Interannual variability of the Mediterranean trophic regimes from ocean color satellites

Abstract. D'Ortenzio and Ribera d'Alcalà (2009, DR09 hereafter) divided the Mediterranean Sea into "bioregions" based on the climatological seasonality (phenology) of phytoplankton. Here we investigate the interannual variability of this bioregionalization. Using 16 years of available ocean color observations (i.e. SeaWiFS and MODIS), we analyzed the spatial distribution of the DR09 trophic regimes on an annual basis. Additionally, we identified new trophic regimes, with seasonal cycles of phytoplankton biomass different from the DR09 climatological description and named "Anomalous". Overall, the classification of the Mediterranean phytoplankton phenology proposed by DR09 (i.e. "No Bloom", "Intermittently", "Bloom" and "Coastal"), is confirmed to be representative of most of the Mediterranean phytoplankton phenologies. The mean spatial distribution of these trophic regimes (i.e. bioregions) over the 16 years studied is also similar to the one proposed by DR09. But at regional scale some annual differences, in their spatial distribution and in the emergence of "Anomalous" trophic regimes, were observed compared to the DR09 description. These dissimilarities with the DR09 study were related to interannual variability in the sub-basin forcing: winter deep convection events, frontal instabilities, inflow of Atlantic or Black Sea Waters and river run-off. The large assortment of phytoplankton phenologies identified in the Mediterranean Sea is thus verified at interannual level, confirming the "sentinel" role of this basin to detect the impact of climate changes on the pelagic environment.

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Interannual variability of the Mediterranean trophic regimes from ocean color satellites

Biogeosciences ◽

10.5194/bg-13-1901-2016 ◽

2016 ◽

Vol 13 (6) ◽

pp. 1901-1917 ◽

Cited By ~ 38

Author(s):

Nicolas Mayot ◽

Fabrizio D'Ortenzio ◽

Maurizio Ribera d'Alcalà ◽

Héloïse Lavigne ◽

Hervé Claustre

Keyword(s):

Spatial Distribution ◽

Mediterranean Sea ◽

Interannual Variability ◽

Deep Convection ◽

Regional Scale ◽

Ocean Color ◽

Annual Variations ◽

Run Off ◽

The Mediterranean ◽

The Impact

Abstract. D'Ortenzio and Ribera d'Alcalà (2009, DR09 hereafter) divided the Mediterranean Sea into “bioregions” based on the climatological seasonality (phenology) of phytoplankton. Here we investigate the interannual variability of this bioregionalization. Using 16 years of available ocean color observations (i.e., SeaWiFS and MODIS), we analyzed the spatial distribution of the DR09 trophic regimes on an annual basis. Additionally, we identified new trophic regimes, exhibiting seasonal cycles of phytoplankton biomass different from the DR09 climatological description and named “Anomalous”. Overall, the classification of the Mediterranean phytoplankton phenology proposed by DR09 (i.e., “No Bloom”, “Intermittently”, “Bloom” and “Coastal”), is confirmed to be representative of most of the Mediterranean phytoplankton phenologies. The mean spatial distribution of these trophic regimes (i.e., bioregions) over the 16 years studied is also similar to the one proposed by DR09, although some annual variations were observed at regional scale. Discrepancies with the DR09 study were related to interannual variability in the sub-basin forcing: winter deep convection events, frontal instabilities, inflow of Atlantic or Black Sea Waters and river run-off. The large assortment of phytoplankton phenologies identified in the Mediterranean Sea is thus verified at the interannual scale, further supporting the “sentinel” role of this basin for detecting the impact of climate changes on the pelagic environment.

