scholarly journals Oxygen budget of the north-western Mediterranean deep- convection region

2021 ◽  
Vol 18 (3) ◽  
pp. 937-960
Author(s):  
Caroline Ulses ◽  
Claude Estournel ◽  
Marine Fourrier ◽  
Laurent Coppola ◽  
Fayçal Kessouri ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Mediterranean Sea ◽  
Atmospheric Oxygen ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Biogeochemical Model ◽  
The North ◽  
Oxygen Budget ◽  
The Mediterranean ◽  
North Western

Abstract. The north-western Mediterranean deep convection plays a crucial role in the general circulation and biogeochemical cycles of the Mediterranean Sea. The DEWEX (DEnse Water EXperiment) project aimed to better understand this role through an intensive observation platform combined with a modelling framework. We developed a three-dimensional coupled physical and biogeochemical model to estimate the cycling and budget of dissolved oxygen in the entire north-western Mediterranean deep-convection area over the period September 2012 to September 2013. After showing that the simulated dissolved oxygen concentrations are in a good agreement with the in situ data collected from research cruises and Argo floats, we analyse the seasonal cycle of the air–sea oxygen exchanges, as well as physical and biogeochemical oxygen fluxes, and we estimate an annual oxygen budget. Our study indicates that the annual air-to-sea fluxes in the deep-convection area amounted to 20 molm-2yr-1. A total of 88 % of the annual uptake of atmospheric oxygen, i.e. 18 mol m−2, occurred during the intense vertical mixing period. The model shows that an amount of 27 mol m−2 of oxygen, injected at the sea surface and produced through photosynthesis, was transferred under the euphotic layer, mainly during deep convection. An amount of 20 mol m−2 of oxygen was then gradually exported in the aphotic layers to the south and west of the western basin, notably, through the spreading of dense waters recently formed. The decline in the deep-convection intensity in this region predicted by the end of the century in recent projections may have important consequences on the overall uptake of atmospheric oxygen in the Mediterranean Sea and on the oxygen exchanges with the Atlantic Ocean, which appear necessary to better quantify in the context of the expansion of low-oxygen zones.

scholarly journals Oxygen budget for the north-western Mediterranean deep convection region

2020 ◽  
Author(s):  
Caroline Ulses ◽  
Claude Estournel ◽  
Marine Fourrier ◽  
Laurent Coppola ◽  
Fayçal Kessouri ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Mediterranean Sea ◽  
Atmospheric Oxygen ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Biogeochemical Model ◽  
The North ◽  
Oxygen Budget ◽  
The Mediterranean ◽  
North Western

Abstract. The north-western Mediterranean deep convection plays a crucial role in the general circulation and biogeochemical cycles of the Mediterranean Sea. The DEWEX (DEnse Water EXperiment) project aimed to better understand this role through an intensive observation platform combined with a modelling framework. We developed a 3 dimensional coupled physical and biogeochemical model to estimate the cycling and budget of dissolved oxygen in the entire north-western Mediterranean deep convection area over the period September 2012 to September 2013. After showing that the simulated dissolved oxygen concentrations are in a good agreement with the in situ data collected from research cruises and Argo floats, we analyze the seasonal cycle of the air-sea oxygen exchanges, as well as physical and biological oxygen fluxes, and we estimate an annual oxygen budget. Our study indicates that the annual air-to-sea fluxes in the deep convection area amounted to 20 mol m−2 yr−1. 88 % of the annual uptake of atmospheric oxygen, i.e. 18 mol m−2, occurred during the intense vertical mixing period. The model shows that an amount of 27 mol m−2 of oxygen, injected at the sea surface and produced through photosynthesis, was transferred under the euphotic layer, mainly during deep convection. An amount of 20 mol m−2 of oxygen was then gradually exported in the aphotic layers to the south and west of the western basin, notably, through the spreading of dense waters recently formed. The decline in the deep convection intensity in this region predicted by the end of the century in recent projections, may have important consequences on the overall uptake of atmospheric oxygen in the Mediterranean Sea and on the oxygen exchanges with the Atlantic Ocean, that appear necessary to better quantify in the context of the expansion of low-oxygen zones.

