Polychlorinated biphenyls and organochlorine pesticides in plastics ingested by seabirds

The occurrence of plastic objects in the digestive tract was assessed in eight species of Procellariiformes collected in southern Brazil and the occurrence of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the ingested plastics pellets and plastic fragments was evaluated. PCBs were detected in plastic pellets (491 ng g⁻¹) and plastic fragments (243-418 ng g⁻¹). Among the OCPs, p,p′-DDE had the highest concentrations, ranging from 68.0 to 99.0 ng g⁻¹. The occurrence of organic pollutants in post-consumer plastics supports the fact that plastics are an important source carrying persistent organic pollutants in the marine environment. Although transfer through the food chain may be the main source of exposure to POPs to seabirds, plastics could be an additional source for the organisms which ingest them, like Procellariiformes which are the seabirds most affected by plastic pollution.     

The global climate monitor system: from climate data-handling to knowledge dissemination

This paper summarizes our work on building a data model and a geovisualization tool that provides access to global climate data: the Global Climate Monitor Web Viewer. Linked to this viewer, a complete set of climate-environmental indicators capable of displaying climate patterns on a global scale that is accessible to any potential user (scientists and laypeople) will be built and published using the same online application. The data currently available correspond to the CRU TS3.21 version of the Climate Research Unit (University of East Anglia) database – a product that provides data at a spatial resolution of half of a degree in latitude and longitude, spanning January 1901 to December 2012, on a monthly basis. Since January 2013, the datasets feeding the system have been the GHCN-CAMS temperature dataset and the Global Precipitation Climatology Centre (GPCC) First Guess precipitation dataset. Climatologists, hydrologists, planners and non-experts users such as media workers, policymakers, non-profit organizations, teachers or students, can access useful climatological information through the Global Climate Monitor system.     

Characterization of Late Cretaceous to Miocene source rocks in the Eastern Mediterranean Sea: An integrated numerical approach of stratigraphic forward modelling and petroleum system modelling

Stratigraphic forward modelling was used to simulate the deposition of Upper Cretaceous, Eocene and Oligo‐Miocene source rocks in the Eastern Mediterranean Sea and, thus, obtain a process‐based 3D prediction of the quantity and quality distribution of organic matter (OM) in the respective intervals. Upper Cretaceous and Eocene models support the idea of an upwelling‐related source rock formation along the Levant Margin and the Eratosthenes Seamount (ESM). Along the margin, source rock facies form a narrow band of 50 km parallel to the palaeo shelf break, with high total organic carbon (TOC) contents of about 1% to 11%, and HI values of 300–500 mg HC/g TOC. On top of the ESM, TOC contents are mainly between 0.5% and 3% and HI values between 150 and 250 mg HC/g TOC. At both locations, TOC and HI values decrease rapidly towards the deeper parts of the basin. In the Oligo‐Miocene intervals, terrestrial OM makes up the highest contribution to the TOC content, as marine organic matter (OM) is diluted by high‐sedimentation rates. In general, TOC contents are low (<1%), but are distributed relatively homogenously throughout the whole basin, creating poor quality, but very thick source rock intervals of 1–2 km of cumulative thickness. The incorporation of these source rock models into a classic petroleum system model could identify several zones of thermal maturation in the respective source rock intervals. Upper Cretaceous source rocks started petroleum generation in the late Palaeocene/early Eocene with peak generation between 20 and 15 Ma ca. 50 km offshore northern Lebanon. Southeast of the ESM, generation started in the early Eocene with peak generation between 18 and 15 Ma. Eocene source rocks started HC generation ca. 25 Ma ago between 50 and 100 km southeast of the ESM and reached the oil to wet gas window at present day. However, until today they have converted less than 20% of their initial kerogen. Although the Miocene source rocks are mostly immature, Oligocene source rocks lie within the oil window in the southern Levant Basin and reached the onset of the wet gas window in the northern Levant Basin. However, only 10%–20% of their initial kerogen have been transformed to date.     

