ROCCH, the French Chemical Contaminant Monitoring Network, regularly provides data for assessing the chemical quality of French coastal waters. Concentrations of trace metals and organic compounds are measured in integrative matrices (bivalves and sediments). Surface sediment samples are collected from 200 to 250 monitoring stations in the English Channel, the Bay of Biscay and Mediterranean lagoons every six years. Results concerning approximately 140 historical and emerging chemical substances (metals, PAHs, PCBs, PBDEs, PFAS …) are submitted to international databases of the Regional Sea Convention (OSPAR for the North East Atlantic and the Barcelona Convention for the Mediterranean) and disseminated to public stakeholders. During the ROCCHSED campaign in spring 2022, three sediment cores, each forty to fifty centimetres long, were collected from three different sites in the Bay of Biscay. Horizons of one to two centimetres in length were dated, sieved and freeze-dried for chemical analysis. The concentrations of metals, PAHs and PCBs were determined in horizons aged from over 150 years to the present in order to define the reference concentration of natural levels and describe the temporal profile of contamination.

'''DEFINITION''' Significant wave height (SWH), expressed in metres, is the average height of the highest third of waves. This OMI provides global maps of the seasonal mean and trend of significant wave height (SWH), as well as time series in three oceanic regions of the same variables and their trends from 2002 to 2020, calculated from the reprocessed global L4 SWH product (WAVE_GLO_PHY_SWH_L4_MY_014_007). The extreme SWH is defined as the 95th percentile of the daily maximum SWH for the selected period and region. The 95th percentile is the value below which 95% of the data points fall, indicating higher than normal wave heights. The mean and 95th percentile of SWH (in m) are calculated for two seasons of the year to take into account the seasonal variability of waves (January, February and March, and July, August and September). Trends have been obtained using linear regression and are expressed in cm/yr. For the time series, the uncertainty around the trend was obtained from the linear regression, while the uncertainty around the mean and 95th percentile was bootstrapped. For the maps, if the p-value obtained from the linear regression is less than 0.05, the trend is considered significant. '''CONTEXT''' Grasping the nature of global ocean surface waves, their variability, and their long-term interannual shifts is essential for climate research and diverse oceanic and coastal applications. The sixth IPCC Assessment Report underscores the significant role waves play in extreme sea level events (Mentaschi et al., 2017), flooding (Storlazzi et al., 2018), and coastal erosion (Barnard et al., 2017). Additionally, waves impact ocean circulation and mediate interactions between air and sea (Donelan et al., 1997) as well as sea-ice interactions (Thomas et al., 2019). Studying these long-term and interannual changes demands precise time series data spanning several decades. Until now, such records have been available only from global model reanalyses or localised in situ observations. While buoy data are valuable, they offer limited local insights and are especially scarce in the southern hemisphere. In contrast, altimeters deliver global, high-quality measurements of significant wave heights (SWH) (Gommenginger et al., 2002). The growing satellite record of SWH now facilitates more extensive global and long-term analyses. By using SWH data from a multi-mission altimetric product from 2002 to 2020, we can calculate global mean SWH and extreme SWH and evaluate their trends, regionally and globally. '''KEY FINDINGS''' From 2002 to 2020, positive trends in both Significant Wave Height (SWH) and extreme SWH are mostly found in the southern hemisphere (a, b). The 95th percentile of wave heights (q95), increases faster than the average values, indicating that extreme waves are growing more rapidly than average wave height (a, b). Extreme SWH’s global maps highlight heavily storms affected regions, including the western North Pacific, the North Atlantic and the eastern tropical Pacific (a). In the North Atlantic, SWH has increased in summertime (July August September) but decreased in winter. Specifically, the 95th percentile SWH trend is decreasing by 2.1 ± 3.3 cm/year, while the mean SWH shows a decrease of 2.2 ± 1.76 cm/year. In the south of Australia, during boreal winter, the 95th percentile SWH is increasing at 2.6 ± 1.5 cm/year (c), with the mean SWH increasing by 0.5 ± 0.66 cm/year (d). Finally, in the Antarctic Circumpolar Current, also in boreal winter, the 95th percentile SWH trend is 3.2 ± 2.14 cm/year (c) and the mean SWH trend is 1.7 ± 0.84 cm/year (d). These patterns highlight the complex and region-specific nature of wave height trends. Further discussion is available in A. Laloue et al. (2024). '''DOI (product):''' https://doi.org/10.48670/mds-00352

Colloque organise par le Conseil scientifique et culturel du PNR des Landes de Gascogne

This product displays the stations where mercury has been measured and the values present in EMODnet Chemistry infrastructure are always above the limit of detection or quantification (LOD/LOQ), i.e quality value equal to 1. It is necessary to take into account that LOD/LOQ can change with time. These products aggregate data by station, producing only one final value for each station (above, below or above/below). EMODnet Chemistry has included the gathering of contaminants data since the beginning of the project in 2009. For the maps for EMODnet Chemistry Phase III, it was requested to plot data per matrix (water,sediment, biota), per biological entity and per chemical substance. The series of relevant map products have been developed according to the criteria D8C1 of the MSFD Directive, specifically focusing on the requirements under the new Commission Decision 2017/848 (17th May 2017). The Commission Decision points to relevant threshold values that are specified in the WFD, as well as relating how these contaminants should be expressed (units and matrix etc.) through the related Directives i.e. Priority substances for Water. EU EQS Directive does not fix any threshold values in sediments. On the contrary Regional Sea Conventions provide some of them, and these values have been taken into account for the development of the visualization products. To produce the maps the following process has been followed: 1. Data collection through SeaDataNet standards (CDI+ODV) 2. Harvesting, harmonization, validation and P01 code decomposition of data 3. SQL query on data sets from point 2 4. Production of map with each point representing at least one record that match the criteria The harmonization of all the data has been the most challenging task considering the heterogeneity of the data sources, sampling protocols. Preliminary processing were necessary to harmonize all the data : • For water: contaminants in the dissolved phase; • For sediment: data on total sediment (regardless of size class) or size class < 2000 μm • For biota: contaminant data will focus on molluscs, on fish (only in the muscle), and on crustaceans • Exclusion of data values equal to 0

