ALBERT

Description: The authors regret an error in the published article, where incorrect data was used to produce Figure 2, showing the temporal development of pH over the duration of the experiment. The corrected Fig. 2 shows that the error did not affect the interpretation of nor the conclusions drawn from the present dataset. The original article has been corrected.

Description: Arctic river deltas are highly dynamic environments in the northern circumpolar permafrost region that are affected by fluvial, coastal, and permafrost-thaw processes. They are characterized by thick sediment deposits containing large but poorly constrained amounts of frozen organic carbon and nitrogen. This study presents new data on soil organic carbon and nitrogen storage as well as accumulation rates from the Ikpikpuk and Fish Creek river deltas, two small, permafrost-dominated Arctic river deltas on the Arctic Coastal Plain of northern Alaska. A soil organic carbon storage of 42.4 ± 1.6 and 37.9 ± 3.5 kg C m− 2 and soil nitrogen storage of 2.1 ± 0.1 and 2.0 ± 0.2 kg N m− 2 was found for the first 2 m of soil for the Ikpikpuk and Fish Creek river delta, respectively. While the upper meter of soil contains 3.57 Tg C, substantial amounts of carbon (3.09 Tg C or 46%) are also stored within the second meter of soil (100–200 cm) in the two deltas. An increasing and inhomogeneous distribution of C with depth is indicative of the dominance of deltaic depositional rather than soil forming processes for soil organic carbon storage. Largely, mid- to late Holocene radiocarbon dates in our cores suggest different carbon accumulation rates for the two deltas for the last 2000 years. Rates up to 28 g C m− 2 year− 1 for the Ikpikpuk river delta are about twice as high as for the Fish Creek river delta. With this study, we highlight the importance of including these highly dynamic permafrost environments in future permafrost carbon estimations.

Description: The ‘Code of Conduct for Responsible Fisheries’ developed by the United Nations Food and Agriculture Organisation has been central for the governance of fisheries. Most responsible fisheries initiatives are market-driven and motivate transitions towards greener economies. These added-value fish economies have increasingly connected fishing grounds to external markets that demand high quality sustainable products. This article problematizes the framework of responsible fishing and examines its intersections with place-base institutional processes in the Pacific coast of Colombia. In doing this, it explores how the concept of ‘responsible fishing’ has been framed, arguing that it has been used to operationalize the expansion of neoliberal processes in the oceans. It draws on small-scale fisheries performed by Afro-descendant people in the Gulf of Tribugá, where responsible fishing narratives have been linked to the creation of marine protected areas and responsible fish supply chains. Two dominant framings of responsible fishing were identified; a 'sustainability’ framing that denotes the sustainable use of fishing resources, and a ‘technical’ framing that refers to the use of environmentally safe practices. However, none of these framings accounts for social responsibility. Instead they have enforced the division of fishing practices between ‘responsible’/‘irresponsible’, and produced static, ahistorical and oversimplified understandings of fishing dynamics. All this has triggered a local need for external control over fisheries governance, disempowering place-based control mechanisms. This article concludes by questioning whether responsible fishing can successfully ensure a sustainable use of fishing resources, or if moving beyond ‘responsibility’ is needed to strengthen local institutional processes and autonomy among coastal peoples.

Description: A mesocosm experiment with intact benthic communities was conducted to evaluate the effects of mine tailings on benthic community structure and biogeochemical processes. Two types of tailings were supplied from process plants using flotation and flocculation chemicals, while a third type was absent of added chemicals. All tailings impacted the sediment community at thin layers, and through more mechanisms than merely hypersedimentation. In general, the strongest impact was observed in a very fine-grained tailings containing flotation chemicals. The second strongest occurred in tailings with no process chemicals. The tailings with flocculation chemicals initiated the weakest response. Fluxes of oxygen, nitrate and ammonium provided some indications on biodegradation of organic phases. Release of phosphate and silicate decreased with increasing layer thickness of all three tailings. A threshold level of 2 cm was identified both for faunal responses and for fluxes of phosphate and silicate. The particular impact mechanisms should receive more attention in future studies in order to minimize the environmental risk associated with tailings disposal.

Description: Increasingly more data have indicated that the 40Ar/39Ar crushing technique provides a very useful approach to determine the mineralization ages of hydrothermal ore deposits. In this study novel gas mixing lines are proposed based on the data of two quartz samples by 40Ar/39Ar crushing. Electron microprobe analyses indicate that the quartz grains contain K-rich silicate microlites. Both quartzs by crushing yield two mixing lines with ages corresponding respectively to those of K-feldspar or sericite (post-mineralization fluids) and muscovite samples (ore-forming fluids). This is the first report that both ages of secondary and primary fluid inclusions (SFIs and PFIs) are confirmed correspondingly by those of the K-rich minerals. This study strongly indicates that the 40Ar/39Ar crushing technique is very useful to determine the ages of geofluid activities. The newly proposed gas mixing patterns are shown on the inverse and normal isochron diagrams, indicating: (1) the mixtures are in different proportions of the PFIs and SFIs in different crushing steps; (2) the gas mixing lines yield PFI ages with low initial 40Ar/36Ar ratios; (3) an intermediate age between PFI and SFI ages cannot be obtained because the progressive crushing technique never release gas mixtures with a constant PFI/SFI proportion for each step. The gas mixing lines are thus interpreted to yield significant geological ages. The mixing patterns will help us better understand the 40Ar/39Ar dating results and be used for references to other isotopic mixing isochron systems.

