The Algerian Current (AC) is unstable and generates mesoscale meanders and eddies. Only anticyclonic eddies can develop and reach diameters over 200 km with vertical extents down to the bottom ( f 3000 m). Algerian Eddies (AEs) first propagate eastward along the Algerian slope at few kilometers per day. In the vicinity of the Channel of Sardinia, a few AEs detach from the Algerian slope and propagate along the Sardinian one. It was hypothesized that AEs then followed a counter-clockwise circuit in the eastern part of the basin. Maximum recorded lifetimes were known to exceed 9 months. Within the framework of the 1-year Eddies and Leddies Interdisciplinary Study off Algeria (ELISA) experiment (1997 -1998), we exhaustively tracked two AEs, using mainly an f 3-year time series of NOAA/AVHRR satellite images. We show that AEs lifetimes can near 3 years, exceeding 33 months at least. We also confirm the long-lived AEs preferential circuit in the eastern part of the Algerian Basin, and specify that it may include several loops (at least three). D

A synthesis of 9 years of hydrographic measurements, acquired during approximately 25 cruises (1992-2000) on the French continental shelf of the Bay of Biscay, is presented. The main focus is upon salinity distribution, as it is little known in this area. The whole of the data set covers 11 months of the year, with some sampling fields repeated several times a year, for multiple years. This timeseries allows temperature and salinity distributions to be studied together with their seasonal, interannual and mesoscale variability. The seasonal trend in temperature can be described in three stages, which are in agreement with past studies. Thermal stratification occurs between May and mid-September in a layer not, vert, similar50 m in thickness, whereas the water column remains homogenous from January to the beginning of April. The mid-September-December period corresponds to the progressive destruction of the thermocline. In contrast, the salinity distribution displays two main seasonal patterns. From March to June, the haline stratification is strong; this is in response to high river runoff and relatively low vertical mixing. In autumn, stratification decreases because of low river discharge and wind-induced vertical mixing. Surface salinity increases by up to 1 psu inshore of the 100-m isobath, from spring to end of summer. The salinity gradient runs cross-shore in spring and along-shore in summer: this is due to the mean wind direction during the previous 6 months (SW from September to March, NW from March to September). Nevertheless, this seasonal signal could be biased by the high inter-annual variability. Indeed, the monthly extent of low surface salinity (S<35) varied between years, this is driven by river runoff over the previous 3-6 months and short-term wind events (not, vert, similar10 days), particularly when they are upwelling-favourable. Forcing at these timescales are responsible also for mesoscale structures, such as lower salinity lenses and wind-induced coastal upwelling off Southern Brittany. In the deeper layers the inter-annual variability of a denser water structure named (the "Cold Pool") is also investigated. Consequently, the inter-annual, seasonal and mesoscale variability in salinity patterns are caused by (i) river runoff from the Loire and Gironde, that reduces surface salinity locally; and (ii) the wind that influences the location of low salinity water masses. Mesoscale structures and the observed links between inter-annual and seasonal variability, raise problems in relation to the interpretation of in situ data, making it impossible to establish the actual mean distribution. There is a pressing need within the Bay of Biscay, for sampling at higher spatial and temporal resolution.

[1] The Eddies and Leddies Interdisciplinary Study in the Algerian Basin (ELISA) experiment (1997)(1998), MAST-3/MTP2/MATER program) was a multidisciplinary and multiplatform experiment designed to study the anticyclonic Algerian Eddies (AEs) generated by the instability of the Algerian Current and their influence on the general circulation and biological phenomena. This paper presents preliminary results of the data obtained over the four year-round cruises ELISA-1 to 4. Two AEs (called 96-1 and 97-1) were tracked with satellite images over their counterclockwise circuit in the eastern Algerian Basin, from the Algerian to the Sardinian slope, and then to the open sea. They have been sampled over different periods and positions. Associated biological response was analyzed considering the hydrodynamical structure and the distribution of chlorophyll and nitrate concentration in the upper 300 m. In summer both AEs (96-1 located along slope and 97-1 located offshore) corresponded to highly oligotrophic areas. The deep chlorophyll maximum was $90-110 m, with concentrations up to $1 mg m À3 , the nitrate concentrations were low down to $250 m in the AEs' central zone. The downward entrainment of chlorophyll along isopycnals in the AEs' peripheral zone was well observed down to $250 m. In spring the maximum integrated chlorophyll concentrations were found offshore, in 96-1, where the upper $150 m were quasi-homogeneous. Lower integrated chlorophyll concentrations were found inshore in 97-1, which was embedded in an Algerian Current meander and remained stratified throughout wintertime. AEs generate secondary phenomena such as small-scale cyclonic shear eddies, where the highest chlorophyll concentrations ($4 mg m À3 ) were found. We show that through the AEs it generates, the Algerian Current can be responsible for producing areas in the coastal zone that are at least as oligotrophic as the eastern Mediterranean and, alternately, for productive areas offshore. As AEs generally follow a counterclockwise circuit in the Algerian Basin, it is inferred that they play an important role in the redistribution of matter on a basin scale. However, the biological response associated with AEs varies according to their history, a combination of trajectory, location, and season, in ways that are not yet clear.

High Frequency Radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past 10 years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A big effort is made in Europe toward a coordinated development of coastal HFR technology and its products within the framework of different European and international initiatives. One recent initiative has been to make an up-to-date inventory of the existing HFR operational systems in Europe, describing the characteristics of the systems, their operational products and applications. This paper offers a comprehensive review on the present status of European HFR network, and discusses the next steps toward the integration of HFR platforms as operational components of the European Ocean Observing System, designed to align and integrate Europe's ocean observing capacity for a truly integrated end-to-end observing system for the European coasts.