scholarly journals Sea surface temperature variability in the central-western Mediterranean Sea during the last 2700 years: a multi-proxy and multi-record approach

2015 ◽  
Vol 11 (6) ◽  
pp. 5439-5508 ◽  
Author(s):  
M. Cisneros ◽  
I. Cacho ◽  
J. Frigola ◽  
M. Canals ◽  
P. Masqué ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Sediment Cores ◽  
Atlantic Multidecadal Oscillation ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Ice Age ◽  
Western Mediterranean Sea ◽  
General Cooling ◽  
Age Model ◽  
Cooling Trend

Abstract. This study analyses the evolution of sea surface conditions during the last 2700 years in the central-western Mediterranean Sea based on six records as measured on five short sediment cores from two sites north of Minorca (cores MINMC06 and HER-MC-MR3). Sea Surface Temperatures (SSTs) were obtained from alkenones and Globigerina bulloides-Mg/Ca ratios combined with δ18O measurements to reconstruct changes in the regional Evaporation–Precipitation (E–P) balance. We reviewed the G. bulloides Mg/Ca-SST calibration and re-adjusted it based on a set of core top measurements from the western Mediterranean Sea. According to the regional oceanographic data, the estimated Mg/Ca-SSTs are interpreted to reflect spring seasonal conditions mainly related to the April–May primary productivity bloom. In contrast, the Alkenone-SSTs signal likely integrates the averaged annual signal. A combination of chronological tools allowed synchronizing the records in a common age model. Subsequently a single anomaly stack record was constructed for each proxy, thus easing to identify the most significant and robust patterns. The warmest SSTs occurred during the Roman Period (RP), which was followed by a general cooling trend interrupted by several centennial-scale oscillations. This general cooling trend could be controlled by changes in the annual mean insolation. Whereas some particularly warm SST intervals took place during the Medieval Climate Anomaly (MCA) the Little Ice Age (LIA) was markedly unstable with some very cold SST events mostly during its second half. The records of the last centuries suggest that relatively low E–P ratios and cold SSTs dominated during negative North Atlantic Oscillation (NAO) phases, although SST records seem to present a close positive connection with the Atlantic Multidecadal Oscillation index (AMO).

scholarly journals Sea surface temperature variability in the central-western Mediterranean Sea during the last 2700 years: a multi-proxy and multi-record approach

2016 ◽  
Vol 12 (4) ◽  
pp. 849-869 ◽  
Author(s):  
Mercè Cisneros ◽  
Isabel Cacho ◽  
Jaime Frigola ◽  
Miquel Canals ◽  
Pere Masqué ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Climatic Variability ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Ice Age ◽  
Globigerina Bulloides ◽  
Proxy Records ◽  
Western Mediterranean Sea ◽  
General Cooling ◽  
Cooling Trend

Abstract. This study presents the reconstructed evolution of sea surface conditions in the central-western Mediterranean Sea during the late Holocene (2700 years) from a set of multi-proxy records as measured on five short sediment cores from two sites north of Minorca (cores MINMC06 and HER-MC-MR3). Sea surface temperatures (SSTs) from alkenones and Globigerina bulloides Mg / Ca ratios are combined with δ18O measurements in order to reconstruct changes in the regional evaporation–precipitation (E–P) balance. We also revisit the G. bulloides Mg / Ca–SST calibration and re-adjusted it based on a set of core-top measurements from the western Mediterranean Sea. Modern regional oceanographic data indicate that Globigerina bulloides Mg / Ca is mainly controlled by seasonal spring SST conditions, related to the April–May primary productivity bloom in the region. In contrast, the alkenone–SST signal represents an integration of the annual signal. The construction of a robust chronological framework in the region allows for the synchronization of the different core sites and the construction of “stacked” proxy records in order to identify the most significant climatic variability patterns. The warmest sustained period occurred during the Roman Period (RP), which was immediately followed by a general cooling trend interrupted by several centennial-scale oscillations. We propose that this general cooling trend could be controlled by changes in the annual mean insolation. Even though some particularly warm SST intervals took place during the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA) was markedly unstable, with some very cold SST events mostly during its second half. Finally, proxy records for the last centuries suggest that relatively low E–P ratios and cold SSTs dominated during negative North Atlantic Oscillation (NAO) phases, although SSTs seem to present a positive connection with the Atlantic Multidecadal Oscillation (AMO) index.

scholarly journals Ocean Surface Anomalies after Strong Winds in the Western Mediterranean Sea

