Although zooplankton was extensively studied in the North Sea, knowledge about winter zooplankton assemblages is still scarce, despite potential influence of zooplankton overwintering stocks on seasonal plankton succession and productivity. Furthermore, several economically and ecologically important fish species reproduce during winter contributing to the zooplankton community as passive members (eggs) or predators (larvae). To shed some light on winter zooplankton distribution, abundance and composition in the Southern North Sea and Eastern English Channel, we defined assemblages based on mesozoo- and ichthyoplankton data sampled between January and February 2008 using fuzzy-clustering and indicator species. Mesozoo- and ichthyoplankton (eggs+larvae) were integrated in a common analysis by using a spatial grid adapted to the datasets and defined by means of a geostatistical method developed in agronomics. Potential environmental drivers of assemblage distribution were evaluated by means of GLMM and comparison with data from 2022 facilitated insight about the inter-annual representativeness of the assemblages. Five zooplankton assemblages were found varying with regard to total zooplankton abundance, dominant and indicator taxa. Spatial variability of abiotic (dissolved nutrients, salinity, depth, temperature, organic matter in suspension, chlorophyll a), biotic variables (phyto- and microplankton composition), water masses and fish spawning grounds were revealed as potential drivers of assemblage distribution. Assemblages off the Rhine-Scheldt estuary and in the German Bight harbored the biggest zooplankton overwintering stocks that might influence the grazing pressure on phytoplankton spring production. Assemblages off the Rhine-Scheldt estuary and covering the English Channel and the Southern Bight were found to be of high importance for herring and plaice larvae. Although further analyses suggested inter-annual representativeness of the assemblages found (2008 vs 2022), the assessment of further years would be necessary to account for potential inter-annual variability. Future studies could profit from the assessment of microzooplankton facilitating insight in fish larvae feeding potential and zooplankton overwintering strategies. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The ARCHYD dataset, which have been collected since 1988, represents the longest long-term hydrologic data sets in Arcachon Bay. The objectives of this monitoring programme are to assess the influence of oceanic and continental inputs on the water quality of the bay and their implications on biological processes. It also aims to estimate the effectiveness of management policies in the bay by providing information on trends and/or shifts in pressure, state, and impact variables. Sampling is carried on stations spread across the entire bay, but since 1988, the number and location of stations have changed slightly to better take into account the gradient of ocean and continental inputs. In 2005, the ARCHYD network was reduced to 8 stations that are still sampled by Ifremer to date. All the stations are sampled at a weekly frequency, at midday, alternately around the low spring tide and the high neap tide. Data are complementary to REPHY dataset. Physico-chemical measures include temperature, salinity, turbidity, suspended matters (organic, mineral), dissolved oxygen and dissolved inorganic nutrients (ammonium, nitrite+nitrate, phosphate, silicate). Biological measures include pigment proxies of phytoplankton biomass and state (chlorophyll a and phaeopigment). Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The Green Edge project was designed to investigate the onset, life and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in arctic ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean food chain, it is crucial to understand how changes in the arctic environment will affect it. Green Edge was a large multidisciplinary collaborative project bringing researchers and technicians from 28 different institutions in seven countries, together aiming at understanding these changes and their impacts on the future. The fieldwork for the Green Edge project took place over two years (2015 and 2016) and was carried out from both an ice camp and a research vessel in the Baffin Bay, Canadian arctic. Here, we describe the data set obtained during the research cruise, which took place aboard the Canadian Coast Guard Ship (CCGS) Amundsen in spring 2016. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

Several sea trials with the newly developed CO2 Seaglider in the Gulf of Alaska and data evaluation with discrete water and underway samples suggest near ‘weather quality’ CO2 data as defined by the Global Ocean Acidification Network. This data set describes one such data set from the CO2 Seaglider, in February of 2023. Please see publication by the same authors at https://doi.org/10.5194/egusphere-2024-1055. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

