NeXOS, developing and evaluating a new generation of in-situ ocean observation systems

Many changes are occurring in the physical, chemistry and biology processes of the ocean. Understanding how these changes are driven is an element of the key environmental descriptors identified by the European Marine Strategy Framework Directive (MSFD) with the ultimate goal being to protect the resource base upon which marine-related economic and social activities depend. The Directive furthers the ecosystem approach to the management of human activities having an impact on the marine environment, integrating the concepts of environmental protection and sustainable use. To meet these goals, in-situ data are necessary for comprehensive modeling and forecasting of ocean dynamics. Yet, collection of in-situ observations is inherently challenging from the perspective of both time and resources. This paper addresses a new generation of acoustic, optical and fishery in-situ sensors that address these challenges. These sensor systems are multifunctional (single sensor systems addressing several phenomena), can be deployed on a large majority of ocean monitoring systems from surface to the seafloor, and operate for long periods with less maintenance. In addition, at the system and user interface level, the publication of data uses processes and formats conforming to OGC SWE standards and consistent with global ocean observing initiatives and ocean modeling portals such as Copernicus marine environment monitoring services. During the last three years, NeXOS has achieved a number of milestones, providing ten new sensors along with important transverse capabilities for anti-fouling and data management. The optical sensors include monitoring of marine contaminants such as hydrocarbons and components of the carbon cycle. New sensor systems for passive acoustic measurements with extended dynamic range include internal post-processing of acoustic information to reduce communication loads. Two additional sensors (chlorophyll-a and oxygen) have been added to the RECOPESCA system to support an Ecosystem Approach to Fisheries (EAF) for improving measurement of stock-relevant parameters, such as fluorescence (proxy of chlorophyll-a) as well as physical parameters (T, S, Depth) and fish species. Interface with the sensors is through a miniaturized smart sensor interface common to all new NeXOS sensor systems and a PUCK implementation facilitates streamlined platform interfaces. A common toolset for web-enabled and reconfigurable downstream services supports marine databases and data facilitators, from SeaDataNet to GOOS and the Global Earth Observation System of Systems (GEOSS). This paper provides description of sensors and their capabilities along with validation testing.Peer Reviewe