Internal Tides Drive Nutrient Fluxes Into the Deep Chlorophyll Maximum Over Mid-ocean Ridges
Internal Tides Drive Nutrient Fluxes Into the Deep Chlorophyll Maximum Over Mid-ocean Ridges
复制标题
内潮汐将养分通量推入大洋中脊的叶绿素深部最大值
DOI：
10.1029/2019gb006214
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发表时间：
2019
影响因子：
5.2
通讯作者：
Tuerena R
中科院分区：
文献类型：
--
作者：
Tuerena R
在世界上的亚热带环流中，从温跃层到表面阳光照射的海洋的营养物质的透环混合被认为是相对较弱的，因为风的能量输入通常较低。内部潮汐与粗糙的地形的相互作用增强了diapycnal混合，但潮汐引起的diapycnal混合在维持营养物质供应的表面亚热带海洋的作用仍然相对未被探索。在北大西洋副热带环流的实地活动中，我们测试了潮汐与地形的相互作用是否会增强上层海洋中的贯叶硝酸盐通量。我们测量了一个数量级的增加diapycnal硝酸盐通量的深叶绿素最大值（DCM）在大西洋中脊相比，邻近的深海。内部潮汐驱动这种增强，与diapycnal硝酸盐供应DCM增加了8倍之间的小潮和大潮。使用全球潮汐消散数据库，我们发现，这种春季小潮增强diapycnal硝酸盐通量是广泛的山脊和海山。因此，洋中脊在维持扩张型大洋的营养供应方面发挥着重要作用，这些发现可能对全球海洋变暖产生重要影响。
Diapycnal mixing of nutrients from the thermocline to the surface sunlit ocean is thought to be relatively weak in the world's subtropical gyres as energy inputs from winds are generally low. The interaction of internal tides with rough topography enhances diapycnal mixing, yet the role of tidally induced diapycnal mixing in sustaining nutrient supply to the surface subtropical ocean remains relatively unexplored. During a field campaign in the North Atlantic subtropical gyre, we tested whether tidal interactions with topography enhance diapycnal nitrate fluxes in the upper ocean. We measured an order of magnitude increase in diapycnal nitrate fluxes to the deep chlorophyll maximum (DCM) over the Mid‐Atlantic Ridge compared to the adjacent deep ocean. Internal tides drive this enhancement, with diapycnal nitrate supply to the DCM increasing by a factor of 8 between neap and spring tides. Using a global tidal dissipation database, we find that this spring‐neap enhancement in diapycnal nitrate fluxes is widespread over ridges and seamounts. Mid‐ocean ridges therefore play an important role in sustaining the nutrient supply to the DCM, and these findings may have important implications in a warming global ocean.