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The contribution of shipping to air pollution in the Mediterranean region – a model evaluation study

10.5194/egusphere-egu21-8344 ◽

2021 ◽

Author(s):

Lea Fink ◽

Volker Matthias ◽

Matthias Karl ◽

Ronny Petrik ◽

Elisa Majamäki ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Mediterranean Sea ◽

Regional Scale ◽

Mediterranean Coast ◽

Emission Model ◽

Ship Emissions ◽

Scale Models ◽

The Mediterranean ◽

The Impact

Shipping has major contribution to emissions of air pollutants like NOx and SO2 and the global maritime transport volumes are projected to increase significantly. The Mediterranean Sea is a region with dense ship traffic. Air quality observations in many cities along the Mediterranean coast indicate high levels of NO2 and particulate matter with significant contributions from ship emissions. To quantify the current impact of shipping on air pollution, models for ship emissions and atmospheric transport can be applied, but model predictions may differ from observational data. To determine how well regional scale chemistry transport models simulate pollutant concentrations, the model outputs from several regional scale models were compared against each other and to measured data. In the framework of the EU H2020 project SCIPPER, ship emission model STEAM and the regional scale models CMAQ and CHIMERE model were applied on a modelling domain covering the Mediterranean Sea. Modeling results were compared to air quality observations at coastal locations. The impact of shipping in the Mediterranean Sea was extracted from the model excluding shipping emissions.&#160;

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Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)

Biogeosciences ◽

10.5194/bg-18-5891-2021 ◽

2021 ◽

Vol 18 (22) ◽

pp. 5891-5902

Author(s):

Stéphanie H. M. Jacquet ◽

Christian Tamburini ◽

Marc Garel ◽

Aurélie Dufour ◽

France Van Vambeke ◽

...

Keyword(s):

Mediterranean Sea ◽

Deep Convection ◽

Western Mediterranean ◽

Late Spring ◽

Small Scale ◽

Dust Deposition ◽

Central Mediterranean ◽

Central Mediterranean Sea ◽

The Mediterranean ◽

The Impact

Abstract. We report on the sub-basin variability in particulate organic carbon (POC) remineralization in the western and central Mediterranean Sea in late spring during the PEACETIME (ProcEss studies at the Air–sEa Interface after dust deposition in the MEditerranean sea) cruise. POC remineralization rates were estimated using the excess biogenic particulate barium (Baxs) inventories in the mesopelagic layers (100–1000 m depth) and compared with prokaryotic heterotrophic production (PHP). Baxs-based mesopelagic remineralization rates (MRs) ranged from 25±2 to 306±70 mgCm-2d-1. MRs were larger in the Algero-Provençal (ALG) Basin than in the Tyrrhenian (TYR) and Ionian (ION) basins. Our Baxs inventories and integrated PHP data also indicated that significant mesopelagic remineralization occurred down to 1000 m depth in the ALG Basin in contrast to the ION and TYR basins, where remineralization was mainly located above 500 m depth. We propose that the higher and deeper MRs in the ALG Basin were sustained by an additional particle export event driven by deep convection. The TYR Basin (in contrast to the ALG and ION basins) presented the impact of a previous dust event, as reflected by our particulate Al water column concentrations. The ION and TYR basins showed small-scale heterogeneity in remineralization processes, reflected by our Baxs inventories and integrated PHP data at the Tyrr long-duration station. This heterogeneity was linked to the mosaic of blooming and non-blooming patches reported in this area during the cruise. In contrast to the western Mediterranean Sea (ALG Basin), the central Mediterranean Sea (ION and TYR basins) showed lower remineralization rates restricted to the upper mesopelagic layer during the late spring PEACETIME cruise.

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Size-dependent survival of European hake juveniles in the Mediterranean Sea

Scientia Marina ◽

10.3989/scimar.04857.16a ◽

2020 ◽

Vol 83 (S1) ◽

pp. 207

Author(s):

Manuel Hidalgo ◽

Alessandro Ligas ◽

José María Bellido ◽

Isabella Bitetto ◽

Pierluiggi Carbonara ◽

...

