OceanGliders Oxygen SOP

The live version of this SOP is on the Ocean Gliders community in GITHUB. The home repository of this publication is in the Ocean Best Practices Repository. This standard operating procedure (SOP) document for dissolved oxygen (DO) aims to guide the user through the steps necessary to collect good quality dissolved oxygen data using ocean gliders for both real time and post deployment data streams

ISOW Spreading and Mixing as Revealed by Deep‐Argo Floats Launched in the Charlie‐Gibbs Fracture Zone

International audienceTo improve our understanding of deep circulation, we deployed five Deep‐Argo floats (0–4,000 m) in the Charlie‐Gibbs Fracture Zone (CGFZ), which channels the flow of Iceland‐Scotland Overflow Water (ISOW), a dense water mass of the North Atlantic Ocean. The floats were programed to drift at 2,750 dbar in the ISOW layer. The floats mainly moved westward in the CGFZ, although some of them followed different routes for few cycles depending on northward intrusions of the North Atlantic Current over the CGFZ. One float revealed a direct route for ISOW from CGFZ to the Deep Western Boundary Current at Flemish Cap. In the CGFZ, oxygen data acquired by the floats revealed that the ISOW layer, characterized by salinity higher than 34.94 and density greater than 27.8 kg/m, was mainly composed of the highly oxygenated ISOW and the less oxygenated North East Atlantic Deep Water (NEADW), a complex water mass from the East Atlantic. In the ISOW layer, the relative contribution of ISOW was generally larger in the northern valley than in the southern valley of CGFZ. Northward intrusions of the North Atlantic Current above the CGFZ increased the relative contribution of NEADW in the northern valley and favors mixing between ISOW and NEADW. The ISOW‐NEADW signal flowing westward from the CGFZ toward the Deep Western Boundary Current was progressively diluted by Labrador Sea Water and Denmark Strait Overflow Water. Oxygen measurements from Deep‐Argo floats are essential for a better understanding and characterization of the mixing and spreading of deep water masses

SUMMER AND WINTER VARIABILITY OF δ¹³C_DIC IN SURFACE WATERS OF SOUTH INDIAN OCEAN

participantThe summer and winter distribution of δ13CDIC in the South-West Indian Ocean is analyzed from surface measurements obtained in 1998-2005 (ten OISO cruises). Based on this dataset, we estimate a decrease in δ13CDIC of -0.017 ‰ yr-1 coherent with the average fCO2 increase of 2.1 µatm yr -1 observed in this region. The seasonal δ13CDIC climatology is thus referenced to the year 2002 by correcting surface δ13CDIC data by -0.017 ‰ yr-1. From 20°S to 60°S surface waters are characterized by higher δ13CDIC during summer than during winter. In summer maxima (δ13CDIC >2‰) are observed in the sub-Antarctic frontal zone where biological activity is enhanced. In winter minima (2 uptake is stronger. As opposed to fCO2 the seasonal δ13CDIC signal is larger in the region 35°S-40°S, with a mean amplitude of ~0.3 ‰; this is attributed to a stronger biological activity in summer (increasing δ13CDIC in the photic zone) and deeper mixing in winter (reducing surface δ13CDIC). In the subtropical oligotrophic waters the seasonal δ13CDIC signal is ~0.15 ‰ and driven by air-sea CO2 flux (sink in winter, near equilibrium in summer). This new δ13CDIC climatology allows identification of a negative δ13CDIC anomaly in the subtropics during summer 2002 associated to an anomalous ocean CO2 sink controlled by sea surface cooling. It is our hope that these results will help to evaluate the oceanic uptake of anthropogenic carbon in this region and to constrain and validate atmospheric inversions and ocean carbon models

Summer and winter distribution of δ¹³C_DIC in surface waters of the South Indian Ocean [20°S-60°S]

International audienceThis paper describes for the first time the summer and winter distributions of sea surface δ13CDIC in the Southern Indian Ocean (20°S-60°S). For this we used δ13CDIC measurements from 10 cruises conducted between 1998 and 2005. For summer and winter, the highest δ13CDIC values (>2‰) are observed in sub-Antarctic waters (40°S-50°S) and attributed mainly to biological activity, enhanced in the vicinity of Crozet and Kerguelen Archipelagoes. The lowest δ13CDIC values are found in subtropical waters (25°S-35°S), with a minimum (13CDIC is higher during summer than during winter in all regions. The largest seasonal amplitude of variation (~0.3‰), observed in the region 35°S-40°S, is attributed to biological activity during summer and to deep vertical mixing during winter. In subtropical oligotrophic waters, the mean seasonal amplitude of variation (~0.15‰) is mainly explained by air-sea CO2 fluxes. On the interannual scale, we also identified a large negative anomaly of δ13CDIC in the subtropical waters during austral summer 2002, associated to an anomalous ocean CO2 sink due to cold conditions during this period

Long-term CO₂ monitoring in the Southern Indian Ocean. “Sustained ocean observing for the next decade”, GAIC2015, Go-Ship/Argo/IOCCP

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The seasonal cycle of δ¹³C_DIC in the North Atlantic subpolar gyre

