Marco Zavatarelli

The Western Mediterranean Deep Water: A proxy for climate change

Reconstructions of Mediterranean ocean temperature fields back to 1950 show a proxy relationship between heat content changes in the North Atlantic and the Western Mediterranean Deep Water (WMDW) formed in the Gulf of Lions in winter, because of consistent air-sea heat fluxes over these areas, strongly correlated to the North Atlantic Oscillation (NAO).

Climatological biogeochemical characteristics of the Adriatic Sea

Abstract A biogeochemical historical data set relative to the Adriatic Sea is analysed to deduce the climatological characteristics of biogeochemical properties (dissolved oxygen, AOU, nitrate, phosphate, silicate and chlorophyll-a) on a seasonal basis. The Adriatic Sea is divided into four regions, the northern Adriatic, in which a region shallower than 40 m and a region deeper than 40 m are distinguished, the middle Adriatic and the southern Adriatic. The basin exhibits a generally decreasing trend of nutrient concentrations from North to South, due to the nutrient input by rivers, occurring particularly in the northern Adriatic, enabling intense phytoplankton developments in winter and autumn. In the northern basin the dominant cyclonic circulation determines a southward nutrient flow along the western coast; however, the resulting horizontal nutrients distribution can be strongly affected by phytoplankton uptake, as in the case of the winter bloom. Strong bacterial regeneration of the organic matter occurs in spring–summer, with a sensible oxygen depletion and nutrient increase at depth. In the middle Adriatic the phytoplankton biomass is much lower than in the northern Adriatic, but its role in controlling the nutrients distribution is relatively more important, because of the reduced influence of river input. In the southern Adriatic the Modified Levantine Intermediate Water (MLIW) is characterized by high nitrate concentrations. However, a detailed picture of the southern basin is prevented by the lack of data. As a tentative result, the analysis of the Redfield ratios seems to confirm that, generally, the Adriatic Sea is a phosphorus limited basin, but also seems to indicate that the surface water in the middle and, particularly, the southern Adriatic might be characterized by nitrogen limitation.

The dynamics of the Adriatic Sea ecosystem. An idealized model study

A biomass-based ecological model is presented here for the Adriatic Sea. The hydrodynamical part is composed of the Princeton Ocean Model, while the European Regional Seas Ecosystem Model describes the biogeochemical processes. An idealized Adriatic basin geometry has been used, with perpetual year seasonal cycle forcing the hydrodynamics and river-borne nutrient input forcing externally the biogeochemical processes. The simulation results highlight the role of the physical processes in determining and maintaining some of the nutrient and phytoplankton biomass distribution and characteristics in the basin. The characteristics of the phytoplankton seasonal cycle have been found to depend, in order of priority, on the river-borne nutrient input and physical horizontal and vertical processes.

Biomass changes and trophic amplification of plankton in a warmer ocean

Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterized by an increase in sea surface temperature of 2.29 ± 0.05 °C leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and regional models, imply the need for caution when extending these considerations into higher trophic levels.

One-dimensional ecosystem model tests in the Po Prodelta area (Northern Adriatic Sea)

Abstract The application of a one-dimensional ecosystem model to a water column in front of the Po Prodelta area in the Northern Adriatic Sea is illustrated here. Validation was carried out for pelagic nutrients and phytoplankton biomasses by comparing simulations with historical data. Calibration was limited to the sediment parameters and to the suspended inorganic matter data from recent PRISMA-I (Programma di RIcerca e Sperimentazione per il Mare Adriatico) data sets. Primary production and nutrient abundance is found to be in overall agreement with climatological observations at the seasonal time scales. Model-data discrepancies are interpreted in the light of model assumptions. Main conclusions concern the importance of the inorganic suspended matter concentrations in determining the seasonal cycle of primary producers hinting to a strong light limitation in algal growth in this river dominated area. The need for further improvements in the pelagic dynamical processes of the silica cycle is also discussed.

Toward Marine Environmental Predictions in the Mediterranean Sea Coastal Areas: A Monitoring Approach

Marine environmental predictions involve the observation and modeling of physical, biogeochemical processes and parameters, fused by advanced data assimilation schemes that optimally merge the observational and numerical modeling information in order to produce forecasts. The result of such system should be interfaced with socio-economic models of sustainable development and management of marine resources. Fusing the deterministic dynamical information about the marine ecosystem with the socio-economic and political knowledge of the marine environment has not been tried yet but it is one of the outstanding challenges in integrated coastal management studies. This paper tries to show a scientific strategy to predict the physical and biochemical components toward marine environmental predictions, being aware that some considerations could be changed in view of the integration with socio-economic models and issues. Here we use prediction in total analogy with forecasting and thus as synonymous of deterministic prognosis of dynamical variables from a pre-defined initial state of the system.

A numerical simulation study of dissolved organic carbon accumulation in the northern Adriatic Sea

The leading author of this paper was supported by a Ph.D. fellowship given to the Environmental Science graduate program of the University of Bologna at Ravenna and by the VECTOR project funded by the Italian Ministry of Research and University. N. Pinardi and M. Zavatarelli were partially supported by the MFSTEP project (EU contract EVK3-CT-2002-00075) and the ADRICOSM Project (funded by the Italian Ministry of Environment and Territory, Division of Environmental Research and Development). Icarus Allen and Marcello Vichi acknowledge the support by the EUR-OCEANS network of excellence (contract 511106).