Several sea trials with the newly developed CO2 Seaglider in the Gulf of Alaska and data evaluation with discrete water and underway samples suggest near ‘weather quality’ CO2 data as defined by the Global Ocean Acidification Network. This data set describes one such data set from the CO2 Seaglider, in May of 2022. Please see publication by the same authors at https://doi.org/10.5194/egusphere-2024-1055. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

This dataset consists of a glider deployment in greater Te Moana-o-Raukawa (Cook Strait) as part of the DeepSouth National Science Challenge in Aotearoa New Zealand. This submission continues from previous deployments uploaded to SEANOE (doi:10.17882/76530). Survey uses a Teledyne Webb Research Slocum G2 glider equipped with a pumped SeaBird CTD to measure conductivity, temperature, and pressure, along with instruments to measure dissolved oxygen, chlorophyll-a fluorescence, backscatter at 470, 532, 660, and 700nm, chromophoric dissolved organic matter (CDOM), and photosynthetically active radiation (PAR). Part-way through the deployment, in order to save battery, the science package was turned on only during downcasts and these subsequently appear as empty casts in the dataset. Science data were processed using the GEOMAR Glider Toolbox (https://git.geomar.de/open-source/geomar_glider_toolbox). Comparison with the previously-utilized SOCIB (Troupin et al. (2015), doi: 10.1016/j.mio.2016.01.001) toolbox shows negligible differences in outputs. Data have been averaged into vertical bins of 1dBar (~1m). Despite processing to minimize lag-error in salinity (following Garau et al., 2011, doi: 10.1175/JTECH-D-10-0503.1), some casts (n=10, out of 4246 total) were made empty after visual inspection in T-S space. Oxygen data were lag-corrected, whereas other variables are presented as-is without further processing. Depth-integrated water velocity derived from GPS and dead-reckoning are included. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

For the 21 years of the study, an examination of trends in chlorophyll concentration revealed a general decline throughout the Gulf over the production period. These trends, extracted from dynamic linear model, also allowed this decline to be quantified. Expressed as a percentage, a large part of the area below the 50 m bathymetric line showed a decrease of at least 10% over the period, corresponding to a value of at least 0.1 µg.l-1. However, the spatial distribution reveals some more local phenomena. In southern Brittany, from Quimper to Vannes, a particular feature appears, with an upward trend over several kilometres along the coast, followed by a pronounced gradient along the coast. This gradient includes a zone where a continuous monotonic increasing trend is observed, then a zone where the trend becomes not significant and finally, about 15 km from the coast, a new zone where a significant continuous monotonic decreasing trend is observed. The increase in chlorophyll a concentration in the very coastal part is greater than 0.1 µg.l-1 over the period. Another peculiarity concerns the central part, located at the edge of the plateau at Cap Ferrat and Pente Aquitaine, where an increase in chlorophyll a was observed, but the variations remained small, being less than 0.1 µg.l-1. About a hundred kilometres south-west of Saint Nazaire, an area of about 40 by 50 km shows a decrease in chlorophyll a of more than 20%, quantified as more than 0.1 µg.l-1 over the period. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The measurements of SPM, particulate TN, TC, Fe, Mn, Al and chlorophyll a, as well as light absorption at 750 nm and 380 nm were done within Estonia-Latvia transboundary project "Towards joint management of the transboundary Gauja/Koiva river basin district" for harmonization of water quality classification system for transboundary water bodies in the Gauja/Koiva river basin district and adjacent areas (in Estonia) in the Gulf of Riga." Measurements were done once in August 2012 along with underwater video observation, water transparency and CTD measurements in coastal waters in shallow part (2 - 12m) of the East coast of the Gulf of Riga. Data were used for Final report on assessment of the quality status of the transboundary water bodies (coastal, lakes, rivers) in Gauja/Koiva river basin district (2013. Kalvane I. and Veidemane K. (eds.))

