North Atlantic western boundary currents are intense dissolved organic carbon streams

In the North Atlantic, there are two main western boundary currents related to the Atlantic Meridional Overturning Circulation (AMOC): the Gulf Stream flowing northward and the Deep Western Boundary Current (DWBC) flowing southward. Here we analyze data from the OVIDE section (GO-SHIP A25 Portugal-Greenland 40-60 degrees N) that crosses the DWBC and the northward extension of the Gulf Stream, the North Atlantic Current. We show that North Atlantic western boundary currents play a key role in the transport of dissolved organic matter, specifically dissolved organic carbon (DOC). Revisited transports and budgets of DOC with new available data identify the eastern Subpolar North Atlantic (eSPNA) as an important source of locally produced organic matter for the North Atlantic and a key region in the supply of bioavailable DOC to the deep ocean. The East Greenland Current, and its upstream source the East Reykjanes Ridge Current on the eastern flank of the mid-Atlantic ridge, are export pathways of bioavailable DOC toward subtropical latitudes. The fast overturning and subsequent remineralization of DOC produced in the autotrophic eSPNA explains up to 38% of the total oxygen consumption in the deep North Atlantic between the OVIDE section and 24 degrees N. Carbon budgets that do not take into account this organic remineralization process overestimates the natural uptake of carbon dioxide (CO2) from the atmosphere by one third. The inclusion of DOC transports in regional carbon budgets reconciles the estimates of CO2 uptake in the North Atlantic between model and observations.FCT: UID/Multi/04326/2019/ CEECINST/00114/2018.info:eu-repo/semantics/publishedVersio

Contrasting drivers and trends of ocean acidification in the subarctic Atlantic

The processes of warming, anthropogenic CO2 (Canth) accumulation, decreasing pHT (increasing [H+]T; concentration in total scale) and calcium carbonate saturation in the subarctic zone of the North Atlantic are unequivocal in the time-series measurements of the Iceland (IS-TS, 1985–2003) and Irminger Sea (IRM-TS, 1983–2013) stations. Both stations show high rates of Canth accumulation with diferent rates of warming, salinifcation and stratifcation linked to regional circulation and dynamics. At the IS-TS, advected and stratifed waters of Arctic origin drive a strong increase in [H+]T, in the surface layer, which is nearly halved in the deep layer (44.7± 3.6 and 25.5 ± 1.0 pmol ­kg−1 ­yr−1, respectively). In contrast, the weak stratifcation at the IRM-TS allows warming, salinifcation and Canth uptake to reach the deep layer. The acidifcation trends are even stronger in the deep layer than in the surface layer (44.2± 1.0 pmol ­kg−1 ­yr−1 and 32.6 ± 3.4 pmol ­kg−1 ­yr−1 of [H+]T, respectively). The driver analysis detects that warming contributes up to 50% to the increase in [H+]T at the IRM-TS but has a small positive efect on calcium carbonate saturation. The Canth increase is the main driver of the observed acidifcation, but it is partially dampened by the northward advection of water with a relatively low natural CO2 content.PRX18/00312, PID2019-104279GB-C21, UIDB/Multi/04326/2020, CEECINST/00114/2018info:eu-repo/semantics/publishedVersio

Precise 210Pb determination with high-efficiency gamma spectrometry for dating of marine sedimentary cores

[EN]In order to establish the chronology of deep-sea sediments from high-resolution 210Pb-dating, the determination of 210Pb and 226Ra activity concentrations needs to be improved. Gamma spectrometry allows determining simultaneously both radionuclides. However, spectrum background is still an issue to obtain high sensitivity. Four deep-sea sediment cores were dated using Mazinger, a gamma spectrometer with high-efficiency and very low-background, and the Constant Rate and Supply model was applied to obtain recent age

The Northeast Atlantic is running out of excess carbonate in the horizon of cold-water corals communities

The oceanic uptake of atmospheric carbon dioxide (CO2) emitted by human activities alters the seawater carbonate system. Here, the chemical status of the Northeast Atlantic is examined by means of a high-quality database of carbon variables based on the GO-SHIP A25 section (1997–2018). The increase of atmospheric CO2 leads to an increase in ocean anthropogenic carbon (Cant) and a decrease in carbonate that is unequivocal in the upper and mid-layers (0–2,500 m depth). In the mid-layer, the carbonate content in the Northeast Atlantic is maintained by the interplay between the northward spreading of recently conveyed Mediterranean Water with excess of carbonate and the arrival of subpolar-origin waters close to carbonate undersaturation. In this study we show a progression to undersaturation with respect to aragonite that could compromise the conservation of the habitats and ecosystem services developed by benthic marine calcifiers inhabiting that depth-range, such as the cold-water corals (CWC) communities. For each additional ppm in atmospheric pCO2 the waters surrounding CWC communities lose carbonate at a rate of − 0.17 ± 0.02 μmol kg−1 ppm−1. The accomplishment of global climate policies to limit global warming below 1.5–2 ℃ will avoid the exhaustion of excess carbonate in the Northeast Atlantic