Mediterranean Sea multiscale variability and environmental management issues: a scientific perspective

The policy implications of the multiscale variability of the marine systems (with particular reference to the Mediterranean Sea) are described and discussed together with the possible pathway of transfer of information from the scientific to the decision making domain. It is emphasized that the current knowledge of the variability of the marine systems no longer allows a fixed, equilibrium centered, concept of the environment, but variability must be fully included in the policy design process.

Linking 1D coastal ocean modelling to environmental management: an ensemble approach

The use of a one-dimensional interdisciplinary numerical model of the coastal ocean as a tool contributing to the formulation of ecosystem-based management (EBM) is explored. The focus is on the definition of an experimental design based on ensemble simulations, integrating variability linked to scenarios (characterised by changes in the system forcing) and to the concurrent variation of selected, and poorly constrained, model parameters. The modelling system used was previously specifically designed for the use in “data-rich” areas, so that horizontal dynamics can be resolved by a diagnostic approach and external inputs can be parameterised by nudging schemes properly calibrated. Ensembles determined by changes in the simulated environmental (physical and biogeochemical) dynamics, under joint forcing and parameterisation variations, highlight the uncertainties associated to the application of specific scenarios that are relevant to EBM, providing an assessment of the reliability of the predicted changes. The work has been carried out by implementing the coupled modelling system BFM-POM1D in an area of Gulf of Trieste (northern Adriatic Sea), considered homogeneous from the point of view of hydrological properties, and forcing it by changing climatic (warming) and anthropogenic (reduction of the land-based nutrient input) pressure. Model parameters affected by considerable uncertainties (due to the lack of relevant observations) were varied jointly with the scenarios of change. The resulting large set of ensemble simulations provided a general estimation of the model uncertainties related to the joint variation of pressures and model parameters. The information of the model result variability aimed at conveying efficiently and comprehensibly the information on the uncertainties/reliability of the model results to non-technical EBM planners and stakeholders, in order to have the model-based information effectively contributing to EBM.

Editorial—the 8th International Workshop on Modeling the Ocean (IWMO 2016) in Bologna, Italy, June 7–10, 2016

The 8th International Workshop on Modeling the Ocean (IWMO 2016) was held on June 7–10, 2016, at one of the oldest universities in Europe—the University of Bologna in Italy (founded 1088 A.D.). The workshop returned to Europe for the second time (the other European IWMO was held in Norway in 2013; Berntsen et al. 2014). Since the establishment of the IWMO in 2009 (Oey et al. 2010a, b), meetings were held four times in Asia, two times in Europe, two times in North America, one time in Australia, and for the 10th anniversary of IWMO, the 2018’s meeting will be held in South America (Brazil) for the first time. The 2016 IWMO meeting celebrated the 20-year anniversary since the first Princeton Ocean Model (POM) users’ group meeting held in June 1996 at Princeton. The early POM users’ group meetings led to the establishment of the IWMO in 2009. The IWMO expands to include different models and a very wide range of topics involving the ocean and its coupled interaction with other aspects of the earth’s environment, as can be seen from this and previous IWMO meeting agendas and related publications. The 20th anniversary event was noted by presentations on the history of ocean modeling over these two decades and an award given by The Historical Oceanography Society to Professor Emeritus George Mellor for his pioneering contribution to turbulence modeling (Mellor and Yamada 1974, 1982), coastal ocean modeling (Blumberg and Mellor 1983), and the development of POM (Blumberg and Mellor 1987), which led the way for many other community ocean models that exist today. About 80 scientists attended the IWMO 2016 meeting, which included nine keynote distinguished speakers, ~ 65 oral presentations, and ~ 25 posters. Continuing with the IWMO tradition, students and postdocs participated in the Outstanding Young Scientist Award competition. Themeeting covered a wide range of topics in ocean modeling, analysis, and processes, and this special issue of Ocean Dynamics represents a collection of 18 peer reviewed papers from participants of IWMO-2016. The papers went through rigorous reviews as regular papers in Ocean Dynamics, with the help of reviewers from IWMO members as well as external experts. The studies in this issue utilized a wide range of hydrodynamic numerical models such as ECOM, FVCOM,NEMO, POM, and ROMS, as well as several wave prediction models such as WAM, SWAN, and WaveWatchIII. Geographically, the studies covered the major oceans (the Atlantic, Indian, and Pacific Oceans) as well as semi-enclosed seas (e.g., theMediterranean and Baltic Seas). The papers can be generally divided into four categories: (1.) Model development, analysis, and data assimilation (Byun and Hart 2017; Cipollone et al. 2017, Jordi et al. 2017; Liu et al. 2017; Wei et al. 2017); (2.) Coastal modeling and process studies (Bie et al. 2017; Ezer 2017; Ezer and Atkinson 2017; Liao et al. 2017; Lu et al. 2017, Trotta et al. 2017); (3.) Surface wave modeling (Clementi et al. 2017; Cieślikiewicz et al. 2017; Gic-Grusza and Dudkowska 2017; Responsible Editor: Jörg-Olaf Wolff