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Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo-diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases and potentially expands coccolithophore niche volume. Research has, however, to date largely overlooked the life cycle of coccolithophores and has instead focused on the diploid life cycle phase of coccolithophores. Through the synthesis and analysis of global scanning electron microscopy (SEM) coccolithophore abundance data (n=2534), we find that calcified haploid coccolithophores generally constitute a minor component of the total coccolithophore abundance (≈ 2 %–15 % depending on season). However, using case studies in the Atlantic Ocean and Mediterranean Sea, we show that, depending on environmental conditions, calcifying haploid coccolithophores can be significant contributors to the coccolithophore standing stock (up to ≈30 %). Furthermore, using hypervolumes to quantify the niche of coccolithophores, we illustrate that the haploid and diploid life cycle phases inhabit contrasting niches and that on average this allows coccolithophores to expand their niche by ≈18.8 %, with a range of 3 %–76 % for individual species. Our results highlight that future coccolithophore research should consider both life cycle stages, as omission of the haploid life cycle phase in current research limits our understanding of coccolithophore ecology. Our results furthermore suggest a different response to nutrient limitation and stratification, which may be of relevance for further climate scenarios. Our compilation highlights the spatial and temporal sparsity of SEM measurements and the need for new molecular techniques to identify uncalcified haploid coccolithophores. Our work also emphasizes the need for further work on the carbonate chemistry niche of the coccolithophore life cycle.

From 2003 to 2013, the Ancona section of CNR-IRBIM (formerly part of CNR-Institute of Marine Science) runned the "Fishery Observing System" (FOS) program aimed at using Italian fishing vessels as Vessels Of Opportunity (VOOs) for the collection of scientifically useful datasets (Falco et al. 2007). Some commercial fishing vessels, targetting small pelagic species in the northern and central Adriatic Sea, were equipped with an integrated system for the collection of information on catches, position of the fishing operation, depth and water temperature during the haul, producing a great amount of data that demonstrated to be helpful both for oceanographic and fishery biology purposes (Carpi et al. 2015; Aydo?du et a. 2016; Sparnocchia et al. 2016; Lucchetti et al. 2018). In 2012, thanks to the participation to some national and international projects (e.g. SSD-Pesca, EU-FP7 JERICO etc.), CNR started the development of a new modular "Fishery & Oceanography Observing System" (FOOS; Patti et al. 2013). New sensors for oceanographic and meteorological data allow nowadays the FOOS to collect more parameters, with higher accuracy and to send them directly to a data center in near real time (Martinelli et al. 2016; Sparnocchia et al. 2017). Furthermore, the FOOS is a multifunction system able to collect various kind of data from the fishing operations and also to send back to the fishermen useful information (e.g. weather and sea forecasts, etc.) through an electronic logbook with an ad hoc software embedded. The new FOOS installed on various kind of fishing vessels targetting different resources, allowed a spatial extension of the monitored areas in the Mediterranean Sea (Patti et al. 2013). CNR-IRBIM implemented the "AdriFOOS" observational system, by installing the FOOS on some commercial fishing boats operating in the Adriatic Sea. Since then the datacenter based in Ancona receives daily data sets of environmental parameters collected along the water column and close to the sea bottom (eg. temperature, salinity, etc.), together with GPS haul tracks, catch amounts per haul, target species sizes and weather information. Some temperature and salinity measurements acquired by the FOOS in the Adriatic Sea from January 2014 to March 2015 were published within the JERICO project and some oxygen and fluorescence profiles obtained in 2017 within the NEXOS project. The dataset here presented contains 14803 depth/temperature profiles collected by 10 vessels of the AdriFOOS fleet in the period 2012-2020. All the profiles were subjected to quality control.Data are flagged according the L20 (SEADATANET MEASURAND QUALIFIER FLAGS).

