Search

[Display omitted] • First monthly nitrous oxide (N 2 O) measurements conducted in the NW Iberian Upwelling in 2017 and 2018. • Marked seasonal cycle of N 2 O concentrations and air-sea fluxes is reported. • Ventilation driven by the upwelling and remineralization modulated the spatial and seasonal pattern. • Higher N 2 O concentration were found in Ria of Vigo compared to Ria of A Coruña. • The NW Iberian Upwelling system acts a moderate source of N 2 O to the atmosphere. Despite their small spatial extent, coastal upwelling systems are an important source of oceanic nitrous oxide (N 2 O) to the atmosphere. To date, hot-spot N 2 O emissions have been reported for low oxygen waters of the eastern boundary upwelling systems at their tropical latitudes, but there is a limited number of studies in their "oxygenated" temperate latitudes. This is the first study of the N 2 O cycle in the NW Iberian Upwelling system, where we investigated the seasonality of the N 2 O concentrations and their emissions to the atmosphere, along with the spatial differences in this coastal region in response to the upwelling. Monthly observations were collected from February 2017 to July 2018, in two hydrographic sections within the Ría of Vigo and Ría of A Coruña, two coastal embayments with contrasting response to the upwelling of the Eastern North Atlantic Central Water (ENACW) in the region. N 2 O concentrations ranged between 8.56 to 12.53 nmol kg−1 (94–121 % of saturation) in the shelf, and from 8.62 to 17.60 nmol kg−1 (94–203 % of saturation) inside the rías, with the highest N 2 O concentration at the bottom, which increase as the upwelling progress from April to October. The air-sea fluxes of N 2 O varied between −1.6 to 3.26 µmol m−2 d−1 in the shelf and −1.53 to 7.00 µmol m−2 d−1 inside the rías. Local differences on the ventilation and remineralization pattern drives the seasonality of N 2 O and differences between Ria of Vigo and Ria of A Coruña, being the higher values of N 2 O concentrations and air-sea fluxes registered in the inner Ria of Vigo. Our study reports the N 2 O emissions of an upwelling system in a temperate latitude, where the upwelling waters are central waters relatively well ventilated in terms of oxygen content, behaving as a moderate low net source of N 2 O to the atmosphere compared to tropical upwelling latitudes, characterised by a lower oxygen content. [ABSTRACT FROM AUTHOR]

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 different rates of warming, salinification and stratification linked to regional circulation and dynamics. At the IS-TS, advected and stratified 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 stratification at the IRM-TS allows warming, salinification and Canth uptake to reach the deep layer. The acidification 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 effect on calcium carbonate saturation. The Canth increase is the main driver of the observed acidification, but it is partially dampened by the northward advection of water with a relatively low natural CO2 content. [ABSTRACT FROM AUTHOR]

Anthropogenic emissions of CO2 to the atmosphere have modified the carbon cycle for more than 2 centuries. As the ocean stores most of the carbon on our planet, there is an important task in unraveling the natural and anthropogenic processes that drive the carbon cycle at different spatial and temporal scales. We contribute to this by designing a global monthly climatology of total dissolved inorganic carbon (TCO2), which offers a robust basis in carbon cycle modeling but also for other studies related to this cycle. A feedforward neural network (dubbed NNGv2LDEO) was configured to extract from the Global Ocean Data Analysis Project version 2.2019 (GLODAPv2.2019) and the Lamont–Doherty Earth Observatory (LDEO) datasets the relations between TCO2 and a set of variables related to the former's variability. The global root mean square error (RMSE) of mapping TCO2 is relatively low for the two datasets (GLODAPv2.2019: 7.2 µmolkg-1 ; LDEO: 11.4 µmolkg-1) and also for independent data, suggesting that the network does not overfit possible errors in data. The ability of NNGv2LDEO to capture the monthly variability of TCO2 was testified through the good reproduction of the seasonal cycle in 10 time series stations spread over different regions of the ocean (RMSE: 3.6 to 13.2 µmolkg-1). The climatology was obtained by passing through NNGv2LDEO the monthly climatological fields of temperature, salinity, and oxygen from the World Ocean Atlas 2013 and phosphate, nitrate, and silicate computed from a neural network fed with the previous fields. The resolution is 1∘×1∘ in the horizontal, 102 depth levels (0–5500 m), and monthly (0–1500 m) to annual (1550–5500 m) temporal resolution, and it is centered around the year 1995. The uncertainty of the climatology is low when compared with climatological values derived from measured TCO2 in the largest time series stations. Furthermore, a computed climatology of partial pressure of CO2 (p CO2) from a previous climatology of total alkalinity and the present one of TCO2 supports the robustness of this product through the good correlation with a widely used p CO2 climatology (Landschützer et al., 2017). Our TCO2 climatology is distributed through the data repository of the Spanish National Research Council (CSIC; 10.20350/digitalCSIC/10551, Broullón et al., 2020). [ABSTRACT FROM AUTHOR]

Anthropogenic emissions of CO2 to the atmosphere have modified the carbon cycle for more than two centuries. As the ocean stores most of the carbon on our planet, there is an important task in unraveling the natural and anthropogenic processes that drive the carbon cycle at different spatial and temporal scales. We contribute to this by designing a global monthly climatology of total dissolved inorganic carbon (TCO2) which offers a robust basis in carbon cycle modeling but also for other studies related to this cycle. A feedforward neural network (dubbed NNGv2LDEO) was configured to extract from the Global Ocean Data Analysis Project version 2.2019 (GLODAPv2.2019) and the Lamont-Doherty Earth Observatory (LDEO) datasets the relations between TCO2 and a set of variables related to the former's variability. The global root-mean-squared error (RMSE) of mapping TCO2 is relatively low for the two datasets (GLODAPv2.2019: 7.2 µmol kg-1; LDEO: 11.4 µmol kg-1) and also for independent data, suggesting that the network does not overfit possible errors in data. The ability of NNGv2LDEO in capturing the monthly variability of TCO2 was testified through the good reproduction of the seasonal cycle in ten time-series stations spread over different regions of the ocean (RMSE: 3.6 to 13.1 µmol kg-1). The climatology was obtained by passing through NNGv2LDEO the monthly climatological fields of temperature, salinity and oxygen from World Ocean Atlas 2013, and phosphate, nitrate and silicate computed from a neural network fed with the previous fields. The resolution is 1º x 1º in the horizontal, 102 depth levels (0-5500 m) and monthly (0-1500 m) to annual (1550-5500 m), and it is centered in the year 1995. The uncertainty of the climatology is low when compared with climatological values derived from measured TCO2 in the largest time-series stations. Furthermore, a computed climatology of partial pressure of CO2 (pCO2) from a previous climatology of total alkalinity and the present one of TCO2 supports the robustness of this product through the good correlation with a widely used pCO2 climatology (Landschützer et al., 2016). Our TCO2 climatology is distributed through the data repository of the Spanish National Research Council (CSIC; http://dx.doi.org/10.20350/digitalCSIC/10551, Broullón et al., 2020). [ABSTRACT FROM AUTHOR]