Dating the Anthropocene in deep-sea sediments: a gamma spectrometric approach

1 poster presented at the International meeting of Sedimentology 2017 in Toulouse, France, from October 10th to 13thUtilizando muestras de sedimentos superficiales obtenidas durante la campaña OVIDE/BOCATS 2016 y una innovadora técnica para establecer cronologías absolutas, se ha obtenido una primera estimación cuantitativa de los flujos de carbono hacia sedimentos profundos en la cuenca subpolar de Irminger. La geocronología basada en espectrometría gamma de alta resolución y bajo fondo con dos detectores simultáneos de germanio hiper-puro (HPGe) es una técnica suficientemente precisa y sensible como para datar sedimentos pelágicos profundos. El papel cuantitativo del Irminger como sumidero de carbono durante el Antropoceno se evaluó combinando una cronología basada en el radionúclido natural 210Pb junto a análisis sedimentológicos y de composición elemental. La tasa media de sedimentación para el canal central del Irminger es de 0.83±0.14 mm·yr-1. Los cálculos de flujos de carbono concluyen que durante el Antropoceno 32±14 g·Cinorg·m-2·año-1 y 4.5±3 g·Corg·m-2·año-1 sedimentan en la cuenca del Irminger, suponiendo un considerable sumidero de carbono en el área cuantificado en más de 22 Tg-C·año−1N

Cold-water corals in the Subpolar North Atlantic Ocean exposed to aragonite undersaturation if the 2 °C global warming target is not met

The net uptake of carbon dioxide (CO2) from the atmosphere is changing the ocean's chemical state. Such changes, commonly known as ocean acidification, include a reduction in pH and the carbonate ion concentration ([CO32−]), which in turn lowers oceanic saturation states (Ω) for calcium carbonate (CaCO3) minerals. The Ω values for aragonite (Ωaragonite; one of the main CaCO3 minerals formed by marine calcifying organisms) influence the calcification rate and geographic distribution of cold-water corals (CWCs), important for biodiversity. Here, high-quality measurements, collected on thirteen cruises along the same track during 1991–2018, are used to determine the long-term changes in Ω aragonite in the Irminger and Iceland Basins of the North Atlantic Ocean, providing the first trends of Ωaragonite in the deep waters of these basins. The entire water column of both basins showed significant negative Ωaragonite trends between −0.0014 ± 0.0002 and −0.0052 ± 0.0007 per year. The decrease in Ω aragonite in the intermediate waters, where nearly half of the CWC reefs of the study region are located, caused the Ωaragonite isolines to rapidly migrate upwards at a rate between 6 and 34 m per year. The main driver of the decline in Ωaragonite in the Irminger and Iceland Basins was the increase in anthropogenic CO2. But this was partially offset by increases in salinity (in Subpolar Mode Water), enhanced ventilation (in upper Labrador Sea Water), and increases in alkalinity (in classical Labrador Sea Water, cLSW; and overflow waters). We also found that water mass aging reinforced the Ωaragonite decrease in cLSW. Based on these Ωaragonite trends over the last three decades, we project that the entire water column of the Irminger and Iceland Basins will likely be undersaturated for aragonite when in equilibrium with an atmospheric mole fraction of CO2 (xCO2) of ~880 ppmv, corresponding to climate model projections for the end of the century based on the highest CO2 emission scenarios. However, intermediate waters will likely be aragonite undersaturated when in equilibrium with an atmospheric xCO2 exceeding ~630 ppmv, an xCO2 level slightly above that corresponding to 2°C global warming, thus exposing CWCs inhabiting the intermediate waters to undersaturation for aragonite

North Atlantic CO2 sink variability revealed by the Go-Ship A25-OVIDE section

EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022.-- This work is distributed under the Creative Commons Attribution 4.0 LicenseAbout 30% of the carbon dioxide derived from human activities (CANTH) has been absorbed by the ocean (DeVries, 2014; Gruber et al., 2019; Friedlingstein et al., 2021), with the North Atlantic (NA) being one of the largest CANTH sinks per unit area (Khatiwala et al., 2013; Sabine et al., 2004). In the NA, oceanic CANTH uptake strongly relies on the meridional overturning circulation and the associated regional winter deep convection. In fact, the formation and deep spreading of Labrador Sea Water stands as a critical CANTH gateway to intermediate and abyssal depths. The NA CANTH uptake has fluctuated over the years according to changes in the North Atlantic Oscillation. Biennial observation of the marine carbonate system along the Go-Ship A25-OVIDE section has allowed us assessing the decadal and interannual variability of the CANTH storage in the subpolarNA from 2002 to 2021. In this study, we investigate 1) the trend of CANTH and 2) the relationship between the CANTH saturation, the apparent oxygen utilization, and the ventilation of the water masses between the A25-OVIDE section and the Greenland-Iceland-Scotland sills during 2002-2021. We divided the A25-OVIDE section into three main basins (Irminger, Iceland, and Eastern NA). Our results show that the Irminger Basin presents a more homogenous CANTH profile and higher CANTH saturation values at depth than the other two basins, which is related to the pronounced convective activity in the Irminger Basin. In contrast, the Eastern NA Basin has higher CANTH values at the surface due to its higher surface temperature, but its deep water masses show the lowest CANTH values since they are the less ventilated in the section. Our analysis also reveals that, overall, the NA CANTH storage has increased during 2002-2021, but varied according to the ventilation changes. While the Eastern NA water masses experienced a relatively constant, although shallower, average ventilation, the Irminger and Iceland Basins underwent a less steady CANTH uptake pattern characterized by alternating periods of strong and weak CANTH storageN