CTD casts collected in East Arm and Bonne Bay during August 3-4 to measure the density stratification with depth. Cast depths range from 50 to 200 m.    Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

As part of the second mission of the (GOCART)-[https://projects.noc.ac.uk/gocart/] (Gauging Ocean organic Carbon fluxes using Autonomous Robotic Technologies) project, funded by the European Research Council, a Slocum glider (unit-405, Doombar) spent about 4 months surveying the top 1000m of a low oxygen region of the Northern Benguela Upwelling region, off the coast of Namibia. The goal of the mission was to characterize the temporal variability in organic carbon flux and remineralisation depth during the spring bloom in a highly productive but low oxygen region in the Benguela Current, off the Namibian coast. The glider was a Teledyne Webb Research (Slocum)-[https://www.teledynemarine.com/brands/webb-research/slocum-glider] G2, equipped with: Seabird Glider Payload CTD (pumped), measuring temperature, conductivity and pressure Sea-Bird WETLabs ECO Puck Triplet BB2FL-SLC scattering fluorescence sensor, measuring chlorophyll fluorescence and optical backscattering at 700 and 532nm Aanderaa 4831 oxygen optode, measuring dissolved oxygen concentration. The glider was deployed at 11.225°E, 19.331°S on 14th February 2018 from the RV Mirabilis, the vessel of the Namibian Ministry of Fisheries, during the second leg of the 2018 Hake Survey off the northern Namibian shelf and recovered on June 19th, 2018 during the (DY090 cruise)-[https://www.bodc.ac.uk/resources/inventories/cruise_inventory/report/16386/] on board RSS Discovery, during the COMICS cruise (Controls over Oceanic Mesopelagic Interior Carbon Storage), funded by the Natural Environmental Research Council. The latter cruise was in the vicinity of the glider from 1st-19th June, 2018. To validate/calibrate the glider sensors, we conducted several targeted casts (where gliders and ships started profiles simultaneously) and non-targeted casts (unplanned matchups where gliders and ships CTD-profiles were within an acceptable range of each other). Bottle samples were collected on all ship CTD profiles. For calibration purposes, we evaluated and determined that casts within 5 km and 12 hours of each other were considered glider ship matchups. These matchups exhibited strong correlation (linear regression r^2 = 0.95).Variables calibrated were salinity, chlorophyll concentration and oxygen concentration. Doombar’s mission was slightly modified 3 times during the 4-month deployment: 1 – Sampling around a 12 km triangle at BN0 (centred at 10.80°E, 18.25°S) from 19/02/2018-27/03/2018: Once the glider reached the site (BN0), it was tasked to survey a triangle with 12 km side, centred at that location. The location of the triangle was chosen based on low currents to help constrain advective processes and the predominantly westward surface currents in the region . The 12km sided triangle was chosen based on the time it took the glider to do a complete circuit, aiming for the glider to take around 1.5 days around the triangle. 2 – Sampling around a 12 km triangle at BN (centred at 10.95°E, 18.05°S) from 27/03/2018-08/06/2018: Given that the mission was to survey a low oxygen region, and oxygen concentrations monitored by the glider weren’t consistently low, on March 26th the glider was re-tasked to establish a new triangle (BN) centred at 10.95°E, 18.05°S, Northeast of the initial sampling site, where lower oxygen concentrations were expected. 3 – Station-keeping (“virtual-mooring”) 1.5km North of BN from 08/06/2018-19/06/2018: Throughout its deployment, Doombar gradually reduced its forward speed from about 4km per 1000m dive to about 1.5km. This meant that the glider could no longer cover the triangle in less than 2 days. So, while the ship was in the vicinity, Doombar was assigned a station keeping mission 1.5 km from the cruise main station, to not only avoid the risk of hitting the glider, but also so that any ship data could contribute to validating glider sensor data. Further information on sensor validation can be found in the netcdf file as well as documented in (Lovecchio et al, 2022)-[https://doi.org/10.1029/2022JC019063]. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.