Synthesis & Modeling Project
Frank Muller-Karger
Synoptic analysis of factors influencing carbon fluxes at the CARIACO continental margin time series

NASA, 36 months

PROJECT DESCRIPTION: 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.



Time-series data from the CARIACO site (cruises 1-54; Nov 08, 1995 - May 11, 2000) have been submitted and are available here.  Additional data from the CARIACO Project are available from http://imars.marine.usf.edu/cariaco


Astor, Y., F. Muller-Karger, and M. I. Scranton. 2003. Seasonal and Interannual Variation in the Hydrography of the Cariaco Basin: Implications for Basin Ventilation. Continental Shelf Research. Vol. 23. No. 1. 125-144.

Astor, Y.; J. Meri and F. Muller-Karger. 1998. Variabilidad estacional hidrográfica en la Fosa de Cariaco. Mem. Soc. de Cienc. Nat. La Salle. Vol LVIII (149). 61-72.

Ho, T-Y., M.I. Scranton, G.T. Taylor, R. Varela, R. Thunell, and F. E. Muller-Karger. 2002. Acetate cycling in the water column of the Cariaco Basin: Seasonal and vertical variability, and implication for carbon cycling. Limnology and Oceanography. 47: 1119-1128.

Muller-Karger, F. E., R. Varela, R. C. Thunell, M. I. Scranton, G. T. Taylor, Y. Astor, E. Tappa, M. A. Goñi, R. N. Sambrotto, H. Zhang, M. McIntyre, B. Marin, C. Hu, M. Iabichella, T.-Y. Ho, and R. H. Weisberg. (Accepted). CARIACO: A Time Series of Primary Production and Vertical Export in the Cariaco Basin. In: JGOFS CMTT Synthesis.

Muller-Karger, F. E., R. Varela, R. Thunell, Y. Astor, H. Zhang, and C. Hu. (In press, 2003). Processes of Coastal Upwelling and Carbon Flux in the Cariaco Basin. Deep-Sea Research II.

Muller-Karger, F. E., R. Varela, R. Thunell, M. Scranton, R. Bohrer, G. Taylor, J. Capelo, Y. Astor, E. Tappa, T. Y. Ho, and J. J. Walsh. 2001. Annual Cycle of Primary Production in the Cariaco Basin: Response to upwelling and implications for vertical export. Journal of Geophysical Research. 106:C3. 4527-4542.

Muller-Karger, F., R. Varela, R. Thunell, M. Scranton, R. Bohrer, G. Taylor, J. Capelo, Y. Astor, E. Tappa, T.-Y. Ho, M. Iabichella, J. J. Walsh, and J. R. Diaz. 2000. The CARIACO Project: Understanding the Link between the Ocean Surface and the Sinking Flux of Particulate Carbon in the Cariaco Basin. EOS. AGU Transactions. Vol. 81. No. 45. pages 529, 534, 535.

Muller-Karger, F. E. 2000. SMP workshop looks at role of continental margins in ocean carbon cycle. In: U.S. JGOFS Newsletter. Volume 10. Number 4. August 2000. U.S. JGOFS Planning Office at Woods Hole Oceanographic Institution. p. 4-6.

Scranton, Mary I., Yrene Astor, Richard Bohrer, Tung-Yuan Ho and Frank Muller-Karger. 2001. Controls on temporal variability of the geochemistry of the deep Cariaco Basin, Deep Sea Research Part I: Oceanographic Research Papers. Volume 48, Issue 7, July 2001, Pages 1605-1625.

Thunell, R., R. Varela, M. Llano, J. Collister, F. Muller-Karger, and R. Bohrer. 2000. Organic carbon flux in an anoxic water column: sediment trap results from the Cariaco Basin. Limnology and Oceanography. 45. 300-308.

Thunell, R. E. Tappa., R. Varela, M. Llano, Y. Astor, F. Muller-Karger, and R. Bohrer. 1999. Increased marine sediment suspension and fluxes following an earthquake. Nature. 398, 233-236.

Walsh, J.J., D.A. Dieterle, F.E. Muller-Karger, R. Bohrer, W.P. Bissett, R.J. Varela, R. Aparicio, R. Diaz, R. Thunell, G.T. Taylor, M.I. Scranton, K.A. Fanning, and E.T. Peltzer. 1999. Simulation of carbon/nitrogen cycling during spring upwelling in the Cariaco Basin. J. Geophys. Res. Vol 104. No. C4, 7,807-7,825.

RELATED PROJECTS: Walsh  "A numerical analysis of new nitrogen sources of NO3 and N2 effecting carbon cycling in the Southern Caribbean Sea: A key to CDOC contamination of satellite color signals"


Frank Muller-Karger
Institute for Marine Remote Sensing/IMaRS
College of Marine Science
University of South FLorida
140 7th Ave. South
St Petersburg, FL 33701
tel: (727) 553-3335, 1186
fax: (727) 553-1103