Preliminary results of high resolution paleoceanography and paleoclimatology during sapropel S1 deposition (South Limnos Basin, North Aegean Sea).

Οι παλαιοπεριβαλλοντικές συνθήκες κατά τη διάρκεια απόθεσης του σαπροπηλού S1 στο Βόρειο Αιγαίο (πυρήνας βαρύτητας Μ-4, μήκους 2,53 m, λεκάνης νότιας Λήμνου) προσδιορίζονται με βάση την ποσοτική ανάλυση μικροπαλαιοντολογικών (βενθονικά και πλαγκτονικά τρηματοφόρα) και γεωχημικών (OC, δ13Corg) δεικτών. Χαρακτηριστικό του πυρήνα Μ-4 είναι η μεγάλη εμφάνιση του S1 που φτάνει το πάχος των 96 cm. Η μελέτη κατέδειξε ότι, το κατώτερο σαπροπηλικό στρώμα S1a αποτέθηκε σε θερμότερες συνθήκες, εντονότερης δυσοξίας, σε σχέση με το ανώτερο σαπροπηλικό στρώμα S1b.. Αύξηση της παραγωγικότητας και καλύτερη διατήρηση του οργανικού υλικού πιστοποιήθηκαν στο κατώτερο τμήμα του S1. Η διακοπή των σαπροπηλικών συνθηκών στα 8,0 Ka BP που χαρακτηρίζεται κυρίως από την αύξηση της σχετικής συχνότητας των συμφυρματοπαγών μορφών των βενθονικών τρηματοφόρων υποστηρίζει συνθήκες υψηλής οξυγόνωσης του πυθμένα και εισροή γλυκών υδάτων.The paleoenviromental conditions during the depositional interval of sapropel S1 in the northeastern Aegean (gravity core M-4, length 2.53 m; south Limnos basin) are studied based on quantitative micropaleontological (benthic and planktonic foraminifera) and geochemical (OC, δ13Corg) analyses. Special feature of core M-4 is the thickness of S1 layer (96 cm). Our study points that sapropelic layer S1a has been deposited in more dysoxic and warmer conditions in respect to S1b. Both primary productivity and preservation of organic material are more intense during the lower part of S1. An interruption of the sapropelic conditions at 8.0 Ka BP which is mainly characterized by the increase of agglutinated foraminiferal forms confirms both higher oxygen bottom conditions and freshwater input

Atmospheric and Oceanographic Forcing Impact Particle Flux Composition and Carbon Sequestration in the Eastern Mediterranean Sea: A Three-Year Time-Series Study in the Deep Ierapetra Basin.

Sinking particles are a critical conduit for the export of organic material from surface waters to the deep ocean. Despite their importance in oceanic carbon cycling, little is known about the biotic composition and seasonal variability of sinking particles reaching abyssal depths. Herein, sinking particle flux data, collected in the deep Ierapetra Basin for a three-year period (June 2010 to June 2013), have been examined at the light of atmospheric and oceanographic parameters and main mass components (lithogenic, opal, carbonates, nitrogen, and organic carbon), stable isotopes of particulate organic carbon (POC) and source-specific lipid biomarkers. Our aim is to improve the current understanding of the dynamics of particle fluxes and the linkages between atmospheric dynamics and ocean biogeochemistry shaping the export of organic matter in the deep Eastern Mediterranean Sea. Overall, particle fluxes showed seasonality and interannual variability over the studied period. POC fluxes peaked in spring April-May 2012 (12.2 mg m−2 d−1) related to extreme atmospheric forcing. Summer export was approximately fourfold higher than mean wintertime, fall, and springtime (except for the episodic event of spring 2012), fueling efficient organic carbon sequestration. Lipid biomarkers indicate a high relative contribution of natural and anthropogenic, marine- and land-derived POC during both spring (April-May) and summer (June-July) reaching the deep-sea floor. Moreover, our results highlight that both seasonal and episodic pulses are crucial for POC export, while the coupling of extreme weather events and atmospheric deposition can trigger the influx of both marine labile carbon and anthropogenic compounds to the deep Levantine Sea. Finally, the comparison of time series data of sinking particulate flux with the corresponding biogeochemical parameters data previously reported for surface sediment samples from the deep-sea shed light on the benthic-pelagic coupling in the study area. Thus, this study underscores that accounting the seasonal and episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of natural and anthropogenic POC sequestration, and for a better understanding of the global carbon cycle

Brine recovery from hypersaline wastewaters from table olive processing by combination of biological treatment and membrane technologies

