Description: Most global ocean models are based on the assumption of a "steady state" ocean. Here, we investigate the validation of this hypothesis for the anthropized Mediterranean Sea. In order to do so, we calculated the mixing coefficients of the water masses detected in this sea via an optimum multiparameter analysis referred to as the MIX approach, using data from the BOUM (2008) and MedSeA (2013) cruises. The comparison of the mixing coefficients of each water mass, between 2008 and 2013, indicates that some of their proportions have significantly changed. Surface water mass proportions did not change significantly (Delta0.05-0.1), while intermediate and deep water mass mixing coefficients of both Eastern and Western basins were significantly modified (~Delata 0.35). This study clearly shows that the Mediterranean seawater is not in a "steady state".

Description: EuroSea brought together key European actors of ocean observation and forecasting with key end users of the ocean observations’ products and services to better integrate existing ocean observation systems and tools, and to bring the coordination to a higher level. The EuroSea WP1 “Governance and coordination of ocean observing and forecasting systems”, in particular, aimed to strengthen the interactions between regional, national, and international observing systems and support the development of a European coordinated system through the Framework of the European Ocean Observing System (EOOS). During the project, the challenges and gaps in the design and coordination of the European ocean observing and forecasting system were identified and mapped. Many gaps and challenges related to the observations of physical, chemical and biological Essential Ocean Variables were identified. Some of these gaps are related to technological advancements, while others are caused by insufficient funding, coordination, management, and cooperation between different entities, as well as limitations in foresight activities, policies and decisions. To enhance the sustainability of European ocean observations, several recommendations were compiled for networks, frameworks, initiatives, Member States, and the European Commission.

Description: The European Ocean Observing and Forecasting System (EOOFS) plays a pivotal role in understanding, monitoring, forecasting, and managing the complex dynamics and resources of Europe's Seas. It serves as a critical interdisciplinary system for addressing a myriad of challenges, from climate change impacts to marine resources management. However, to ensure its continued effectiveness, it is essential to identify and address the gaps within this system and provide actionable recommendations for improvements at short- and long-term. Therefore, this document serves as a baseline that can guide the funders and supporters of the EOOFS, as well as the various stakeholders directly or indirectly related to the EOOFS, towards the gaps that hinder better monitoring and prediction of various ocean phenomena, along the ocean observing value chain. The main identified gaps are related to spatial and temporal coverage of data and products of the EOOFS, the data integration and accessibility by various types of users, the uncertainties of projections, the technological challenges, as well as to the engagement of various actors and the communication of results and services to them. The main recommendations to be taken into consideration for addressing all highlighted gaps are detailed in the report for every phenomenon and component of the ocean value chain. These recommendations are not provided just to satisfy the academic interest of the EOOFS community, however, they may have profound implications for multiple sectors and the society as a whole, if taken into consideration. This is due to the fact that the EOOFS is essential for climate change mitigation and adaptation measures, in improving the efficiency of the marine resources’ management, in enhancing the resilience of marine and coastal ecosystems as well as coastal cities and infrastructures against disasters and extreme events, for shipping and navigation safety, and for the scientific advancements and innovations of Europe in the field of marine science that serves the society. We propose a scoring approach that can evaluate the EOOFS readiness level (RL) in monitoring ocean phenomena, on a regular basis and in a systematic way. We have demonstrated the usefulness of this approach by implementing it based on our assessment and the feedback of the EOOFS community. The main results clearly show that the EOOFS has “Fitness for Purpose” readiness levels (RL 7) in the three main pillars of the value chain (Input, Process, and Output) only for one ocean phenomenon, while 83% of ocean phenomena have RLs varying from 1 (Idea) to 4 (Trial). A deeper analysis of the scoring results reflects that the EOOFS major gaps are predominantly concentrated in two of its three pillars: the coordination and observational elements (Process) and data management and information products (Output) (Figure 1). In a changing world that is affecting all aspects of European lives, it is crucial to significantly invest and support the EOOFS to better monitor and accurately predict the European Seas, and provide sustained services that can help businesses and improve the resilience of communities and resources.

