Assessment of the effects of a port expansion on algae appearance in a costal bay through mathematical modelling. Application to San Lorenzo Bay (North Spain)

Andrés García, María Luisa Sámano, José A. Juanes, Raúl Medina, José A. Revilla and César Álvarez

Ecological Modelling, 2010, vol. 221, issue 10, 1413-1426

Abstract: In the last years several episodes of algae appearance affecting bathing areas have been observed in San Lorenzo Bay (north of Spain). The analysis of the collected algae revealed that they might come from near intertidal or shallow subtidal zones due to eutrophication processes or through drift algae movement by the action of marine currents. In the vicinity of this area, the expansion of the Port of Gijón (now under construction) supposes a significant modification of the coastal geometry. The magnitude of such an expansion could cause changes in the patterns of currents in the bay, with the consequent alteration of the observed algal appearance phenomena. A mathematical modelling study to evaluate the risk of generation of eutrophication processes in the San Lorenzo Bay area and the transport of drift algae from near sea bed areas was developed. This study required the use of different hydrodynamic models in order to characterize the currents caused by tides, winds and waves. The eutrophication processes in the bay were analyzed with a depth-averaged two-dimensional eutrophication model which deals with eight water quality variables. Calibration of model parameters with the observed data from a field survey was performed. A reasonable agreement with the field measurements was achieved. Model results showed that the maximum phytoplankton concentrations were below eutrophic conditions. Although, the port expansion has led to an increment of phytoplankton concentrations, chlorophyll a levels were not representative of eutrophic conditions. To analyse the transport of drift algae, a methodology based on the utilization of a two-dimensional model which solves the depth-averaged advection-diffusion equation considering seaweed as a conservative tracer was developed and applied. Numerical modelling allowed the identification of the coastal areas that seems to be the source of the seaweed found on the beach. It was also proven that port expansion does not significantly affect drift algae transport in the area.

Keywords: Eutrophication; Drift algae; Numerical modelling; Phytoplankton; Port expansion; San Lorenzo Bay (search for similar items in EconPapers)
Date: 2010
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0304380010000736
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:ecomod:v:221:y:2010:i:10:p:1413-1426

DOI: 10.1016/j.ecolmodel.2010.02.002

Access Statistics for this article

Ecological Modelling is currently edited by Brian D. Fath

More articles in Ecological Modelling from Elsevier
Bibliographic data for series maintained by Catherine Liu ().