Fluctuations in export productivity over the last century from sediments of a southern Chilean fjord (44°S)
Fluctuations in export productivity over the last century from sediments of a southern Chilean fjord (44°S)
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上个世纪智利南部峡湾（南纬 44°）沉积物出口生产率的波动
DOI：
10.1016/j.ecss.2005.07.005
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发表时间：
2005
影响因子：
2.8
通讯作者：
N. Silva
中科院分区：
文献类型：
--
作者：
J. Sepúlveda;S. Pantoja;K. Hughen;C. Lange;Fidelina González;P. Muñoz;L. Rebolledo;Rodrigo Pulgar Castro;S. Contreras;A. Ávila;P. Rossel;Gisella Lorca;M. Salamanca;N. Silva
在这里，我们提出了第一个重建的变化，在上个世纪的Puyuhuapi峡湾在智利南部的表面初级生产力，使用各种参数（硅藻，生物硅，总有机碳，叶绿素和蛋白质）作为生产力代理。从峡湾的头部和中心的两个沉积物芯进行了分析和比较，以获得在这两个不同的沉积环境中的生产力的过去的变化的见解。在峡湾头部发现的较高的沉积速率是由于较浅的水柱和因岩床的出现而限制的循环相结合的结果。此外，沉积物混合深度估计从210铅数据表明，亚氧条件可能占主导地位的底层水和沉积物-水界面在这个位置。在上个世纪，Puyuhuapi峡湾的生产力的特点是从19世纪末到20世纪80年代初不断增加，然后下降，直到20世纪90年代末，然后再次上升到今天的值。降雨量对生产力的影响是最显着的低降雨量期间，这正好与Puyuhuapi峡湾内的整体生产力下降。在研究区域的生产力和降雨量的同时变化表明，海洋生产力可以在当地规模的大气-海洋相互作用。在区域一级，该地区的海洋生产力可能与厄尔尼诺南方涛动等其他大规模过程有关。
Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from210Pb data suggest that suboxic conditions may dominate the bottom water and the sediment–water interface in this location. Productivity of the Puyuhuapi fjord during the last century was characterized by a constant increase from the late 19th century to the early 1980s, then decreased until the late 1990s, and then rose again to present-day values. The influence of rainfall on productivity was most noticeable during periods of low rainfall, which coincided with decreased overall productivity within the Puyuhuapi fjord. Simultaneous variations in productivity and rainfall in the study area suggest that marine productivity could respond to atmospheric–oceanic interactions at a local scale. At a regional scale, marine productivity of the area may be related to other large-scale processes such as the El Niño Southern Oscillation.