Global climatologies of the seawater CO2 chemistry variables are necessary to assess the marine carbon cycle in depth. The climatologies should adequately capture seasonal variability to properly address ocean acidification and similar issues related to the carbon cycle. Total alkalinity (AT) is one variable of the seawater CO2 chemistry system involved in ocean acidification and frequently measured. We used the Global Ocean Data Analysis Project version 2.2019 (GLODAPv2) to extract relationships among the drivers of the AT variability and AT concentration using a neural network (NNGv2) to generate a monthly climatology. The GLODAPv2 quality-controlled dataset used was modeled by the NNGv2 with a root-mean-squared error (RMSE) of 5.3 µ mol kg -1. Validation tests with independent datasets revealed the good generalization of the network. Data from five ocean time-series stations showed an acceptable RMSE range of 3–6.2 µ mol kg -1. Successful modeling of the monthly AT variability in the time series suggests that the NNGv2 is a good candidate to generate a monthly climatology. The climatological fields of AT were obtained passing through the NNGv2 the World Ocean Atlas 2013 (WOA13) monthly climatologies of temperature, salinity, and oxygen and the computed climatologies of nutrients from the previous ones with a neural network. The spatiotemporal resolution is set by WOA13: 1 ∘ × 1 ∘ in the horizontal, 102 depth levels (0–5500 m) in the vertical and monthly (0–1500 m) to annual (1550–5500 m) temporal resolution. The product is distributed through the data repository of the Spanish National Research Council (CSIC; 10.20350/digitalCSIC/8644, Broullón et al., 2019). [ABSTRACT FROM AUTHOR]

Global climatologies of the seawater CO2 chemistry variables are necessary to assess the marine carbon cycle in depth. The seasonal variability should be adequately captured in them to properly address issues such as ocean acidification. Total alkalinity (AT) is one variable of the seawater CO2 chemistry system involved in ocean acidification and frequently measured during campaigns assessing the marine carbon cycle. We took advantage of the data product Global Ocean Data Analysis Project version 2 (GLODAPv2) to extract the relations between the drivers of the AT variability and this variable using a neural network to generate a monthly climatology. 99% of the GLODAPv2 dataset used was modelled by the network with a root-mean-squared error (RMSE) of 5.1 µmol kg-1. The validation carried out using independent datasets revealed the good generalization of the network. Five ocean time-series stations used as an independent test showed an acceptable RMSE in the range of 3.1-6.2 µmol kg-1. The successful modeling of the monthly variability of AT in the time-series makes our network a good candidate to generate a monthly climatology. It was obtained passing the climatologies of the World Ocean Atlas 2013 (WOA13) through the network. The spatiotemporal resolution of the climatology is determined by the one of WOA13: 1ºx1º in the horizontal, 102 depth levels (0-5500m) in the vertical, and 12 months. We offer the product as a service to the scientific community at the data repository of the Spanish National Research Council (CSIC; doi: http://dx.doi.org/10.20350/digitalCSIC/8564) with the purpose to contribute to a continuous improvement of the understanding of the global carbon cycle. [ABSTRACT FROM AUTHOR]

Background: Haemophilus parasuis is the etiological agent of Glässer's disease in swine. H. parasuis comprises strains with heterogeneous virulence capacity, from non-virulent to highly virulent. Determination of the pathogenic potential of the strains is important for diagnosis and disease control. The virulence-associated trimeric autotransporters (vtaA) genes have been used to predict H. parasuis virulence by PCR amplification of their translocator domains. Here, we report a new and improved PCR designed to detect a different domain of the vtaA genes, the leader sequence (LS) as a diagnostic tool to predict virulence. Methods: A collection of 360 H. parasuis strains was tested by PCR with LS specific primers. Results of the PCR were compared with the clinical origin of the strains and, for a subset of strains, with their phagocytosis and serum resistance using a Chi-square test. Results: LS-PCR was specific to H. parasuis, and allowed the differential detection of the leader sequences found in clinical and non-clinical isolates. Significant correlation was observed between the results of the LS-PCR and the clinical origin (organ of isolation) of the strains, as well as with their phagocytosis and serum susceptibility, indicating that this PCR is a good predictor of the virulence of the strains. In addition, this new PCR showed a full correlation with the previously validated PCR based on the translocator domain. LS-PCR could be performed in a wide range of annealing temperatures without losing specificity. Conclusion: This newly described PCR based on the leader sequence of the vtaA genes, LS-PCR, is a robust test for the prediction of the virulence potential of H. parasuis strains. [ABSTRACT FROM AUTHOR]

Graph: Figure 6 Acidification trends and drivers decomposition (T,S, nDIC and nTA) for the seasonally detrended average time series of total hydrogen ions concentration in pmol/kg/yr ( [H+]T, A) and for excess of [CO3= ] over the [CO3= ] at aragonite saturation in µmol/kg/yr ( ex[CO3=], B). Additionally, the article contains a repeated error where the symbol for "pmol" was incorrectly given as "nmol" in the Results section, under the subheading "Acidifcation drivers", in Figure 6 legend, and in the Conclusions. "Average trends obtained with the seasonally detrended data the in situ temperature (T in °C yr SP -1 sp ), salinity (S in yr SP -1 sp ), Total Alkalinity (TA in µmol kg SP -1 sp yr SP -1 sp ), salinity-normalized alkalinity (nTA in µmol kg SP -1 sp yr SP -1 sp ), total dissolved inorganic carbon (DIC in µmol kg SP -1 sp yr SP -1 sp ), salinity-normalized dissolved inorganic carbon (nDIC in µmol kg SP -1 sp yr SP -1 sp ), in situ pH in total scale (pHT yr SP -1 sp ), total hydrogen ion concentrations ([H+]T in nanomol kg SP -1 sp yr SP -1 sp ), ion carbonate concentration excess over aragonite saturation (exCO SB 3 sb = in µmol kg SP -1 sp yr SP -1 sp ), and anthropogenic CO SB 2 sb ." now reads: "Average trends obtained with the seasonally detrended data the in situ temperature (T in °C yr SP -1 sp ), salinity (S in yr SP -1 sp ), Total Alkalinity (TA in µmol kg SP -1 sp yr SP -1 sp ), salinity-normalized alkalinity (nTA in µmol kg SP -1 sp yr SP -1 sp ), total dissolved inorganic carbon (DIC in µmol kg SP -1 sp yr SP -1 sp ), salinity-normalized dissolved inorganic carbon (nDIC in µmol kg SP -1 sp yr SP -1 sp ), in situ pH in total scale (pHT yr SP -1 sp ), total hydrogen ion concentrations ([H+]T in picomol kg SP -1 sp yr SP -1 sp ), ion carbonate concentration excess over aragonite saturation (exCO SB 3 sb = in µmol kg SP -1 sp yr SP -1 sp ), and anthropogenic CO SB 2 sb .". [Extracted from the article]

Abstract: The Southern Ocean (SO) is a major part of the global ocean circulation. The formation and mixing of water masses in the SO cause changes in the northward flow of the Meridional Overturning Circulation and as a consequence, in the Earth’s climate. There have been numerous studies of the SO but a full understanding is difficult to achieve due to the complexity of the processes of formation and mixing of the different water masses. This work aims to clarify some of these aspects through an extended Optimum Multiparametric analysis, using data downloaded from the GLODAP and CARINA databases. A total of 11 source water masses were selected accurately describe the physical and biochemical properties of the SO. Shelf surface waters were included in order to accommodate the complex shelf processes involved in the formation of Antarctic bottom Waters. The methodology here developed takes into account the remineralisation of organic matter and as an improvement; the variability of data related to the processes of dissolution of CaCO3 and opal. The results from this analysis are accurate and reliable and led to very informative conclusions. Thus, a volumetric census is presented, which confirms Circumpolar Deep Water (CDW; 53±3% of the SO volume) as the most volumetrically important water mass in the SO; followed by Antarctic Bottom Water (AABW; 17±0.9%) and North Atlantic Deep Water (NADW; 13±0.8%). AABW properties are the result of the predefined combination of its three major types, i.e., 77% Weddell Sea Bottom Water, 20% Ross Sea Bottom Water and 3% Adélie Bottom Water. CDW comprises 65% AABW, 30% NADW and 5% Antarctic Intermediate Water, according to the relationship between their conservative properties (potential temperature and salinity). Therefore, the volume occupied by AABW and NADW in the SO rises to 51±2% and 28±0.8%, respectively. The ratio between AABW and NADW is 1.79±0.03, which is inside the expected range of 1–3. Considering the Atlantic sector of the SO (70°W–80°E), which is the more relevant in terms of AABW production (AABW represents 60±0.2% of the volume of the sector), the estimated ventilation time is approximately 250years, the same period as for the whole SO. This demonstrates the very important role of shelf processes in the quantity of AABW formed in the SO and its crucial role in terms of global climate. [Copyright &y& Elsevier]