2019 ◽  
Vol 7 (6) ◽  
pp. 182
Author(s):  
Francesco Ragone ◽  
Andrea Meli ◽  
Anna Napoli ◽  
Claudia Pasquero
Keyword(s):  
Mediterranean Sea ◽  
Winter Season ◽  
Heat Content ◽  
Sea Surface Height ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Height Anomaly ◽  
Surface Cooling ◽  
Western Mediterranean Sea ◽  
Wind Events

The Western Mediterranean Sea is often subject to intense winds, especially during the winter season. Intense winds induce surface cooling associated with anomalous ocean heat loss, upwelling and diapycnal mixing. In this study we investigate the overall impact of extreme wind events on the upper ocean in the Western Mediterranean sea using sea surface temperature and sea surface height observational data products over the period 1993–2014. We show that the largest thermal anomaly is observed a couple of days after the intense wind event and that it is dependent on the wind intensity. During winter, when deep water formation occurs, it persists for over a month. During summer, when the thermocline is very shallow, the recovery time scale is typically less than 10 days. The sea surface height signal reaches a minimum in correspondence to the intense wind, and normal conditions recover in about six weeks. Unlike for intense winds in the tropics associated to the passage of tropical cyclones, no long term sea surface height anomaly is observed, indicating that the water column heat content is not significantly modified. The observed recovery times suggest instead the possibility of feedbacks on the dynamics of intense cyclones at sub-monthly time scales.

scholarly journals Ecology of the Atlantic black skipjack Euthynnus alletteratus (Osteichthyes: Scombridae) in the western Mediterranean Sea inferred by parasitological analysis

Parasitology ◽  
2016 ◽  
Vol 143 (10) ◽  
pp. 1330-1339 ◽  
Author(s):  
SALVATORE MELE ◽  
M. GRAZIA PENNINO ◽  
M. CRISTINA PIRAS ◽  
DAVID MACÍAS ◽  
M. JOSÉ GÓMEZ-VIVES ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Small Scale ◽  
Interannual Variations ◽  
Western Atlantic ◽  
Parasite Abundance ◽  
Western Atlantic Ocean ◽  
Western Mediterranean Sea

SUMMARYBetween 2008 and 2011, the head of 150 Euthynnus alletteratus (Osteichthyes: Scombridae) caught inshore off the southeastern Iberian coast (western Mediterranean Sea) were examined for parasites. Two monogeneans, four didymozoid trematodes and four copepods were found. Parasite abundance showed a positive relationship with the annual sea surface temperature, except for Pseudocycnus appendiculatus, but negative with the sea depth (Capsala manteri, Neonematobothrium cf. kawakawa and Caligus bonito). Prevalences and mean abundances differed significantly among sampling areas, except for C. manteri, Oesophagocystis sp. 2 and Ceratocolax euthynni, and sampling years (Melanocystis cf. kawakawa, N.cf. kawakawa, P. appendiculatus and Unicolax collateralis). Results indicate that the parasite abundances of E. alletteratus in the western Mediterranean Sea depend mainly on regional environmental variables, which can show interannual variations. The presence of pelagic parasites, i.e. didymozoids and P. appendiculatus, could indicate that E. alletteratus migrates between inshore and offshore pelagic domains. The different parasite faunas reported in E. alletteratus populations from the western Atlantic Ocean and the Mediterranean Sea appear to point out the geographical host isolation. These results suggest that E. alletteratus inhabiting the western Mediterranean Sea performs inshore-offshore small-scale migrations, and not transoceanic migrations between the western Atlantic Ocean and Mediterranean Sea.

scholarly journals Ocean signature of intense wind events in the Western Mediterranean Sea

2018 ◽  
Author(s):  
Francesco Ragone ◽  
Andrea Meli ◽  
Anna Napoli ◽  
Claudia Pasquero
Keyword(s):  
Mediterranean Sea ◽  
Winter Season ◽  
Heat Content ◽  
Sea Surface Height ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Height Anomaly ◽  
Surface Cooling ◽  
Western Mediterranean Sea ◽  
Wind Events

Abstract. The Western Mediterranean Sea is often subject to intense winds, especially during the winter season. The effects of the enhanced enthalpy and momentum fluxes on the upper ocean is investigated using sea surface temperature and sea surface height observational data products in the period 1993–2014. The maximum surface cooling associated with the anomalous ocean heat loss, with upwelling, and with diapycnal mixing is shown to occur a couple of days after the intense wind event, to be dependent on the wind intensity and to persist for over a month during winter, when deep water is formed, and for about 10 days during summer, when the thermocline is very shallow. The sea surface height signal reaches a minimum in correspondence of the intense wind, and normal conditions recover in about six weeks. Unlike for intense winds in the tropics, associated to tropical cyclones, no long term sea surface height anomaly is observed, indicating that the water column heat content is not significantly modified.