[EN] The fermentation brines from table olive processing (FTOP) are hypersaline effluents (conductivities higher than 75 mS·cm-1) with high organic matter concentrations (COD around 10 g·L-1), which also include phenolic compounds (between 700 and 1500 mg TY·L-1). In this work, an integrated process for the FTOP reuse as brine in the table olive processing has been evaluated. This integrated process consisted of a biological treatment followed by a membrane system, which included ultrafiltration (UF) plus nanofiltration (NF). The biological treatment was carried out by 6 L laboratory sequencing batch reactor (SBR). UF and NF were performed in laboratory plants for flat membranes of 0.0125 and 0.0072 m2, respectively. Each stream generated during the FTOP treatment (SBR effluent, and UF and NF permeates) were evaluated. The SBR eliminated around 80% of COD and 71% of total phenols concentration. In the final NF permeate the COD concentration was lower than 125 mg·L-1; while the turbidity, colour and phenolic compounds, were completely removed.The authors of this work thank the financial support of CDTI (Centre for Development Technological Industrial) depending on the Spanish Ministry of Science and Innovation.Ferrer-Polonio, E.; Carbonell Alcaina, C.; Mendoza Roca, JA.; Iborra Clar, A.; Alvarez Blanco, S.; Bes-Piá, M.; Pastor Alcañiz, L. (2017). Brine recovery from hypersaline wastewaters from table olive processing by combination of biological treatment and membrane technologies. Journal of Cleaner Production. 142:1377-1386. doi:10.1016/j.jclepro.2016.11.169S1377138614

First reconstruction of the last 2K climate variability in the NW Mediterranean (north Aegean Sea): organic geochemical evidence

International audienc

Sources and downward fluxes of polycyclic aromatic hydrocarbons in the open southwestern Black Sea

International audienc

Assessment of the eruptive activity and identification of the mud breccia's source in the Olimpi mud volcano field, Eastern Mediterranean

Even though the intensity and frequency of the eruptive episodes of deep-sea mud volcanoes (MVs) substantially regulate the methane fluxes into the hydrosphere and the development of the near-seafloor sulfate zone that affects the position of the gas hydrate stability zone, these factors are not yet adequately investigated. Moreover, the evaluation of the eruptive sediment's thermal maturity may provide solid documentation of the petroleum generation potential in high depths below seafloor (bsf). Hence, the present study, through the integration of sedimentary facies analysis with hydrocarbon biomarker analysis (based on the concentrations of long-chain (C25–C35) n-alkanes, hopanes and steranes), supported by swath bathymetry data, examined five sediment cores recovered from the Gelendzhik, Moscow, Milano, Leipzig and Heraklion MVs of the Olimpi mud volcano field (OMVF) on the central Mediterranean Ridge. The main objective of this investigation was to assess the ‘modern’ eruptive activity in the OMVF and identify the mud breccia's origin and mobilization depth (based on its maturity level), and the ages of the source beds. Among the studied MVs, Milano, Leipzig and Heraklion appear ‘recently’ active, while Moscow perhaps remains in dormancy for at least one century. The eruptive activity in the OMVF seems to be, generally, vigorous and persistent, while it is linked with several source beds of variable stratigraphy or environmental condition. The multiple eruptive episodes, occurring as uninterrupted events or via pulses, create conditions that perhaps favour high releases of methane into the water column as well as the growth of the gas hydrate phase near the seafloor. The identified ‘modern’ mudflows appear thermally immature for oil generation, while they most probably originate from terrestrial source beds located not deeper than 2 km bsf. A Messinian age could be suggested for the principal sources of the very soft to soft mud breccias of the OMVF, while stratigraphic horizons of Early-Middle Miocene might be proposed as the likely major sources for the firm to very stiff mud breccias of the area. © 2019 Elsevier Lt

Sea surface temperatures and environmental conditions during the “warm Pliocene” interval (~ 4.1–3.2 Ma) in the Eastern Mediterranean (Cyprus)

Organic geochemical (alkenones) and micropaleontological (nannofossil) data from the Pissouri South section (PPS) in the island of Cyprus provided a detailed description of the paleoclimatic (sea surface temperature-SST) and paleoenvironmental conditions during the “warm Pliocene” (c. 4.1–3.25 Ma) in the Eastern Mediterranean. We found that the suite of sapropel events recorded in the studied interval took place under conditions of increased SST, enhanced water column stratification and development of a productive deep chlorophyll maximum (DCM), as witnessed by the dominance of Florisphaera profunda species. Such conditions are similar to those prevailing during Quaternary sapropel formation, triggered by freshwater discharges from the N. African margin due to insolation-driven intensification of the African monsoon. The absence of F. profunda in Pliocene sapropels from central Mediterranean records highlights the sensitive response of the eastern basin to freshwater perturbations. Comparisons between alkenone and calcareous nannofossil assemblage patterns infer Pseudoemiliania lacunosa as the main alkenone producer in sapropel layers; yet Reticulofenestra spp. contribution cannot be ruled out. The first Pliocene alkenone-SST record in the E. Mediterranean presented here documents the “warm Pliocene” period (~ 4.1–3.25 Ma) characterized by mean SST of c. 26 °C. Distinct SST minima at ~ 3.9 Ma, 3.58 Ma and between 3.34 and 3.31 Ma, correspond to the MIS Gi16, MIS MG12 and MIS M2 global cooling episodes, before the onset of the Northern Hemisphere glaciation. Our findings imply that the peak of the MIS M2 cooling in the Eastern Mediterranean may be up to ~ 40 kyrs older than the age attributed before to benthic stable oxygen isotopes records of this event. © 2017 Elsevier B.V

Sea surface temperatures and environmental conditions during the “warm Pliocene” interval (~ 4.1–3.2 Ma) in the Eastern Mediterranean (Cyprus)

International audienc

Composition and sources of sedimentary organic matter in deep basins of the North-Eastern Mediterranean Sea

International audienc