Here we present a merged and calibrated dataset of temperature, practical salinity and dissolved organic matter (DOM) fluorescence obtained from several Ice Tethered Profilers (ITPs) deployed across the central Arctic (2011-2016). The data offer a unique spatial coverage of the distribution of DOM in the surface 800 m below Arctic sea ice. A total of 5044 profiles are gathered. The ITP data are level 3 data products pressure-bin-averaged at 1-db vertical resolution with depth down to either 200 or approximately 750 m. Data (max 800m depth) from CTD casts made during two oceanographic cruises are also included. These were used as part of the calibration and validation of the ITP calibration routines. The cruises were PS94 (ARK-XXIX/3) with POLARSTERN in 2015 and NAACOS with DANA in 2012. The presented DOM fluorescence data are smoothed, corrected for instrument drift and calibrated to provide intercomparable data across the sensors. Fluorescence is reported in Raman Units (nm-1), and comparable to laboratory measurements conducted according to current community recommendations.
Other research product . Collection . Other ORP type . 2020
Ocean margin sediments have been considered as important sources of dissolved organic carbon (DOC) to the deep ocean, yet the contribution from advective settings has just started to be acknowledged. Here we present evidence showing that near-surface heating of sediment in the Guaymas Basin, a young extensional depression, causes mass production and discharge of reactive dissolved organic matter (DOM). In the sediment heated up to ~100 °C, we found unexpectedly low DOC concentrations in the pore waters, reflecting the combined effect of thermal desorption and advective fluid flow. Heating experiments suggested DOC production to be a rapid, abiotic process with the DOC concentration increasing exponentially with temperature. The high proportions of total hydrolyzable amino acids and presence of chemical species affiliated with activated hydrocarbons, carbohydrates and peptides indicate high reactivity of the DOM. Model simulation suggests that at the local scale, near-surface heating of sediment creates short and massive DOC discharge events that elevate the bottom-water DOC concentration. Because of the heterogeneous distribution of high heat flow areas, the expulsion of reactive DOM is spotty at any given time. We conclude that hydrothermal heating of young rift sediments alter deep-ocean budgets of bioavailable DOM, creating organic-rich habitats for benthic life.
Other research product . Collection . Other ORP type . 2019
The southern westerly wind belt (SWW) interacts with the Antarctic Circumpolar Current and strongly impacts the Southern Ocean carbon budget, and Antarctic ice-sheet dynamics across glacial- interglacial cycles. We investigated precipitation-driven sediment input changes to the Southeast Pacific off the southern margin of the Atacama Desert in Chile over the past one million years, revealing strong precession (19/23-ka) cycles. Our simulations with 2 ocean-atmosphere general circulation models suggest that observed cyclic rainfall changes are linked to meridional shifts in water vapor transport from the tropical Pacific toward the southern Atacama Desert. These changes reflect a precessional modulation of the split in the austral winter South Pacific jet stream. For precession maxima, we infer significantly enhanced rainfall in the southern Atacama Desert due to a stronger South Pacific split jet with enhanced subtropical/subpolar jets, and a weakermidlatitude jet. Conversely, we derive dry conditions in northern Chile related to reduced subtropical/subpolar jets and an enhanced midlatitude jet for precession minima. The presence of precessional cycles in the Pacific SWW, and lack thereof in other basins, indicate that orbital-scale changes of the SWW were not zonally homogeneous across the Southern Hemisphere, in contrast to the hemispherewide shifts of the SWW suggested for glacial terminations. The strengthening of the jet is unique to the South Pacific realm and might have affected winter-controlled changes in the mixed layer depth, the formation of intermediate water, and the built-up of sea-ice around Antarctica, with implications for the global overturning circulation and the oceanic storage of atmospheric CO2.
Other research product . Other ORP type . Collection . 2019
The RECAP ice core was drilled on Renland ice cap, coastal East Greenland, in May-June 2015. This dataset presents the first complete timescale for the ice core record, based on impurity (dust and chemistry) as well as gas content measurements. The underlying dust particle and gas (CH4, d15N and d18Oair) data are presented. Strontium and Neodymium measurements of potential dust source samples collected from exposed terrain in central East Greenland are also presented. The timescale is called 'RECAP GICC05modelext Time Scale (version 1/3-2018)' and has been synchronized to the existing GICC05modelext timescale. All synchronization tiepoints are presented.
Other research product . Collection . Other ORP type . 2019
We present the first synthesis of global peatland extent through the last glacial cycle (130 ka) based on >975 detailed stratigraphic descriptions from exposures, soil pits, and sediment cores. Buried peats are defined as organic-rich sediments overlain by mineral sediments. Also included are deposits rich in wetland macrofossils indicated a local peatland environment. The dataset includes location (lat/long), chronologic information (when available), a description of the buried peat sediment, overlying and underlying sediments, whether geochemical information is available, and the original references.