Diel vertical migration (DVM) is a survival strategy adopted by zooplankton that we investigated in the Corsica Channel using acoustic Doppler current profiler (ADCP) data from April 2014 to November 2016. The principal aim of the study is to characterize migration patterns and biomass temporal evolution of zooplankton along the water column. The ADCP measured vertical velocity and echo intensity in the water column range between about 70 and 390 m (the bottom depth is 443 m). During the investigated period, zooplanktonic biomass had a well-defined daily and seasonal cycle, with peaks occurring in late winter to spring (2015 and 2016) when the stratification of the water column is weaker. Zooplanktonic biomass temporal distribution in the whole water column is well correlated with biomass of primary producers, estimated with satellite data. Zooplanktonic blooming and non-blooming periods have been identified and studied separately. During the non-blooming period zooplanktonic biomass was most abundant in the upper and the deep layers, while during the blooming period the upper-layer maximum in zooplanktonic biomass disappeared and the deep layer with high zooplanktonic biomass became thicker. These two layers are likely to correspond to two different zooplanktonic communities. The evolution of zooplanktonic biomass is well correlated with chlorophyll, with phytoplankton biomass peaks preceding the upper-layer secondary production by a lag of about 3.5 weeks. Nocturnal DVM appears to be the main pattern during both periods, but reverse and twilight migration are also detected. Nocturnal DVM was more evident at mid-water than in the deep and the upper layers. DVM occurred with different intensities during blooming and non-blooming periods. One of the main outcomes is that the principal drivers for DVM are light intensity and stratification, but other factors, like the moon cycle and primary production, are also taken in consideration.

A detailed survey of a high Arctic fjord (Kongsfjorden, Svalbard), subjected to a large glacier discharge, was carried out from 24 July to 13 August 2016. Field activities addressed the identification of the effects of glacier and iceberg melting on the evolution of nutrient, dissolved organic matter and carbonate systems in this coastal marine environment. Hydrological (CTD downcasts) and biogeochemical (bottle sampling) data were collected during six oceanographic surveys in the inner area of the fjord, in concomitance to the annual phase of maximum air warming. An extensive sampling was also carried out in all glacier drainage systems located around the fjord and from several iceberg samples, in order to characterize all freshwater loads. The dataset includes hydrological data (T, Sal., density) carbonate chemistry data (pH, DIC, TA) and the concentrations of dissolved oxygen (DO), inorganic nutrients (NO3-, NO2-, NH4+, PO43-, SiO2), dissolved organic matter (DOC, DON) and some micronutrients (Fe, Mn).

At every station, pressure (P), salinity (S), potential temperature (?) dissolved oxygen concentration (DO) and Fluorescence have been acquired and are part of the database

time series has been collected by the Italian Consiglio Nazionale delle Ricerche (CNR) in a station located at about 3500 m depth in the central Tyrrhenian Sea (39° 46.85 N, 011° 53.00 E) over the period 2003-2016. The dataset contains 21 hydrological profiles (Pressure (dbar), Temperature (ITS-90, °C) and Salinity) performed on average every six months, with a lack of data in the period 2007-2010.

In this paper we provide an overview of new knowledge on oxygen depletion (hypoxia) and related phenomena in aquatic systems resulting from the EU-FP7 project HYPOX ("In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and landlocked water bodies", http://www.hypox.net). In view of the anticipated oxygen loss in aquatic systems due to eutrophication and climate change, HYPOX was set up to improve capacities to monitor hypoxia as well as to understand its causes and consequences. Temporal dynamics and spatial patterns of hypoxia were analyzed in field studies in various aquatic environments, including the Baltic Sea, the Black Sea, Scottish and Scandinavian fjords, Ionian Sea lagoons and embayments, and Swiss lakes. Examples of episodic and rapid (hours) occurrences of hypoxia, as well as seasonal changes in bottom-water oxygenation in stratified systems, are discussed. Geologically driven hypoxia caused by gas seepage is demonstrated. Using novel technologies, temporal and spatial patterns of water-column oxygenation, from basin-scale seasonal patterns to meter-scale sub-micromolar oxygen distributions, were resolved. Existing multidecadal monitoring data were used to demonstrate the imprint of climate change and eutrophication on long-term oxygen distributions. Organic and inorganic proxies were used to extend investigations on past oxygen conditions to centennial and even longer timescales that cannot be resolved by monitoring. The effects of hypoxia on faunal communities and biogeochemical processes were also addressed in the project. An investigation of benthic fauna is presented as an example of hypoxia-devastated benthic communities that slowly recover upon a reduction in eutrophication in a system where naturally occurring hypoxia overlaps with anthropogenic hypoxia. Biogeochemical investigations reveal that oxygen intrusions have a strong effect on the microbially mediated redox cycling of elements. Observations and modeling studies of the sediments demonstrate the effect of seasonally changing oxygen conditions on benthic mineralization pathways and fluxes. Data quality and access are crucial in hypoxia research. Technical issues are therefore also addressed, including the availability of suitable sensor technology to resolve the gradual changes in bottom-water oxygen in marine systems that can be expected as a result of climate change. Using cabled observatories as examples, we show how the benefit of continuous oxygen monitoring can be maximized by adopting proper quality control. Finally, we discuss strategies for state-of-the-art data archiving and dissemination in compliance with global standards, and how ocean observations can contribute to global earth observation attempts.