Both polyamines and methionine derivatives are nitrogen compounds directly related to the regulation of gene expression. In silico predictions and experimental evidence suggest a cross-talk between polyamine and methionine metabolism in mammalian tissues. Since liver is the major organ that controls nitrogen metabolism of the whole organism, it is the best tissue to further test this hypothesis in vivo. In this work, we studied the effects of the chronic administration of a methionine-supplemented diet (0.5% Met in drinking water for 5 months) on the liver of mice (designated as MET-mice). Metabolic and proteomic approaches were performed and the data obtained were subjected to biocomputational analysis. Results showed that a supplemental methionine intake can indeed regulate biogenic amine metabolism in an in vivo model by multiple mechanisms including metabolic regulation and specific gene demethylation. Furthermore, putative systemic effects were investigated by molecular and cellular biology methods. Among other results, altered expression levels of multiple inflammation and cell proliferation/death balance markers were found and macrophage activation was observed. Overall, the results presented here will be of interest across a variety of biomedical disciplines, including nutrition, orphan diseases, immunology and oncology. [ABSTRACT FROM AUTHOR]

Coastal upwelling regions, which are affected by equatorward-wind variability, are among the most productive areas of the oceans. It has been suggested that global warming will lead to a general strengthening of coastal upwelling, with important ecological implications and an impact on fisheries. However, in the case of the Iberian upwelling, the long-term analysis of climatological variables described here reveals a weakening in coastal upwelling. This is linked to a decrease of zonal sea level pressure gradient, and correlated with an observed increase of sea surface temperature and North Atlantic Oscillation. Weakening of coastal upwelling has led to quantifiable modifications of the ecosystem. In outer shelf waters a drop in new production over the last 40 years is likely related to the reduction of sardine landings at local harbors. On the other hand, in inner shelf and Ria waters, the observed weakening of upwelling has slowed down the residual circulation that introduces nutrients to the euphotic layer, and has increased the stability of the water column. The drop in nutrient levels has been compensated by an increase of organic matter remineralization. The phytoplankton community has responded to those environmental trends with an increase in the percentage of dinoflagellates and Pseudonitzschia spp. and a reduction in total diatoms. The former favors the proliferation of harmful algal blooms and reduces the permitted harvesting period for the mussel aquaculture industry. The demise of the sardine fishery and the potential threat to the mussel culture could have serious socio-economic consequences for the region. [ABSTRACT FROM AUTHOR]

Abstract: We show the vertical distributions of temperature, salinity, nutrients, oxygen, CO2 fugacity (fCO2), pH and chlorophyll-a at the end of the winter 1984 in the northeast sector of the Atlantic Ocean between 40°N and 47°N. The intense vertical mixing due to winter cooling resulting in homogeneous water column layers as deep as 300 m at 47°N and, getting shallower further south to 100 m at 40°N. This northward increasing of the winter mixed layer was accompanied with a northward increasing trend in nutrients and CO2 and a decreasing in temperature, salinity, oxygen, pH and chlorophyll-a. Taking into account these observations, we analyse the winter mixing effect on the CO2 uptake of the newly formed water masses. The mixed-layer CO2 values were very close to the expected values supposing that the new water masses were formed under conditions of CO2 atmospheric equilibrium and were subsequently subjected to convective mixing with aged waters from below the main pycnocline. We also show the occurrence of a significant phytoplankton biomass through the entire winter mixed layer. This phenomenon, previously coined as ‘phyto-convection’ [Backhaus, J.O., Wehde, H., Hegseth, E.N., Kämpf, J., 1999. ‘Phyto-convection’: the role of oceanic convection in primary production. Mar. Ecol., Prog. Ser. 189, 77–92] affects the nutrient and CO2 levels of the newly formed water masses and it is an indicator of the extremely fast vertical velocities through the winter mixed layer. [Copyright &y& Elsevier]

Presents a study that developed an approach to improve the back-calculation technique for estimating anthropogenic carbon dioxide (CO[sub2]) for deep sea research. Details on the back-calculation technique; Analysis of the inorganic to organic carbon decomposition ratio; Evidence of an inaccurate estimation of preformed alkalinity and total inorganic carbon in equilibrium with pre-industrial atmosphere; Examination of a case study that reevaluated anthropogenic CO[sub2].

Presents a study which investigated the temporal evolution of anthropogenic carbon dioxide input in the eastern North Atlantic ocean from 1977 to the 1997 period. Parameters and technique used to estimate the anthropogenic carbon; Set of cruises studied; Mechanism contributing to the eastern boundary ventilation.

Examines the role played by the Portugal Current System in the ventilation of the different modes of Eastern North Atlantic Central Water (ENACW). Details on ENACW variability at the scale of the Iberian Basin; Thermohaline and geostrophic fields during a Portugal Coastal Countercurrent (PCCC) event; Chemical fields during contrasting PCCC events.

Introduces several methodological improvements in a potentiometric technique for determining seawater alkalinity. Master parameters that define the seawater carbon dioxide system; Material and methods; Example of a typical sequence of alkalinity analysis in a batch of measurements.

Studies the distribution of dissolved and particulate organic carbon and nitrogen at the Catalan coast in the Northwestern Mediterranean in June 1995. Materials and methods used on the study; Results; Discussion.

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. [ABSTRACT FROM AUTHOR]

The present study focuses on the Ría de Vigo (NW Spain), a coastal embayment influenced by the Canary Current Upwelling System, which is among the world's significant Eastern Boundary Upwelling Ecosystems. The research assesses historical changes in the marine carbonate system by generating 25-year weekly time series at six stations. Assessing ocean acidification in the region is complex due to diverse factors influencing coastal carbon dynamics, making predictions more challenging. To capture the specific dynamics in Ría de Vigo, ensembles of Neural Networks were applied. These networks were trained with a data set obtained in several oceanographic cruises, in order to retrieve pH, hydrogen ion concentration and alkalinity, achieving a root mean square error of 0.0272 pH units, 0.588 nmol kg - 1 , and 10.6 μ mol kg - 1 , respectively. Subsequently, time series of the selected variables were generated, applying data of predictors measured at the aforementioned stations. An increase in normalized alkalinity was observed for all stations, except in the surface layer at the innermost location. A decrease in pH and an increase in hydrogen ion concentration were observed for all points, with trends that exceed reported rates of ocean acidification in the open ocean. [ABSTRACT FROM AUTHOR]

Seawater pH is undergoing a decreasing trend due to the absorption of atmospheric CO2, a phenomenon known as ocean acidification (OA). Biogeochemical processes occurring naturally in the ocean also change pH and hence, for an accurate assessment of OA, the contribution of the natural component to the total pH variation must be quantified. In this work, we used 11 years (2005–2015) of biogeochemical measurements collected at the Strait of Gibraltar to estimate decadal trends of pH in two major Mediterranean water masses, the Western Mediterranean Deep Water (WMDW) and the Levantine Intermediate Water (LIW) and assess the magnitude of natural and anthropogenic components on the total pH change. The assessment was also performed in the North Atlantic Central Water (NACW) feeding the Mediterranean Sea. Our analysis revealed a significant human impact on all water masses in terms of accumulation of anthropogenic CO2. However, the decadal pH decline found in the WMDW and the NACW was markedly affected by natural processes, which accounted for by nearly 60% and 40% of the total pH decrease, respectively. The LIW did not exhibit a significant pH temporal trend although data indicated natural and anthropogenic perturbations on its biogeochemical signatures. [ABSTRACT FROM AUTHOR]

