北极快速变化的生态环境响应

北冰洋由于其特殊的地理位置,成为全球变化响应最为敏感的地区。本文聚焦北极海冰变化幅度最大的西北冰洋,从营养盐、叶绿素、浮游植物群落和沉积碳埋藏等变化来讨论海洋生态环境对北极快速变化的响应。尽管太平洋北向流和北极周边河流输入加强可以增加西北冰洋上层营养盐储库,但由于夏季硅藻旺发向沉积物迁出大量生源元素,使得上层营养盐相对亏损,部分海域存在显著的氮限制和硅限制。随海冰减退,尽管夏末海盆区浮游植物呈现小型化趋势,但西北冰洋总体上浮游植物现存量和初级生产力呈现增高的趋势;伴随叶绿素极大层下移、北扩,以硅藻为代表的生物泵过程得以更高效的运转。在沉积物埋藏的有机碳中,除原先北冰洋生态系统占据重要比份的冰藻外,硅藻等藻类的有机碳埋藏也逐渐增加。西北冰洋海洋初级生产力的增加不仅促进了生物泵的运转和碳的埋藏,而且给海洋生态系统提供了更多的食物来源。北极海域目前已成为全球碳源汇格局变化最大、海洋生态系统改变最显著的地区之一。

Marine ecological and environmental responses to the Arctic rapid change

This paper focuses on the background of rapid change in the west Arctic, investigates the marine ecological environmental responses to the Arctic rapid change on the aspects of the variation of nutrients, chlorophyll, phytoplankton community and sedimentary carbon buried in the western Arctic Ocean. Due to its special geographical location, the Arctic Ocean has become the most sensitive area for the regional response of climate change. In the last two decades, as the consequences of Arctic sea water temperature rises, rapid sea ice melting, light limitation disappearing, the upper layer of nutrients are fully utilized, chlorophyll increasing and chlorophyll maximum layer moves down and expands to the north, and the marine biological pump is running more efficiently. In addition to the ice algae, which once played an important role in the Arctic ecosystem, organic carbon from photosynthesis such as diatom has aslo gradually increased in the water column and buried in sediments. The increase in primary productivity in the western Arctic not only increases carbon sink in the sediment, but also provides more food sources for marine ecosystems.