Hysteresis conditions the vertical position of deep chlorophyll maximum in the temperate ocean
Hysteresis conditions the vertical position of deep chlorophyll maximum in the temperate ocean
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DOI：
10.1002/gbc.20093
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发表时间：
2013-12
影响因子：
5.2
通讯作者：
G. Navarro;J. Ruiz
中科院分区：
文献类型：
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作者：
G. Navarro;J. Ruiz
深海叶绿素最大值是海洋的普遍特征。在温带地区，DCM通常与经常在很大的垂直范围内移动的等密度面有关。DCM和等密度线之间的这种普遍联系仍然无法解释目前的理论，我们在这里表明，它出现在水柱的季节性历史。分析形成的9000多个季节性DCM在世界各地的海洋始终位于春季/夏季DCM在温带海洋的垂直位置在前一个冬季混合层的密度，独立于这个密度值和未来的深度。这些结果表明，DCM的形成不能理解没有滞后，仅考虑瞬时响应的浮游植物垂直梯度的物理和化学领域。目前的理论DCM形成不能解释为什么春季和夏季DCM系统地发现在密度等于以前的混合层，其中爆发已经发生。结果表明，DCM不是对瞬时物理强迫做出反应，而是作为自我保护的生物结构，与特定的等密度线相关，因为它们有能力改变物理化学环境。结合遥感器测量海洋表面的盐度和温度，这种对DCM动力学的新理解有可能通过卫星改善三维初级生产的量化。这种对海洋生物过程的代表性的显著增强也可以使对变暖海洋中未来生物地球化学情景的预测变得越来越现实。
Deep chlorophyll maxima (DCMs) are widespread features of oceans. In temperate regions, DCMs are commonly associated with isopycnal surfaces that frequently move over a wide vertical range. This general association between DCMs and isopycnals remains unexplained by present theories, and we show here that it emerges from the seasonal history of the water column. Analysis of the formation of more than 9000 seasonal DCMs throughout the world's oceans consistently locates the vertical position of spring/summer DCMs in temperate seas at the density of the previous winter mixed layer, independently of this density value and future depth. These results indicate that DCM formation cannot be understood without hysteresis by solely considering the instantaneous response of phytoplankton to vertical gradients in physical and chemical fields. Present theories for DCM formation cannot explain why spring and summer DCMs are systematically found at a density equal to that of the previous mixed layer where a bloom has occurred. Rather than reacting to instantaneous physical forcing, the results indicate that DCMs operate as self‐preserving biological structures that are associated with particular isopycnals because of their capacity to modify the physicochemical environment. Combined with remote sensors to measure salinity and temperature in the surface ocean, this new understanding of DCM dynamics has the potential to improve the quantification of three‐dimensional primary production via satellites. This significant enhancement of the representation of oceanic biological processes can also allow increasingly realistic predictions of future biogeochemical scenarios in a warming ocean.