Seawater carbonate chemistry and accumulation of radiotracers in squid, Loligo vulgaris during experiments, 2011

The anthropogenic release of carbon dioxide (CO2) into the atmosphere leads to an increase in the CO2 partial pressure (pCO2) in the ocean, which may reach 950 ?atm by the end of the 21st century. The resulting hypercapnia (high pCO2) and decreasing pH ("ocean acidification") are expected to have appreciable effects on water-breathing organisms, especially on their early-life stages. For organisms like squid that lay their eggs in coastal areas where the embryo and then paralarva are also exposed to metal contamination, there is a need for information on how ocean acidification may influence trace element bioaccumulation during their development. In this study, we investigated the effects of enhanced levels of pCO2 (380, 850 and 1500 ?atm corresponding to pHT of 8.1, 7.85 and 7.60) on the accumulation of dissolved 110mAg, 109Cd, 57Co, 203Hg, 54Mn and 65Zn radiotracers in the whole egg strand and in the different compartments of the egg of Loligo vulgaris during the embryonic development and also in hatchlings during their first days of paralarval life. Retention properties of the eggshell for 110mAg, 203Hg and 65Zn were affected by the pCO2 treatments. In the embryo, increasing seawater pCO2 enhanced the uptake of both 110mAg and 65Zn while 203Hg showed a minimum concentration factor (CF) at the intermediate pCO2. 65Zn incorporation in statoliths also increased with increasing pCO2. Conversely, uptake of 109Cd and 54Mn in the embryo decreased as a function of increasing pCO2. Only the accumulation of 57Co in embryos was not affected by increasing pCO2. In paralarvae, the CF of 110mAg increased with increasing pCO2, whereas the 57Co CF was reduced at the highest pCO2 and 203Hg showed a maximal uptake rate at the intermediate pCO2. 54Mn and 65Zn accumulation in paralarvae were not significantly modified by hypercapnic conditions. Our results suggest a combined effect of pH on the adsorption and protective properties of the eggshell and of hypercapnia on the metabolism of embryo and paralarvae, both causing changes to the accumulation of metals in the tissues of L. vulgaris.

Major, trace and rare earth element concentration of ODP Site 210-1277 basalts, Newfoundland margin

Drilling of the distal Newfoundland margin at Ocean Drilling Program Site 1277 recovered part of the transition between exhumed sub-continental mantle lithosphere and normal mid-ocean-ridge basalt (N-MORB) volcanism perhaps related to the initiation of seafloor spreading, which may have occurred near the Aptian/Albian boundary, coincident with the final separation of subcontinental mantle lithosphere. Subcontinental mantle lithosphere was recovered near the crest of a basement high, the Mauzy Ridge. This ridge lies near magnetic Anomaly M1 and is inferred to be of Barremian age. The recovered section is dominated by serpentinized spinel harzburgite, with subordinate dunite and minor gabbroic intrusives, and it includes inferred high-temperature ductile shear zones. The serpentinite is capped by foliated gabbro cataclasite that is interpreted as the product of a major seafloor extensional detachment. The serpentinized harzburgite beneath is highly depleted subcontinental mantle lithosphere that was exhumed to create new seafloor within the ocean-continent transition zone. After inferred removal of overlying brittle crust, the detachment was eroded, producing multiple mass flows that were dominated by clasts of serpentinite and gabbro in a lithoclastic and calcareous matrix. Basaltic lavas were erupted spasmodically, mainly as sheet flows, with subordinate lava breccia, hyaloclastite, and possible pillow lava. The sedimentary-volcanic succession and the exhumed mantle lithosphere experienced later high-angle extensional fracturing and probably faulting. Extensional fissures opened incrementally and were filled with silt-sized carbonate, basalt-derived clastic sediment, and hyaloclastite, forming neptunian dykes and geopetal structures. Chemical analysis of representative basalts for major elements and trace elements were made using a high-precision, high-accuracy X-ray fluorescence method (utilizing increased count times) and by whole-rock inductively coupled plasma-mass spectrometry that yielded additional evidence for rare earth elements. The analyses indicate N-MORB to slightly enriched compositions. The MORB was produced by relatively high degree melting of a fertile mantle source that differed strongly from the cored serpentinized peridotites. The basalts exhibit a distinct negative Nb anomaly on MORB-normalized plots that can be explained by prior extraction of melt from upper mantle that had previously been affected by subduction, possibly during closure of the Iapetus or Rheic oceans. In the proposed interpretation, mantle lithosphere was exhumed to the seafloor and experienced mass wasting to form serpentinite-rich mass flows. The interbedded MORB records the beginning of a transition to "normal" seafloor spreading. This interpretation takes into account drilling results from the Iberia-Galicia margin and the Jurassic Alps-Apennines.

The effect of a reduction of nitrogen and phosphorus to eutrophic and mesotrophic conditions towards silver nanoparticle (AgNP) on freshwater green algae species

We investigated the sensitivity of algae towards silver nanoparticles with OECD test medium and lower nutrient concentrations under standard test conditions to improve comparability and to exclude any other confounding factor aside nutrient levels. Two unicellular freshwater microalgae Desmodesmus subspicatus and Raphidocelis subcapitata were chosen due to their status as standard test organisms for the algae growth inhibition test and the response to changes in nutrient supply was compared. The original medium was used as the reference (standard). For the other four media, the amount of either nitrogen or phosphorus in the medium was lowered from half (50%) to one-fourth (25 %) of that of the OECD guideline, resulting in the following media: 50% N, 25% N, 50% P and 25% P medium. As test substance, the OECD reference material NM-300K was used. For this reason, the characterization of AgNP was done using DLS and Absorption spectra (UV/vis). Actual silver concentrations and ionic silver concentrations were measured at the highest test concentration used (100 µg Ag L-1) in R. subcapitata treatments only to reduce the number of samples. All tests were run according to the OECD guideline 201 with sterilized 50 mL cell culture flask. Each medium was tested using the test conditions for culturing with 3 replicates. Test concentrations for both algae species were 0, 25, 50 and 100 µg Ag L-1 for OECD, 50% P and 25% P while for both N reductions, the silver concentrations were 0, 10, 25 and 100 µg Ag L-1. Samples for determining the algal density were taken at every 24 h.