ALBERT

Description: Two Slocum gliders (units 331 and 439) were deployed during RRS Discovery expedition DY081 on July 17th 2017 at 62.9°N, 52.6°W, approximately 40 km off the Greenland shelf break, travelled North along the coast in a zig-zag pattern between the shelf and deep waters, and were recovered 8 days later from 63.7°N, 53.1°W and 62.9° N, 52.7°W respectively on July 24th 2017. Gliders profiled from the surface to 1000 m, except during the two excursions onto the shelf, once south and once north of the Godthåb Trough, where they followed the bathymetry. Each glider was fitted with a pumped CTD and bio-optical sensors (WET Labs puck). These bio-optical sensors measure optical backscattering (in the form of volume scattering function), chlorophyll fluorescence, and UV fluorescence for fluorescing dissolved organic matter (FDOM), a subset of coloured organic matter (CDOM). This dataset contains raw and processed/gridded data files from the glider deployments. The raw data are contained as .dbd and .ebd files in ***_raw_data.zip folders for each of glider unit 331 and 439. The data were processed using the SOCIB glider toolbox (https://github.com/socib/glider_toolbox) and saved as a NetCDF (processed_***.nc) with the following variables: longitude, latitude, time (Julian Day), pressure, eastward velocity, northward velocity, temperature (not thermally corrected), salinity (not thermally corrected), chlorophyll fluorescence (not corrected for quenching), coloured organic matter (cdom), backscatter (volume scattering function) and oxygen concentration. The expedition report is provided and metadata can be found in the processed/gridded data files.

Description: Discrete measurements of particulate organic carbon (POC) concentration and flux were made on the RRS Discovery during COMICS cruise DY086 at site P3 in the South Atlantic from November to December, 2017 (Giering et al. 2023). Data is from a variety of equipment including marine snow catchers, neutrally-buoyant sediment traps (PELAGRA) and a stand-alone pump system. Marine snow catchers settled on-deck for 2 hours. Slow sinking particles were collected from the base and fast sinking particles were collected from the tray. These data were used along with bottle POC data to calibrate glider backscatter data from the GOCART project.

Description: Physical, chemical and biogeochemical measurements derived from CTD-rosette deployments during three visits to site P3 (November to December, 2017) in the South Atlantic. Measurements were made during COMICS cruise DY086 on the RRS Discovery using a trace metal free Titanium Rosette (events 4, 7, 15, 19, 24, 26, 29) and a Stainless Steel Rosette (all other events). Physical parameters include temperature, salinity, density, photosynthetically active radiation and turbulence; chemical parameters include dissolved oxygen, dissolved oxygen saturation, nitrate, phosphate and silicate; biogeochemical parameters include turbidity, beam transmittance, beam attenuation, fluorescence, particulate organic carbon (POC), dissolved organic carbon (DOC), chlorophyll-a, net primary productivity (NPP), ambient leucine assimilation and bacterial cell count. To determine turbulence, a downward facing lowered acoustic doppler current profiler (LADCP, Teledyne Workhorse Monitor 300 kHz ADCP) was attached to the CTD frame. Shear and strain, which are obtained from velocity and density measurements, were used to estimate the dissipation rate of turbulent kinetic energy and the diapycnal eddy diffusivity from a fine-scale parameterisation. Estimates are calculated by parameterising internal wave-wave interactions and assuming that wave breaking modulates turbulent mixing. A detailed description of the method for calculating diffusivity from LADCP and CTD can be found in Kunze et al. (2006). Two datasets with different vertical resolutions were produced: one in which the shear is integrated from 150 to 300 m and the strain over 20-150 m, and one in which the shear is integrated from 70 to 200 m and the strain over 30-200 m. Nutrients (nitrate, phosphate, silicate) were determined via colourimetric analysis (see cruise report, Giering and Sanders, 2019), POC was determined as described in Giering et al. (2023), DOC and DOC flux were determined as described in Lovecchio et al. (2023), NPP was determined as described in Poulton et al. (2019), and ambient leucine assimilation and bacterial cell count were determined as described in Rayne et al. (2024). Bacterial abundance and leucine assimilation were made from bottle samples of six CTD casts of the stainless-steel rosette. Water was collected at six depths (6 m, deep-chlorophyll maximum, mixed layer depth + 10, 100, 250 and 500 m). Acid-cleaned HDPE carboys and tubing were used for sampling. Samples were then stored in the dark and at in-situ temperature prior to on-board laboratory sample preparation or analysis. Flow cytometry was used to measure bacterial abundance. Room temperature paraformaldehyde was used to fix 1.6 ml samples for 30 minutes. Then, using liquid nitrogen, the samples were flash frozen and stored at -80°C. Samples were then defrosted before being stained using SYBR Green I and run through the flow cytometer (BD FACSort™). The method of Hill et al. (2013) was applied to determine prokaryotic leucine assimilation using L-[4,5-³H] leucine which has a specific activity of 89.3 Ci/mmol­. In the mixed and upper layers of the water column, the protocol in Zubkov et al. (2007) was followed. Below the mixed layer, adaptions to the method included reducing the concentration of ³H-Leucine to 0.005, 0.01, 0.025, 0.04 and 0.05 nM; increasing experimental volumes to 30 ml; enhancing incubation times to 30, 60, 90 and 120 min. These adaptions were made to improve accuracy where lower rates of leucine assimilation were expected. Data were provided by the British Oceanographic Data Centre and funded by the National Environment Research Council.

