Sardine and anchovy as bioindicators of metal content in Greek coastal waters

Metal and element concentrations (Li, Na, Mg, P, Ca, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Pd, Cd, Cs, Ba, Hg, Tl, Pb, U) were monitored in the tissues of sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) from six Greek coastal areas subjected to different natural and anthropogenic forcings in order to be assessed as bioindicator species of marine metal pollution. Sardine and anchovy provided a thorough view of the metal pollution load of each site in accordance with local pollution sources. The wide range of pressures applied in Elefsina Gulf and Thermaikos Gulf are depicted in the large number and the kind of elements reaching maximum concentrations among the sites (e.g. Pb, Cu, Hg, As in Elefsina Gulf, and Cd, Ni, P in Thermaikos Gulf) while in the rest of the sites (Amvrakikos Gulf, Strymonian Sea, Thracian Sea, Artemisium Straits), few elements were found at maximum levels. Statistically significant site-specific differences in metal content were detected. The differentiation in metal content of the fish tissues among the sites could be attributed to anthropogenic pressures, different background levels and environmental conditions. Sardine and anchovy can be evaluated as appropriate, reliable and useful bioindicator species of marine metal pollution

Decline of seagrass (Posidonia oceanica) production over two decades in the face of warming of the Eastern Mediterranean Sea

* The response of Posidonia oceanica meadows to global warming of the Eastern Mediterranean Sea, where the increase in sea surface temperature (SST) is particularly severe, is poorly investigated. * Here, we reconstructed the long-term P. oceanica production in 60 meadows along the Greek Seas over two decades (1997–2018), using lepidochronology. We determined the effect of warming on production by reconstructing the annual and maximum (i.e. August) SST, considering the role of other production drivers related to water quality (i.e. Chla, suspended particulate matter, Secchi depth). * Grand mean (±SE) production across all sites and the study period was 48 ± 1.1 mg DW per shoot yr−1. Production over the last two decades followed a trajectory of decrease, which was related to the concurrent increase in annual SST and SSTaug. Annual SST \u3e 20°C and SSTaug \u3e 26.5°C was related to production decline (GAMM, P \u3c 0.05), while the rest of the tested factors did not help explain the production pattern. * Our results indicate a persistent and increasing threat for Eastern Mediterranean meadows, drawing attention to management authorities, highlighting the necessity of reducing local impacts to enhance the resilience of seagrass meadows to global change threats

Aquatic Global Passive Sampling (AQUA-GAPS) Revisited – First Steps towards a Network of Networks for Organic Contaminants in the Aquatic Environment

Organic contaminants, in particular persistent organic pollutants (POPs), adversely affect water quality and aquatic food webs across the globe. As of now, there is no globally consistent information available on concentrations of dissolved POPs in water bodies. The advance of passive sampling techniques has made it possible to establish a global monitoring program for these compounds in the waters of the world, which we call the Aquatic Global Passive Sampling (AQUA-GAPS) network. A recent expert meeting discussed the background, motivations, and strategic approaches of AQUA-GAPS, and its implementation as a network of networks for monitoring organic contaminants (e.g., POPs and others contaminants of concern). Initially, AQUA-GAPS will demonstrate its operating principle via two proof-of-concept studies focused on the detection of legacy and emerging POPs in freshwater and coastal marine sites using both polyethylene and silicone passive samplers. AQUA-GAPS is set-up as a decentralized network, which is open to other participants from around the world to participate in deployments and to initiate new studies. In particular, participants are sought to initiate deployments and studies investigating the presence of legacy and emerging POPs in Africa, Central and South America

Microplastics increase the marine production of particulate forms of organic matter

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AQUA-GAPS/MONET-Derived Concentrations and Trends of PAHs and Polycyclic Musks across Global Waters

Polycyclic aromatic hydrocarbons (PAHs), released from petrogenic, pyrogenic or diagenetic sources (degradation of wood materials), are of global concern due to their adverse effects, and potential for long-range transport. While dissolved PAHs have been frequently reported in the literature, there has been no consistent approach of sampling across water bodies. Passive samplers from the AQUA/GAPS-MONET initiative were deployed at 46 sites (28 marine and 18 freshwater), and analyzed for 28 PAHs and six polycyclic musks (PCMs) centrally. Freely dissolved PAH concentrations were dominated by phenanthrene (mean concentration 1500 pg L-1; median 530 pg L-1) and other low molecular weight compounds. Greatest concentrations of phenanthrene, fluoranthene, and pyrene were typically from the same sites, mostly in Europe and North America. Of the PCMs, only galaxolide (72% of samples) and tonalide (61%) were regularly detected, and were significantly cross-correlated. Benchmarking of PAHs relative to penta- and hexachlorobenzene confirmed that the most remote sites (Arctic, Antarctic, and mountain lakes) displayed below average PAH concentrations. Concentrations of 11 of 28 PAHs, galaxolide and tonalide were positively correlated (P < 0.05) with population density within a radius of 5 km of the sampling site. Characteristic PAH ratios gave conflicting results, likely reflecting multiple PAH sources and postemission changes.Authors thank the RECETOX Research Infrastructure (No LM2023069) financed by the Ministry of Education, Youth and Sport for supportive background. The research was supported by Czech Science Foundation Grant No. 20-04676X. We thank all deployment teams (SI Table S2) for their help.Peer reviewe

