1,738 publications from this institution
The dark ocean, the waters below 200 m depth, comprises about 95% of the volume of the ocean, but its contribution to the metabolism of the ocean is poorly quantified. Here we show that the respiration rate of microplankton declines exponentially at a rate of 0.53 km −1 in the dark ocean, and is enhanced at the interface between the mesopelagic and the abyssal layers (1,000–2,000 m). The respiratory CO 2 production in the dark ocean, estimated at 20 to 33.3 Gt C yr −1 , renders it a major component of the carbon flux in the biosphere.
El número 205 de la revista Controversia fue diseñado y construido con el apoyo del Instituto de Estudios Interculturales de la Universidad Javeriana de Cali, que delegó en Carlos Duarte la tarea de editor del dossier. Así, esta edición plantea preguntas y propone debates en torno a los desafíos que, para la nación multicultural, significa “La interculturalidad, la convivencia y las gobernanzas territoriales”. El reto de la interculturalidad se explica porque en el objetivo de hacer efectivos los derechos territoriales de las poblaciones rurales en el país, el Estado y las organizaciones étnico-campesinas enfrentan hoy, además de las tradicionales dificultades del sector agrario, el reto de construir ordenamientos territoriales que fortalezcan espacios de convivencia social y productiva. Como hemos visto en los últimos meses, lo anterior adquiere aún mayor relevancia ante la expectativa del escenario de posacuerdo, donde las espacialidades y gobernanzas rurales implementadas por los movimientos sociales jugarán un papel protagónico en la sostenibilidad y desarrollo del campo colombiano. Palabras Clave: Interculturalidad, Gobernanzas territoriales, Poblacion rural, Estado
The implications of differences in plant size for seagrass productivlty were examined based on an extensive compilation of data on architecture and growth of seagrass species.The analysis revealed strong allometric relationships between the size of different components, particularly a close scaling of the size of leaves, shoots, and fruits to rhizome diameter, as well as strong relationships between shoot size and the dynamics (e.g turnover rate, plastochrone interval, and longevity) of seagrass leaves and rhizomes of different species.The decrease in rhizome elongation rates and leaf turnover rates with increasing seagrass size demonstrates the importance of architecture for seagrass productivlty, and also provides explanations for the different ecological roles of small, colonizing species, and large, climax seagrass species.In addition, these results demonstrate that while habitat conditions have important Influences on seagrass productivity, differences in size may explain the vast range of turnover tlmes, plastochrone intervals, and module longevities, encountered among seagrass species.
Presentacion para el 9th European Marine Biology Symposium (49TH EMBS), 7-12 september 2014, S. Petersburg, Russia.-- 1 page
Abstract The gradient in the partial pressure of carbon dioxide ( p CO 2 ) across the air‐sea boundary layer is the main driving force for the air‐sea CO 2 flux. Global data bases for surface seawater p CO 2 are actually based on p CO 2 measurements from several meters below the sea surface, assuming a homogeneous distribution between the diffusive boundary layer and the upper top meters of the ocean. Compiling vertical profiles of p CO 2 , temperature, and dissolved oxygen in the upper 5–8 m of the ocean from different biogeographical areas, we detected a mean difference between the boundary layer and 5 m p CO 2 of 13 ± 1 µatm. Temperature gradients accounted for only 11% of this p CO 2 gradient in the top meters of the ocean; thus, pointing to a heterogeneous biological activity underneath the air‐sea boundary layer as the main factor controlling the top meters p CO 2 variability. Observations of p CO 2 just beneath the air‐sea boundary layer should be further investigated in order to estimate possible biases in calculating global air‐sea CO 2 fluxes.