Acidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs can have a relevant contribution to the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. However, little is known about TEPs distribution, carbon export, and residence times below the export (200 m) and sequestration (1000 m) depths. We provide the first comprehensive inventory of TEP from the ocean surface to a depth of 4000 meters in the tropical and subtropical Atlantic, Indian, and Pacific Oceans, evaluating its contribution to carbon export and sequestration into the deep ocean. Results indicate that TEP concentration is primarily determined by primary production, with higher concentrations located above the deep chlorophyll maxima. In the deep ocean, TEP concentrations are lower yet mirror the concentrations in the surface, demonstrating the significance of TEP sinking below both the export compartment (2.8 Pg C yr-1; 27% of total POC flux at 200 m) and the sequestration compartment (0.8 Pg C yr-1; 36% of total POC flux at 1000 m). In situ incubation experiments conducted across ocean basins indicate short TEP residence times, averaging 27 and 333 days in the export and sequestration compartments, respectively. These findings reveal that the export and subsequent sequestration of carbon by TEP sinking into the deep ocean diverts it from the long times observed for the dissolved carbon fraction (i.e. centuries) in the global carbon cycle.

Primary Presenter: Isabel Reche, Universidad de Granada (ireche@ugr.es)

Authors:

Isabel Reche, Universidad de Granada  (ireche@ugr.es)

Ignacio Peralta-Maraver, Universidad de Granada  (peraltamaraver@ugr.es)

Eva Ortega-Retuerta, Laboratoire d’Océanographie Microbienne, Observatoire Océanologique, Banyuls-sur-Mer, France  (ortegaretuerta@obs-banyuls.fr)

Ignacio Mazuecos, Universidad de Granada  ()

Teresa Catalá, Universidad de Granada  (teresc@ugr.es)

Irene Forn, CSIC  (forn@icm.csic.es)

Félix Picazo, Universidad de Granada  (fpicazo@ugr.es)

Emilio Marañón, Universidad de Vigo  (em@uvigo.es)

Pedro Cermeño, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain  (pedrocermeno@icm.csic.es)

Natalia González, Universidad Rey Juan Carlos  (natalia.gonzalez@urjc.es)

Cristina Sobrino, Universidad de Vigo  (sobrinoc@uvigo.es)

Ana Fernández, Universidad de Vigo  (afcarrera@uvigo.es)

María Huete-Ortega, Universidad de Vigo  (mhuete@uvigo.es)

Daffne López-Sandoval, King Abdullah University of Science and Technology  (daffne.lopezsandoval@kaust.edu.sa)

Montserrat Vidal, Universitat de Barcelona  (montsevidal@ub.edu)

Xosé Anxelu Morán, Centro Oceanográfico de Gijón/Xixón (IEO, CSIC), 33212 Gijón/Xixón, Spain  (xelu.moran@ieo.csic.es)

Xosé Antón Álvarez-Salgado, CSIC  (xsalgado@iim.csic.es)

Susana Agustí, King Abdullah University of Science and Technology  (susana.agusti@kaust.edu.sa)

Carlos Duarte, King Abdullah University of Science and Technology  (carlos.duarte@kaust.edu.sa)

Josep M., CSIC  (pepgasol@icm.csic.es)

Javier Arístegui, Universidad de Las Palmas de Gran Canaria  (javier.aristegui@ulpgc.es)