Study of the atmospheric physical-chemical and transport processes governing the budget of PAHs in the Eastern Mediterranean Basin

Studies dealing with the mass balance in western Mediterranean Sea have shown that this region is continually acting as a reservoir of persistent organic pollutants (POPs), including polynuclear aromatic hydrocarbons (PAHs). Since the atmosphere is supposed to be a major source of PTSs to this region, investigation of the occurrence and behavior of these compounds in the Mediterranean basin atmosphere, is of great importance. Study of atmospheric and transport process of PAHs in the eastern Mediterranean marine environment, as well as intensive seasonal samplings were performed from 2000- 2002. Atmospheric, dry and wet deposition samples were collected monthly in the eastern Mediterranean. Sea water, sedimentary particulate matter and superficial sediment samples from the marine environment were also collected. The Environmental Chemical Processes Laboratory (E.C.P.L) station, University of Crete, situated in the northeast coast of Crete, was used as a control station for fate of PAHs in eastern Mediterranean atmosphere. Geographical distribution of PAHs was carried out during two field expeditions with research vessels &Aigeo, Philia&. Air samples were collected from a number of different stations over the eastern Mediterranean seawater surface. Atmospheric sources of PAHs were studied through seasonal sampling in the urban area of Heraklion. Sources of PAHs were determined using concentration diagnostic ratio and multivariate statistical analysis. Total concentration of PAHs in Heraklion atmosphere varied from 44.3 to 129.2 ng m-3. A clear seasonal trend was observed in particulate concentration of PAHs with maximum values detected during winter. Seasonal trends of gas particulate distribution account for most variations of PAHs concentration in air particles. Emissions from vehicles and fossil fuel burning are major sources of PAHs in Heraklion atmosphere. Total concentration of PAHs in the remote area of Finokalia varied form 4.14 to 57.16 ng m-3 and gas phase PAHs contribute 90% or more of total atmospheric levels. Long-range transport is a major source of PAHs in the eastern Mediterranean atmosphere. Atmospheric samples with highest concentrations of PAHs originated in eastern and central Europe. Contrarily, samples with lowest concentrations originated in the southwest. Concentration of gas phase PAHs was equally distributed over the eastern Mediterranean Sea while particulate phase was significantly higher close to urban areas. Gas phase reaction of PAHs with OH radicals, is an important production process of highly mutagenic and carcinogenic nitro-PAHs. During 17-21/08/01 in Finokalia, concentration of 2-NF and 2-NP varied from 3.35 to 78.88 pg m-3 and from 2.22 to 21.98 pg m-3 respectively. Highest concentrations were determined during noon hours, characteristic of reactions between gas PAHs with OH radicals Air/ sea exchange is estimated to introduce 865 tonnes of PAHs per year in the whole eastern Mediterranean basin, while wet and dry deposition fluxes were 235 and 75 tonnes per year, respectively. The vast majority (98.9 %) of total atmospheric input (934.5 ‘g m-2 y-1) into the marine environment remains in the euphotic zone. Sedimentation rates of total PAHs at depths of 250m and 1440m were 10.29 and 8.27 ‘g m-2 y-1 respectively, during the period 1/5/2001 to 15/10/2001. These rates account for only 1.1 and 0.8 % of total atmospheric deposition. Average concentration of total PAHs in the sediment varied from 2.2 to1056.2 ng g-1 dry weight. Average BC and OC contents varied from 0.3 to 5.6 mg g-1 and from 2.9 to 21.4 mg g-1 dry weight, respectively. Significant correlation (R2=0.94, p<0.001) between pyrogenic PAHs and black carbon content in coastal marine sediments further suggests the importance of atmospheric input of PAHs to the Eastern Mediterranean marine ecosystem.