Pentadal time-series of the area in the North Atlantic (IHO, 1953) where ice occurred. On a 1 degree grid find all cells that experienced ice in at least 1 month of each 5 year period between 1915 and 2014, and then calculate the total area that these cells covered.

to deliver maps showing the extent of the trawling fishing grounds for identifying the areas which are most disturbed by bottom trawling over the past ten years and identifying the gaps of fishing vessels’ tracking systems in the Mediterranean Sea

On a yearly basis, mussel farming produces around 13 000 metric tons of mussel in the Pertuis Charentais sounds (Pertuis Breton et Pertuis d’Antioche). This represents 23% of the Blue mussel (Mytilus edulis) production along the French Atlantic coastline. Production is characterized in this area by to types of growout systems: the ‘bouchot’ type culture using wooden poles(p) and off-shore longlines(l). Environmental conditions are mainly estuarine. Taking into account those cultural practices, the REMOULA monitoring network has been deployed since 2000 to provide baseline information to better understand the Blue mussel (Aiguillon(p) and Filières Pertuis Breton(l)) or trimester (Roulières(p), Marsilly(p), Yves(p), Boyard-bouchot(p) – completed by the stations Saumonards Filières(l) and Filières Chatellaillon 2(l)  (2008 to 2012).  Between 2000 and 2005 the mussel batches monitoring lasted 12 months whereas it lasted 15 months from 2006 to 2012. The initial batch of mussel is originating from the spat settlement the previous year and calibrated. On the 8 monitoring stations, calibrated mussel batches were deployed into bags (120 mussels/bag). Biometric data are measured during each monthly survey (30 individuals) and a mortality rate estimated. Additional information is obtained through biochemical analysis (proteins, lipids, carbohydrates) on 3 mussel pools of 10 individuals in 2000, 2001, 2002, 2003 and 2004. Moreover gametogenic data are collected on 15 mussels (2003 and 2004). The data storage is organized using the Quadrige2 system and characterized by individual field campaign. Coastal monitoring data  Available parameters : Individual measurement :  length, shell weight, dry meat weight. Width and height at the beginning and the campaign end. Average measurement : individual weight (3x10 individuals), Calculated data: Lawrence & Scott indicator, Walne and Mann indicator, meat indicator, mortality rate % Observations : Pinnotheres and Polydora infestations, parasites. Gametic status : identification of 8 maturation stages (0, 1, 2, 3A1, 3A2, 3B, 3C, 3D) according to Lubet (1959) and Suarez (2005) Biochemical data : analytical protocols - Proteins : Lowry et al (1951) modified Razet et al (1976). Lipids : Marsh and Weinstein (1966). Carbohydrates and Glycogen Dubois et al (1956). The shellfish biochemical proximate composition reviewed by Faury, Geairon, Moal, Pouvreau, Razet, Ropert and Soletchnik (2003).

'''Short description:''' The Mean Dynamic Topography MDT-CMEMS_2024_EUR is an estimate of the mean over the 1993-2012 period of the sea surface height above geoid for the European Seas. This is consistent with the reference time period also used in the SSALTO DUACS products '''DOI (product) :''' https://doi.org/10.48670/mds-00337

Moving 6-year analysis of Water body dissolved inorganic nitrogen in the NorthEast Atlantic for each season: - winter: January-March, - spring: April-June, - summer: July-September, - autumn: October-December. Every year of the time dimension corresponds to the 6-year centred average of each season. 6-year periods span from 1971/1976 until 2016/2021. Observation data span from 1971 to 2021. Depth levels (IODE standard depths): [0.0, 5.0, 10.0, 20.0, 30.0, 40.0, 50.0, 75.0, 100.0, 125.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 700.0, 800.0, 900.0, 1000.0, 1100.0, 1200.0, 1300.0, 1400.0, 1500.0, 1750.0, 2000.0]. Data sources: observational data from SeaDataNet/EMODNet Chemistry Data Network. Descrption of DIVAnd analysis: the computation was done with DIVAnd (Data-Interpolating Variational Analysis in n dimensions), version 2.7.4, using GEBCO 30 sec topography for the spatial connectivity of water masses. The horizontal resolution of the produced DIVAnd maps is 0.1 degrees. Horizontal correlation length varies from 400km in open sea regions to 50km at the coast. Vertical correlation length is defined as twice the vertical resolution. Signal-to-noise ratio was fixed to 1 for vertical profiles and 0.1 for time series to account for the redundancy in the time series observations. A logarithmic transformation (DIVAnd.Anam.loglin) was applied to the data prior to the analysis to avoid unrealistic negative values. Background field: a vertically-filtered profile of the seasonal data mean value (including all years) is substracted from the data. Detrending of data: no, advection constraint applied: no. Units: umol/l.