Keyword(s):

Mediterranean Sea ◽

Western Mediterranean ◽

Juvenile Stage ◽

Ontogenetic Changes ◽

Size Dependent ◽

Negative Effect ◽

The Mediterranean ◽

The One ◽

The Impact ◽

European Hake

Most studies on European hake focus on the recruitment process and nursery areas, whereas the information is comparatively limited on the ecology of the juvenile stage (ca. second year of life)—the one most exploited by the Mediterranean trawl fisheries. Using information of the MEDITS programme, we provide a spatial and temporal assessment of the influence of body size and growth on hake survival from recruits (age 0) to juveniles (age 1), along with the impact of surface temperature and chlorophyll variability. At a biogeographic scale, size-dependent survival is supported, with areas with higher mean length of recruits and juveniles yielding higher survival. A similar pattern was observed at interannual level in some western Mediterranean areas, also mediated by a density-dependent effect on growth. However, the most recurrent inter-annual pattern was a negative effect of size on survival, which could be attributed to potential ontogenetic changes in catchability and underrepresentation of intra-annual recruitment pulses that are seasonally inaccessible to the MEDITS survey. Results also evidence that survival in the Alboran and Adriatic seas is dependent on the primary production variability, and that Corsica and Sardinia could be potential feeding grounds receiving juveniles from neighbouring areas. The present study reveals the importance of size- and growth-dependent survival in the juvenile stage of European hake in the Mediterranean Sea.

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Impact of air–sea coupling on the climate change signal over the Iberian Peninsula

Climate Dynamics ◽

10.1007/s00382-021-05812-x ◽

2021 ◽

Author(s):

Alba de la Vara ◽

William Cabos ◽

Dmitry V. Sein ◽

Claas Teichmann ◽

Daniela Jacob

Keyword(s):

Climate Change ◽

Iberian Peninsula ◽

Mediterranean Sea ◽

Large Scale ◽

Regional Distribution ◽

Coupled Model ◽

Climate Change Signal ◽

The North ◽

The Mediterranean ◽

The Impact

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

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Variations in Moisture Supply from the Mediterranean Sea during Meteorological Drought Episodes over Central Europe

Atmosphere ◽

10.3390/atmos9070278 ◽

2018 ◽

Vol 9 (7) ◽

pp. 278 ◽

Cited By ~ 8

Author(s):

Milica Stojanovic ◽

Anita Drumond ◽

Raquel Nieto ◽

Luis Gimeno

Keyword(s):

Linear Relationship ◽

Mediterranean Sea ◽

Central Europe ◽

Linear Regression Analysis ◽

Meteorological Drought ◽

Time Analysis ◽

Moisture Supply ◽

The Mediterranean ◽

The One ◽

Annual Summer

The climate in Central Europe (CEU) during the 20th century is characterized by an overall temperature increase. Severe and prolonged drought events began occurring towards the end and these have continued into the 21st century. This study aims to analyze variations in the moisture supply from the Mediterranean Sea (MDS) during meteorological drought episodes occurring over the CEU region over the last three decades. A total of 51 meteorological drought episodes (22 with summer onsets, and 29 with winter) are identified over the CEU during the period 1980–2015 through the one-month Standardized Precipitation Evapotranspiration Index (SPEI-1), and their respective indicators, including duration, severity, intensity, and peak values, are then computed. Lagrangian forward-in-time analysis reveals that negative anomalies of moisture coming from the MDS prevail in all episodes except seven. Linear regression analysis between variations in the MDS anomalies and indicators of the drought episodes shows a significant linear relationship between severity, duration, peak values (winter), and MDS anomalies, which implies that drought episodes last longer and are more severe with an increase in the negative anomaly of moisture supply from the MDS. Nevertheless, no linear relationship is found between the intensity and peak values (annual, summer) of drought episodes and anomalies in the moisture contribution from the MDS.