International audienceThis study introduces for the first time the δ13CDIC seasonality in the North Atlantic subpolar gyre (NASPG) using δ13CDIC data obtained in 2005-2006 and 2010-2012 with dissolved inorganic carbon (DIC) and nutrient observations. On the seasonal scale, the NASPG is characterized by higher δ13CDIC values during summer than during winter, with a seasonal amplitude between 0.70 ± 0.10‰ (August 2010-March 2011) and 0.77 ± 0.07‰ (2005-2006). This is mainly attributed to photosynthetic activity in summer and to a deep remineralization process during winter convection, sometimes influenced by ocean dynamics and carbonate pumps. There is also a strong and negative linear relationship between δ13CDIC and DIC during all seasons. Winter data also showed a large decrease in δ13CDIC associated with an increase in DIC between 2006 and 2011-2012, but the observed time rates (-0.04‰ yr-1and +1.7 μmol kg-1 yr-1) are much larger than the expected anthropogenic signal

Ocean carbonate system variability in the North Atlantic Subpolar surface water (1993-2017)

The North Atlantic is one of the major ocean sinks for natural and anthropogenic atmospheric CO 2. Given the variability of the circulation, convective processes or warming-cooling recognized in the high latitudes in this region , a better understanding of the CO 2 sink temporal variability and associated acidification needs a close inspection of seasonal, interannual to multidecadal observations. In this study, we investigate the evolution of CO 2 uptake and ocean acidification in the North Atlantic Subpolar Gyre (50-64 • N) using repeated observations collected over the last 3 decades in the framework of the long-term monitoring program SURATLANT (SURveillance de l'ATLANTique). Over the full period (1993-2017) pH decreases (−0.0017 yr −1) and fugacity of CO 2 (f CO 2) increases (+1.70 µatm yr −1). The trend of f CO 2 in surface water is slightly less than the atmospheric rate (+1.96 µatm yr −1). This is mainly due to dissolved inorganic carbon (DIC) increase associated with the anthropogenic signal. However, over shorter periods (4-10 years) and depending on the season, we detect significant variability investigated in more detail in this study. Data obtained between 1993 and 1997 suggest a rapid increase in f CO 2 in summer (up to +14 µatm yr −1) that was driven by a significant warming and an increase in DIC for a short period. Similar f CO 2 trends are observed between 2001 and 2007 during both summer and winter, but, without significant warming detected, these trends are mainly explained by an increase in DIC and a decrease in alkalinity. This also leads to a pH decrease but with contrasting trends depending on the region and season (between −0.006 and −0.013 yr −1). Conversely , data obtained during the last decade (2008-2017) in summer show a cooling of surface waters and an increase in alkalinity, leading to a strong decrease in surface f CO 2 (between −4.4 and −2.3 µatm yr −1 ; i.e., the ocean CO 2 sink increases). Surprisingly, during summer, pH increases up to +0.0052 yr −1 in the southern subpolar gyre. Overall, our results show that, in addition to the accumulation of anthro-pogenic CO 2 , the temporal changes in the uptake of CO 2 and ocean acidification in the North Atlantic Subpolar Gyre present significant multiannual variability, not clearly directly associated with the North Atlantic Oscillation (NAO). With such variability it is uncertain to predict the near-future evolution of air-sea CO 2 fluxes and pH in this region. Thus, it is highly recommended to maintain long-term observations to monitor these properties in the next decade

Long (GT)n repeat in the promoter region of heme oxygenase-1 is associated with severe graft-versus-host disease

info:eu-repo/semantics/nonPublishe

D4.11 Recommendations for the data management and structure for BGC extension within the Argo system at EU level (including recommendations of task 4.2.1)

<p>Report providing recommendations for the data management and structure for the BGC extension at the European level.</p&gt

Anthropogenic carbon changes in the Irminger Basin (1981-2006): Coupling δ¹³C_DIC and DIC observations

International audienceThe North Atlantic subpolar gyre is considered to be one of the strongest marine anthropogenic CO2 sinks, a consequence of extensive deep convection occurring during winter. Observations collected in this region since 1981 have shown large changes in Dissolved Inorganic Carbon (DIC) concentrations in intermediate and deep waters, which have been attributed to both anthropogenic CO2 penetration and natural variability in the ocean carbon cycle (Wanninkhof et al., 2010). In this context, we describe new δ13CDIC observations obtained in the Irminger Basin during two OVIDE cruises (2002 and 2006) which we compare to historical data (TTO-NAS 1981) in order to estimate the oceanic 13C Suess Effect over the more than twenty years that separates these surveys. The data reveal a significant decrease in δ13CDIC, of between - 0.3‰ and - 0.4‰ from 1981 to 2006. The anthropogenic change, extracted by using the extended Multi Linear Regression (eMLR) approach, explains 75% of this signal for oldest water mass and 90% for youngest. The reminding signal is due to the natural processes, such as remineralization and vertical mixing. The eMLR method was also applied to DIC measurements which i) reveal strong relationships between the increase of anthropogenic CO2 and the oceanic 13C Suess Effect over the whole water column during the 25-year period and ii) support the hypothesis of change in the Cant storage rate in the Irminger Basin between 1981 and 2006