Inter-Research > MEPS > v418 > p57-71  
MEPS
Marine Ecology Progress Series

via Mailchimp

MEPS 418:57-71 (2010)  -  DOI: https://doi.org/10.3354/meps08812

Dissolved oxygen in contrasting estuaries of the Bay of Biscay: effects of temperature, river discharge and chlorophyll a

Arantza Iriarte1,*, Guillermo Aravena1, Fernando Villate1, Ibon Uriarte2, Berta Ibáñez3,7, Marcos Llope4,6, Nils Chr. Stenseth4,5

1Laboratory of Ecology, Department of Plant Biology and Ecology, Faculty of Science and Technology, University of the Basque Country, PO Box 644, 48080 Bilbao, Spain
2Laboratory of Ecology, Department of Plant Biology and Ecology, Faculty of Pharmacy, University of the Basque Country,  Paseo de la Universidad 7, 01006 Gasteiz, Spain
3Basque Foundation for Health Innovation and Research (BIOEF), 48015 Sondika, Bizkaia, Spain
4Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1066 Blindern,
0316 Oslo, Norway
5Flødevigen Marine Research Station, Institute of Marine Research, 4817 His, Norway
6Present address: Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Cádiz, Puerto Pesquero, Muelle de Levante s/n, PO Box 2609, 11006 Cádiz, Andalucía, Spain
7Present address: Biomedical Research Center, 31008 Pamplona, Spain

ABSTRACT: The effects of environmental factors on variations of dissolved oxygen (DO) saturation was assessed in 2 estuaries (Bilbao and Urdaibai) in the Bay of Biscay with contrasting hydrography and anthropogenic impact, for the period 1997 to 2006, using generalised additive models (GAMs) and generalised additive mixed models (GAMMs). Spatial and temporal variations in DO saturation and the current severity and extent of hypoxia were higher in the culturally eutrophicated and stratified Bilbao estuary. Seasonal patterns of DO saturation and the hierarchy of factors controlling them differed both between estuaries and between salinity zones. In the inner Bilbao estuary, the main factor explaining DO-saturation variations was temperature, with a dominant effect on oxygen consumption processes. In contrast, in the outer Bilbao estuary, the main factor explaining DO-saturation variations was chlorophyll a, suggesting that the effect of oxygen production through photosynthesis was stronger than that of oxygen consumption. In the inner Urdaibai estuary, both a negative relationship with temperature and a positive relationship with chlorophyll a were detected. The outer Urdaibai estuary showed strong water-column mixing and very high tidal flushing, and ventilation processes were more important than oxygen production or consumption processes. River discharge affected DO saturation only at the inner waters, but when the effects of several variables on DO-saturation variability were tested in an additive model, river discharge was excluded from the models. The effects of temperature-dependent processes on DO-saturation dynamics decreased from the inner to the outer zones of both estuaries.


KEY WORDS: Dissolved oxygen · Chlorophyll · Temperature · River discharge · Estuary · Generalised additive models · Bay of Biscay


Full text in pdf format 
Cite this article as: Iriarte A, Aravena G, Villate F, Uriarte I, Ibáñez B, Llope M, Stenseth NC (2010) Dissolved oxygen in contrasting estuaries of the Bay of Biscay: effects of temperature, river discharge and chlorophyll a. Mar Ecol Prog Ser 418:57-71. https://doi.org/10.3354/meps08812

Export citation
Mail this link - Contents Mailing Lists - RSS
Facebook - - linkedIn