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The spatio-temporal distribution of lightning over Israel and the neighboring area and its relation to regional synoptic systems

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-2125-2011 ◽

2011 ◽

Vol 11 (8) ◽

pp. 2125-2135 ◽

Cited By ~ 21

Author(s):

S. Shalev ◽

H. Saaroni ◽

T. Izsak ◽

Y. Yair ◽

B. Ziv

Keyword(s):

Spatial Distribution ◽

Mediterranean Sea ◽

Temporal Distribution ◽

Lightning Activity ◽

Eastern Coast ◽

Synoptic Situation ◽

Lightning Flash ◽

The Mediterranean ◽

Spatio Temporal ◽

Neighboring Area

Abstract. The spatio-temporal distribution of lightning flashes over Israel and the neighboring area and its relation to the regional synoptic systems has been studied, based on data obtained from the Israel Lightning Location System (ILLS) operated by the Israel Electric Corporation (IEC). The system detects cloud-to-ground lightning discharges in a range of ~500 km around central Israel (32.5° N, 35° E). The study period was defined for annual activity from August through July, for 5 seasons in the period 2004–2010. The spatial distribution of lightning flash density indicates the highest concentration over the Mediterranean Sea, attributed to the contribution of moisture as well as sensible and latent heat fluxes from the sea surface. Other centers of high density appear along the coastal plain, orographic barriers, especially in northern Israel, and downwind from the metropolitan area of Tel Aviv, Israel. The intra-annual distribution shows an absence of lightning during the summer months (JJA) due to the persistent subsidence over the region. The vast majority of lightning activity occurs during 7 months, October to April. Although over 65 % of the rainfall in Israel is obtained during the winter months (DJF), only 35 % of lightning flashes occur in these months. October is the richest month, with 40 % of total annual flashes. This is attributed both to tropical intrusions, i.e., Red Sea Troughs (RST), which are characterized by intense static instability and convection, and to Cyprus Lows (CLs) arriving from the west. Based on daily study of the spatial distribution of lightning, three patterns have been defined; "land", "maritime" and "hybrid". CLs cause high flash density over the Mediterranean Sea, whereas some of the RST days are typified by flashes over land. The pattern defined "hybrid" is a combination of the other 2 patterns. On CL days, only the maritime pattern was noted, whereas in RST days all 3 patterns were found, including the maritime pattern. It is suggested that atmospheric processes associated with RST produce the land pattern. Hence, the occurrence of a maritime pattern in days identified as RST reflects an "apparent RST". The hybrid pattern was associated with an RST located east of Israel. This synoptic type produced the typical flash maximum over the land, but the upper-level trough together with the onshore winds it induced over the eastern coast of the Mediterranean resulted in lightning activity over the sea as well, similar to that of CLs. It is suggested that the spatial distribution patterns of lightning may better identify the synoptic system responsible, a CL, an "active RST" or an "apparent RST". The electrical activity thus serves as a "fingerprint" for the synoptic situation responsible for its generation.

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Coupled Ocean–Atmosphere Response to Seasonal Modulation of Ocean Color: Impact on Interannual Climate Simulations in the Tropical Pacific

Journal of Climate ◽

10.1175/jcli3958.1 ◽

2007 ◽

Vol 20 (2) ◽

pp. 353-374 ◽

Cited By ~ 39

Author(s):

J. Ballabrera-Poy ◽

R. Murtugudde ◽

R-H. Zhang ◽

A. J. Busalacchi

Keyword(s):

Solar Radiation ◽

Interannual Variability ◽

Seasonal Cycle ◽

General Circulation ◽

Ocean Color ◽

Circulation Model ◽

Enso Events ◽

Ocean Atmosphere ◽

Atmosphere Model ◽

The Impact

Abstract The ability to use remotely sensed ocean color data to parameterize biogenic heating in a coupled ocean–atmosphere model is investigated. The model used is a hybrid coupled model recently developed at the Earth System Science Interdisciplinary Center (ESSIC) by coupling an ocean general circulation model with a statistical atmosphere model for wind stress anomalies. The impact of the seasonal cycle of water turbidity on the annual mean, seasonal cycle, and interannual variability of the coupled system is investigated using three simulations differing in the parameterization of the vertical attenuation of downwelling solar radiation: (i) a control simulation using a constant 17-m attenuation depth, (ii) a simulation with the spatially varying annual mean of the satellite-derived attenuation depth, and (iii) a simulation accounting for the seasonal cycle of the attenuation depth. The results indicate that a more realistic attenuation of solar radiation slightly reduces the cold bias of the model. While a realistic attenuation of solar radiation hardly affects the annual mean and the seasonal cycle due to anomaly coupling, it significantly affects the interannual variability, especially when the seasonal cycle of the attenuation depth is used. The seasonal cycle of the attenuation depth interacts with the low-frequency equatorial dynamics to enhance warm and cold anomalies, which are further amplified via positive air–sea feedbacks. These results also indicate that interannual variability of the attenuation depths is required to capture the asymmetric biological feedbacks during cold and warm ENSO events.