The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth system model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979–2008) and a climate change projection (2039–2068), together with coupled transient runs (1850–2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PB of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Centre (LRZ) in Garching, Germany. About 140 TB of post-processed data are stored on the CINECA supercomputing centre archives and are freely accessible to the community thanks to an EUDAT data pilot project. This paper presents the technical and scientific set-up of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given. An improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increase is observed. It is also shown that including stochastic parameterisation in the low-resolution runs helps to improve some aspects of the tropical climate – specifically the Madden–Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small-scale processes on the large-scale climate variability either explicitly (with high-resolution simulations) or stochastically (in low-resolution simulations).

The boron isotopic composition (δ11B) of marine carbonates (e.g. corals) is increasingly utilised as a proxy for paleo-pH, with the strong correlation between δ11B of marine calcifiers and seawater pH now well documented. However, the potential roles of other environmental parameters that may also influence both the boron isotopic composition and boron concentration into coral aragonite are poorly known. To overcome this, the tropical scleractinian coral Acropora sp. was cultured under 3 different temperatures (22, 25 and 28 °C) and two light conditions (200 and 400 μmol photon m−2 s−1). The δ11B indicates an increase in internal pH that is dependent on the light conditions. Changes in light intensities from 200 to 400 μmol photon m−2 s−1 seem to indicate an apparent decrease in pH at the site of calcification, contrary to what is expected in most models of light-enhanced calcification. Thus, variations in light conditions chosen to mimic average annual variations of the natural environments where Acropora sp. colonies can be found could bias pH reconstructions by about 0.05 units. For both light conditions, a significant impact of temperature on δ11B can be observed between 22 and 25 °C, corresponding to an increase of about 0.02 pH-units, while no further δ11B increase can be observed from 25 to 28 °C. This non-linear temperature effect complicates the determination of a correction factor. B / Ca ratios decrease with increasing light, consistent with the decrease in pH at the site of calcification under enhanced light intensities. When all the other parameters are constant, boron concentrations in Acropora sp. increase with increasing temperatures and increasing carbonate ion concentrations. These observations contradict previous studies where B / Ca in corals was found to vary inversely with temperature, suggesting that the controlling factors driving boron concentrations have not yet been adequately identified and might be influenced by other environmental variables and/or species-specific responses.

Laboratory experiments were performed to study the dynamics of three- dimensional mechanically generated waves propagating over an oblique current in partial opposition. The flow velocity varied along the mean wave direction of propagation with an increasing trend between the wave-maker and the centre of the tank. Tests with regular wave packets traversing the area of positive current gradient showed that the concurrent increase of wave steepness triggered modulational instability on otherwise stable wave trains and hence induced the development of very large amplitude waves. In random directional wave fields, the presence of the oblique current resulted in a weak reinforcement of wave instability with a subsequent increase of the probability of occurrence of extreme events. This seems to partially compensate the suppression of strongly non-Gaussian properties due to directional energy distribution.