Dataset: CARIACO continental margin time series data, 1995-2000 (U.S. JGOFS Synthesis & Modeling Phase project results)

The present SMP proposal seeks to integrate synoptic observations from satellite platforms into the ongoing data collection, synthesis, and modeling efforts conducted at a continental margin time series station. We will use regional and basin-scale ocean color, infrared, scatterometer, and selected altimeter observations to study spatial and temporal variability of parameters that influence the distribution of phytoplankton, primary productivity, dispersal of dissolved organic matter, and the vertical flux of organic material at a time series station. A series of hypotheses relevant to Element # 2 of the JGOFS SMP Research Goals are posed. The primary null hypothesis is that regional and large-scale ocean phenomena do not have a significant effect on the partitioning of carbon into various pools along a continental margin. Secondary hypotheses address which oceanographic processes are most relevant to components of the carbon budget. The synthesis of field and satellite data will be closely linked with the numerical modeling effort of Dr. John J. Walsh (USF) to simulate fluxes within the Cariaco Basin (submitted as a separate SMP proposal).

CARIACO (CArbon Retention In A Colored Ocean) is a multidisciplinary oceanographic time series program established in the Cariaco Basin (Caribbean Sea) to define a budget which assesses the total CO₂ upwelled with deep, nutrient-rich water with respect to annual export of organic carbon from surface waters. The series was implemented in November 1995, with funding from the NSF in collaboration with the Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CONICIT) of Venezuela. In February, 1997, NASA selected CARIACO to be part of the SIMBIOS network for validation of satellite ocean color products. The time series is located at 10.50 N, 64.66 W, and consists of a mooring with 4 sediment traps (200, 400, 800, 1200 m; bi-weekly sample integrations), an upward-looking Acoustic Doppler Current Profiler (ADCP, 200 m), and monthly cruises to examine the composition and light absorption properties of organic particulate and dissolved matter, the taxonomy of phytoplankton and general classification of bacteria, biological productivity (phytoplankton and bacteria), physical/chemical properties including nutrient, oxygen, and the carbonate system, and hyperspectral reflectance measurements.

The Cariaco basin is ideal for a carbon flux study because it forms a natural sediment trap in a continental shelf area where advection below 150 m is restricted. Therefore, the sinking flux of organic matter is sequestered into the basin, making it easier to quantify compared to other continental margins. Indeed, Cariaco is a natural recorder of climate change. This is the only permanently anoxic basin in the world's oceans, and as such serves as an oceanic analog of the Black Sea.

There is increasing evidence that the tropical Atlantic, and particularly the Caribbean Sea, may function as barometers of global change. Indeed, the Caribbean experiences the most marked of the El Niño teleconnections in the Atlantic Ocean. The CARIACO time series will help assess the influence of these large-scale phenomena on carbon flux along a continental margin. This study will also complement flux estimates obtained at deep-ocean JGOFS time series stations (HOTS and BATS) and will help develop strategies for using satellites to address fluxes at other continental margin sites. This study will therefore help in modeling the ocean's role in climate change. The results will be widely distributed, in a manner accessible and understandable to the general public.

The proposed activity will be carried out at an institution which is preoccupied with scientific education. The proposed program will support a graduate student and a post-doctoral fellow, but the activities will also incorporate other graduate students and research associates, and middle-and high-school teachers through Project Oceanography, a distance learning program spearheaded by the USF Department of Marine Science. FMK also tutors several students from the Center for Advanced Technologies at Lakewood High. These students support programming and data-analysis efforts. Finally, CARIACO helps educate Latin American scientists and students by carrying out a field and data analysis program in Venezuela.