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Angers, France

Von Schuckmann K.,Aix - Marseille University | Sallee J.-B.,Paris-Sorbonne University | Sallee J.-B.,British Antarctic Survey | Chambers D.,University of South Florida | And 5 more authors.
Ocean Science | Year: 2014

Variations in the world's ocean heat storage and its associated volume changes are a key factor to gauge global warming and to assess the earth's energy and sea level budget. Estimating global ocean heat content (GOHC) and global steric sea level (GSSL) with temperature/salinity data from the Argo network reveals a positive change of 0.5 ± 0.1 W m-2 (applied to the surface area of the ocean) and 0.5 ± 0.1 mm year-1 during the years 2005 to 2012, averaged between 60° S and 60° N and the 10-1500 m depth layer. In this study, we present an intercomparison of three global ocean observing systems: the Argo network, satellite gravimetry from GRACE and satellite altimetry. Their consistency is investigated from an Argo perspective at global and regional scales during the period 2005-2010. Although we can close the recent global ocean sea level budget within uncertainties, sampling inconsistencies need to be corrected for an accurate global budget due to systematic biases in GOHC and GSSL in the Tropical Ocean. Our findings show that the area around the Tropical Asian Archipelago (TAA) is important to closing the global sea level budget on interannual to decadal timescales, pointing out that the steric estimate from Argo is biased low, as the current mapping methods are insufficient to recover the steric signal in the TAA region. Both the large regional variability and the uncertainties in the current observing system prevent us from extracting indirect information regarding deep-ocean changes. This emphasizes the importance of continuing sustained effort in measuring the deep ocean from ship platforms and by beginning a much needed automated deep-Argo network. Source

Ouassas M.,University Ibn Zohr | Lefrere L.,University Ibn Zohr | Ait Alla A.,University Ibn Zohr | Agnaou M.,University Ibn Zohr | And 2 more authors.
Journal of Materials and Environmental Science | Year: 2015

The Khnifiss lagoon is one of the most important wetlands along the Moroccan Atlantic coastline. Situated in a Saharan area, this ecosystem is highly diverse in terms of both fauna and flora, but has not been extensively studied. In an attempt to provide more information about the biological resources of the Khnifiss lagoon, investigations on some aspects of the biology of the annelid polychaete Marphysa sanguinea were undertaken from February 2005 to January 2006, and are reported here. In term of our study, the sex ratio was close to 1:1. The oocytes were classified into three classes which vary in size during the reproductive cycle. According to the mean oocytes diameter, the highest gametogenic activity occurred in August. We found that the spawning period coincided with the warm water temperatures present between May and July. The results highlighted the impact of abiotic characteristics which are unique to the Khnifiss lagoon which are influenced by the arid climate of the Sahara and by the Canary Current upwelling. Source

Masse J.-P.,Aix - Marseille University | Maksoud S.,CNRS Oceanic Domains Laboratory | Fenerci-Masse M.,Aix - Marseille University | Granier B.,UBO | And 2 more authors.
Carnets de Geologie | Year: 2015

The presence in Lebanon of Offneria murgensis and Offneria nicolinae, two characteristic components of the Early Aptian Arabo-African rudist faunas, fills a distributional gap of the corresponding assemblage between the Arabic and African occurrences, on the one hand, and the Apulian occurrences, on the other hand. This fauna bears out the palaeogeographic placement of Lebanon on the southern Mediterranean Tethys margin established by palaeostructural reconstructions. The associated micropaleontological elements suggest an earliest Aptian age (early Bedoulian) for the Offneria murgensis - O. nicolinae assemblage found in the “Falaise de Blanche” stratigraphic interval, instead of a late Early Aptian age as proposed for most of the peri-Adriatic and Middle East occurrences recognized so far. These caprinid specimens are characterized by relatively modest sizes, moreover other rudists commonly part of the assemblage are lacking. The dominance of caprinids in the study area suggests a distal platform setting, i.e., close proximity to the platform edge. © 2015, Carnets de Geologie. All rights reserved. Source

Out of the few records of rudists from the Cretaceous strata of the South Atlantic coastal basins only two refer to Brazilian localities. However, petrographic analyses demonstrate that these shells should be assigned to Ostreids or to Pycnodontids rather than to Rudistids. More specifically, the domain considered herein, north of the Río Grande Rise -Walvis Ridge barrier, was part of the warm-water "tropical" realm, but it was not part of the Mesogean domain because both Rudistids and Orbitolinas are missing. In addition, the scarcity of corals leads us to ascribe the taphonomic assemblage to the Chloralgal facies. Neither generalized hypersalinity or extreme sea-water tempe-ratures seem to account for these biotic peculiarities. Instead, our alternative hypothesis favors the driving role played by oceanic circulation in the dispersal of the benthic organisms. © 2015, Carnets de Geologie. All rights reserved. Source

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