Seasonal changes in particulate biogenic and lithogenic silica in the upwelling system off Concepción (～36°S), Chile,and their relationship to fluctuations in marine productivity and continental input |
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| Institution: | 1. Programa Doctorado en Ciencias Biológicas Mención Botánica, Departamento de Botánica, Universidad de Concepción, Casilla 160-C, Concepción, Chile;2. Departamento de Oceanografía, Universidad de Concepción, Casilla 160-C, Concepción, Chile;3. Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental (FONDAP-COPAS), Universidad de Concepción, Casilla 160-C, Concepción, Chile;4. Universidad Austral de Chile, Instituto de Biología Marina, Casilla 567, Valdivia, Chile;5. Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Bilbao 449, Coyhaique, Chile;1. Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, PO Box 1020, Valparaíso, Chile;2. Aquatic Ecosystem Functioning Lab (LAFE), Department of Aquatic System, Faculty of Environmental Sciences & Environmental Sciences Center EULA Chile, Universidad de Concepción, Concepción, Chile;1. Institut für Paläontologie und Geobiologie, Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians Universität München, Germany;2. GeoBio-Center, Ludwig-Maximilians Universität München, Germany;3. Institut für Geographie, Friedrich-Alexander-Universität Erlangen–Nürnberg, Kochstr. 4/4, 91054 Erlangen, Germany;4. Departamento de Oceanografía, Programa Copas Sur-Austral, Universidad de Concepcíon, Chile;5. Geopolar, Institut für Geographie, Universität Bremen, Germany;6. Facultad de Recursos Naturales, Escuela de Ciencias del Mar, Pontificia Universidad Catolica de Valpara?so, Valpara?so, Chile;1. Department of Civil and Coastal Engineering, University of Florida, Gainesville, FL 32611, USA;2. Departamento de Oceanografía, Universidad de Concepción, Campus Concepción, Víctor Lamas 1290, Casilla 160-C, código postal 4070043 Concepción, Chile;3. Centro COPAS Sur-Austral, Universidad de Concepción, Campus Concepción, Víctor Lamas 1290, Casilla 160-C, código postal 4070043 Concepción, Chile;1. Physics Department, California Polytechnic State University, San Luis Obispo, CA, USA;2. Tenera Environmental, San Luis Obispo, CA, USA;1. Instituto Antártico Chileno (INACH), Plaza Muñoz Gamero 1055, Punta Arenas, Chile;2. Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile;3. Renard Center of Marine Geology (RCMG), Ghent University, Krijgslaan 281 S8, 9000 Gent, Belgium;4. Departamento de Oceanografía, Universidad de Concepción, Barrio Universitario, Concepción, Chile;5. Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad de Concepción, Barrio Universitario, Concepción, Chile;6. Pontificia Universidad Católica de Valparaíso, Escuela de Ciencias del Mar, Avenida Altamirano 1480, Valparaíso, Chile;7. Postgrado en Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Barrio Universitario, Concepción, Chile;1. Departamento de Biología Marina, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile;2. Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Raúl Bitrán S/N, La Serena, Chile;3. Institut für Geographie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany;4. GeoBio-Center and Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians Universität München, Germany |
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| Abstract: | We analyzed the temporal and vertical distribution of biogenic (BSi) and lithogenic (LSi) silica, and diatom abundance in the upwelling center off Concepción, Chile, from April 2004 to May 2005. Measurements were performed at the FONDAP COPAS Time Series Station 18 (36°30.8′S, 73°07.7′W; 88 m water depth), and were combined with primary production estimates and river runoff data to assess the relationships between water column BSi and primary production, and between LSi and river runoff. Throughout the sampling period, water-column-integrated (0–80 m) BSi averaged 252±287 mmol m?2, and was about six times higher than average LSi (44±30 mmol m?2). The highest water column BSi observed during the upwelling season (786±281 mmol m?2) coincided with increments in total diatom abundance, and high integrated chlorophyll a concentration and primary production. In contrast, LSi was nearly two times higher in winter (85±43 mmol m?2) than the annual average, in agreement with the period of substantial discharges from the Itata and Bio-Bio rivers. The observed temporal patterns in BSi and LSi are coincident with primary production-related factors and riverine outflow, respectively, suggesting that the BSi and LSi pools are separate. With respect to the vertical distribution in the water column, most of the BSi and diatoms were found in surface waters (0–30 m depth), whereas LSi was most abundant at depth. Our study attempts to make an inventory of both BSi and LSi in the water column off Concepción, and gives the present-day background information necessary to assess potential future changes in the hydrological cycle that, in turn, may induce modifications in the Si path from the watersheds to the ocean. |
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