Oceanographic Conditions of the Eastern Tropical Pacific
Oceanographic Conditions of the Eastern Tropical Pacific
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DOI：
10.1007/978-94-017-7499-4_3
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发表时间：
2017-01-01
期刊：
影响因子：
--
通讯作者：
Lavin, Miguel F.
中科院分区：
文献类型：
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作者：
Fiedler, Paul C.;Lavin, Miguel F.
东太平洋暖池支持造礁珊瑚以及独特的浮游生物、鱼类、海洋哺乳动物和鸟类群落。该栖息地的特点是温暖、低盐度的地表水位于强而浅的温跃层之上。它的南部以南赤道洋流和赤道冷舌为界，西北以较凉爽且含盐量较高的副热带水为界，北部和南部以东部冷边界流（加利福尼亚和秘鲁洋流）为界。大陆边界通过冬季间隙风影响大气强迫，并导致多雨的热带辐合带位于赤道以北和暖池上方。描述了冲击珊瑚礁的波浪、潮汐和热带气旋的模式。水团和环流的结构和变化由该地区内外的太阳和大气过程决定。在加拉帕戈斯群岛以西，地表环流主要是东西向的赤道流。在海岸附近，表面环流受到海岸边界、局地风、涡流以及与东部边界流的相互作用的影响。初级生产力取决于赤道沿线的海洋上升流以及沿海水域的上升流和风混合的当地中心。东部热带太平洋表层水域生产力中等。浮游植物的生产力因缺乏微量营养素溶解铁而受到限制，除非当地沿海过程提供了来源，因此硝酸盐等常量营养素永远不会耗尽。描述了太阳强迫、风、降雨、地表温度和盐度以及其他环境特征的季节性变化，尽管该地区的季节性不如高纬度地区那么明显。相比之下，厄尔尼诺-南方涛动在整个热带印度-太平洋地区引起的年际变化在该地区非常重要（第 4 章）。急温跃层以下氧气消耗严重，对中层和温跃层以下的底栖生物造成影响。地表水的 pH 值相对较低，并且碳酸盐略微饱和。预计气候变化将导致该地区未来的海洋学变化：地表水变暖和酸化、分层增加和生产力降低以及缺氧水上升/混合到表层。这些变化可能会影响生活在东热带太平洋的生物体和种群。
The eastern Pacific warm pool supports reef-building corals, as well as distinct communities of plankton, fishes, marine mammals and birds. This habitat is characterized by warm, low-salinity surface water lying on top of a strong, shallow thermocline. It is bounded by the South Equatorial Current and equatorial cold tongue to the south, cooler and more saline subtropical water to the northwest, and cold eastern boundary currents to the north and south (California and Peru Currents). The continental boundary influences atmospheric forcing by gap winds during winter and by causing the rainy Intertropical Convergence Zone to be located north of the equator and over the warm pool. Patterns of waves, tides and tropical cyclones impinging on coral reefs are described. The structure and variability of water masses and circulation are determined by solar and atmospheric processes, both within and outside of the region. To the west of the Galapagos, surface circulation is predominantly the east-west equatorial currents. Near the coast, surface circulation is modified by the coastal boundary, local winds, eddies, and interaction with eastern boundary currents. Primary productivity depends on oceanic upwelling along the equator and local centers of upwelling and wind mixing in coastal waters. Eastern tropical Pacific surface waters are moderately productive. Phytoplankton productivity is limited by a lack of the micronutrient dissolved iron, except where local coastal processes provide a source, so that macronutrients such as nitrate are never depleted. Seasonal changes in solar forcing, winds, rainfall, surface temperature and salinity, and other environmental characteristics are described, although seasonality in this region is not as pronounced as at higher latitudes. In contrast, interannual variations caused by the El Nino-Southern Oscillation across the entire tropical Indo-Pacific are very important in this region (Chap. 4). Oxygen depletion is extreme below the sharp thermocline, with consequences for mesopelagic and subthermocline benthic organisms. Surface waters are relatively low pH and marginally carbonate-saturated. Climate change is predicted to lead to future oceanographic changes in this region: warming and acidification of surface waters, increased stratification and reduced productivity, and upwelling/mixing of hypoxic waters into the surface layer. These changes are likely to affect organisms and populations living in the eastern tropical Pacific.