scholarly journals On the trophic regimes of the Mediterranean Sea: a satellite analysis

2008 ◽  
Vol 5 (4) ◽  
pp. 2959-2983 ◽  
Author(s):  
F. D'Ortenzio ◽  
M. Ribera d'Alcalà
Keyword(s):  
Mediterranean Sea ◽  
Spring Bloom ◽  
Marine Ecosystem ◽  
Chlorophyll Concentration ◽  
Western Mediterranean ◽  
Physical Forcing ◽  
The North ◽  
The Mediterranean ◽  
Satellite Analysis ◽  
North Western

Abstract. The ten years of the SeaWiFS satellite surface chlorophyll concentration observations, presently available, were used to characterize the biogeography of the Mediterranean Sea and the seasonal cycle of the surface biomass in different areas of the basin. The K-means cluster analysis was applied on the satellite time-series of chlorophyll concentration. The resulting coherent patterns were then explained on the basis of the present knowledge of the basin functioning. Winter biomass enhancements were shown to occur in most of the basin and last for 2–3 months depending on the region. Classical spring bloom regimes were also observed, regularly in the North Western Mediterranean, and intermittently in four others specific areas. The analysis confirmed that the Mediterranean Sea is an ideal area to evaluate the impacts of the external physical forcing on the marine ecosystem functioning.

scholarly journals On the trophic regimes of the Mediterranean Sea: a satellite analysis

2009 ◽  
Vol 6 (2) ◽  
pp. 139-148 ◽  
Author(s):  
F. D'Ortenzio ◽  
M. Ribera d'Alcalà
Keyword(s):  
Mediterranean Sea ◽  
Spring Bloom ◽  
Chlorophyll Concentration ◽  
Temporal Trends ◽  
Western Mediterranean ◽  
Present Knowledge ◽  
The North ◽  
The Mediterranean ◽  
Satellite Analysis ◽  
North Western

Abstract. The ten years of the SeaWiFS satellite surface chlorophyll concentration observations, presently available, were used to characterize the biogeography of the Mediterranean Sea and the seasonal cycle of the surface biomass in different areas of the basin. The K-means cluster analysis was applied on the satellite time-series of chlorophyll concentration. The resulting coherent patterns were then explained on the basis of the present knowledge of the basin's functioning. Winter biomass enhancements were shown to occur in most of the basin and last for 2–3 months depending on the region. Classical spring bloom regimes were also observed, regularly in the North Western Mediterranean, and intermittently in four other specific areas. The geographical correspondence between specific clusters and regions showing high values of mean chlorophyll concentration indicates that, at least in the Mediterranean Sea, accumulations of phytoplankton are observed only where specific temporal trends are present.

Feeding ecology of striped dolphins, Stenella coeruleoalba, in the north-western Mediterranean Sea based on stable isotope analyses

2011 ◽  
Vol 92 (8) ◽  
pp. 1677-1687 ◽  
Author(s):  
A.M. Meissner ◽  
C.D. MacLeod ◽  
P. Richard ◽  
V. Ridoux ◽  
G. Pierce
Keyword(s):  
Stable Isotope ◽  
Mediterranean Sea ◽  
Trophic Level ◽  
Western Mediterranean ◽  
Stenella Coeruleoalba ◽  
The North ◽  
Western Mediterranean Sea ◽  
The Mediterranean ◽  
Isotope Analyses ◽  
North Western

The feeding ecology of striped dolphin, Stenella coeruleoalba, in the north-western Mediterranean Sea was studied using stable isotope analyses. Carbon and nitrogen stable isotope ratios were measured in skin and muscle tissues of stranded and by-caught dolphins from six geographical areas in the Mediterranean Sea and Atlantic Ocean. Variation in δ15N in relation to dolphin size is attributed to changes in diet. Nursing calves have a higher trophic level than weaned animals and their δ15N values decrease progressively until weaning, estimated to be at a body length of around 155 cm. δ15N values then increased for larger individuals which suggests changes in diet for mature dolphins. Geographical differences in diet were apparent between the Atlantic and the Mediterranean, although no clear differences were apparent between the five Mediterranean areas. Comparisons of the nitrogen isotope ratios of skin and muscle highlighted a higher fractionation in skin compared to the muscle tissue. Values of δ13C also increased with body length although it appears that this is not only driven by trophic level enrichment. δ13C increases before weaning and the difference in trophic level between newly-weaned and mature dolphins was twice as high for carbon as for nitrogen. Ontogenetic changes in carbon isotope composition may therefore be driven by feeding on deep water prey and dolphin movements outside the coastal feeding grounds. Indeed, seasonal variations in δ13C are suspected to be driven by migration within the Mediterranean basin.

