Session E1: The 2 and 3D Hydrodynamic Functioning of a Fish Migration River Through the “Afsluitdijk”

Abstract: The “Afsluitdijk” is an icon in the Netherlands. It is the 32 km long closure barrier, which separates the nature of the tidal Wadden Sea from the fresh IJssel lake. It was built for safety and economic developments between 1927 and 1932. Fish like salmon, eel and smelt, have great trouble in passing the remaining discharge gates near Den Oever and Kornwerderzand. The “FishMigrationRiver (FMR) Afsluitdijk” is a unique project near Kornwerderzand, allowing a variety of fish to reach their spawn, bread and living grounds. The FMR creates an intertidal zone, where fresh and saline water meet and fish might migrate, without jeopardizing the safety or increasing the salinity on the IJssel lake. Call it a barrier for water and salt, but open for fish almost continuously. An important step for the evaluation of the functioning of the FMR is the hydraulic operability. A series of hydrodynamic investigations was carried out to evaluate the various aspects of the FMR. They concern, the water exchange, the salinity, the velocities, the morphology and of course the behaviour of the fish.This presentation focus is on the hydraulic functioning of the FMR. Other presentations in this session focus on the ecological part of the FMR

A chronic bioassay with the estuarine amphipod Corophium volutator : Test method description and confounding factors

Methods of conducting a chronic sediment toxicity test with the estuarine amphipod Corophium volutator are described. They consist of a 49-day exposure, after which mortality, growth and reproduction are determined. Pilot experiments were used to optimize test design parameters such as temperature, duration, feeding and refreshing regimes, and effects of indigenous organisms. By way of further validation, the present study focused on the effects of four different parameters: oxygen saturation, salinity, ammonium and nitrite. These confounding factors might play an important role especially if the test is used for risk assessment of field-contaminated sediments. It is concluded that the present experimental design is well suited for chronic sediment exposures with C. volutator. The test can be performed at a broad range of salinity values, provided that controls are performed at the same salinity. Results further demonstrate that with the endpoints growth and reproduction this chronic test procedure is a factor 7-18 more sensitive to ammonium and nitrate than the standardized acute bioassay (endpoint mortality)

Other participants:

Abstract. We study a number of aspects of the colonisation of the Eastern Scheldt by the Japanese Oyster. We formulate and analyse some simple models of the spatial spreading, and determine a rough dependence of the spreading behaviour on parameters. We examine the suggestion of reducing salinity by opening freshwater dams, with the aim of reducing oyster fertility, and make predictions of the effect of such measures. Finally, we present an outline of a large-scale simulation taking into account detailed data on the geometry and sea floor properties of the Eastern Scheldt

The European Marine Observation and Data Network (EMODnet): Visions and Roles of the Gateway to Marine Data in Europe

Marine data are needed for many purposes: for acquiring a better scientific understanding of the marine environment, but also, increasingly, as marine knowledge for decision making as well as developing products and services supporting economic growth. Data must be of sufficient quality to meet the specific users' needs. It must also be accessible in a timely manner. And yet, despite being critical, this timely access to known-quality data proves challenging. Europe's marine data have traditionally been collected by a myriad of entities with the result that much of our data are scattered throughout unconnected databases and repositories. Even when data are available, they are often not compatible, making the sharing of the information and data aggregation particularly challenging. In this paper, we present how the European Marine Observation and Data network (EMODnet) has developed over the last decade to tackle these issues. Today, EMODnet is comprised of more than 150 organizations which gather marine data, metadata, and data products and make them more easily accessible for a wider range of users. EMODnet currently consists of seven sub-portals: bathymetry, geology, physics, chemistry, biology, seabed habitats, and human activities. In addition, Sea-basin Checkpoints have been established to assess the observation capacity in the North Sea, Mediterranean, Atlantic, Baltic, Artic, and Black Sea. The Checkpoints identify whether the observation infrastructure in Europe meets the needs of users by undertaking a number of challenges. To complement this, a Data Ingestion Service has been set up to tackle the problem of the wealth of marine data that remain unavailable, by reaching out to data holders, explaining the benefits of sharing their data and offering a support service to assist them in releasing their data and making them available through EMODnet. The EMODnet Central Portal (www.emodnet.eu) provides a single point of access to these services, which are free to access and use. The strategic vision of EMODnet in the next decade is also presented, together with key focal areas toward a more user-oriented service, including EMODnet for business, internationalization for global users, and stakeholder engagement to connect the diverse communities across the marine knowledge value chain

Polar Ocean Observations: A Critical Gap in the Observing System and Its Effect on Environmental Predictions From Hours to a Season

International audienceThere is a growing need for operational oceanographic predictions in both the Arctic and Antarctic polar regions. In the former, this is driven by a declining ice cover accompanied by an increase in maritime traffic and exploitation of marine resources. Oceanographic predictions in the Antarctic are also important, both to support Antarctic operations and also to help elucidate processes governing sea ice and ice shelf stability. However, a significant gap exists in the ocean observing system in polar regions, compared to most areas of the global ocean, hindering the reliability of ocean and sea ice forecasts. This gap can also be seen from the spread in ocean and sea ice reanalyses for polar regions which provide an estimate of their uncertainty. The reduced reliability of polar predictions may affect the quality of various applications including search and rescue, coupling with numerical weather and seasonal predictions, historical reconstructions (reanalysis), aquaculture and environmental management including environmental emergency response. Here, we outline the status of existing near-real time ocean observational efforts in polar regions, discuss gaps, and explore perspectives for the future. Specific recommendations include a renewed call for open access to data, especially real-time data, as a critical capability for improved sea ice and weather forecasting and other environmental prediction needs. Dedicated efforts are also needed to make use of additional observations made as part of the Year of Polar Prediction (YOPP; 2017–2019) to inform optimal observing system design. To provide a polar extension to the Argo network, it is recommended that a network of ice-borne sea ice and upper-ocean observing buoys be deployed and supported operationally in ice-covered areas together with autonomous profiling floats and gliders (potentially with ice detection capability) in seasonally ice covered seas. Finally, additional efforts to better measure and parameterize surface exchanges in polar regions are much needed to improve coupled environmental prediction