Data from: Human-induced marine ecological degradation: micropaleontological perspectives

We analyzed published downcore microfossil records from 150 studies and reinterpreted them from an ecological degradation perspective to address the following, critical but still imperfectly answered questions: (1) How is the timing of human-induced degradation of marine ecosystems different among regions? (2) What are the dominant causes of human-induced marine ecological degradation? (3) How can we better document natural variability and thereby avoid the problem of shifting baselines of comparison as degradation progresses over time? The results indicated that: (1) ecological degradation in marine systems began significantly earlier in Europe and North America (~1800s) compared to Asia (post-1900) due to earlier industrialization in European and North American countries, (2) ecological degradation accelerated globally in the late 20th century due to post-World War II economic growth, (3) recovery from the degraded state in late 20th century following various restoration efforts and environmental regulations occurred only in limited localities. Though complex in detail, typical signs of ecological degradation were diversity decline, dramatic changes in total abundance, decrease of benthic and/or sensitive species, and increase of planktic, resistant, toxic, and/or introduced species. The predominant cause of degradation detected in these microfossil records was nutrient enrichment and the resulting symptoms of eutrophication, including hypoxia. Other causes also played considerable roles in some areas, including severe metal pollution around mining sites, water acidification by acidic wastewater, and salinity changes from construction of causeways, dikes, and channels, deforestation and land clearance. Microfossils enable reconstruction of the ecological history of the past 102–103 years or even more, and, in conjunction with statistical modeling approaches using independent proxy records of climate and human-induced environmental changes, future research will enable workers to better address Shifting Baseline Syndrome and separate anthropogenic impacts from background natural variability.

本研究整合分析了150项已发表的岩芯微化石（microfossil）记录，并从生态退化视角对其进行重新解读，旨在解答以下几个关键却尚未得到充分解答的科学问题：（1）不同区域内，人类活动引发的海洋生态退化的发生时间存在何种差异？（2）人类活动导致的海洋生态退化的主导驱动因素是什么？（3）我们应如何更好地记录自然环境波动，从而避免随退化进程推移而出现的比较基准偏移问题？

研究结果表明：（1）受欧美工业化进程更早的影响，海洋生态退化在欧洲与北美地区的起始时间（约19世纪）显著早于亚洲（20世纪之后）；（2）受第二次世界大战后经济复苏与增长的推动，20世纪后期全球范围内的海洋生态退化进程显著加快；（3）尽管在20世纪后期实施了多项修复举措与环境规制，但仅在少数局部区域实现了退化生态系统的恢复。

尽管具体表现形式复杂多样，但海洋生态退化的典型特征包括：物种多样性下降、总丰度发生显著变化、底栖（benthic）和/或敏感物种丰度降低，以及浮游（planktic）、耐污、有毒或外来入侵物种丰度上升。

通过上述微化石记录所揭示的退化主导驱动因素为营养盐富集及其引发的富营养化症状，包括低氧（hypoxia）现象。在部分区域，其他因素也对生态退化起到了显著作用，包括矿区周边的重金属重度污染、酸性废水引发的水体酸化，以及筑堤、建闸与开凿航道导致的盐度变化，还有森林砍伐与土地开垦活动。

微化石可用于重建过去102至103年甚至更久远的生态历史；未来结合利用气候与人为环境变化独立代用指标（proxy records）开展的统计建模方法，将有助于研究者更好地应对基线偏移综合征（Shifting Baseline Syndrome），并将人为活动影响与背景自然波动区分开来。