的应用
个人名片：
张衎博士于2018年在中国地质科学院地质研究所获得地球化学博士学位，其间作为联合培养博士研究生赴英国利兹大学开展了为期14个月的交流访问。2019至2024年在厦门大学从事博士后研究工作。2025年5月加盟厦门大学海洋与地球学院海洋化学与地球化学系，任助理教授；并于同年8月成为海洋生物地球化学全国重点实验室的固定科研人员。迄今，已在Nature Geoscience、Limnology and Oceanography、Chemical Geology等期刊发表多篇学术论文。曾获地学领域研究生最高奖——“李四光优秀博士研究生奖”，并入选博士后创新人才支持计划。
如有兴趣了解张衎博士的更多情况，欢迎访问个人主页https://mel2.xmu.edu.cn/faculty/kanzhang/，或联系zhangkan@xmu.edu.cn 。
Dr. Kan Zhang — Focusing on the biogeochemical cycling of trace metals mediated by marine particles
In the vast expanse of the ocean, beyond the familiar presence of salt, fish, and corals, lie trace metals that occur in extremely low concentrations yet play a crucial role. They are like the “vitamins” of the ocean—minute in amount, but involved in nearly every aspect of marine life, from building cellular structures to synthesizing proteins. Some trace metals, such as iron (Fe), zinc (Zn), and manganese (Mn), are essential micronutrients for marine organisms; others, including copper (Cu), cadmium (Cd), and lead (Pb), can become potentially toxic when their concentrations are elevated. In addition, elements such as the rare earth elements (REEs) can serve as tracers that help identify water mass sources and track large-scale ocean circulation. Therefore, unraveling the biogeochemical cycles of these trace metals is essential not only for advancing knowledge of modern ocean ecosystems and their responses to climate change, but also for shedding light on the evolution of Earth’s past environments.
Dr. Kan Zhang’s exploration of marine biogeochemical cycles began with her research on the co-evolution of early life and the environment on Earth. During her doctoral studies, she established a precise quantitative dissolution method for rare earth element studies of bulk carbonate rocks, which laid the foundation for extracting robust paleo-oceanographic information from sedimentary records. Applying this method to the Mesoproterozoic type section at Jixian, Tianjin, she reported the first evidence of a paleo-ocean oxidation event dating back to ~1.57 billion years ago. She further proposed that this event was closely linked to the emergence of the earliest large multicellular eukaryotes, thereby challenging the prevailing view of a relatively stable surface environment during the “Boring Billion (1.8–0.8 billion years)”. These findings were published in Nature Geoscience (Zhang et al. 2018) and Chemical Geology (Zhang et al. 2015), with a Nature Geoscience News & Views article in the same issue highlighting the significance of this breakthrough discovery (Hammarlund. 2018).
In her postdoctoral work, Dr. Kan Zhang extended her research from the ancient to the modern ocean. Leveraging her expertise in elemental geochemistry, she investigated the biogeochemical cycling of trace metals in marine particles, including iron, zinc, manganese, cadmium, copper, cobalt, lead, and rare earth elements. She took the lead in establishing China’s first clean sampling and analytical system for particulate trace element studies in the open ocean, and actively participated in several comprenhensive oceanographic expeditions. These include China’s first independently conducted GEOTRACES section cruise (an international program investigating the biogeochemical cycling of trace elements and their isotopes in the global ocean), the summer and winter cruises of the NSFC Major Program “Carbon-FE (carbon fixation and export in the oligotrophic ocean)”, the “Kuroshio Extension” cruise of the NSFC Shiptime Sharing Project, and the “PIN-Pump (nitrogen, phosphorus and iron regulation and evolution of the biological pump in the Northwest Pacific)” cruise of the National Key Research and Development Program. Drawing on first-hand observational data from the northwestern Pacific, her work not only advanced qualitative and quantitative understanding of the sources and biogeochemical cycling of trace nutrients in this region, but also offered new insights into the applicability and limitations of geochemical proxies in paleoceanography (2024 Limnol Oceanogr, 2025 Global Planet. Change).
Kan’s future research will center on marine biogeochemistry of elements and isotopes, with research themes include but not limited to: 1) biogeochemical cycles of trace metals in the ocean; 2) multi-element stoichiometry of marine phytoplankton; 3) application of elements and their stable isotopes in paleoceanography research.
For more information about Dr. Kan Zhang, please visit her website https://mel2.xmu.edu.cn/faculty/kanzhang/, or contact her at zhangkan@xmu.edu.cn.
Personal Profile
Dr. Kan Zhang received her PhD in Geochemistry from the Institute of Geology, Chinese Academy of Geological Sciences in 2018. During her doctoral studies, she participated in a 14-month joint training program at the University of Leeds, UK. From 2019 to 2024, she pursued postdoctoral research at Xiamen University. In May 2025, she joined the Department of Marine Chemistry and Geochemistry at the College of Ocean and Earth Sciences, Xiamen University, as an Assistant Professor. And in August of the same year, she became a faculty member at the State Key Laboratory of Marine Environmental Science (MEL). To date, she has published multiple research articles in leading journals such as Nature Geoscience, Limnology and Oceanography, and Chemical Geology. Her honors include the “Li Siguang Outstanding Doctoral Student Award” — the most prestigious award for graduate students in the geosciences, and selection for the Postdoctoral Innovative Talent Support Program of the China Postdoctoral Science Foundation.
