Operating Cabled Underwater Observatories in Rough Shelf-Sea Environments:A Technological Challenge

Cabled coastal observatories are often seen as future-oriented marine technology that enables science to conduct observational and experimental studies under water year-round, independent of physical accessibility to the target area. Additionally, the availability of (unrestricted) electricity and an Internet connection under water allows the operation of complex experimental setups and sensor systems for longer periods of time, thus creating a kind of laboratory beneath the water. After successful operation for several decades in the terrestrial and atmospheric research field, remote controlled observatory technology finally also enables marine scientists to take advantage of the rapidly developing communication technology. The continuous operation of two cabled observatories in the southern North Sea and off the Svalbard coast since 2012 shows that even highly complex sensor systems, such as stereo-optical cameras, video plankton recorders or systems for measuring the marine carbonate system, can be successfully operated remotely year-round facilitating continuous scientific access to areas that are difficult to reach, such as the polar seas or the North Sea. Experience also shows, however, that the challenges of operating a cabled coastal observatory go far beyond the provision of electricity and network connection under water. In this manuscript, the essential developmental stages of the "COSYNA Shallow Water Underwater Node" system are presented, and the difficulties and solutions that have arisen in the course of operation since 2012 are addressed with regard to technical, organizational and scientific aspects.</p

The Coastal Observing System for Northern and Arctic Seas (COSYNA)

The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as an example of an Arctic coast that is under strong pressure due to global change. The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publicly available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public

Coastal Ocean Forecasting: system integration and evaluation

Kourafalou, V.H. et al.ecent advances in Coastal Ocean Forecasting Systems (COFS) are discussed. Emphasis is given to the integration of the observational and modeling components, each developed in the context of monitoring and forecasting in the coastal seas. These integrated systems must be linked to larger scale systems toward seamless data sets, nowcasts and forecasts (from the global ocean, through the continental shelf and to the nearshore regions). Emerging capabilities include: methods to optimize coastal/regional observational networks; and probabilistic approaches to address both science and applications related to COFS. International collaboration is essential to exchange best practices, achieve common frameworks and establish standards.V. Kourafalou acknowledges support from NOAA (NA13OAR4830224 and NA11NOS4780045). M. Herzfeld is thankful to the eReefs marine modeling team and partners (CSIRO: Commonwealth Industrial and Scientific Research Organization; SIEF: Science and Industry Endowment Fund; AIMS: Australian Institute of Marine Science). The system CGOFS_ECS (material contributed by X. Zhu) is supported by the National Natural Science Foundation of China (contract #41222038). E. V. Stanev acknowledges the input from COSYNA, which is supported by the Helmholtz Association of German Research CentersPeer Reviewe

Maximum sinking velocities of suspended particulate matter in a coastal transition zone

Marine coastal ecosystem functioning is crucially linked to the transport and fate of suspended particulate matter (SPM). Transport of SPM is controlled by, amongst other factors, sinking velocity ws. Since the ws of cohesive SPM aggregates varies significantly with size and composition of the mineral and organic origin, ws exhibits large spatial variability along gradients of turbulence, SPM concentration (SPMC) and SPM composition. In this study, we retrieved ws for the German Bight, North Sea, by combining measured vertical turbidity profiles with simulation results for turbulent eddy diffusivity. We analyzed ws with respect to modeled prevailing dissipation rates ϵ and found that mean ws were significantly enhanced around log10(ϵ (m2 s−3)) ≈ −5.5. This ϵ region is typically found at water depths of approximately 15 to 20 m along cross-shore transects. Across this zone, SPMC declines towards the offshore waters and a change in particle composition occurs. This characterizes a transition zone with potentially enhanced vertical fluxes. Our findings contribute to the conceptual understanding of nutrient cycling in the coastal region which is as follows. Previous studies identified an estuarine circulation. Its residual landward-oriented bottom currents are loaded with SPM, particularly within the transition zone. This retains and traps fine sediments and particulate-bound nutrients in coastal waters where organic components of SPM become remineralized. Residual surface currents transport dissolved nutrients offshore, where they are again consumed by phytoplankton. Algae excrete extracellular polymeric substances which are known to mediate mineral aggregation and thus sedimentation. This probably takes place particularly in the transition zone and completes the coastal nutrient cycle. The efficiency of the transition zone for retention is thus suggested as an important mechanism that underlies the often observed nutrient gradients towards the coast.BMBF/PACEBMBF/FKZ 030634ABMBF/FKZ 03F0667AHelmholtz Society/PACESNiedersächsisches Ministerium für Wissenschaft und Kultur (MWK)Niedersächsisches Ministerium für Umwelt und Klimaschutz (MUK)Coastal Observing System for Northern and Arctic Seas (COSYNA

Best Practices in Stakeholder Engagement, Data Dissemination and Exploitation

Identification of successful stakeholder engagement mechanisms and tools to make available, disseminate and visualize ocean observations/data serving as guidance to AtlantO