Μελέτες για τον προσδιορισμό του ισοζυγίου μάζας στη δυτική Μεσόγειο έχουν δείξει ότι η ατμοσφαιρική οδός αποτελεί το σημαντικότερο μονοπάτι εισαγωγής των ανθεκτικών οργανικών ρυπαντών (Persistent Organic Pollutants ή POPs) συμπεριλαμβανομένων και των πολυαρωματικών υδρογονανθράκων (ΠΑΥ) στο θαλάσσιο περιβάλλον. Η έλλειψη ολιστικών μελετών στη λεκάνη της ανατολικής Μεσογείου καθιστά τη μελέτη της συμπεριφοράς των ενώσεων αυτών στην ατμόσφαιρα και στο θαλάσσιο περιβάλλον της εν λόγω περιοχής ιδιαίτερα σημαντική. Για την κατανόηση των ατμοσφαιρικών διεργασιών και των διεργασιών μεταφοράς των ΠΑΥ στο θαλάσσιο περιβάλλον της ανατολικής Μεσόγειου πραγματοποιήθηκαν εποχιακές και εντατικές δειγματοληψίες το χρονικό διάστημα 2000-2002. Συλλέχθηκαν δείγματα αερολυμάτων, ξηρής και υγρής εναπόθεσης από την ατμόσφαιρα της ανατολικής Μεσογείου. Επίσης, πραγματοποιήθηκαν δειγματοληψίες θαλασσινού νερού, καθιζάνοντος σω‘ατιδιακού υλικού και ιζήματος από το θαλάσσιο περιβάλλον της περιοχής μελέτης. Ο σταθμός του Εργαστηρίου Περιβαλλοντικών Χημικών & διεργασιών (Ε.ΠΕ.ΧΗ.&Ι) του Πανεπιστημίου Κρήτης που βρίσκεται στα βορειοανατολικά παράλια της Κρήτης χρησιμοποιήθηκε ως σταθμός αναφοράς του γίγνεσθαι των ΠΑΥ στην ατμόσφαιρα της ανατολικής Μεσογείου. Για τη μελέτη της χωρικής διακύμανσης των ΠΑΥ πραγματοποιήθηκαν δύο αποστολές με τα ερευνητικά πλοία «ΑΙΓΑΙΟ» και «ΦΙΛΙΑ» και δείγματα αέρα συλλέχθηκαν από διάφορους σταθμούς πάνω από την επιφάνεια της θάλασσας της ανατολικής Μεσογείου. Για την εκτίμηση των πηγών των ΠΑΥ στην ατμόσφαιρα πραγματοποιήθηκαν εποχιακές δειγματοληψίες αέρα στην αστική περιοχή του Ηρακλείου. Οι πηγές των ΠΑΥ μελετήθηκαν με τη χρήση διαγνωστικών λόγων συγκέντρωσης καθώς και με τη χρήση πολυμεταβλητών στατιστικής ανάλυσης. Η συνολική συγκέντρωση των ΠΑΥ στην ατμόσφαιρα του Ηρακλείου κυμάνθηκε από 44.3 έως 129.2 ng m-3. Παρατηρήθηκε σημαντική εποχιακή διακύμανση στη συγκέντρωση των ΠΑΥ στη σωματιδιακή φάση με το μέγιστο να παρουσιάζεται κατά τη διάρκεια του χει‘ώνα. Η εποχιακή ‘εταβολή της αέριας/ σω‘ατιδιακής κατανομής εξηγεί σε ένα μεγάλο ποσοστό την διακύμανση της συγκέντρωσης των ΠΑΥ στα σωματίδια της ατμόσφαιρας. Οι εκπομπές από τα τροχοφόρα και η καύση ορυκτών καυσίμων είναι ση‘αντικότερη πηγή των ΠΑΥ στην ατμόσφαιρα του Ηρακλείου. Η συνολική συγκέντρωση των ΠΑΥ στην ατμόσφαιρα της Φινοκαλιάς κυμάνθηκε από 4.14 έως 57.16 ng m-3 και η αέρια φάση των ΠΑΥ συμμετέχει σε ποσοστό άνω του 90% στη συνολική συγκέντρωσή τους στην ατμόσφαιρα. Η μεταφορά από μεγάλη απόσταση είναι η κυριότερη πηγή ΠΑΥ στην ανατολική Μεσόγειο. Στα ατμοσφαιρικά δείγματα στα οποία προσδιορίστηκαν οι μεγαλύτερες συγκεντρώσεις ΠΑΥ οι αέριες μάζες είχαν προέλευση από την κεντρική και ανατολική Ευρώπη. Αντίθετα στα δείγματα με τις μικρότερες συγκεντρώσεις οι αέριες μάζες είχαν νοτιοδυτική προέλευση. Η συγκέντρωση των ΠΑΥ στην αέρια φάση παρουσίασε ομοιόμορφη χωρική κατανομή πάνω από τη θάλασσα της ανατολικής Μεσογείου ενώ αντίθετα η σωματιδιακή φάση ήταν σημαντικά μεγαλύτερη σε περιοχές κοντά στα αστικά κέντρα. Η αντίδραση των ΠΑΥ με τις ρίζες ΟΗ στην αέρια φάση της ατμόσφαιρας της ανατολικής Μεσογείου είναι σημαντική διεργασία παραγωγής των ιδιαίτερα τοξικών νίτρο υποκατεστημένων ΠΑΥ. Η συγκέντρωση του 2-ΝΟ2-Φλουορανθενίου και του 2- ΝΟ2-Πυρενίου το χρονικό διάστημα 17-21/8/01 στην ατμόσφαιρα της Φινοκαλιάς κυμάνθηκε από 3.35 έως 70.88 pg m-3 και από 2.22 έως 21.98 pg m-3 αντίστοιχα. Οι μέγιστες συγκεντρώσεις προσδιορίστηκαν κατά τις μεσημβρινές ώρες ενδεικτικές των αντιδράσεων των αερίων ΠΑΥ με τις ρίζες ΟΗ. Η εναλλαγή των ΠΑΥ μεταξύ του αέρα και της θάλασσας υπολογίστηκε να εισάγει 865 τόνους ανά έτος στο θαλάσσιο οικοσύστημα της ανατολικής Μεσογείου. Οι ροές των ΠΑΥ που υπολογίστηκαν για τη ξηρή και την υγρή εναπόθεση ήταν 235 και 75 τόνους ανά έτος αντίστοιχα. Το 98.9% της συνολικής ποσότητας που εισάγεται στο θαλάσσιο περιβάλλον της ανατολικής Μεσογείου παραμένει στη εύφωτη ζώνη. Ο ρυθμός ιζηματαπόθεσης των συνολικών ΠΑΥ την περίοδο 1/5/2001 έως 15/10/01 στα βάθη 250m και 1440m ήταν 10.29 και 8.27 μg m-2 y-1 αντίστοιχα. Ο ρυθμός αυτός αντιστοιχεί στο 1.1 και στο 0.8% της συνολικής ατμοσφαιρικής εναπόθεσης των ΠΑΥ στην περιοχή μελέτης. Η συγκέντρωση των συνολικών ΠΑΥ στα επιφανειακά θαλάσσια ιζήματα ποίκιλλε από 2.2 έως 1056.2 ng g-1 ξηρού ιζήματος. Η συγκέντρωση του στοιχειακού άνθρακα (BC) και του οργανικού άνθρακα (ΟC) κυμάνθηκε από 0.3 έως 5.6 mg g-1 και από 2.9 έως 21.4 mg g-1 ξηρού βάρους αντίστοιχα. H σημαντική συσχέτιση μεταξύ των πυρογενών ΠΑΥ και του στοιχειακού άνθρακα (R2=0.94, P<0.001) στα θαλάσσια ιζήματα υποδεικνύει τη ση‘αντική συνεισφορά της ατμοσφαιρικής οδού στη ροή των πολυαρωματικών υδρογονανθράκων στη ανατολικής Μεσογείου