A data product of 17 653 discrete samples from 3343 oceanographic stations combining measurements of pH, alkalinity and other biogeochemical parameters off the northwestern Iberian Peninsula from June 1976 to September 2018 is presented in this study. The oceanography cruises funded by 24 projects were primarily carried out in the Ría de Vigo coastal inlet but also in an area ranging from the Bay of Biscay to the Portuguese coast. The robust seasonal cycles and long-term trends were only calculated along a longitudinal section, gathering data from the coastal and oceanic zone of the Iberian upwelling system. The pH in the surface waters of these separated regions, which were highly variable due to intense photosynthesis and the remineralization of organic matter, showed an interannual acidification ranging from -0.0012 to -0.0039 yr -1 that grew towards the coastline. This result is obtained despite the buffering capacity increasing in the coastal waters further inland as shown by the increase in alkalinity by 1.1±0.7 and 2.6±1.0 µ mol kg -1 yr -1 in the inner and outer Ría de Vigo respectively, driven by interannual changes in the surface salinity of 0.0193±0.0056 and 0.0426±0.016 psu yr -1 respectively. The loss of the vertical salinity gradient in the long-term trend in the inner ria was consistent with other significant biogeochemical changes such as a lower oxygen concentration and fertilization of the surface waters. These findings seem to be related to a growing footprint of sediment remineralization of organic matter in the surface layer of a more homogeneous water column. Data are available at 10.20350/digitalCSIC/12498 (Pérez et al., 2020). [ABSTRACT FROM AUTHOR]

A data product of 17,653 discrete samples from 3,357 oceanographic stations combining measurements of pH, alkalinity and other biogeochemical parameters off the North-western Iberian Peninsula from June 1976 to September 2018 is presented in this study. The oceanography cruises funded by 24 projects were primarily carried out in the Ría de Vigo coastal inlet, but also in an area ranging from the Bay of Biscay to the Portuguese coast. The robust seasonal cycles and long-term trends were only calculated along a longitudinal section, gathering data from the coastal and oceanic zone of the Iberian Upwelling System. The pH in the surface waters of these separated regions, which were highly variable due to intense photosynthesis and the remineralization of organic matter, showed an interannual acidification ranging from -0.0016 yr-1 to -0.0032 yr-1 that grew towards the coastline. This result is obtained despite the buffering capacity increasing in the coastal waters further inland as shown by the increase in alkalinity by 1.1±0.7 μmol kg-1 yr-1 and 2.6±1.0 μmol kg-1 yr-1 in the inner and outer Ría de Vigo respectively, driven by interannual changes in the surface salinity of 0.0193±0.0056 psu yr-1 and 0.0426±0.016 psu yr-1 respectively. The loss of the vertical salinity gradient in the long-term trend in the inner ria was consistent with other significant biogeochemical changes such as a lower oxygen concentration and fertilization of the surface waters. These findings seem to be related to a growing footprint of sediment remineralization of organic matter in the surface layer of a more homogeneous water column. Data are available at: https://doi.org/10.20350/digitalCSIC/12498 (Pérez et al., 2020). [ABSTRACT FROM AUTHOR]

Oceanic Acidification is the process that describes a shift in the acid-base equilibrium caused by the rise of the CO2 concentration in the ocean. The project A.RIOS lists among its goals to establish an observation network of oceanic acidification in the Rías and the Galician shelf (NW Iberia). Included in that observation network, an autonomous instrument for spectrophotometric measurements of seawater pH was deployed at the Ría de Vigo during four periods between November 2017 and May 2019. We present here the pH data for those deployments along with temperature, salinity, and pressure data. All the data is available through an unrestricted repository at https://doi.pangaea.de/10.1594/PANGAEA.909933 (Varela et al., 2019). In the author's opinion, this dataset significantly improves the temporal resolution of the pH database in the Ría of Vigo. [ABSTRACT FROM AUTHOR]

The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing regular compilations of surface to bottom ocean biogeochemical bottle data, with an emphasis on seawater inorganic carbon chemistry and related variables determined through chemical analysis of seawater samples. GLODAPv2.2023 is an update of the previous version, GLODAPv2.2022 (Lauvset et al., 2022). The major changes are as follows: data from 23 new cruises were added. In addition, a number of changes were made to the data included in GLODAPv2.2022. GLODAPv2.2023 includes measurements from more than 1.4 million water samples from the global oceans collected on 1108 cruises. The data for the now 13 GLODAP core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, chlorofluorocarbon-11 (CFC-11), CFC-12, CFC-113, CCl 4 , and SF 6) have undergone extensive quality control with a focus on the systematic evaluation of bias. The data are available in two formats: (i) as submitted by the data originator but converted to World Ocean Circulation Experiment (WOCE) exchange format and (ii) as a merged data product with adjustments applied to minimize bias. For the present annual update, adjustments for the 23 new cruises were derived by comparing those data with the data from the 1085 quality-controlled cruises in the GLODAPv2.2022 data product using crossover analysis. SF 6 data from all cruises were evaluated by comparison with CFC-12 data measured on the same cruises. For nutrients and ocean carbon dioxide (CO 2), chemistry comparisons to estimates based on empirical algorithms provided additional context for adjustment decisions. The adjustments that we applied are intended to remove potential biases from errors related to measurement, calibration, and data-handling practices without removing known or likely time trends or variations in the variables evaluated. The compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 µ mol kg -1 in dissolved inorganic carbon, 4 µ mol kg -1 in total alkalinity, 0.01–0.02 in pH (depending on region), and 5 % in the halogenated transient tracers. The other variables included in the compilation, such as isotopic tracers and discrete CO 2 fugacity (f CO 2), were not subjected to bias comparison or adjustments. The original data, their documentation, and DOI codes are available at the Ocean Carbon and Acidification Data System of NOAA National Centers for Environmental Information (NCEI), which also provides access to the merged data product. This is provided as a single global file and as four regional ones – the Arctic, Atlantic, Indian, and Pacific oceans – under https://doi.org/10.25921/zyrq-ht66 (Lauvset et al., 2023). These bias-adjusted product files also include significant ancillary and approximated data, which were obtained by interpolation of, or calculation from, measured data. This living data update documents the GLODAPv2.2023 methods and provides a broad overview of the secondary quality control procedures and results. [ABSTRACT FROM AUTHOR]