scholarly journals Further spreading of the non-indigenous bryozoan Celleporaria brunnea in the Mediterranean Sea: port to port morphological variations

2015 ◽  
Author(s):  
Jasmine Ferrario ◽  
Agnese Marchini ◽  
Martina Marić ◽  
Dan Minchin ◽  
Anna Occhipinti-Ambrogi
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Indigenous Species ◽  
Large Variability ◽  
Morphometric Characters ◽  
Morphological Variations ◽  
The North ◽  
Western Mediterranean Sea ◽  
The Pacific ◽  
The Mediterranean

The Pacific cheilostome bryozoan Celleporaria brunnea (Hincks, 1884), a non-indigenous species already known for the Mediterranean Sea, was recorded in 2013-2014 from nine Italian port localities (Genoa, Santa Margherita Ligure, La Spezia, Leghorn, Viareggio, Olbia, Porto Rotondo, Porto Torres and Castelsardo) in the North-western Mediterranean Sea; in 2014 it was also found for the first time in the Adriatic Sea, in the marina “Kornati”, Biograd na Moru (Croatia). In Italy, specimens of C. brunnea were found in 44 out of 105 samples (48% from harbour sites ad 52% from marinas). These data confirm and update the distribution of C. brunnea in the Mediterranean Sea, and provide evidence that recreational boating is a vector responsible for the successful spread of this species. Previous literature data have shown the existence of differences in orifice and interzooidal avicularia length and width among different localities of the invaded range of C. brunnea. Therefore, measurements of orifice and avicularia were assessed for respectively 30 zooids and 8 to 30 interzooidal avicularia for both Italian and Croatian localities, and compared with literature data, in order to verify the existence of differences in the populations of C. brunnea that could reflect the geographic pattern of its invasion range. Our data show high variability of orifice measures among and within localities: zooids with broader than long orifice coexisted with others displaying longer than broad orifice, or similar values for both length and width. The morphological variation of C. brunnea in these localities, and above all the large variability of samples within single localities or even within colonies poses questions on the reliability of such morphometric characters for inter and intraspecific evaluations.

scholarly journals A new species of Pista Malmgren, 1866 (Polychaeta, Terebellidae) from the north-western Mediterranean Sea

ZooKeys ◽  
2019 ◽  
Vol 838 ◽  
pp. 71-84
Author(s):  
Céline Labrune ◽  
Nicolas Lavesque ◽  
Paulo Bonifácio ◽  
Pat Hutchings
Keyword(s):  
New Species ◽  
Mediterranean Sea ◽  
Anterior Part ◽  
Posterior Part ◽  
Western Mediterranean ◽  
Single Pair ◽  
The North ◽  
Western Mediterranean Sea ◽  
North Western ◽  
A New Species

A new species of Terebellidae, Pistacolinisp. n., has been identified from the harbour of Banyuls-sur-Mer, north-western Mediterranean Sea. This new species was found in very high densities, exclusively in gravelly sand deposited manually, and was not found in the original source habitat of the gravel. This species is characterized by the colour of the ventral shields with pinkish anterior part and a blood red posterior part in live specimens, a pair of unequal-sized plumose branchiae inserted on segment II and anterior thoracic neuropodia with long-handled uncini. The presence of long-handled uncini even in the smallest specimens constitutes the major difference between Pistacolinisp. n. and other Pista species with a single pair of branchiae such as P.lornensis and P.bansei.

Sign in / Sign up

Export Citation Format

Share Document