N′-phenylacetohydrazide derivatives as potent Ebola virus entry inhibitors with an improved pharmacokinetic profile

19 p.-6 fig.-7 tab.-1 graph. abst.Ebola virus (EBOV) is a single-strand RNA virus belonging to the Filoviridae family, which has been associated to most Ebola virus disease outbreaks to date, including the West African and the North Kivu epidemics between 2013 and 2022. This unprecedented health emergency prompted the search for effective medical countermeasures. Following up on the carbazole hit identified in our previous studies, we synthetized a new series of compounds, which demonstrated to prevent EBOV infection in cells by acting as virus entry inhibitors. The in vitro inhibitory activity was evaluated through the screening against surrogate models based on viral pseudotypes and further confirmed using replicative EBOV. Docking and molecular dynamics simulations joined to saturation transfer difference–nuclear magnetic resonance (STD–NMR) and mutagenesis experiments to elucidate the biological target of the most potent compounds. Finally, in vitro metabolic stability and in vivo pharmacokinetic studies were performed to confirm their therapeutic potential.The project leading to these results has received funding from “la Caixa” Foundation under the project code LCF/PR/HR19/52160012. This research was partially supported through ERA-NET-2021-862605. Cofounded by AEI, Spain (PCI2021-121939 (C.A.), PID2019-105237GB-I00 (A.C.), PID2021-122825OB (C.A.), and PID2021-122223OB-I00 (C.G.)), Instituto de Salud Carlos III (CIBERINFEC and FIS PI2100989), and the European Commission Horizon 2020 Framework Programme (Project VIRUSCAN FETPROACT-2016: 731868 and Project EPIC-CROWN-2 ID: 101046084). This research work was also funded by the European Commission–NextGenerationEU (Regulation EU 2020/2094), through CSIC’s Global Health Platform (PTI Salud Global). M.M.-T holds a predoctoral FPU grant (FPU18/03493) from MICINNPeer reviewe

Activation of NF-kB Pathway by Virus Infection Requires Rb Expression

The retinoblastoma protein Rb is a tumor suppressor involved in cell cycle control, differentiation, and inhibition of oncogenic transformation. Besides these roles, additional functions in the control of immune response have been suggested. In the present study we investigated the consequences of loss of Rb in viral infection. Here we show that virus replication is increased by the absence of Rb, and that Rb is required for the activation of the NF-kB pathway in response to virus infection. These results reveal a novel role for tumor suppressor Rb in viral infection surveillance and further extend the concept of a link between tumor suppressors and antiviral activity

Experimental Evolution of an Oncolytic Vesicular Stomatitis Virus with Increased Selectivity for p53-Deficient Cells

Experimental evolution has been used for various biotechnological applications including protein and microbial cell engineering, but less commonly in the field of oncolytic virotherapy. Here, we sought to adapt a rapidly evolving RNA virus to cells deficient for the tumor suppressor gene p53, a hallmark of cancer cells. To achieve this goal, we established four independent evolution lines of the vesicular stomatitis virus (VSV) in p53-knockout mouse embryonic fibroblasts (p53−/− MEFs) under conditions favoring the action of natural selection. We found that some evolved viruses showed increased fitness and cytotoxicity in p53−/− cells but not in isogenic p53+/+ cells, indicating gene-specific adaptation. However, full-length sequencing revealed no obvious or previously described genetic changes associated with oncolytic activity. Half-maximal effective dose (EC50) assays in mouse p53-positive colon cancer (CT26) and p53-deficient breast cancer (4T1) cells indicated that the evolved viruses were more effective against 4T1 cells than the parental virus or a reference oncolytic VSV (MΔ51), but showed no increased efficacy against CT26 cells. In vivo assays using 4T1 syngeneic tumor models showed that one of the evolved lines significantly delayed tumor growth compared to mice treated with the parental virus or untreated controls, and was able to induce transient tumor suppression. Our results show that RNA viruses can be specifically adapted typical cancer features such as p53 inactivation, and illustrate the usefulness of experimental evolution for oncolytic virotherapy