The ocean is a major carbon sink and takes up 25%–30% of the anthropogenically emitted CO2. A state‐of‐the‐art method to quantify this sink are global ocean biogeochemistry models (GOBMs), but their simulated CO2 uptake differs between models and is systematically lower than estimates based on statistical methods using surface ocean pCO2 and interior ocean measurements. Here, we provide an in‐depth evaluation of ocean carbon sink estimates from 1980 to 2018 from a GOBM ensemble. As sources of inter‐model differences and ensemble‐mean biases our study identifies (a) the model setup, such as the length of the spin‐up, the starting date of the simulation, and carbon fluxes from rivers and into sediments, (b) the simulated ocean circulation, such as Atlantic Meridional Overturning Circulation and Southern Ocean mode and intermediate water formation, and (c) the simulated oceanic buffer capacity. Our analysis suggests that a late starting date and biases in the ocean circulation cause a too low anthropogenic CO2 uptake across the GOBM ensemble. Surface ocean biogeochemistry biases might also cause simulated anthropogenic fluxes to be too low, but the current setup prevents a robust assessment. For simulations of the ocean carbon sink, we recommend in the short‐term to (a) start simulations at a common date before the industrialization and the associated atmospheric CO2 increase, (b) conduct a sufficiently long spin‐up such that the GOBMs reach steady‐state, and (c) provide key metrics for circulation, biogeochemistry, and the land‐ocean interface. In the long‐term, we recommend improving the representation of these metrics in the GOBMs. Plain Language Summary: In this study, we evaluate the performance of state‐of‐art global ocean biogeochemistry models (GOBMs) in simulating CO2 fluxes across the air‐sea interface from 1980 to 2018 for the Global Carbon Budget. Across these GOBMs, the simulated CO2 uptake is systematically lower than that of observation‐based estimates and the estimates differ also substantially between GOBMs. As reasons for the too low carbon sink of the GOBMs, we find that the simulations of several GOBMs were initialized after the start of the industrial revolution and that the majority of the considered GOBMs underestimate the large‐scale ocean circulation in the Atlantic. The different initialization times of the simulations as well as different strengths of the simulated ocean circulation across the global ocean also partly explain the inter‐model differences for the ocean carbon sink. Our analysis of the influence of GOBM dynamics on their simulated carbon sink was impeded by the fact that not all GOBMs had the same initial stability and that the riverine component of the ocean carbon sink is highly uncertain in both observations and GOBMs. Based on our evaluation, we give recommendations for follow up studies. Key Points: The simulated CO2‐uptake by global ocean biogeochemistry models (GOBMs) in the second phase of the REgional Carbon Cycle Assessment and Processes project is systematically lower than observation‐based estimatesThis underestimation can, to first order, be explained by the simulation setup as well as biases in surface chemistry and ocean circulationConcrete steps forward are proposed to improve simulations of the ocean carbon sink by GOBMs [ABSTRACT FROM AUTHOR]

• A large DIC sink due the biological pump is quantified in the eSPNA. • The eSPNA is an autotrophic area of DIC sink (168 ± 53 kmol·s−1) and oxygen uptake. • Whole-water column biogeochemical budgets are based on 14 years of observations. • Budgets of elements C, O, N, P and Si are consistently integrated and optimized. The eastern subpolar North Atlantic (eSPNA) is a key region in the Atlantic Meridional Overturning Circulation (AMOC), playing an important role in biogeochemical cycles and climate regulation. Quantitative basin-scale biogeochemical budgets are still scarce despite the current need of establishing baselines of knowledge in a changing ocean. The physico-chemical data from the eight repetitions of the OVIDE section (2002–2016) are an unique opportunity to develop a novel evaluation of biogeochemical budgets in the eSPNA by combining robust and well established decadal mean mass transports with carbon variables, oxygen and inorganic nutrients in a full-depth inverse box model. The net balance between the carbon fixation and the respiration throughout the whole water column shows that the eSPNA is an important dissolved inorganic carbon (DIC) sink area where 119 ± 43 kmol·s−1 and 49 ± 31 kmol·s−1 of organic and inorganic carbon, respectively, are currently exported. The uptake due to mixed layer depth oxygenation of 807 ± 114 kmol·s−1 of oxygen from the atmosphere and its subsequent southward export are responsible for deep Atlantic Ocean oxygenation. Deep water formation processes connect the northward upper limb with the southward lower limb of the AMOC leading to tracer export to the deep ocean. With regard to the net macronutrient budgets, all element consumptions are balanced within uncertainties. The results presented here for carbon export and oxygen uptake are in agreement with the upper range of previous observations based on different methods. The findings of this integrated budget driven by circulation in the highly dynamic region of the eSPNA can be taken as a reference in future biogeochemical evaluations of the North Atlantic. [ABSTRACT FROM AUTHOR]

The article presents a research study on the bone marrow derived mast cells (MC) as a model to characterize histamine and polyamines metabolism. It states that the intracellular content of putrescine, histamine, spermidine and spermine were determined by fluorimetry. It furthur states the antagonistic relationship between histamine and polyamines in MCs during the differentiation of the following cell type.

The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing regular compilations of surface-to-bottom ocean biogeochemical bottle data, with an emphasis on seawater inorganic carbon chemistry and related variables determined through chemical analysis of seawater samples. GLODAPv2.2023 is an update of the previous version, GLODAPv2.2022 (Lauvset et al., 2022). The major changes are as follows: data from 23 new cruises were added. In addition, a number of changes were made to data included in GLODAPv2.2022. GLODAPv2.2023 includes measurements from more than1.4 million water samples from the global oceans collected on 1108 cruises. The data for the now 13 GLODAP core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, chlorofluorocarbon-11 (CFC-11), CFC-12, CFC-113, CCl4, and SF6) have undergone extensive quality control with a focus on systematic evaluation of bias. The data are available in two formats: (i) as submitted by the data originator but converted to World Ocean Circulation Experiment (WOCE) exchange format and (ii) as a merged data product with adjustments applied to minimize bias. For the present annual update, adjustments for the 23 new cruises were derived by comparing those data with the data from the 1085 quality-controlled cruises in the GLODAPv2.2022 data product using crossover analysis. SF6 data from all cruises were evaluated by comparison with CFC-12 data measured on the same cruises. For nutrients and ocean carbon dioxide (CO2) chemistry comparisons to estimates based on empirical algorithms provided additional context for adjustment decisions. The adjustments that we applied are intended to remove potential biases from errors related to measurement, calibration, and data handling practices without removing known or likely time trends or variations in the variables evaluated. The compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 mol kg-1 in dissolved inorganic carbon, mol kg-1 in total alkalinity, 0.01-0.02 in pH (depending on region), and 5 % in the halogenated transient tracers. The other variables included in the compilation, such as isotopic tracers and discrete CO2 fugacity (fCO2), were not subjected to bias comparison or adjustments. The original data, their documentation and DOI codes are available at the Ocean Carbon and Acidification Data System of NOAA NCEI, which also provides access to the merged data product. This is provided as a single global file and as four regional ones - the Arctic, Atlantic, Indian, and Pacific oceans - under https://doi.org/10.25921/zyrq-ht66 (Lauvset et al., 2023). These bias-adjusted product files also include significant ancillary and approximated data, which were obtained by interpolation of, or calculation from, measured data. This living data update documents the GLODAPv2.2023 methods and provides a broad overview of the secondary quality control procedures and results. [ABSTRACT FROM AUTHOR]

A significant fraction of anthropogenic carbon dioxide (CO2) released to the atmosphere is absorbed by the oceans, leading to a range of chemical changes and causing ocean acidification (OA). Assessing the impact of OA on marine ecosystems requires the accurate detection of the rate of seawater pH change. This work reports the results of nearly 3 years of continuous pH measurements in the Mediterranean Sea at the Strait of Gibraltar GIFT time series station. We document a remarkable decreasing annual trend of −0.0044 ± 0.00006 in the Mediterranean pH, which can be interpreted as an indicator of acidification in the basin based on high frequency records. Modeling pH data of the Mediterranean outflow allowed to discriminate between the pH values of its two main constituent water masses, the Levantine Intermediate Water (LIW) and the Western Mediterranean Deep Water (WMDW). Both water masses also exhibited a decline in pH with time, particularly the WMDW, which can be related to their different biogeochemical nature and processes occurring during transit time from formation sites to the Strait of Gibraltar. [ABSTRACT FROM AUTHOR]