scholarly journals Geochronology and palaeoclimatic context of submerged siliciclastic beachrock formation in the western Mediterranean Sea

2021 ◽  
Vol 85 (4) ◽  
pp. 225-244
Author(s):  
Carles Roqué Pau ◽  
Mario Zarroca Hernández ◽  
Rogelio Linares Santiago
Keyword(s):  
Mediterranean Sea ◽  
Coarse Sand ◽  
Western Mediterranean ◽  
Ice Age ◽  
Phase Iii ◽  
Swash Zone ◽  
The North ◽  
Western Mediterranean Sea ◽  
Magnesium Calcite ◽  
High Magnesium Calcite

This article describes the geomorphological and petrological characteristics of 19 submerged beachrocks located on the north Catalan coast (western Mediterranean Sea). Their length ranges between 8 and 1039 m, their width between 1.5 and 86.5 m and their thickness between 0.4 and 3.25 m. They are siliciclastic beachrocks consisting of well-rounded gravels with a very coarse sand matrix, and they have a low proportion of bioclasts (<1%). Cementation occurred in the swash zone and adjacent foreshore due to the precipitation of high magnesium calcite. From absolute dates (14C and optically stimulated luminescence) and anthropic artifacts, three phases of formation attributable to the Late Holocene were identified. Phase I corresponds to the warm and humid Roman Period and was recorded at a level below -3.75 m mean sea level (MSL). Phase II corresponds to the warm and arid Medieval Climate Anomaly and was recorded at +0.25 m to -2.5 m MSL. Phase III corresponds to the Little Ice Age and Industrial Period and was recorded at levels ranging from +0.5 m to -3.0 m MSL. Good temporal correspondence between the chronology of the cementation phases and warm and/or dry palaeoclimatic conditions can be established.

scholarly journals Development of coccolithophore-based transfer functions in the Western Mediterranean Sea: a sea surface salinity reconstruction for the last 15.5 kyr

2015 ◽  
Vol 11 (4) ◽  
pp. 3759-3798
Author(s):  
B. Ausín ◽  
I. Hernández-Almeida ◽  
J.-A. Flores ◽  
F.-J. Sierro ◽  
M. Grosjean ◽  
...  
Keyword(s):  
Transfer Function ◽  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Weighted Averaging ◽  
Alboran Sea ◽  
Surface Salinity ◽  
Western Mediterranean Sea ◽  
Alborán Sea

Abstract. A new dataset of 88 marine surface sediment samples and related oceanic environmental variables (temperature, salinity, chlorophyll a, oxygen, etc.) was studied to quantify the relationship between assemblages of coccolithophore species and modern environmental conditions in the Western Mediterranean Sea and the Atlantic Ocean, west of the Strait of Gibraltar. Multivariate statistical analyses revealed that coccolithophore species were primarily related to the sea surface salinity (SSS) gradient, which explains an independent and significant proportion of variance in the coccolithophore data. A quantitative coccolithophore-based transfer function to estimate SSS was developed using the Modern Analog Technique (MAT) and weighted-averaging partial-least square regression (WA-PLS). The bootstrapped regression coefficient (R2boot) was 0.85MAT and 0.80WA-PLS, with root-mean square error of prediction (RMSEP) of 0.29MAT and 0.30WA-PLS (psu). The resulting transfer function was applied to fossil coccolithophore assemblages in the highly resolved (∼ 65 yr) sediment core CEUTA10PC08 from the Alboran Sea (Western Mediterranean) in order to reconstruct SSS for the last 25 kyr. The reliability of the reconstruction was evaluated by assessing the degree of similarity between fossil and modern coccolithophore assemblage, and comparison of reconstruction with fossil ordination scores. Analogs were poor for the stadials associated with Heinrich Event 2 and 1 and part of the Last Glacial Maximum. Good analogs indicate more reliable reconstruction of the SSS for the last 15.5 kyr. During this period, several millennial and centennial SSS changes were observed and associated with variations in the Atlantic Water entering the Alboran Sea, sea-level oscillations, and arid or humid atmospheric conditions in the Western Mediterranean.

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