Nutrients and fine particulate matter released from sea bass (

Mass budget of the sea bass (Dicentrarchus labrax) farming losses was examined. Experiments were carried out in April, September and November 2001 in tanks of 8.5 m3 containing sea bass of 1, 31 and 53 g, respectively. Samples were taken at the input and discharge points of the tank at hourly intervals over 24 h. They were later analysed for nutrient concentration, as well as particulate organic carbon and nitrogen, chlorophyll a (Chl a) and total bacterial abundance. Despite the high water supply (exchange rate: 50% h−1), NH4 concentration was significantly higher in discharge water than in input water in all three experiments independent of fish size. The same was found to hold true for PO4 for part of the day (April, November) or for the entire day (September). NO3 and SiO2 ions did not show any differences during April. Particulate organic carbon (POC) and nitrogen (PON) were higher in the discharge water in all seasons. Chl a concentration was higher in the discharge water during the entire day in September whereas bacteria presented higher counts in the output water only during part of the day in April. It was found that 5−7% of the nitrogen supplied is released into the water column as fine particulate material in the form of PON and 21−29% as NH4. A small proportion (13−16%) of supplied phosphorus (P) was released as PO4. The results provided in the present paper are useful in assessing environmental changes in water quality in the vicinity of fish farms in the Mediterranean