Seawater was sampled from different depths in the North Atlantic Ocean (Canary Islands region) and distributed among three different labsfor the determination of titration alkalinity. Analysis was performed by potentiometric methods, involving titration in a closed cell, titration in an open cell and a two end-point acid addition method. Theprecision, which is the sample reproducibility taken from the mean standard deviation for replicate measurements, was between 0.45 and 0.90 mumol - kg-1 for the individual labs. Accuracy, here taken as the deviation for the values of a lab from the mean of all three, was mostly below 1 mumol kg-1 and never exceeded 0.1% of the sample value. Mean standard deviation for all labs and all samples was 0.87 mumol kg-1, once the individual methods werecalibrated using certified reference material (CRM). Without CRM calibration, the mean standard deviation would increase to 2.8 mumol kg-1. The conclusion is that current high precision methods for alkalinity measurements calibrated with CRMs are able to reach similar accuracy as the measurement of total dissolved inorganic carbon by coulometry and therefore allow for the precise determination of the oceanic carbon dioxide system by using the two measured parameters. [ABSTRACT FROM AUTHOR]

This study constituted the first attempt to measure dissolved calcium ([Ca 2 + ] meas ) in the subtropical North Atlantic, during a zonal transoceanic cruise along 24.5°N (WOCE A05 section), in summer 1992. [Ca 2 + ] meas was obtained in 20 full-depth equidistant stations along the section, showing that their gradients are rather sensitive to horizontal and vertical water mass distribution. Deep waters along 24.5°N systematically show a positive calcium excess of 20 ± 14 μmol·kg − 1 , i.e., more [Ca 2 + ] than expected by CaCO 3 dissolution and organic matter oxidation (estimated by total alkalinity and nitrate). CaCO 3 settling and benthic dissolution accounts for 70% and the North Atlantic plus Arctic riverine inputs of HCO 3 − for the remaining 30%. Combining [Ca 2 + ] meas and CO 2 data sets, carbonate mineral saturation states distributions for aragonite and calcite can be obtained. The two solubility ratios resulted, on average, 0.5% smaller than if conservative behavior for Ca 2 + was assumed (an approach widely followed when [Ca 2 + ] meas is unknown). As a result, shallower saturation horizon depths for both carbonate states (19 dbar for aragonite and 10 dbar for calcite) are yielded if [Ca 2 + ] meas is taken into account instead than estimated from salinity. [ABSTRACT FROM AUTHOR]

During the Cither 3 cruise along WOCE section A14, where 107 full-water column stations were surveyed, pH and alkalinity were measured potentiometrically. Corrections carried out on the raw data set have allowed us to improve the data quality. The correction procedure was focused on monitoring: (i) calibrations, (ii) liquid junction potentialand (iii) seawater sub-standards; CO2 reference material (CRM) has been used to check this procedure. Accuracy of pH15 measurements (NBS scale) and alkalinity was 0.004 and 1.4 pmol.kg-1, respectively. Certified total inorganic carbon on CRM,batch 24, is 1987.55 mu mol.kg- 1. A value of 1987.8 1 2.2 mu mol.kg-1 was obtained following the correction procedure. This improvement was independently verified by means of the covariances between nitrate and pH, and between silicate and normalized alkalinity in North Atlantic Deep Water. [ABSTRACT FROM AUTHOR]

Diatoms play a key role in the marine silica cycle, but recent studies have shown that sponges can also have an important effect on this dynamic. They accumulate large stocks of biogenic silica within their bodies over long periods, which are thought to vary little on an intra-annual scale. The observation of an abrupt decline in sponge biomass in parallel with large increases in abundance of a spongivorous nudibranch (Doris verrucosa) led us to conduct a year-long study on the effect of nudibranch predation on the silicon budget of a sponge (Hymeniacidon perlevis) population. After 5 months of predation, the abundance of sponge individuals did not change but their biomass decreased by 95%, of which 48% was explained by nudibranch predation. About 97% of sponge spicules ingested by nudibranchs while feeding was excreted, most of them unbroken, implying a high rate of sponge silica deposition in the surrounding sediments. After predation, sponges partially recovered their biomass stocks within 7 months. This involved a rapid growth rate and large assimilation of dissolved silicon. Surprisingly, the highest rates of silicon absorption occurred when dissolved silicon concentration in seawater was minimal (< 1.5 µM). These findings suggest that the annual sponge predation-recovery cycle triggers unprecedented intra-annual changes in sponge silicon stocks and boosts the cycling of this nutrient. They also highlight the need for intra-annual data collection to understand the dynamics and resilience of sponge ecosystem functioning. [ABSTRACT FROM AUTHOR]

In coastal systems, planktonic and benthic silicifiers compete for the pool of dissolved silicon, a nutrient required to make their skeletons. The contribution of planktonic diatoms to the silicon cycle in coastal systems is often well characterized, while that of benthic silicifiers such as sponges has rarely been quantified. Herein, silicon fluxes and stocks are quantified for the sponge fauna in the benthic communities of the Bay of Brest (France). A total of 45 siliceous sponge species living in the Bay account for a silicon standing stock of 1215 tons, while that of diatoms is only 27 tons. The silicon reservoir accumulated as sponge skeletons in the surface sediments of the Bay rises to 1775 tons, while that of diatom skeletons is only 248 tons. These comparatively large stocks of sponge silicon were estimated to cycle two orders of magnitude slower than the diatom stocks. Sponge silicon stocks need years to decades to be renewed, while diatom turnover lasts only days. Although the sponge monitoring over the last 6 yr indicates no major changes of the sponge stocks, our results do not allow us to conclude if the silicon sponge budget of the Bay is at steady state, and potential scenarios are discussed. The findings buttress the idea that sponges and diatoms play contrasting roles in the marine silicon cycle. The budgets of these two major silicon users need to be integrated and their connections revealed, if we aim to improve our understanding of the silicon cycling in coastal ecosystems. [ABSTRACT FROM AUTHOR]

The decreasing seawater pH trend associated with increasing atmospheric carbon dioxide levels is an issue of concern due to possible negative consequences for marine organisms, especially calcifiers. Globally, coastal areas represent important transitional land-ocean zones with complex interactions between biological, physical and chemical processes. Here, we evaluated the pH variability at two sites in the coastal area of the Balearic Sea (Western Mediterranean). High resolution pH data along with temperature, salinity, and also dissolved oxygen were obtained with autonomous sensors from 2018 to 2021 in order to determine the temporal pH variability and the principal drivers involved. By using environmental datasets of temperature, salinity and dissolved oxygen, Recurrent Neural Networks were trained to predict pH and fill data gaps. Longer environmental time series (2012–2021) were used to obtain the pH trend using reconstructed data. The best predictions show a rate of - 0.0020 ± 0.00054 pH units year - 1 , which is in good agreement with other observations of pH rates in coastal areas. The methodology presented here opens the possibility to obtain pH trends when only limited pH observations are available, if other variables are accessible. Potentially, this could be a way to reliably fill the unavoidable gaps present in time series data provided by sensors. [ABSTRACT FROM AUTHOR]

Abstract: This work estimates new regionalized empirical parameterizations for preformed alkalinity (AT o) and the CO2 air–sea disequilibrium (∆Cdis). Both are key terms for the computation of anthropogenic CO2 in the back-calculation methods. Data from the subsurface layer (75–180m depth range) covering an area from North to South and from 19°E to 67.5°W (Pacific and Indian oceans) were taken from GLODAP (The Global Ocean Data Analysis Project) database. The subsurface layer is proved as a reliable reference for representing the main characteristics of the different water masses of the oceans. Besides, handing data from the two ocean basins altogether makes the new parameterizations of AT o and ∆Cdis to be more globally consistent. Nevertheless, each ocean basin, at least in some regions, has different oceanographic characteristics based on its proper dynamical processes and water masses formation. In order to maintain each ocean basin ‘identity’ the whole domain was divided in six different regions (two of them sharing waters from Pacific and Indian oceans) and parameterizations in each region for both terms were obtained. Previously, data were transformed into a grid of 4°lat.×5°lon. and the results obtained from the parameterizations were visualized and compare with pCO2 climatologies. From the comparisons with previous ∆Cdis estimations good results are obtained showing the reliability and robustness of the new regionalized empiric parameterizations. [ABSTRACT FROM AUTHOR]

