Collaborative Research: Particulate Organic Carbon Fluxes and Sediment Accumulation in the Cariaco Basin

Cariaco盆地是委内瑞拉近海大陆架上的一个1400米深的凹陷，其中缺氧的水覆盖了有机质含量高(1-5wt%)的层状沉积物。这些纹层是初级生产力和加勒比海南部陆源沉积物输入的季节性变化造成的，包含了热带大西洋过去气候变化的高分辨率记录。在这项合作工作中，南佛罗里达大学(USF)、南卡罗来纳大学(USC)和纽约州立大学(SUNY)的研究人员试图将Cariaco盆地的水文、初级生产力、水柱微生物活动、垂直颗粒通量和沉积物累积速率测量整合为一个综合数据，以了解当代沉积模式如何反映这种气候和海洋变化。中心目标是了解控制初级生产力和Cariaco盆地颗粒垂直通量之间关系的因素。该项目将延续1995年11月开始的在北纬10‘30’，西经‘40’的月观测时间序列，该时间序列是在加勒比有色海洋碳保持计划下进行的。这包括继续部署一个有四个沉积物捕集器(275米、350米、450米和1200米)的系泊设备，在每个深度每两周采集一次样品。作为对捕集器的补充，将配备两个声学多普勒海流剖面仪(ADCP)的系泊设备，一个向上看，另一个从大约250米深向下看，以测量从基床以下到海面的海流，为期三年。每年，在卡里亚科站与盆地外北纬11‘40’，西经‘40’之间进行一条横断面，以帮助了解侵入和上涌所涉及的源水特征。将使用当地和遥感数据检查区域风和海平面，以确定上升流的强迫主要是通过当地还是回旋尺度的过程发生。Cariaco盆地的沉积物将被收集和分析，以重建Cariaco盆地过去一个世纪的海洋状况，并为更大规模的古海洋学研究提供窗口。该项目意义重大，因为它提供了正确解释加勒比沉积物中记录的过去气候变化所需的地面资料。

ABSTRACTOCE-0118349The Cariaco Basin is a 1,400-m deep depression on the continental shelf off Venezuela in which anoxic waters cover laminated sediments with high organic matter content (1-5 wt%). These laminae, which result from seasonal variations in primary productivity and terrigenous sediment input along the southern the Caribbean Sea, contain a high-resolution record of past climate change in the tropical Atlantic Ocean. In this collaborative effort, researchers at the University of South Florida (USF), the University of South Carolina (USC), and the State University of New York (SUNY) seek to integrate hydrographic, primary productivity, water column microbial activity, vertical particulate flux, and sediment accumulation rate measurements in the Cariaco Basin into a synthesis to understand how contemporary sedimentation patterns reflect this climatic and oceanographic variability. The central objective is to understand the factors that control the relationship between primary production and the vertical flux of particles in the Cariaco Basin. This project will continue the current time series of monthly observations at 10'30' N, 64'40' W that began in November, 1995, under the CARIACO (CArbon Retention In A Colored Ocean) Program. This includes continuing deployment of a mooring with four sediment traps (275, 350, 450, and 1,200 m) to provide bi-weekly sample collections at each depth. Complementing the traps will be a mooring with two Acoustic Doppler Current Profilers (ADCP), one looking up and the other looking down from a depth of about 250 m, to measure currents from below the sill depth to the surface for a three-year period. Each year, one transect will be conducted between the CARIACO station and 11'40' N, 64'40' W outside the basin, to help understand the characteristics of source water involved in intrusions and upwelling. Regional wind and sea level will be examined using both local and remotely-sensed data to establish whether forcing for upwelling occurs primarily through local or gyre-scale processes. Sediments from the Cariaco basin will be collected and analyzed to reconstruct the oceanographic condition in the Cariaco Basin over the past century and provide a window for longer-scale paleoceanographic studies. The program is significant because it provides groundtruthing needed for proper interpretation of past climate changes recorded in the Cariaco sediments.