Phytoplankton functional groups: Short‐term variation in a tropical tidal‐forced estuarine system

Functional groups have become an important tool for characterizing communities of marine and estuarine environments. Their use also holds promise for a better understanding of the temporal dynamics of phytoplankton. This study aimed to evaluate the contributions of phytoplankton size fractions and functional groups characterizing short‐term variation throughout tidal cycles and between dry and rainy seasons in a tropical estuarine system. Camamu Bay is an oligotrophic estuarine system that is under strong influence from tropical shelf waters and is characterized by high salinity and low concentrations of dissolved nutrients. Surface‐water samples were collected at nine sampling sites distributed among the three hydrodynamic regions of the bay, and at a mooring, at 3‐hr intervals during tidal cycles (12 hr each) in both the rainy and the dry season. Although the abundances of the phytoplankton fractions (pico‐, nano‐, and micro‐) were higher in the rainy season and during periods of higher tide, they were not significantly higher. The phytoplankton community in the bay comprises three functional groups: GI = “colonial” (i.e., chain‐forming diatoms and filamentous cyanobacteria); GII = “GALD >40” (i.e., pennate and centric diatoms with MDL >40 µm), and GIII = “flagellates” (i.e., species with motility via flagella). Nanoflagellates were the most abundant form in the bay, while chain‐forming diatoms, in particular, contributed to the microphytoplankton fraction during both the rainy and dry seasons. Functional groups, as defined by cluster analysis, reflected ecological strategies compatible with the high hydrodynamics of Camamu Bay, which is characterized by processes of tidal‐forced intense mixing, mainly during periods of spring tides. The phytoplankton of the bay was found to possess a series of attributes (functional traits) that endow them with some resistance to sinking. Functional diversity indexes (FEve, FDiv, and FDis) indicated a stable community without significant short‐term variation due to low variability in the environmental conditions of the system during the study period.     

Responses of testate amoebae assemblages (Amoebozoa: Arcellinida) to recent volcanic eruptions,inferred from the sediment record in Laguna Verde,southern Patagonia,Argentina

Journal of Paleolimnology - There is little knowledge about testate amoebae in lakes and their responses to volcanic eruptions. To address this knowledge gap, we studied the paleoecology of these...     

Chemical Characterisation of Chromites by XRF Spectrometry

The present study was undertaken to establish and validate a methodology for determining the chemical composition of chromite ores, as no detailed information could be found in the literature. Chromite ores from South Africa, Kazajistan and Mongolia were analysed. X-ray fluorescence (XRF) spectrometry was used for chemical characterisation. Sample preparation in the form of fused beads was optimised in terms of sample:flux ratio, type of flux, type of release agent, fusion temperature and time. Calibration and validation samples were prepared from mixtures of reference materials. The proposed methodology was then used in an interlaboratory test for preparing a new chromite-rich reference material.
L'analyse présentée id a été entreprise afin d'établir et de valider une méthodologie pour déterminer la composition chimique de minerals de chromite, car aucune information détaillée là dessus ne pouvait etre trouvée dans la littérature. Des minerals de chromite d'Afrique du Sud, du Kazakhstan et de Mongolie ont été analysés par spectrométrie de Fluorescence de Rayons X (XRF) afin d'être caractérisés chimiquement. La préparation des échantillons afin d'obtenir des perles fondues a été optimisée en termes du rapport "échantillon/fondant", type de fondant, d'agent mouillant, température et durée de fusion. La calibration et la validation ont été faites à partir de mixtures de matériau de référence. La méthodologie proposée a été ensuite appliquée à un test d'inter-comparaison en vue de préparer un nouveau matériau de référence riche en chromite .     

Biomonitoring with benthic macroalgae and direct assay of heavy metals in seawater of the Oporto coast (northwest Portugal)