Ocean acidification is expected to affect marine organisms in the near future. Furthermore, abrupt short-term fluctuations in seawater p CO 2 characteristic of near-shore coastal regions and high-density aquaculture sites currently have the potential to influence organismal and community functioning by altering animal behaviour. While anti-predator responses in fishes exposed to elevated p CO 2 are well documented, such responses in benthic marine invertebrates are poorly studied. We used high frequency, non-invasive biosensors to test whether or not short term (3-week) exposure to elevated p CO 2 could impact behavioural responses to the threat of predation in adult Mediterranean mussels from Galicia on the northwestern coast of Spain. Predator alarm cues (crushed conspecifics) resulted in a prolonged (1 h) reduction in the degree of valve opening (−20%) but had no clear effect on overall valve movement activity, while elevated p CO 2 did not affect either response. Our results add to the increasing body of evidence suggesting that the effects of end-of-century p CO 2 levels on marine animal behaviour are likely weak. Nonetheless, longer-term exposures spanning multiple generations are needed to better understand how ocean acidification might impact behavioural responses to predation in marine bivalves. • Tested effects of elevated CO 2 on valve gaping responses to predator alarm cues in Mediterranean mussels. • Mussels reduced valve gaping in response to predator alarm cues; no change in valve movement activity. • Elevated CO 2 had no effect on baseline behaviour nor responses to predator cues. • Behavioural responses to predator cues in bivalves appear robust to high CO 2. [ABSTRACT FROM AUTHOR]

Abstract Evaluation of biogeochemical processes in Anthropocene deep-sea sediments require accurate dating techniques. Here we show the results of an approach using high resolution low level background gamma spectrometry with two simultaneous hyper-pure germanium (HPGe) detectors. The quantitative role of the deepest zones (>3000 m depth) of the Irminger Basin (Subpolar North Atlantic Ocean) as a carbon sink during the Anthropocene is evaluated combining a chronology based in the natural radionuclide 210Pb with sedimentological analysis and elemental composition. The average sedimentation rate of the central Irminger is 1.28 ± 0.18 mm·yr−1, with a mean weighted flux to the sediment for inorganic and organic carbon of 46 ± 15 g·C inorg ·m−2·yr−1 and 8 ± 1 g·C org ·m−2·yr−1. The biogenic fraction of the mass flux is increased since the XXth century. The contribution of the deepest zones of the Irminger Basin to the Anthropocene carbon sequestration in the North Atlantic Ocean is considerable at basin-scale. Highlights • Sedimentation rate in the central Irminger is quite high for a deep-sea basin. • Anthropocene carbon burial in the Irminger Basin is considerable (~1 Tg-C·yr−1). • Input of biogenic material is enhanced since the onset of the Anthropocene. [ABSTRACT FROM AUTHOR]

We quantify the oceanic sink for anthropogenic carbon dioxide (CO2) over the period 1994 to 2007 by using observations from the global repeat hydrography program and contrasting them to observations from the 1990s. Using a linear regression–based method, we find a global increase in the anthropogenic CO2 inventory of 34 ± 4 petagrams of carbon (Pg C) between 1994 and 2007. This is equivalent to an average uptake rate of 2.6 ± 0.3 Pg C year−1 and represents 31 ± 4% of the global anthropogenic CO2 emissions over this period. Although this global ocean sink estimate is consistent with the expectation of the ocean uptake having increased in proportion to the rise in atmospheric CO2, substantial regional differences in storage rate are found, likely owing to climate variability–driven changes in ocean circulation. [ABSTRACT FROM AUTHOR]

Summary: Porcine circovirus 3 (PCV‐3) is an emerging circovirus species that has recently been reported in different countries around the world, suggesting a widespread circulation. In this study, sera samples originating from 654 pigs of different production phases and clinical/pathological conditions, submitted for diagnostic purposes between 1996 and 2017, were randomly selected. Detection of PCV‐3 genome in such samples was attempted with a previously described PCR method, and the partial genome sequence was obtained from selected PCV‐3‐positive samples from different years. Compiled data confirmed that PCV‐3 has been circulating in the Spanish pig population since 1996. The overall frequency of PCV‐3 PCR‐positive samples in the study period was 11.47% (75 of 654). Phylogenetic analysis of twelve PCV‐3 partial sequences obtained showed a high nucleotide identity with the already known PCV‐3 sequences, with minor variations among years. No significant correlation was found between the detection of PCV‐3 and any production phase nor clinical/pathological condition. These results confirm PCV‐3 circulation at least since 1996 in the Spanish pig population with a low/moderate frequency. Although the information obtained was limited, PCV‐3 did not appear to be linked to any specific pathological condition or age group. [ABSTRACT FROM AUTHOR]

The analysis of the natural variability of seawater (Ta, Ω aragonite and pCO2) at Rodas Beach (NW Iberian Peninsula, Spain) revealed an increase of acidification. However, such pH change was not linked to any detrimental effect of the shell taphonomic characteristics of live razor clams harvested during distinct temporal series (length, thickness, organic content or strength). Temperature affected negatively shell strength and thickness, although the large correlation between the environmental variables would limit the individual characterization. Modelled trends in pH (and Ω aragonite) showed a significant decrease in the last 20 years, despite Ω > 1. Therefore, more recent shells are being secreted in a progressively less saturated carbonate environment and, consequently, more prone to suffer dissolution (and weakening) in projected climatic scenarios. When shells of harvested razor clams were exposed to projected climatic scenarios in the laboratory, dissolution rates were significantly greater for cold-acidic scenarios (more corrosive) as compared to warm-acidic. The median dissolution time (DT50) for shells under the cold-acidic scenario was reduced by half (15 years) when compared to the values observed for shells under current water chemistry conditions (30 years). Galician coastline, often characterised by p CO2-rich and cold waters due to upwelling system, would represent the most corrosive scenario for the shells according to the responses monitored in our survey which highlight future compromise for the ecosystem services supplied by these hard skeletons. Future climate scenarios might condition performance of bivalves but also more complex processes related to carbonate structures. Local biodiversity may be lowered which may reduce the possibility that many species find shelter and feeding grounds, diminishing the optimal substrate for other organisms as needed elements for optimal services in the ecosystems. • Variability in Ta, Ω aragonite and pCO 2 revealed an increase of acidification but no changes were noted in shell taphonomy. • Temperature affected negatively shell strength and thickness, despite large correlation between environmental variables. • Dissolution was greater for cold-acidic tests, mean DT 50 being reduced by half as compared to current conditions. • Recent shells are being secreted in a progressively less saturated carbonate environment, therefore more prone to be dissolved. • Marine shells support ecosystem services that may change in future conditions and affect biodiversity and optimal functioning. [ABSTRACT FROM AUTHOR]

