Search

Your search keyword '"Torres, Américo I."' showing total 8 results
Start Over Author "Torres, Américo I."
8 results on '"Torres, Américo I."'

1. Global subterranean estuaries modify groundwater nutrient loading to the ocean

Author

Wilson, Stephanie J, Moody, Amy, McKenzie, Tristan, Cardenas, M Bayani, Luijendijk, Elco, Sawyer, Audrey H, Wilson, Alicia, Michael, Holly A, Xu, Bochao, Knee, Karen L, Cho, Hyung‐Mi, Weinstein, Yishai, Paytan, Adina, Moosdorf, Nils, Chen, Chen‐Tung Aurthur, Beck, Melanie, Lopez, Cody, Murgulet, Dorina, Kim, Guebuem, Charette, Mathew A, Waska, Hannelore, Ibánhez, J Severino P, Chaillou, Gwénaëlle, Oehler, Till, Onodera, Shin‐ichi, Saito, Mitsuyo, Rodellas, Valenti, Dimova, Natasha, Montiel, Daniel, Dulai, Henrietta, Richardson, Christina, Du, Jinzhou, Petermann, Eric, Chen, Xiaogang, Davis, Kay L, Lamontagne, Sebastien, Sugimoto, Ryo, Wang, Guizhi, Li, Hailong, Torres, Américo I, Demir, Cansu, Bristol, Emily, Connolly, Craig T, McClelland, James W, Silva, Brenno J, Tait, Douglas, Kumar, BSK, Viswanadham, R, Sarma, VVSS, Silva‐Filho, Emmanoel, Shiller, Alan, Lecher, Alanna, Tamborski, Joseph, Bokuniewicz, Henry, Rocha, Carlos, Reckhardt, Anja, Böttcher, Michael Ernst, Jiang, Shan, Stieglitz, Thomas, Gbewezoun, Houégnon Géraud Vinel, Charbonnier, Céline, Anschutz, Pierre, Hernández‐Terrones, Laura M, Babu, Suresh, Szymczycha, Beata, Sadat‐Noori, Mahmood, Niencheski, Felipe, Null, Kimberly, Tobias, Craig, Song, Bongkeun, Anderson, Iris C, and Santos, Isaac R

Subjects
Earth Sciences, Oceanography
Abstract

Abstract: Terrestrial groundwater travels through subterranean estuaries before reaching the sea. Groundwater‐derived nutrients drive coastal water quality, primary production, and eutrophication. We determined how dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and dissolved organic nitrogen (DON) are transformed within subterranean estuaries and estimated submarine groundwater discharge (SGD) nutrient loads compiling > 10,000 groundwater samples from 216 sites worldwide. Nutrients exhibited complex, nonconservative behavior in subterranean estuaries. Fresh groundwater DIN and DIP are usually produced, and DON is consumed during transport. Median total SGD (saline and fresh) fluxes globally were 5.4, 2.6, and 0.18 Tmol yr−1 for DIN, DON, and DIP, respectively. Despite large natural variability, total SGD fluxes likely exceed global riverine nutrient export. Fresh SGD is a small source of new nutrients, but saline SGD is an important source of mostly recycled nutrients. Nutrients exported via SGD via subterranean estuaries are critical to coastal biogeochemistry and a significant nutrient source to the oceans.

Published
2024

7. Nitrate reduction activity determined with a continuous flow-through system in sediments from a subantarctic coastal environment

Author

Torres, Américo I, Gil, Mónica N, and Esteves, José Luis

Subjects
ammonium, denitrification, Argentinean Patagonia, Nitrato, Patagonia argentina, denitrificación, amonio, Nitrate, reactor
Abstract

Sedimentation and accumulation of autochthonous and allochthonous organic detritus in marine sediments stimulate microbial activity, consume dissolved oxygen and decrease redox potential. In anaerobic conditions, other electron acceptors are utilized in organic matter oxidation process. Nitrate reduction is an important pathway which is related with nitrogen cycling and oxidation. The purpose of this study was to assess the nitrate reduction activity in sediments of Encerrada Bay, which is under a strong anthropogenic influence from Ushuaia city. Sediment samples were taken in September 2007 with a Van-Veen dredge and stored in darkness. Nitrate reduction activity was estimated in vitro using continuous flow-through system. Nitrate uptake rate followed a Michaelis-Menten kinetic where Km and Vmax values were equal to 1028 mM and 2.7 µmol g-1 h-1, respectively. We concluded that nitrate is used principally as terminal electron acceptor during the oxidation of organic compounds in sediment of Encerrada Bay. La sedimentación y acumulación de detritos orgánicos autóctonos y alóctonos en el sedimento marino, favorece la actividad microbiana, consume el oxígeno disuelto y disminuye el potencial de óxido-reducción. En condiciones anaeróbicas otros aceptores de electrones son utilizados en los procesos de oxidación de la materia orgánica. La reducción de nitrato es un proceso importante que está relacionado con el ciclo del nitrógeno y la oxidación. El objetivo de este estudio fue estimar la actividad nitrato reductora en sedimentos de la Bahía Encerrada, la cual se encuentra sometida a una fuerte influencia antropogénica desde la ciudad de Ushuaia. Las muestras de sedimento fueron tomadas en septiembre de 2007 con draga Van-Veen y almacenadas en oscuridad. La actividad nitrato reductora fue estimada in vitro mediante un sistema de flujo continuo. La tasa de incorporación de nitrato se aproximó a una cinética del tipo Michaelis-Menten donde los valores de Km y Vmax fueron 1028 mM y 2,7 µmol g-1 h-1, respectivamente. Se concluye que el nitrato es utilizado preponderantemente como aceptor final de electrones durante la oxidación de compuestos orgánicos en el sedimento de Bahía Encerrada.

Published
2012

Catalog

Books, media, physical & digital resources
See catalog results