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

Abstract

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.

Seasonal and inter‐annual variability in the heatwave tolerance of the kelpSaccharina latissima(Laminariales, Phaeophyceae)

“…The SST around Helgoland is monitored continuously by the COSYNA (Coastal Observation System for Northern and Arctic Seas) underwater node system (Fischer et al 2020) in the MarGate experimental field in a depth of 10 m, providing real‐time measurements of the SST. As a result of strong tidal currents, no thermal stratification establishes within the first 10 m of water depth and differences in SSTs are not significant (Wiltshire et al 2010).…”

Solar radiation and solar radiation driven cycles in warming and freshwater discharge control seasonal and inter‐annual phytoplankton chlorophyll a and taxonomic composition in a high Arctic fjord (Kongsfjorden, Spitsbergen)

“…The ferry box system of the AWIPEV underwater observatory on the southern shore of Kongsfjorden obtains water from 12 m depth in front of the "Old Pier" of Ny Ålesund (N 78 54.2, E 11 54.0) (Fischer et al 2016(Fischer et al , 2020. This site was free of sea ice cover during the investigated years, which was low and confined to the sheltered northern inner fjord (Pavlova et al 2019).…”

Arctic kelp forest decline -- a consequence of melting glaciers?

“…PAR (photosynthetically active radiation) and turbidity data were measured year-round with a sampling frequency of 1hz (1sec -1 ) in the framework of the AWIPEV-COSYNA underwater observatory in Ny Alesund (UMT 8763953degN, 433992degE, for map see Figure 2). For a detailed description of the AWIPEV-COSYNA underwater observatory see Fischer et al (2017) and Fischer et al (2020). Briefly, the system comprises a land-based FerryBox system equipped with various hydrographic sensors receiving water from a remote-controlled underwater pump station at 11m water depth.…”