An integrated open-coastal biogeochemistry, ecosystem and biodiversity observatory of the eastern Mediterranean – the Cretan Sea component of the POSEIDON system

Abstract

Abstract. There is a general scarcity of oceanic observations that concurrently examine air–sea interactions, coastal–open-ocean processes and physical–biogeochemical processes, in appropriate spatiotemporal scales and under continuous, long-term data acquisition schemes. In the Mediterranean Sea, the resulting knowledge gaps and observing challenges increase due to its oligotrophic character, especially in the eastern part of the basin. The oligotrophic open Cretan Sea's biogeochemistry is considered to be representative of a greater Mediterranean area up to 106 km2, and understanding its features may be useful on even larger oceanic scales, since the Mediterranean Sea has been considered a miniature model of the global ocean. The spatiotemporal coverage of biogeochemical (BGC) observations in the Cretan Sea has progressively increased over the last decades, especially since the creation of the POSEIDON observing system, which has adopted a multiplatform, multivariable approach, supporting BGC data acquisition. The current POSEIDON system's status includes open and coastal sea fixed platforms, a Ferrybox (FB) system and Bio-Argo autonomous floats that remotely deliver fluorescence as a proxy of chlorophyll-a (Chl-a), O2, pH and pCO2 data, as well as BGC-related physical variables. Since 2010, the list has been further expanded to other BGC (nutrients, vertical particulate matter fluxes), ecosystem and biodiversity (from viruses up to zooplankton) variables, thanks to the addition of sediment traps, frequent research vessel (R/V) visits for seawater–plankton sampling and an acoustic Doppler current profiler (ADCP) delivering information on macrozooplankton–micronekton vertical migration (in the epipelagic to mesopelagic layer). Gliders and drifters are the new (currently under integration to the existing system) platforms, supporting BGC monitoring. Land-based facilities, such as data centres, technical support infrastructure, calibration laboratory and mesocosms, support and give added value to the observatory. The data gathered from these platforms are used to improve the quality of the BGC-ecosystem model predictions, which have recently incorporated atmospheric nutrient deposition processes and assimilation of satellite Chl-a data. Besides addressing open scientific questions at regional and international levels, examples of which are presented, the observatory provides user-oriented services to marine policy makers and the society, and is a technological test bed for new and/or cost-efficient BGC sensor technology and marine equipment. It is part of European and international observing programs, playing a key role in regional data handling and participating in harmonization and best practices procedures. Future expansion plans consider the evolving scientific and society priorities, balanced with sustainable management.

Novel metrics based on Biogeochemical Argo data to improve the model uncertainty evaluation of the CMEMS Mediterranean marine ecosystem forecasts

“…The Mediterranean Sea Monitoring and Forecasting Centre (Med-MFC; Tonani et al, 2013) is one of the regional systems and is composed of the physical system "Med-PHY" (Tonani et al, 2008;Oddo et al, 2009), which drives the biogeochemical system "Med-BIO" (Lazzari et al, 2010(Lazzari et al, , 2012 and the wave system "Med-WAV" (Ravdas et al, 2018). In recent years, following the CMEMS requirements, the Med-MFC has been consistently upgraded in the physical (Oddo et al, 2014;Clementi et al, 2017;Pistoia et al, 2018), wave , and biogeochemical components (Cossarini et al, 2015;Lazzari et al, 2016), including also data assimilation (Teruzzi et al, 2014;Storto et al, 2015).…”

ROSACE: A Proposed European Design for the Copernicus Ocean Colour System Vicarious Calibration Infrastructure

“…From this buoy, a vast array of oceanographic and biogeochemical data has been, and continues to be, gathered for the area. Augmenting the data from the buoy itself are monthly sampling site visits, FerryBox data from the Athens-Crete ferry that passes to the west of the buoy, multiple deployment Argo profiler data of the local area and data from an AUV/glider that is autonomously and continuously operating on transects past the buoy [35].…”

“…The following sections further detail the site's characteristics that support its prime suitability for Copernicus OC-SVC. When combined with logistical considerations, the best site in the Cretan Sea is in the vicinity of the HCMR operational physical and biogeochemical monitoring buoy (E1-M3A) [35]. This location, referred to as MSEA similarly to [24], is at 35°44' N, 25°20' E approximately 26 nmi (48 km) north of the HCMR headquarters in Crete.…”

Toward a European Coastal Observing Network to Provide Better Answers to Science and to Societal Challenges; The JERICO Research Infrastructure

“…Initiated in 2010, the JERICO-FP7 project was the first Europe-wide effort toward the harmonization and coordination (Petihakis et al, 2015) of major coastal observing platforms including FerryBoxes, gliders, and fixed platforms (Ostrowski et al, 2016;Baschek et al, 2017;Laakso et al, 2018;Petihakis et al, 2018). (Table 1: exemple of regional infrastructure) Key physical and biogeochemical (e.g., oxygen and pCO 2 ) parameters were considered for harmonization, while emerging technologies such as Sediment Profiler Imagery and time-laps cameras were assessed.…”