The Oceanography and Modelling of the Pontevedra Ria (NW Spain)
type: CreativeWork
description: A multidisciplinary study the oceanography of the Pontevedra Ria (NW Spain), including hydrography, biogeochemistiy and biogeochemical modelling, has been performed. The hydrographical variability of the Pontevedra Ria was dependent on freshwater inputs and upwelling of nutrient-rich East North Atlantic Central Water from the shelf. Intrusions of the Poleward Current were also detected during winter. A stratified box model approach predicted that upwelling water fluxes into the ria of 2-4x10³ m³ s-1, of which >30% rises to the surface waters inside the ria. Freshwater residence time varied from ~4-9 d in the central ria and 1-4 d in the internal ria. Nutrients concentrations showed a strong fluvial and oceanic signal, with a clear zone of near-bed aerobic remineralisation in the internal ria. Nutrient flux experiments showed that high nutrient fluxes, particularly ammonium (3.5 mg N mˉ² hˉ¹), coincided with period of high water influx to the ria. These were related to stirring of quasi-benthic phytodetrital fluff. Denitrification was a major fate for particulate organic nitrogen in the sediment, averaging 2.5 mg N m ˉ² h ˉ¹ for the spring and dry season. A non-steady state nutrient budget revealed that the central and internal zones of the Pontevedra Ria display different biogeochemical characteristics. Net community production (NCP) based on phosphate uptake was spatially and temporally variable, with rates of 9.6 and 20.2 mg C m ˉ² h ˉ¹ in central and internal rias in spring, respectively, and 30.3 and 29.0 mg C m ˉ² h ˉ¹ in the dry season. Previously unquantified benthic nutrient inputs were important, and up to 25% of NCP was due to the sediment nutrient flux in the dry season. Denitrification calculated with the nutrient budget equalled 1.82 and 5.66 mg N m ˉ² h ˉ¹ in the dry season in the central and internal ria, respectively, and was equal to 27 and 42% of dry season NCP. The robustness of the box model was questioned, and found to be an unsuitable modelling…
abstract: A multidisciplinary study the oceanography of the Pontevedra Ria (NW Spain), including hydrography, biogeochemistiy and biogeochemical modelling, has been performed. The hydrographical variability of the Pontevedra Ria was dependent on freshwater inputs and upwelling of nutrient-rich East North Atlantic Central Water from the shelf. Intrusions of the Poleward Current were also detected during winter. A stratified box model approach predicted that upwelling water fluxes into the ria of 2-4x10³ m³ s-1, of which >30% rises to the surface waters inside the ria. Freshwater residence time varied from ~4-9 d in the central ria and 1-4 d in the internal ria. Nutrients concentrations showed a strong fluvial and oceanic signal, with a clear zone of near-bed aerobic remineralisation in the internal ria. Nutrient flux experiments showed that high nutrient fluxes, particularly ammonium (3.5 mg N mˉ² hˉ¹), coincided with period of high water influx to the ria. These were related to stirring of quasi-benthic phytodetrital fluff. Denitrification was a major fate for particulate organic nitrogen in the sediment, averaging 2.5 mg N m ˉ² h ˉ¹ for the spring and dry season. A non-steady state nutrient budget revealed that the central and internal zones of the Pontevedra Ria display different biogeochemical characteristics. Net community production (NCP) based on phosphate uptake was spatially and temporally variable, with rates of 9.6 and 20.2 mg C m ˉ² h ˉ¹ in central and internal rias in spring, respectively, and 30.3 and 29.0 mg C m ˉ² h ˉ¹ in the dry season. Previously unquantified benthic nutrient inputs were important, and up to 25% of NCP was due to the sediment nutrient flux in the dry season. Denitrification calculated with the nutrient budget equalled 1.82 and 5.66 mg N m ˉ² h ˉ¹ in the dry season in the central and internal ria, respectively, and was equal to 27 and 42% of dry season NCP. The robustness of the box model was questioned, and found to be an unsuitable modelling…
author: Dale, Andrew W.
language: eng
date published: 2003-01-01T08:00:00Z
date modified: 2026-07-24T03:48:35Z
provider: University of Plymouth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Plymouth