Seasonal and inter-annual variability in properties of surface water off Santander, Bay of Biscay, 1991–1995

Abstract

The annual cycle of temperature, salinity and nutrients of surface waters (up to 100 m depth) was studied from June 1991 to December 1995 in a cross-shelf section over the continental shelf waters off Santander (southern Bay of Biscay). The time se:ries showed that the temperature followed the expected seasonal. warming and cooling pattern, which determines a seasonal process of stratification and mixing of the water column. The stratification period occurs annually between May and October in a layer of about 50 m depth from the neritic station be:yond to the shelf-break. In the period between November and April the water column remained mixed. During spring and summer low salinity values were found in the surface due to continental runoff and advection from oceanic waters. In late autumn and winter, the salinity pattern was governed by an influx of salty water associated with the poleward current. As in other temperate latitudes, nitrates showed the highest values in winter throughout the water column and the lowest values at the surface during the stratified period. Wind-induced upwelling events were observed mainly in summer, which are characterised by low temperatures (< 12 "C), high salinity and nutrient concentrations. The inter-annual variability of temperature showed a warming trend in the upper layers but this sign was not found at 100 m depth. In salinity a decreasing trend was observed throughout the water column, and this feature corresponds to the relaxing of the high salinity anomaly detected in the North Atlantic at the beginning of the 1990s. Both trends were coherent in the cross-shelf section from the coast to the slope. 0 Elsevier, F'aris Bay of Biscay I hyldrographical conditions I surface water I time series

Shell oxygen isotope values and sclerochronology of the limpet Patella vulgata Linnaeus 1758 from northern Iberia: Implications for the reconstruction of past seawater temperatures

“…A C C E P T E D M A N U S C R I P T (Álvarez et al, 2011;Lavín et al, 1998). The water related to these upwelling events in the region is generally Eastern North Atlantic Central Water (ENACW), which is a cold and salty water mass.…”

Mixed layer depth (MLD) variability in the southern Bay of Biscay. Deepening of winter MLDs concurrent with generalized upper water warming trends?

“…This area is influenced by the extension of the Iberian Poleward Current (IPC), a geostrophically balanced poleward flow, trapped within 50 km of the shelf edge and due to a cross-slope density gradient, which is established in wintertime at the slope of the Iberian margin. The IPC carries warm and salty waters towards the southern waters of the Bay of Biscay (Pingree and Cann 1990;Lavín et al 1998;García-Soto et al 2002;Cabanas et al 2003). Thus, in general, in oceanic waters of the southern Bay of Biscay, advective effects are weak supporting the use of a one-dimensional model.…”

“…IEOS6 is only 6 km apart from the 200-m isobath, and so in some aspects it could be considered as a shelf break station although it is at 850 m depth. Its position at the inner slope is affected by advective processes such as IPC intrusions (Lavín et al 1998 …”

“…We expect the simulations to be representative of the oceanic area). Another advective pattern is related to the arrival in summer months of surface low-salinity waters of continental origin (Lavín et al 1998). These advective sources are accounted for in the model through the relaxation term, so they depend on the existence of a high-frequency time series of profiles.…”

Climate change impacts on coastal and pelagic environments in the southeastern Bay of Biscay

“…1b) for the period 1947-2001 indicates a decreasing trend in the mean annual temperature; this is due to the warm periods at the end of the 1940s and the 1960s (Borja et al 2000). However, Koutsikopoulos et al (1998) (Lavín et al 1998), 1986(Valencia 1993) and 1986(ICES 2004. This pattern shows that increasing trends are related more to mild winter SST periods than to very high summer SST values (Koutsikopoulos et al 1998, Borja et al 2000.…”