Harmonisation and dissemination of TSG data from IEO research vessels

Advances in the harmonisation and dissemination of underway data from research vessels in the Spanish Institute of Oceanography (IEO) fleets will be presented.Peer Reviewe

Spatial and temporal variability of Nutrients in the Ría de Vigo

The Ría of Vigo (Galicia, NW Spain) is an estuary located in the northern boundary (42–43°N) of the eastern North Atlantic upwelling system. Since 1994, the Instituto Español de Oceanografía (IEO), as part of RADIALES program, has been monitoring, in a monthly basis, a hydrographic standard section composed of 4 oceanographic stations located in the inner, medium and outer part of the ría. In addition to hydrographic profiles, biogeochemical and plankton samples have been collected. The average values of the main nutrients in the study area and its inter- and intra-annual variability in relation with the oceanographic features are represented in order to establish reference and range values for the different seasons

Improving the knowledge of sub-surface temperature, salinity and fluorescence variability patterns on the Southern Coast of Galicia

Since 2008, the Instituto Español de Oceanografía (IEO) keeps installed a thermosalinometer (TSG) on board of R/V J.M. Navaz that operates on Galician coastal waters. Weekly, it covers the area between Vigo and Muros in the framework of an harmful algal bloom monitoring. High resolution and quality coastal data are very important in order to develop accurate behavior models. The TSG continuously measures the sea subsurface salinity, temperature, and fluorescence along the ships tracks. The classical approach to distribution maps is performing objective analysis of the collected data and assumes errors associated to coastal features. Data-Interpolating Variational Analysis (DIVA) allows the spatial interpolation of data over an adaptable mesh grid, taking into account coastlines and inlets, but also advection constraints. Calculations are optimized and rely on a finite element resolution and the software allows optimizing the analysis parameters, checking for duplicates and performing quality controls. The results of performing and compare DIVA and objective analysis show slight differences that can be appreciated between the inner part of the inlets and the open sea areas. The relative length of the whole data set allows considering also monthly, seasonal and annual variability. These climatological results, that will be updated systematically, can be useful not only for scientific research but also for coastal management activities. All this products, together with quality check flags and metadata information, give added value to the original TSG measures and that will allow a future reuse of data

Development of sustainable tools (Database and software) for Marine Litter Data management

Entregable del proyecto CleanAtlanticEste entregable describe diversas herramientas de utilidad para la gestión de datos de basura marina

Hydrographic variability (1994-2020) in the Ría de Vigo and adjacent shelf (NW Iberia)

The Spanish Institute of Oceanography (IEO-CSIC) carries out monthly oceanographic samplings at across-shelf sections off the northern Spanish coast under the monitoring program RADIALES (https://www.seriestemporales-ieo.net/). This is a multidisciplinary marine research effort addressing long-term variability issues at the ecosystem level (Bode et al., 2015; Valdés et al., 2002). Currently, the monitoring program includes 5 perpendicular coastal transects in Northern Spain: Santander, Gijón, Cudillero, A Coruña and Vigo. Focusing on the section located in the Ría de Vigo and adjacent shelf, we have analysed a 27-year time series (1994 - 2020) of temperature and salinity obtained through CTD profiles in three stations, two inside the Ría (~30 and ~40 m depth) and one in the mid-shelf (~90 m depth). This study summarizes the hydrographic variability in the region through the construction of a local climatology. In addition, long-term trends and interannual changes in seasonality are examined. The results show a change in the salinity regime in medium depth waters in 2013, although not in temperature. Near the surface, the temperature undergoes a negative shift from 2016, in correspondence with the entry of the AMO into a new negative phase

Seasonal variability of oceanographic conditions off NW Galician waters influencing the early life trophic ecology of European hake Merluccius merluccius by stable isotope analysis

Stable isotopes of nitrogen (δ15N) and carbón (δ13C) have been used as tracers for analyzing the trophic ecology of European hake larvae collected during the winter and summer of 2012 off NW Galicia. The sampling times correspond to periods of high and low hake spawning activity, respectively. Trophic enrichment was analyzed using as baseline two different plankton size fractions, corresponding to micro- (55-200μm) and mesozooplankton (>200μm). During both seasons, the δ15N signatures of hake larvae showed higher values than the zooplankton fractions. The first survey carried out in late February was characterized by a preceding marked upwelling, low geostrophic velocities in the hydrographic circulation and an intense mixing of the water column. This environmental scenario is hypothesizing that originated a great nutrient availability for primary consumers showed its effect in the low δ15N values observed in plankton and hake larvae. During July, the environmental setting corresponded to period where the water column was stratified, an anticyclonic gyre was formed in the center of the study area that concentrated particles and weak upwelling conditions and strong geostrophic currents where found. This scenario was characterized hypothetically by low nutrient availability in which production is mainly based on regenerated nutrients which would explain the higher δ15N values found during this period. On the other hand, the greater δ13C values observed in summer in comparison to winter suggest differences in the energetic sources of carbon (Fig. 1). The discussion of results is centered in how oceanographic variability conditions signatures of stable isotope fractionation in the early life trophic food web influencing the variable trophic pathways of larval hake subject to contrasting environmental conditions, thereby affecting their larval nutritional condition as estimated by RNA/DNA ratios and the Fulton index. This study was financed by the projects: CRAMER-CTM2010-21856-CO3 y ECOPREGA-10MMA602021P

Shifts in the seasonal trophic ecology of larvae and juveniles of European hake (Merluccius merluccius): From the Galician upwelling system (NW Spain).

The trophic ecology of European hake (Merluccius merluccius) larvae and early-juveniles from the Iberian shelf off Galicia (NW Spain) are assessed by means of stable isotopes (SIA) and nutritional condition in conjunction with hydrobiological variations observed during the winter and summer season of 2012. Hake early-juveniles (18–47 mm SL) showed higher δ15N than larvae (3–11 mm SL) together with the microzooplankton (55–200 μm) and mesozooplankton (>200 μm) during both seasons. Low δ15N values and high variability in both zooplankton and hake larvae were found during winter coinciding with an unusually strong upwelling event. Inversely, high δ15N content in zooplankton in summer suggests strong nitrogen reutilization. However, hake larvae sampled in summer had a higher RNA:DNA ratio in line with higher Fulton condition factors than those sampled in winter. Higher δ13C values for microzooplankton and mesozooplankton and hake larvae in summer compared to late winter point to prey availability differences. The relationship between nitrogen and carbon stable isotopes versus size or weight suggests an ontogenetic shift in the diet of hake larvae. Early-juveniles had a lower isotopic niche width compared to larvae in both late winter and summer, indicating a trophic specialization related to changes following settlement process from planktonic life to demersal habitat. Higher trophic specialization was observed in summer, which recorded a narrower isotopic niche and higher trophic position estimations.En prensa2,04