Abraham E R, Law C S, Boyd P W, Lavender S J, Maldonado M T, Bowie A R
National Institute for Water and Atmospheric Research, Kilbirnie, Wellington, New Zealand.
Nature. 2000 Oct 12;407(6805):727-30. doi: 10.1038/35037555.
The growth of populations is known to be influenced by dispersal, which has often been described as purely diffusive. In the open ocean, however, the tendrils and filaments of phytoplankton populations provide evidence for dispersal by stirring. Despite the apparent importance of horizontal stirring for plankton ecology, this process remains poorly characterized. Here we investigate the development of a discrete phytoplankton bloom, which was initiated by the iron fertilization of a patch of water (7 km in diameter) in the Southern Ocean. Satellite images show a striking, 150-km-long bloom near the experimental site, six weeks after the initial fertilization. We argue that the ribbon-like bloom was produced from the fertilized patch through stirring, growth and diffusion, and we derive an estimate of the stirring rate. In this case, stirring acts as an important control on bloom development, mixing phytoplankton and iron out of the patch, but also entraining silicate. This may have prevented the onset of silicate limitation, and so allowed the bloom to continue for as long as there was sufficient iron. Stirring in the ocean is likely to be variable, so blooms that are initially similar may develop very differently.
众所周知，种群增长受扩散影响，扩散常被描述为纯粹的扩散过程。然而，在开阔海洋中，浮游植物种群的卷须和细丝为搅拌扩散提供了证据。尽管水平搅拌对浮游生物生态学具有明显重要性，但这一过程仍未得到充分描述。在此，我们研究了南大洋一片直径7公里水域的铁施肥引发的离散浮游植物水华的发展情况。卫星图像显示，初始施肥六周后，实验地点附近出现了一条长达150公里的显著水华。我们认为，带状水华是由施肥区域通过搅拌、生长和扩散形成的，并且我们估算了搅拌速率。在这种情况下，搅拌对水华发展起到重要控制作用，将浮游植物和铁从区域中混合出去，但也夹带了硅酸盐。这可能阻止了硅酸盐限制的出现，因此只要有足够的铁，水华就能持续。海洋中的搅拌可能是可变的，所以最初相似的水华可能会有非常不同的发展。
