n.喷出；上喷；上升流
动词upwell的现在分词形式.
Eventually, currents and upwelling from the depths bring the dead stuff back to the top, where it stimulates more phytoplankton growth. 最终，来自深层的水流和上升流会将死物质带到表层，并刺激更多的浮游植物生长。