Description: Harmonisation data management procedures and implementing FAIR principles with the target to serve the data infrastructures: Copernicus Marine Service and EMODnet (first stage) as well as SeaDataNet and historical National Oceanographic Data Centres (later stage)

Description: Ocean acidification (OA) is a serious consequence of climate change with complex organism-to-ecosystem effects that have been observed through field observations but are mainly derived from experimental studies. Although OA trends and the resulting biological impacts are likely exacerbated in the semi-enclosed and highly populated Mediterranean Sea, some fundamental knowledge gaps still exist. These gaps are at tributed to both the uneven capacity for OA research that exists between Mediterranean countries, as well as to the subtle and long-term biological, physical and chemical interactions that define OA impacts. In this paper, we systematically analyzed the different aspects of OA research in the Mediterranean region based on two sources: the United Nation’s International Atomic Energy Agency’s (IAEA) Ocean Acidification International Coordination Center (OA-ICC) database, and an extensive survey. Our analysis shows that 1) there is an uneven geographic capacity in OA research, and illustrates that both the Algero-Provencal and Ionian sub-basins are currently the least studied Mediterranean areas, 2) the carbonate system is still poorly quantified in coastal zones, and long-term time-series are still sparse across the Mediterranean Sea, which is a challenge for studying its variability and assessing coastal OA trends, 3) the most studied groups of organisms are autotrophs (algae, phanerogams, phytoplankton), mollusks, and corals, while microbes, small mollusks (mainly pteropods), and sponges are among the least studied, 4) there is an overall paucity in socio-economic, paleontological, and modeling studies in the Mediterranean Sea, and 5) in spite of general resource availability and the agreement for improved and coordinated OA governance, there is a lack of consistent OA policies in the Mediterranean Sea. In addition to highlighting the current status, trends and gaps of OA research, this work also provides recommendations, based on both our literature assessment and a survey that targeted the Mediterranean OA scientific community. In light of the ongoing 2021-2030 United Nations Decade of Ocean Science for Sustainable Development, this work might provide a guideline to close gaps of knowledge in the Mediterranean OA research.

Description: The spectrophotometric methodology for carbonate ion determination in seawater was first published in 2008 and has been continuously evolving in terms of reagents and formulations. Although being fast, relatively simple, affordable, and potentially easy to implement in different platforms and facilities for discrete and autonomous observations, its use is not widespread in the ocean acidification community. This study uses a merged overdetermined CO2 system data set (carbonate ion, pH, and alkalinity) obtained from 2009 to 2020 to assess the differences among the five current approaches of the methodology through an internal consistency analysis and discussing the sources of uncertainty. Overall, the results show that none of the approaches meet the climate goal (+/- 1 % standard uncertainty) for ocean acidification studies for the whole carbonate ion content range in this study but usually fulfill the weather goal (+/- 10 % standard uncertainty). The inconsistencies observed among approaches compromise the consistency of data sets among regions and through time, highlighting the need for a validated standard operating procedure for spectrophotometric carbonate ion measurements as already available for the other measurable CO2 variables.

Description: Highlights: • First abundance of MPs in offshore sediments along South-Eastern Mediterranean • Mean MPs ranged between 1126 ± 1363 MPs/kg. • Most abundant shapes were fibers and films. • Most abundant polymer types were PP and PE. • Coastal landfills and wastewater discharges shaped spatial distribution of MPs. Few studies on microplastics (MPs) in the marine environment have been conducted along the Eastern part of the Mediterranean Sea and even fewer along the Lebanese coast. This study aims to determine MPs contamination for the first-time in coastal and continental shelf sediments collected along the Lebanese shores, South-Eastern Mediterranean Sea. Sediments were collected as transects in 10 sites with a total of 23 samples between 2 and 120 m depth and suspected MPs were assessed by moving farther from land-based sources. Microplastics concentrations ranged between 0 and 4500 MPs/kg of dry sediment (1126 ± 1363 MPs/kg). Polypropylene, polyethylene, polyethylene terephthalate and polystyrene were the polymers identified on micro-Raman. Coastal landfills and raw sewage effluents were identified as the main sources and routes for MPs into the Lebanese coastal marine environment. This study serves as the first database reporting MPs in continental shelf sediments in the South-Eastern Mediterranean

Description: The ocean observing system needs to be ensured by high-level integration and coordination to guarantee its longterm sustainability, efficient accessibility and usability by a wide range of users. Enormous advancements and efforts toward these objectives have been already conducted in Europe, partly through the activities of the IOC-UNESCO's International Oceanographic Data and Information Exchange (IODE) and EuroGOOS DATAMEQ working group, although there is still room for additional progress and gaps to be addressed. During the past two decades, a series of standards for data and metadata formats as well as exchange protocols have been established within the marine community where projects, organizations and data integrators like JCOMM, RDA (Research Data Alliance), EuroGOOS, EMODnet, SeaDataNet and Copernicus played a significant role. Taking into consideration that harmonized data are a key element in maintaining a usable and interoperable ocean observing system, this paper aims to provide some recommendations for the harmonization of the marine in situ networks involved in EuroSEA, which would be a useful product for the European data integrators, particularly EMODnet, SeaDataNet and Copernicus Marine service. This document proposes recommendations to enhance the in situ networks based on the assessment of what has been previously done.