scholarly journals On the barium–oxygen consumption relationship in the Mediterranean Sea: implications for mesopelagic marine snow remineralization

2021 ◽  
Vol 18 (6) ◽  
pp. 2205-2212
Author(s):  
Stéphanie H. M. Jacquet ◽  
Dominique Lefèvre ◽  
Christian Tamburini ◽  
Marc Garel ◽  
Frédéric A. C. Le Moigne ◽  
...  

Abstract. In the ocean, remineralization rate associated with sinking particles is a crucial variable. Since the 1990s, particulate biogenic barium (Baxs) has been used as an indicator of carbon remineralization by applying a transfer function relating Baxs to O2 consumption (Dehairs's transfer function, Southern Ocean-based). Here, we tested its validity in the Mediterranean Sea (ANTARES/EMSO-LO) for the first time by investigating connections between Baxs, prokaryotic heterotrophic production (PHP) and oxygen consumption (JO2-Opt; optodes measurement). We show that (1) higher Baxs (409 pM; 100–500 m) occurs in situations where integrated PHP (PHP100/500=0.90) is located deeper, (2) higher Baxs occurs with increasing JO2-Opt, and (3) there is similar magnitude between JO2-Opt (3.14 mmol m−2 d−1; 175–450 m) and JO2-Ba (4.59 mmol m−2 d−1; transfer function). Overall, Baxs, PHP and JO2 relationships follow trends observed earlier in the Southern Ocean. We conclude that such a transfer function could apply in the Mediterranean Sea.

2020 ◽  
Author(s):  
Stéphanie H. M. Jacquet ◽  
Dominique Lefèvre ◽  
Christian Tamburini ◽  
Marc Garel ◽  
Frédéric A. C. Le Moigne ◽  
...  

Abstract. In the ocean, remineralisation rate associated with sinking particles is a crucial variable. Since the 90's, particulate biogenic barium (Baxs) has been used as an indicator of carbon remineralization by applying a transfer function relating Baxs to O2 consumption (Dehairs's transfer function, Southern Ocean-based). Here, we tested its validity in the Mediterranean Sea (ANTARES / EMSO-LO) for the first time by investigating connections between Baxs, prokaryotic heterotrophic production (PHP) and oxygen consumption (JO2-Opt; optodes measurement). We show that: (1) higher Baxs (409 pM; 100–500 m) in situations where integrated PHP (PHP100/500 = 0.90) is located deeper, (2) higher Baxs with increasing JO2-Opt, and (3) similar magnitude between JO2-Opt (3.14 mmol m−2 d−1; 175–450 m) and JO2-Ba (4.59 mmol m−2 d−1; transfer function). Overall, Baxs, PHP and JO2 relationships follow trends observed in the Southern Ocean. We believe that such transfer function could apply in the Mediterranean Sea with no restriction.


2020 ◽  
Author(s):  
Stéphanie H. M. Jacquet ◽  
Christian Tamburini ◽  
Marc Garel ◽  
Aurélie Dufour ◽  
France Van-Vambeke ◽  
...  

Abstract. We report on the sub-basins variability of particulate organic carbon (POC) remineralization in the central and western Mediterranean Sea during a late spring period (PEACETIME cruise). POC remineralization rates (MR) were estimated using the excess non-lithogenic particulate barium (Baxs) inventories in mesopelagic waters (100–1000 m) and compared with prokaryotic heterotrophic production (PHP). MR range from 25 ± 2 to 306 ± 70 mg C m−2 d−1. Results reveal larger MR processes in the Algerian (ALG) basin compared to the Tyrrhenian (TYR) and Ionian (ION) basins. Baxs inventories and PHP also indicates that significant remineralization occurs over the whole mesopelagic layers in the ALG basin in contrast to the ION and TYR basins where remineralization is mainly located in the upper 500 m horizon. We propose that this may be due to particle injection pumps likely driven by strong winter convection in the Western basin of the Mediterranean Sea. This implies significant differences in the remineralization length scale of POC in the central Mediterranean Sea relative to the western region.


2016 ◽  
Vol 60 (4) ◽  
pp. 2513-2515 ◽  
Author(s):  
Soumia Brahmi ◽  
Abdelaziz Touati ◽  
Axelle Cadière ◽  
Nassima Djahmi ◽  
Alix Pantel ◽  
...  

ABSTRACTTo determine the occurrence of carbapenem-resistantAcinetobacter baumanniiin fish fished from the Mediterranean Sea near the Bejaia coast (Algeria), we studied 300 gills and gut samples that had been randomly and prospectively collected during 1 year. After screening on selective agar media, using PCR arrays and whole-genome sequencing, we identified for the first time two OXA-23-producingA. baumanniistrains belonging to the widespread sequence type 2 (ST2)/international clone II and harboring aminoglycoside-modifying enzymes [aac(6′)-Ib andaac(3′)-I genes].


