Distribution of Euphausia mucronata at the upwelling area of Peninsula Mejillones, northern Chile: The influence of the oxygen minimum layer
Distribution of Euphausia mucronata at the upwelling area of Peninsula Mejillones, northern Chile: The influence of the oxygen minimum layer
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智利北部梅希约内斯半岛上升流区的磷虾分布：最低含氧层的影响
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发表时间：
2000
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影响因子：
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通讯作者：
C. Irribarren
中科院分区：
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作者：
R. Escribano;V. Marín;C. Irribarren
1996年12月，在上升流活跃期间，对从半岛Mejillones（智利北方）周围53个站采集的浮游动物样品进行了分析，这些样品来自两个地层：0-50米和150-200米，研究了洪堡海流特有的磷虾-Euphausia mucronata的水平和垂直分布。利用CTDO和荧光仪提供的信息，分析了海洋学变量对E. mucronata。E. mucronata在半岛全境均有分布，但南部地区聚集度较大，尤其是在深层。逐步多元回归分析表明，没有一个变量（温度，盐度和叶绿素）是显着相关的物种的数量丰富度。然而，有一个显着的影响，深度的最小氧层（OML），定义为0.5毫升O2 l-1，对综合丰度的物种，这样的个人更有可能被发现在该地区的OML更深。垂直分布参数表明其迁移模式为昼夜型。这个参数也与距离海岸线。由于上升流的活跃，近岸海域的OML急剧上升，但仍有近岸海域的OML仍然很深。因此E. mucronata似乎聚集在上升流透镜体和丝状体周围，那里浮游植物更集中，但同时避免OML太浅的地方。
Analysis of zooplankton samples from 53 stations obtained around Peninsula Mejillones (Northern Chile), from two strata: 0-50 m and 150-200 m, during active upwelling in December 1996, allowed the study of horizontal and vertical distribution of Euphausia mucronata, endemic Krill of the Humboldt Current. Information from CTDO and a fluorometer was used to analyze the influence of oceanographic variables on distribution of E. mucronata. E. mucronata was found distributed all around the Peninsula, although with greater aggregations in the southern area, especially in the deeper layer. Stepwise multiple regression showed that none of the variables (temperature, salinity and chlorophyll) was significantly correlated to numerical abundance of the species. However there was a significant effect of depth of the oxygen minimum layer (OML), defined as 0.5 ml O2 l-1, on integrated abundance of the species, such that individuals are more likely to be found in areas where the OML is deeper. A vertical distribution parameter suggested a diurnal migrational pattern. This parameter was also correlated with distance to shoreline. The OML rises abrutply in nearshore areas because of active upwelling, but there are still nearshore zones where the OML remains deep. Therefore E. mucronata appears to aggregate around the upwelling lenses and filaments, where phytoplankton is more concentrated, but at the same time avoiding places where the OML is too shallow.