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Introduction to the project DUNE, a DUst experiment in a low Nutrient, low chlorophyll Ecosystem

Biogeosciences Discussions ◽

10.5194/bgd-10-12491-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 12491-12527 ◽

Cited By ~ 10

Author(s):

C. Guieu ◽

F. Dulac ◽

C. Ridame ◽

P. Pondaven

Keyword(s):

Trace Elements ◽

Atmospheric Deposition ◽

Mediterranean Sea ◽

Surface Waters ◽

Carbon Pump ◽

Mesocosm Experiments ◽

The Mediterranean ◽

Atmospheric Inputs ◽

Oligotrophic Ecosystem ◽

The Impact

Abstract. The main goal of the project DUNE was to estimate the impact of atmospheric deposition on an oligotrophic ecosystem based on mesocosm experiments simulating strong atmospheric inputs of Aeolian dust. Atmospheric deposition is now recognized as a significant source of macro- and micro-nutrients for the surface ocean, but the quantification of its role on the biological carbon pump is still poorly determined. We proposed in DUNE to investigate the role of atmospheric inputs on the functioning of an oligotrophic system particularly well adapted to this kind of study: the Mediterranean Sea. The Mediterranean Sea – etymologically, sea surrounded by land – is submitted to atmospheric inputs that are very variable both in frequency and intensity. During the thermal stratification period, only atmospheric deposition is prone to fertilize Mediterranean surface waters which has become very oligotrophic due to the nutrient depletion (after the spring bloom). This paper describes the objectives of DUNE and the implementation plan of a series of mesocosms experiments during which either wet or dry and a succession of two wet deposition fluxes of 10 g m−2 of Saharan dust have been simulated. After the presentation of the main biogeochemical initial conditions of the site at the time of each experiment, a general overview of the papers published in this special issue is presented, including laboratory results on the solubility of trace elements in erodible soils in addition to results from the mesocosm experiments. Our mesocosm experiments aimed at being representative of real atmospheric deposition events onto the surface of oligotrophic marine waters and were an original attempt to consider the vertical dimension in the study of the fate of atmospheric deposition within surface waters. Results obtained can be more easily extrapolated to quantify budgets and parameterize processes such as particle migration through a "captured water column". The strong simulated dust deposition events were found to impact the dissolved concentrations of inorganic dissolved phosphorus, nitrogen, iron and other trace elements. In the case of Fe, adsorption on sinking particles yields a decrease in dissolved concentration unless binding ligands were produced following a former deposition input and associated fertilization. For the first time, a quantification of the C export induced by the aerosol addition was possible. Description and parameterization of biotic (heterotrophs and autotrophs, including diazotrophs) and abiotic processes (ballast effect due to lithogenic particles) after dust addition in sea surface water, result in a net particulate organic carbon export in part controlled by the "lithogenic carbon pump".

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High diversified benthic habitats in a tidal Mediterranean sub-tropical environment: the case of the Gulf of Gabès (Tunisia)

10.7287/peerj.preprints.26537 ◽

2018 ◽

Author(s):

Abir Fersi ◽

Nawfel Mosbahi ◽

Ali Bakalem ◽

Jean-Philippe Pezy ◽

Alexandrine Baffreau ◽

...

Keyword(s):

Mediterranean Sea ◽

Eastern Mediterranean ◽

Tropical Environment ◽

Gulf Of Gabes ◽

Annual Cycles ◽

Gulf Of Gabès ◽

Zostera Noltei ◽

Sediment Types ◽

The Mediterranean ◽

The Impact

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.

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