2012 ◽  
Vol 13 (1) ◽  
pp. 89 ◽  
Author(s):  
L.M. FERRERO-VICENTE ◽  
A. LOYA-FERNANDEZ ◽  
C. MARCO-MENDEZ ◽  
E. MARTINEZ-GARCIA ◽  
J.I. SAIZ-SALINAS ◽  
...  

Specimens of the sipunculan worm Phascolion (Phascolion) caupo Hendrix, 1975 have been collected for the first time in the Mediterranean Sea, thus increasing the number of known sipunculan species of up to 36 in this area. They were encountered on soft bottoms from the coast of San Pedro del Pinatar (Western Mediterranean). Thirty specimens were collected at a depth ranging from 32.6 to 37.2 m, mainly in sandy substrata with high load of silt and clays. 80% of the individuals were found inhabiting empty shells of gastropods or empty tubes of serpulid polychaetes.


1991 ◽  
Vol 61 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Eleni Voultsiadou-Koukoura ◽  
R.W.M. van Soest

A representative of the genus Hemiasterella Carter, 1879 was found for the first time in the Mediterranean Sea during sampling in the shallow waters of the northern Aegean Sea. The new species, H. aristoteliana, is compared with Atlantic Hemiasterella elongata Topsent, 1928. The status of the family Hemiasterellidae is discussed.


2019 ◽  
Vol 366 (24) ◽  
Author(s):  
Elena Bovio ◽  
Estelle Sfecci ◽  
Anna Poli ◽  
Giorgio Gnavi ◽  
Valeria Prigione ◽  
...  

ABSTRACT Marine fungi are part of the huge and understudied biodiversity hosted in the sea. To broaden the knowledge on fungi inhabiting the Mediterranean Sea and their role in sponge holobiont, three sponges namely Aplysina cavernicola, Crambe crambe and Phorbas tenacior were collected in Villefranche sur Mer, (France) at about 25 m depth. The fungal communities associated with the sponges were isolated using different techniques to increase the numbers of fungi isolated. All fungi were identified to species level giving rise to 19, 13 and 3 species for P. tenacior, A. cavernicola and C. crambe, respectively. Of note, 35.7% and 50.0% of the species detected were either reported for the first time in the marine environment or in association with sponges. The mini-satellite analysis confirmed the uniqueness of the mycobiota of each sponge, leading to think that the sponge, with its metabolome, may shape the microbial community.


1979 ◽  
Vol 46 (2) ◽  
pp. 298-301
Author(s):  
R. R. Schmidt ◽  
S. Kaplan ◽  
J. J. Smith

Stage 34 (8-day) and 41 (15-day) chick embryos (Gallus gallus; in ovo) were exposed (3 min) to two separate amounts of mechanical (shaking) stress. Oxygen consumption determinations, following a temperature equilibration period (60 min), were made on entire, intact eggs using a Warburg apparatus equipped with 130-ml flasks modified to hold the egg. Shaking at 300 excursions per minute (epm) resulted in depressed O2 consumption by stages 34 and 41. Only stage 34 embryos had markedly depressed O2 consumption values when shaken at 100 epm. When exposed to 300 epm and reincubated for either 1, 2, or 4 hr prior to O2 consumption determinations stage 34 embryos, following an early return to control levels exhibited a marked fall in O2 consumption by 4 h reincubation. The stage 41 embryos, on the other hand, demonstrated a gradual rise to control O2 consumption levels by 4 h reincubation. Oxygen consumption has now been shown for the first time in an embryonic system (at two distinct developmental stages) to be functionally impaired by mechanically induced stress.


Parasitology ◽  
1999 ◽  
Vol 119 (6) ◽  
pp. 635-648 ◽  
Author(s):  
P. SASAL ◽  
N. NIQUIL ◽  
P. BARTOLI

The aim of this work was to study the structure of the parasite communities of Digeneans of 2 families of Teleost fishes (Sparidae and Labridae) of the Mediterranean sea. We tried to quantify the importance of both the microhabitat requirements of the parasite species and the effect of host biological factors on the parasite communities. We applied, for the first time in parasite community studies, the Canonical Correspondence Analysis (CCA) to analyse (i) the spatial distribution of parasite species within the digestive tract of the hosts; (ii) the host's biological factors (such as diet, host length, gregariousness and abundance) that may influence this spatial distribution of parasite species. Our results showed that potential microhabitats were vacant in the 2 host families studied revealing a lack of niche saturation because either there was little inter- and/or intraspecific competition or there were enough available space and resources within the host. Our results also indicated that the position of the parasite in the digestive tract is much more important than host biological factors for the structure of parasite community. Finally, we highlight the potential use of the CCA method for controlling for phylogenetic constraints in multi-species analyses.


Author(s):  
J. Dulĉić ◽  
A. Pallaoro

Lessepsian migrant Siganus rivulatus is reported for the first time from the Adriatic Sea, substantially further north than its usual area of occurrence in the Mediterranean Sea. Two specimens (111 mm total length [TL] and 149 mm TL) were captured by beach seine on 5 October 2002 off islet Bobara, near Cavtat (southern Adriatic). Morphometric and meristic characteristics of the specimens are provided. The possible explanations of this occurrence are discussed.


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