Description: Nitric oxide (NO) is a short-lived compound of the marine nitrogen cycle. However, measurements of NO in seawater are analytically challenging and our knowledge about its oceanic distribution is, therefore, rudimentary. NO was measured in the oxygen minimum zone (OMZ) of the eastern tropical South Pacific Ocean (ETSP) off Peru during R/V Meteor cruise M93 in February/March 2013. NO concentrations ranged from close to or below the detection limit (0.5nmolL-1) in the surface layer to 9.5nmolL-1 in the OMZ. NO concentrations increased significantly when oxygen (O2) concentrations dropped below 1-2μmolL-1. We found positive correlations between NO and NO2 - as well as between NO and the abundance of archaeal amoA, a marker gene for archaeal nitrifiers. No trends between NO and nirS and hzo, marker genes for canonical denitrification and anammox, respectively, were found. To this end, we conclude that NO off Peru was mainly produced by archaeal nitrifier-denitrification at low O2 concentrations in the OMZ.

Description: The vertical distributions of early developmental stages of oceanic fishes were investigated across the tropical and equatorial Atlantic, from oligotrophic waters close to the Brazilian coast to more productive waters close to the Mauritanian Upwelling Region. Stratification of the water column was observed throughout the study region. Fishes were caught with a MOCNESS-1 net with mouth area of 1 m2 at 11 stations. Each station was sampled both during the day and at night within a single 24-h period. The investigation covered both larvae and transforming stages from the surface to 800 m depth. Distribution patterns were analysed, and weighted mean depths for the larvae and transforming stages of each species were calculated for day and night conditions. Forty-seven different species were found. The highest number of species occurred in the three stations south of Cape Verde Islands, characterized by a mixture of South Atlantic Central Water (SACW) and Eastern North Atlantic Central Water (ENACW). There was a marked drop in species richness in the three stations closer to the African upwelling, dominated by ENACW. The highest abundances occurred in the families Myctophidae, Sternoptychidae, Gonostomatidae and Phosichthyidae. Day and night vertical distributions of larvae and transforming stages showed contrasting patterns, both in the depths of the main concentration layers in the water column, and in the diel migration patterns (where these were observed). Larvae generally showed a preference for the upper mixed layer (ca. 0–50 m) and upper thermocline (ca. 50–100 m), except for sternoptychids, which were also abundant in the lower thermocline layer (100–200 m) and even extended into the mesopelagic zone (down to 500 m). Transforming stages showed a more widespread distribution, with main concentrations in the mesopelagic zone (200–800 m). Larvae showed peak concentrations in the more illuminated and zooplankton-rich upper mixed layers during the day and a wider distribution through the upper 100 m during the night. For most species, transforming stages were concentrated in the mesopelagic layers both day and night, although in some species (Diaphus cf. vanhoeffeni and Vinciguerria nimbaria), the transforming stages displayed vertical migration into the upper 100 m at night, in a manner similar to their adult stages.

Description: We present the application of a micro/macro parareal algorithm for a 1-D energy balance climate model with discontinuous and non-monotone coefficients and forcing terms. The micro/macro parareal method uses a coarse propagator, based on a (macroscopic) 0-D approximation of the underlying (microscopic) 1-D model. We compare the performance of the method using different versions of the macro model, as well as different numerical schemes for the micro propagator, namely an explicit Euler method with constant stepsize and an adaptive library routine. We study convergence of the method and the theoretical gain in computational time in a realization on parallel processors. We show that, in this example and for all settings, the micro/macro parareal method converges in fewer iterations than the number of used parareal subintervals, and that a theoretical gain in performance of up to 10 is possible.

Description: Isocitrate dehydrogenase (IDH) is one of the key enzymes in the tricarboxylic acid cycle, and IDH mutations have been associated with many cancers, including glioblastoma, sarcoma, acute myeloid leukemia, etc. Three natural steroids 1–3 from Ganoderma sinense, a unique and rare edible-medicinal fungi in China, were found as potential IDH1 inhibitors by virtual ligand screening method. Among the three compounds, 3 showed the highest binding affinity to IDH1 with significant calculated binding free energy. Enzymatic kinetics demonstrated that 3 inhibited mutant enzyme in a noncompetitive manner. The half effective concentration of 3 for reducing the concentration of D-2HG in HT1080 cells was 35.97 μM. The levels of histone H3K9me3 methylation in HT1080 cells were reduced by treating with 3. Furthermore, knockdown of mutant IDH1 in HT1080 cells decreased the anti-proliferative sensitivity to 3. In short, our findings highlight that compound 3 may have clinical potential in tumor therapies as an effective inhibitor of mutant IDH1.