Description: Binned median of Slocum G2 glider data from 0 to 1000 m depth. The data were collected in the northern Benguela region between 14 February 2018 and 19 June 2018 at a site approximately 100 km from the coast. The glider sampled continuously following a triangular path of ~12 km per side roughly centred on 10.8°E, 18.1°S. The glider sampled only on the upward dive with a vertical resolution of ~20 cm, emerging 5 to 6 times per day. Temperature, Conductivity and Depth were measured with a standard Slocum Glider Payload CTD (pumped) from Seabird (SN 9109). Dissolved oxygen was measured with an Aanderaa optode, model 4831 (SN286). Depth-averaged currents (DAC) for each 1000 m downward and upward dive were estimated from the difference between the glider's actual and predicted surfacing locations. Glider surface currents were also estimated at each surfacing via linear regression of GPS location with respect to time. Salinity and oxygen data were calibrated against shipboard CTD bottle samples. The data have been binned (median) into 6 hourly, 2 m depth bins for all variables while the currents timeseries were binned daily (median). 1D variables consist of: time (seconds since 00:00:00 on 1 January 0000), depth (meters), longitude (degrees East), latitude (degrees South), zonal and meridional glider surface currents (U_surf and V_surf, m/s), and zonal and meridional glider depth averaged currents (U_dac and V_dac, m/s). 2D variables consist of: conservative temperature (°C), absolute salinity (g/kg), potential density (kg/m³), and dissolved oxygen concentration (µmol/kg).

Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Brazelton, W. J., McGonigle, J. M., Motamedi, S., Pendleton, H. L., Twing, K. I., Miller, B. C., Lowe, W. J., Hoffman, A. M., Prator, C. A., Chadwick, G. L., Anderson, R. E., Thomas, E., Butterfield, D. A., Aquino, K. A., Fruh-Green, G. L., Schrenk, M. O., & Lang, S. Q. Metabolic strategies shared by basement residents of the lost city hydrothermal field. Applied and Environmental Microbiology, 88(17), (2022): e00929-22, https://doi.org/10.1128/aem.00929-22.

Description: Alkaline fluids venting from chimneys of the Lost City hydrothermal field flow from a potentially vast microbial habitat within the seafloor where energy and organic molecules are released by chemical reactions within rocks uplifted from Earth’s mantle. In this study, we investigated hydrothermal fluids venting from Lost City chimneys as windows into subseafloor environments where the products of geochemical reactions, such as molecular hydrogen (H2), formate, and methane, may be the only available sources of energy for biological activity. Our deep sequencing of metagenomes and metatranscriptomes from these hydrothermal fluids revealed a few key species of archaea and bacteria that are likely to play critical roles in the subseafloor microbial ecosystem. We identified a population of Thermodesulfovibrionales (belonging to phylum Nitrospirota) as a prevalent sulfate-reducing bacterium that may be responsible for much of the consumption of H2 and sulfate in Lost City fluids. Metagenome-assembled genomes (MAGs) classified as Methanosarcinaceae and Candidatus Bipolaricaulota were also recovered from venting fluids and represent potential methanogenic and acetogenic members of the subseafloor ecosystem. These genomes share novel hydrogenases and formate dehydrogenase-like sequences that may be unique to hydrothermal environments where H2 and formate are much more abundant than carbon dioxide. The results of this study include multiple examples of metabolic strategies that appear to be advantageous in hydrothermal and subsurface alkaline environments where energy and carbon are provided by geochemical reactions.

Description: This work was supported by NSF awards to W.J.B. and S.Q.L. (OCE-1536702/1536405), the NASA Astrobiology Institute Rock-Powered Life team, a NASA Postdoctoral fellowship to J.M.M., the Swiss National Science Foundation, and the Deep Carbon Observatory.

