Collaborative Research: The Cariaco Basin Oceanographic Time Series Program

This award will provide three more years of support to three U.S. institutions -- University of South Florida, University of South Carolina at Columbia, and Stony Brook University -- for the CARIACO Basin Ocean Time-Series, located in the anoxic Cariaco Basin on the Venezuelan continental margin. In continuous operation since November, 1995, the scientific goal of CARIACO is to understand the relationships between hydrography, plankton community composition, primary production, microbial activity, terrigenous inputs, particle and other fluxes, and other processes of element cycling in the water column, and how their variation is preserved in seafloor sediments. The program strives to serve the ocean carbon and biogeochemistry (OCB) and the paleoclimate research communities by maintaining an observing facility in the Cariaco Basin that provides core observations and samples, and facilitates researcher access to a unique, world-renown tropical continental margin setting. A central tenet of CARIACO is that the data stream produced there aids in the interpretation of oceanic carbon fluxes and global climate variability. Understanding processes that affect sinking material is key to understanding the "biological carbon pump" and processes that transfer materials from the surface ocean and adjacent land to the bottom. Since the Cariaco Basin only exchanges surface waters with the adjacent Caribbean Sea above a shallow (< 140 m) sill, anoxia prevails below ~250 m. These conditions preserve an excellent varved sediment record that is used by the international community to study Holocene and late Pleistocene climate change. The OCB community recognizes that we are approaching a "state shift" in the global biosphere due to interactions between natural climate variability and human activities. Ocean time series like CARIACO play a critical role in documenting and evaluating the mechanisms whereby marine ecosystems respond to subtle changes in climate. Indeed, the research team has documented dramatic changes in the Cariaco Basin over the past 17 years that reflect transformations over larger space and time scales. They attribute many of these ecosystem and biogeochemical changes to a northward migration of the Intertropical Convergence Zone. Broader impacts: The CARIACO Ocean Time-Series owes its success to strong collaborations established with scientists in Venezuela, the US, and other countries. It contributes to development of a growing global observatory focused on measuring ecological processes and understanding impacts of large-scale changes in the Earth system. CARIACO is an IGBP-LOICZ program relevant to international carbon cycle and broader oceanographic research. By providing climate proxies that improve the accuracy of past climate assessments, CARIACO directly addresses the goals of the CLIVAR and PAGES initiatives of the World Climate Research Programme and the International Geosphere-Biosphere Programme. The science also helps understand socio-economic impacts of ecosystem variability, such as the collapse of the sardine fishery and catastrophic weather events seen in the last decade in the region. CARIACO nurtures international scientific cooperation. Venezuelan funding for local scientists to participate in this joint effort is an important incentive to continue this program. CARIACO has had a significant impact on technology transfer and capacity building in Latin America, by providing regional scientists with opportunities to participate in a project that addresses issues of global relevance. CARIACO also exposes U.S. students and scientists to an international research community and to the cultures of the Caribbean and Latin America. The research team intends to continue proactive efforts to develop scientific and technical links between CARIACO, BATS, HOT, and various other OCB Program efforts.