The concentrations of dissolved Cd, Cu, Hg and Pb in seawater and algae (Enteromorpha spp. and Porphyra spp.) were determined in parallel on three beaches located in the Oporto coast (Portugal), during 8 successive months, comprising periods of low and high biological productivity. The concentrations of dissolved metals in seawater varied markedly during the sampling period and exhibited seasonality. The concentrations of Cd were high in autumn and winter, but low in spring. The concentrations of Cu and Hg were high in autumn, low in winter and peaked in May. The concentrations of Pb were low in autumn and winter, and also peaked in May. It is likely that biological activity was, at least partially, responsible for the observed seasonal changes. The mean concentrations of dissolved metals in seawater were similar to those reported for polluted and industrialized european coastal areas. Metal concentration factors, calculated month-to-month for each alga, metal and site, varied markedly during the sampling period, indicating that concentration factors based on single or few determinations could be misleading. On the contrary, mean concentration factors (calculated by dividing the mean metal concentration in the algae by the mean metal concentration in seawater) were relatively constant at all three sites, indicating that in the Oporto coast, Enteromorpha spp. can be used to estimate the mean concentration of dissolved Cd, Cu and Hg in seawater, and Porphyra spp., the mean concentration of Cd, Cu and Pb. However, considering that future estimates of the concentrations of these metals in seawater should be based on determinations of the metal contents in Enteromorpha spp. and Porphyra spp. carried out on several occasions spanning a considerable period of time, the use of these algae as monitors of heavy metal pollution can have limited practical advantages over the direct assay of the metals in seawater.     

Plastic ingestion by Procellariiformes in Southern Brazil

The Procellariiformes are the birds most affected by plastic pollution. Plastic fragments and pellets were the most frequent items found in the digestive tract of eight species of Procellariiformes incidentally caught by longline fisheries as well as beached birds in Southern Brazil. Plastic objects were found in 62% of the petrels and 12% of the albatrosses. The Great shearwater, Manx shearwater, Cory's shearwater and Antarctic fulmar were found to have greater quantities and frequencies of occurrence of plastic. There was no significant difference in the number of plastics between the birds from longline fisheries and beached birds. No correlation was found between the number of prey and number of plastics in the digestive tract of the birds analyzed, but this does not discard the hypothesis that, in some cases, the presence of plastic in the digestive tract has a negative effect on the feeding efficiency of these birds.     

Evidence for Strong Copper(I) Complexation by Organic Ligands in Seawater

Thiols like glutathione and cysteine form such stable complexes with copper(I) that they preclude the presence of copper(II). Conventionally seawater is titrated with copper(II) whilst monitoring the labile or reactive copper concentration by voltammetry or with other techniques, to determine the concentration of copper(II) binding complexing ligands in seawater. Titrations of seawater to which copper(I) binding ligands have been added reveal that the copper(I) binding ligands are detected when seawater is titrated with copper(II). The copper(II) in seawater is reduced to copper(I) within 2 to 40 minutes depending on the nature of the copper(I) binding ligand. The titrations of seawater with copper(II) thus give a response to the presence of copper(I) binding ligands indiscernible from that for copper(II) binding ligands. The stoichiometry of the detected apparent ligand concentrations for given concentrations of glutathione and cysteine suggest that 2 : 1 (thiol : Cu) complexes are formed. This was confirmed using voltammetry of free glutathione. Values of 21.2 and 22.2 were found for log _CuL for glutathione and cysteine respectively (for the reaction of Cu + 2L CuL₂). The complex stability is similar to that of natural organic species in the oceanic water column. The high stability of the copper(I) complexes was apparent from values of 32.1 and 32.6 for log Cu(I)L2 (for the reaction Cu⁺ + 2L CuL₂) for the copper(I) complexes with glutathione and cysteine in seawater. Glutathione and other thiols are common in the marine system including the water column. It is therefore possible that at least some of the ligands detected in seawater, and previously assumed to be copper(II) binding ligands, are in fact strongly complexed as copper(I). The copper(I) oxidation state may thus be stabilised in seawater.     

Bulk transfer velocity to and from natural and artificial surfaces

A wide set of published mass and heat transfer data is reviewed in terms of the stochastic renewal theory. A simple model is then proposed describing the transfer in terms of the fluid bulk properties. Two expressions are presented and they enable us to evaluate the bulk transfer velocity as a function of the turbulence of the flow for smooth and fully-rough surfaces in large ranges of Schmidt (or Prandtl) and Reynolds numbers. The transfer over transitional surfaces can also be evaluated by using a simple criterion for the choice of the right expression. The proposed relationships agree satisfactorily with data from laboratory and atmospheric measurements, for both solid and liquid surfaces.