Description: The Greenland Ice Sheet has been a major contributor to global sea-level rise in recent decades, and it is expected to continue to be so. Although increases in glacier flow and surface melting have been driven by oceanic and atmospheric warming, the magnitude and trajectory of the ice sheet’s mass imbalance remain uncertain. Here we compare and combine 26 individual satellite measurements of changes in the ice sheet’s volume, flow and gravitational potential to produce a reconciled estimate of its mass balance. The ice sheet was close to a state of balance in the 1990s, but annual losses have risen since then, peaking at 345 ± 66 billion tonnes per year in 2011. In all, Greenland lost 3,902 ± 342 billion tonnes of ice between 1992 and 2018, causing the mean sea level to rise by 10.8 ± 0.9 millimetres. Using three regional climate models, we show that the reduced surface mass balance has driven 1,964 ± 565 billion tonnes (50.3 per cent) of the ice loss owing to increased meltwater runoff. The remaining 1,938 ± 541 billion tonnes (49.7 per cent) of ice loss was due to increased glacier dynamical imbalance, which rose from 46 ± 37 billion tonnes per year in the 1990s to 87 ± 25 billion tonnes per year since then. The total rate of ice loss slowed to 222 ± 30 billion tonnes per year between 2013 and 2017, on average, as atmospheric circulation favoured cooler conditions and ocean temperatures fell at the terminus of Jakobshavn Isbræ. Cumulative ice losses from Greenland as a whole have been close to the rates predicted by the Intergovernmental Panel on Climate Change for their high-end climate warming scenario, which forecast an additional 70 to 130 millimetres of global sea-level rise by 2100 compared with their central estimate.

Description: Published

Description: 233–239

Description: 4A. Oceanografia e clima

Description: JCR Journal

Description: The F-35 Joint Strike Fighter is the most costly aircraft acquisition program in Defense Department history. RAND assessed the potential for savings by reconfiguring the U.S. Air Force’s combat-coded F-35s into larger squadrons, adjusting the Primary Aerospace Vehicle Authorized (PAA) mix across the Active and Reserve Components, and adjusting the percentage of PAA permanently assigned to locations in the continental United States.

Description: Originally published in 2005. Throughout the fractious years of the mid-nineteenth century, Abraham Lincoln's speeches imparted reason and guidance to a troubled nation. Lincoln's words were never universally praised. But they resonated with fellow legislators and the public, especially when he spoke on such volatile subjects as mob rule, temperance, the Mexican War, slavery and its expansion, and the justice of a war for freedom and union.In this close examination, John Channing Briggs reveals how the process of studying, writing, and delivering speeches helped Lincoln develop the ideas with which he would so profoundly change history. Briggs follows Lincoln's thought process through a careful chronological reading of his oratory, ranging from Lincoln's 1838 speech to the Springfield Lyceum to his second inaugural address.Recalling David Herbert Donald's celebrated revisionist essays (Lincoln Reconsidered, 1947), Briggs's study provides students of Lincoln with new insight into his words, intentions, and image.

Description: The F-35 Joint Strike Fighter is the most costly aircraft acquisition program in Defense Department history. RAND assessed the potential for savings by reconfiguring the U.S. Air Force’s combat-coded F-35s into larger squadrons, adjusting the Primary Aerospace Vehicle Authorized (PAA) mix across the Active and Reserve Components, and adjusting the percentage of PAA permanently assigned to locations in the continental United States.

Description: Debates about gender are everywhere. Is it an inner identity, a biological fact, or an oppressive system? Should we respect it or resist it? What Even Is Gender? shifts the conversation in a fresh direction, arguing that these debates rest on a shared mistake: the idea that there is one thing called "gender" that both sides are arguing about. The authors distinguish a range of phenomena that established vocabulary often lumps together. This sheds light on the equivocations and false dichotomies of "gender" talk, and how they deny many of us the tools to make our needs, experiences, and concerns intelligible to others or even to ourselves. The authors develop a conceptual toolkit that helps alleviate the harms that result from the limitations of familiar approaches. They propose a pluralistic concept of "gender feels" that distinguishes among our experiences of diverse facets of gendered life. They develop a flexible approach to gender categories that reflects the value of self-determination. And they suggest that what we need is not one universal language of gender but an awareness of individual variation and a willingness to adjust to changing contexts and circumstances. A bold and thought-provoking approach to thinking about gender, What Even Is Gender? will be of great interest to those in philosophy, gender studies, sociology, and LGBTQIA+ studies.