The New Seafloor Observatory (OBSEA) for Remote and Long-Term Coastal Ecosystem Monitoring

Abstract

A suitable sampling technology to identify species and to estimate population dynamics based on individual counts at different temporal levels in relation to habitat variations is increasingly important for fishery management and biodiversity studies. In the past two decades, as interest in exploring the oceans for valuable resources and in protecting these resources from overexploitation have grown, the number of cabled (permanent) submarine multiparametric platforms with video stations has increased. Prior to the development of seafloor observatories, the majority of autonomous stations were battery powered and stored data locally. The recently installed low-cost, multiparametric, expandable, cabled coastal Seafloor Observatory (OBSEA), located 4 km off of Vilanova i la Gertrú, Barcelona, at a depth of 20 m, is directly connected to a ground station by a telecommunication cable; thus, it is not affected by the limitations associated with previous observation technologies. OBSEA is part of the European Multidisciplinary Seafloor Observatory (EMSO) infrastructure, and its activities are included among the Network of Excellence of the European Seas Observatory NETwork (ESONET). OBSEA enables remote, long-term, and continuous surveys of the local ecosystem by acquiring synchronous multiparametric habitat data and bio-data with the following sensors: Conductivity-Temperature-Depth (CTD) sensors for salinity, temperature, and pressure; Acoustic Doppler Current Profilers (ADCP) for current speed and direction, including a turbidity meter and a fluorometer (for the determination of chlorophyll concentration); a hydrophone; a seismometer; and finally, a video camera for automated image analysis in relation to species classification and tracking. Images can be monitored in real time, and all data can be stored for future studies. In this article, the various components of OBSEA are described, including its hardware (the sensors and the network of marine and land nodes), software (data acquisition, transmission, processing, and storage), and multiparametric measurement (habitat and bio-data time series) capabilities. A one-month multiparametric survey of habitat parameters was conducted during 2009 and 2010 to demonstrate these functions. An automated video image analysis protocol was also developed for fish counting in the water column, a method that can be used with cabled coastal observatories working with still images. Finally, bio-data time series were coupled with data from other oceanographic sensors to demonstrate the utility of OBSEA in studies of ecosystem dynamics.

First year of practical experiences of the new Arctic AWIPEV-COSYNA cabled Underwater Observatory in Kongsfjorden, Spitsbergen

“…During these times, however, almost no information is available in most Arctic fjord systems (Kwasniewski, 2003). Understanding polar ecosystems in the context of global warming and expected or already observed ecosystem changes (Müller et al, 2011;Bartsch et al, 2016) is, however, crucial for thoroughly understanding the ecosystem behaviour in polar areas.…”

“…This bi-modal hydrographic situation leads to a complex spatio-temporal pattern in the fjord hydrography with an occasionally more Atlantic and in other instances more Arctic characteristic with respect to the water masses, even in the inner fjord system (Svendsen et al, 2002). Due to an increased advection rate of warmer Atlantic water masses in the fjord systems over the last decade (Cottier et al, 2005), the first signs of an overall warming of the fjord system have been observed, with an overall decrease in seasonal ice coverage (Walczowski et al, 2012), signifi- cant changes in the phytoplankton community (Hegseth and Tverberg, 2013;Willis et al, 2006), changes in the depth distribution of macroalgae in the shallow waters (Bartsch et al, 2016) and in the macrozoobenthos community (Parr at al., 2015), as well as an increase in turbidity due to increased meltwater runoff from the glaciers (Peterson et al, 2002;Bartsch et al, 2016). Although Renaud et al (2011) and Voronkov et al (2013) recently started to study the foodchain length, trophic levels, and the main feeding groups in Kongsfjorden, our knowledge of the temporal and spatial dynamics of the higher trophic levels of the food web is still extremely limited (Stempniewicz et al, 2007).…”

“…The Kongsfjorden shallow water ecosystem is characterized by large kelp beds of different species of macroalgae between 0 and approximately 12-15 m water depth (Bartsch et al, 2016). The site where the observatory has been set up is, therefore, characteristic of the fjord habitat and provides a highly diverse habitat with a steep wall completely covered with large macroalgae followed by a sandy to muddy slope that begins at approximately 11 m water depth at the base station of the observatory.…”

“…To the best of our knowledge, there are only a small number of studies and observatories available worldwide that are trying to also assess higher trophic levels with remote controlled optical systems (Aguzzi et al, 2011;Buckland et al, 2005;Fischer et al, 2007b;Wehkamp and Fischer, 2014), and even fewer with regard to quantitative assessments with respect to a specimen's abundances and species-specific length-frequency analysis in an area. Because these technologies will certainly develop and improve over the next years, this study also discusses certain specific requirements and challenges for such systems, especially for shallow water Arctic areas.…”

Intervention AUVs: The Next Challenge

“…The intervention tasks to be demonstrated include docking to a custom sub-sea panel, fixed-based manipulation for both valve turning and hot stab connection, and free floating manipulation for camera dome de-fouling. The final demonstration will be carried out in the OBSEA (Aguzzi et al (2011)) expandable seafloor observatory cabled to the shoreline in the Catalan coast. The final experiments plan to demonstrate high bandwidth data communication between the I-AUV and the observatory and from it to the world wide web through the observatory web page.…”