The decadal mean circulation in the northern North Atlantic was assessed for the early 21st century from repeated ship-based measurements along the Greenland-Portugal OVIDE line, from satellite altimetry and from earlier reported transports across 59.5°N and at the Greenland-Scotland sills. The remarkable quantitative agreement between all data sets allowed us to draw circulation pathways with a high level of confidence. The North Atlantic Current (NAC) system is composed of three main branches, referred to as the northern, central and southern branches, which were traced from the Mid-Atlantic Ridge (MAR), to the Irminger Sea, the Greenland-Scotland Ridge and the subtropical gyre. At OVIDE, the northern and central branches of the NAC fill the whole water column and their top-to-bottom integrated transports were estimated at 11.0 ± 3 Sv and 14.2 ± 6.4 Sv (1 Sv = 10 6 m 3 s −1 ), respectively. Those two branches feed the cyclonic circulation in the Iceland Basin and the flow over the Reykjanes Ridge into the Irminger Sea. This cross-ridge flow was estimated at 11.3 ± 4.2 Sv westward, north of 58.5°N. The southern NAC branch is strongly surface-intensified and most of its top-to-bottom integrated transport, estimated at 16.6 ± 2 Sv, is found in the upper layer. It is composed of two parts: the northern part contributes to the flow over the Rockall Plateau and through the Rockall Trough toward the Iceland-Scotland Ridge; the southern part feeds the anticyclonic circulation toward the subtropical gyre. Summing over the three NAC branches, the top-to-bottom transport of the NAC across OVIDE was estimated at 41.8 ± 3.7 Sv. Because of the surface-intensification of the southern NAC branch, the intermediate water is transported to the northeast Atlantic mostly by the northern and central branches of the NAC (11.9 ± 1.8 Sv eastward). This water circulates cyclonically in the Iceland Basin and anticyclonically in the West European Basin, with similar transport intensities. In the deep layer of the Iceland Basin, Iceland-Scotland Overflow Water (ISOW) spreads southwestward along three pathways on the eastern flank of the Reykjanes Ridge. The associated transport was estimated at 3.2 ± 0.4 Sv. The two shallowest pathways turn around the Reykjanes Ridge toward the Irminger Sea where they head northward. A northeastward transport of deep water is observed in the deep extension of the northern and central branches of the NAC, east of the MAR. In the Irminger Sea our transport estimates for the Irminger Current, Irminger Gyre, East Greenland Irminger Current and Deep Western Boundary Current are in line with previous work. [ABSTRACT FROM AUTHOR]

Version 2 of the Global Ocean Data Analysis Project (GLODAPv2) data product is composed of data from 724 scientific cruises covering the global ocean. It includes data assembled during the previous efforts GLODAPv1.1 (Global Ocean Data Analysis Project version 1.1) in 2004, CARINA (CARbon IN the Atlantic) in 2009/2010, and PACIFICA (PACIFic ocean Interior CArbon) in 2013, as well as data from an additional 168 cruises. Data for 12 core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have been subjected to extensive quality control, including systematic evaluation of bias. The data are available in two formats: (i) as submitted but updated to WOCE exchange format and (ii) as a merged and internally consistent data product. In the latter, adjustments have been applied to remove significant biases, respecting occurrences of any known or likely time trends or variations. Adjustments applied by previous efforts were re-evaluated. Hence, GLODAPv2 is not a simple merging of previous products with some new data added but a unique, internally consistent data product. This compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1% in oxygen, 2% in nitrate, 2% in silicate, 2% in phosphate, 4 μmol kg-1 in dissolved inorganic carbon, 6 μmol kg-1 in total alkalinity, 0.005 in pH, and 5% for the halogenated transient tracers. The original data and their documentation and doi codes are available at the Carbon Dioxide Information Analysis Center (http://cdiac.ornl.gov/oceans/GLODAPv2/). This site also provides access to the calibrated data product, which is provided as a single global file or four regional ones - the Arctic, Atlantic, Indian, and Pacific oceans - under the doi:10.3334/CDIAC/OTG.NDP093_GLODAPv2. The product files also include significant ancillary and approximated data. These were obtained by interpolation of, or calculation from, measured data. This paper documents the GLODAPv2 methods and products and includes a broad overview of the secondary quality control results. The magnitude of and reasoning behind each adjustment is available on a per-cruise and per-variable basis in the online Adjustment Table. [ABSTRACT FROM AUTHOR]

We present a mapped climatology (GLODAPv2.2016b) of ocean biogeochemical variables based on the new GLODAP version 2 data product (Olsen et al., 2016; Key et al., 2015), which covers all ocean basins over the years 1972 to 2013. The quality-controlled and internally consistent GLODAPv2 was used to create global 1°x 1° mapped climatologies of salinity, temperature, oxygen, nitrate, phosphate, silicate, total dissolved inorganic carbon (TCO2), total alkalinity (TAlk), pH, and CaCO3 saturation states using the Data-Interpolating Variational Analysis (DIVA) mapping method. Improving on maps based on an earlier but similar dataset, GLODAPv1.1, this climatology also covers the Arctic Ocean. Climatologies were created for 33 standard depth surfaces. The conceivably confounding temporal trends in TCO2 and pH due to anthropogenic influence were removed prior to mapping by normalizing these data to the year 2002 using first-order calculations of anthropogenic carbon accumulation rates. We additionally provide maps of accumulated anthropogenic carbon in the year 2002 and of preindustrial TCO2. For all parameters, all data from the full 1972-2013 period were used, including data that did not receive full secondary quality control. [ABSTRACT FROM AUTHOR]

Measurements of ocean pH, alkalinity, and carbonate ion concentrations ([CO32-]) during three cruises in the Atlantic Ocean and one in the Mediterranean Sea were used to assess the reliability of the recent spectrophotometric [CO32-] methodology and to determine aragonite saturation states. Measurements of [CO32-] along the Atlantic Ocean showed high consistency with the [CO32-] values calculated from pH and alkalinity, with negligible biases (0.4 ± 3.4 µmol·kg-1). In the warm, salty, high alkalinity and high pH Mediterranean waters, the spectrophotometric [CO32-] methodology underestimates the measured [CO32-] (4.0 ± 5.0 µmol·kg-1), with anomalies positively correlated to salinity. These waters also exhibited high in situ [CO32-] compared to the expected aragonite saturation. The very high buffering capacity allows the Mediterranean Sea waters to remain over the saturation level of aragonite for long periods of time. Conversely, the relatively thick layer of undersaturated waters between 500 and 1000 m depths in the Tropical Atlantic is expected to progress to even more negative undersaturation values. Moreover, the northern North Atlantic presents [CO32-] slightly above the level of aragonite saturation, and the expected anthropogenic acidification could result in reductions of the aragonite saturation levels during future decades, acting as a stressor for the large population of cold-water-coral communities. [ABSTRACT FROM AUTHOR]

Global ocean acidification is caused primarily by the ocean's uptake of CO2 as a consequence of increasing atmospheric CO2 levels. We present observations of the oceanic decrease in pH at the basin scale (50°S-36°N) for the Atlantic Ocean over two decades (1993-2013). Changes in pH associated with the uptake of anthropogenic CO2 (ΔpHCant) and with variations caused by biological activity and ocean circulation (ΔpHNat) are evaluated for different water masses. Output from an Institut Pierre Simon Laplace climate model is used to place the results into a longer-term perspective and to elucidate the mechanisms responsible for pH change. The largest decreases in pH (ΔpH) were observed in central, mode, and intermediate waters, with a maximum ΔpH value in South Atlantic Central Waters of -0.042 ± 0.003. The ΔpH trended toward zero in deep and bottom waters. Observations and model results show that pH changes generally are dominated by the anthropogenic component, which accounts for rates between -0.0015 and -0.0020/y in the central waters. The anthropogenic and natural components are of the same order of magnitude and reinforce one another in mode and intermediate waters over the time period. Large negative ΔpHNat values observed in mode and intermediate waters are driven primarily by changes in CO2 content and are consistent with (i) a poleward shift of the formation region during the positive phase of the Southern Annular Mode in the South Atlantic and (ii) an increase in the rate of the water mass formation in the North Atlantic. [ABSTRACT FROM AUTHOR]