Other research product . Other ORP type . Collection . 2019
These datasets contain a six-year long record of shell morphology of the polar planktic foraminifera Neogloboquadrina pachyderma (sensu stricto) from near Palmer Station, Antarctica. The PARFLUX Mark 78H 21-sample trap was deployed in 170m water depth as part of the Palmer Long Term Ecological Research program (total water column depth 350 m, 64° 30'S, 66° 00'W). For manual analysis: Specimens were imaged using Olympus SZX7 transmitted light microscope, QImaging FAST 1394 camera and Q-Capture software. Image backgrounds were adjusted in Adobe PhotoshopCC 2015. Morphological parameters were measured using ImageProPlus 6.2. For automated analysis: Bulk samples measured using automated microscope and image analysis system that scans and captures images via a 12 MP Olympus CC12 camera attached to a Wild MZ3 incident light microscope (Analysis3.0)
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° × 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. The GLODAPv2.2016b global 1° × 1° mapped climatologies, including error fields and ancillary information, are available at the GLODAPv2 web page at the Carbon Dioxide Information Analysis Center (CDIAC; doi:10.3334/CDIAC/OTG.NDP093_GLODAPv2).
Sabine, C. L.; Hankin, S.; Koyuk, H.; Bakker, D. C. E.; Pfeil, B.; Olsen, A.; Metzl, N.; Kozyr, A.; Fassbender, A.; Manke, A.; +66 more
Sabine, C. L.; Hankin, S.; Koyuk, H.; Bakker, D. C. E.; Pfeil, B.; Olsen, A.; Metzl, N.; Kozyr, A.; Fassbender, A.; Manke, A.; Malczyk, J.; Akl, J.; Alin, S. R.; Bellerby, R. G. J.; Borges, A.; Boutin, J.; Brown, P. J.; Cai, W.-J.; Chavez, F. P.; Chen, A.; Cosca, C.; Feely, R. A.; González-Dávila, M.; Goyet, C.; Hardman-Mountford, N.; Heinze, C.; Hoppema, M.; Hunt, C. W.; Hydes, D.; Ishii, M.; Johannessen, T.; Key, R. M.; Körtzinger, A.; Landschützer, P.; Lauvset, S. K.; Lefèvre, N.; Lenton, A.; Lourantou, A.; Merlivat, L.; Midorikawa, T.; Mintrop, L.; Miyazaki, C.; Murata, A.; Nakadate, A.; Nakano, Y.; Nakaoka, S.; Nojiri, Y.; Omar, A. M.; Padin, X. A.; Park, G.-H.; Paterson, K.; Perez, F. F.; Pierrot, D.; Poisson, A.; Ríos, A. F.; Salisbury, J.; Santana-Casiano, J. M.; Sarma, V. V. S. S.; Schlitzer, R.; Schneider, B.; Schuster, U.; Sieger, R.; Skjelvan, I.; Steinhoff, T.; Suzuki, T.; Takahashi, T.; Tedesco, K.; Telszewski, M.; Thomas, H.; Tilbrook, B.; Vandemark, D.; Veness, T.; Watson, A. J.; Weiss, R.; Wong, C. S.; Yoshikawa-Inoue, H.;
Publisher: Copernicus Publications
Project: EC | CARBOCHANGE (264879), NSF | Support for International... (0938349), NSF | Support for the Intergove... (1068958)
As a response to public demand for a well-documented, quality controlled, publically available, global surface ocean carbon dioxide (CO2) data set, the international marine carbon science community developed the Surface Ocean CO2 Atlas (SOCAT). The first SOCAT product is a collection of 6.3 million quality controlled surface CO2 data from the global oceans and coastal seas, spanning four decades (1968–2007). The SOCAT gridded data presented here is the second data product to come from the SOCAT project. Recognizing that some groups may have trouble working with millions of measurements, the SOCAT gridded product was generated to provide a robust, regularly spaced CO2 fugacity (fCO2) product with minimal spatial and temporal interpolation, which should be easier to work with for many applications. Gridded SOCAT is rich with information that has not been fully explored yet (e.g., regional differences in the seasonal cycles), but also contains biases and limitations that the user needs to recognize and address (e.g., local influences on values in some coastal regions).
Other research product . Collection . Other ORP type . 2018
Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
Project: EC | ICEMASS (320816), NSF | Automated, High Resolutio... (1542736), NSF | The Polar Geospatial Info... (1043681)
In permafrost areas, seasonal freeze-thaw cycles result in upward and downward movements of the ground. For some permafrost areas, long-term downward movements were reported during the last decade. We measured seasonal and multi-year ground movements in a yedoma region of the Lena River Delta, Siberia, in 2013–2017, using reference rods installed deep in the permafrost. The seasonal subsidence was 1.7 ± 1.5 cm in the cold summer of 2013 and 4.8 ± 2 cm in the warm summer of 2014. Furthermore, we measured a pronounced multi-year net subsidence of 9.3 ± 5.7 cm from spring 2013 to the end of summer 2017. Importantly, we observed a high spatial variability of subsidence of up to 6 cm across a sub-meter horizontal scale. In summer 2013, we accompanied our field measurements with Differential Synthetic Aperture Radar Interferometry (DInSAR) on repeat-pass TerraSAR-X (TSX) data from the summer of 2013 to detect summer thaw subsidence over the same study area. Interferometry was strongly affected by a fast phase coherence loss, atmospheric artifacts, and possibly the choice of reference point. A cumulative ground movement map, built from a continuous interferogram stack, did not reveal a subsidence on the upland but showed a distinct subsidence of up to 2 cm in most of the thermokarst basins. There, the spatial pattern of DInSAR-measured subsidence corresponded well with relative surface wetness identified with the near infra-red band of a high-resolution optical image. Our study suggests that (i) although X-band SAR has serious limitations for ground movement monitoring in permafrost landscapes, it can provide valuable information for specific environments like thermokarst basins, and (ii) due to the high sub-pixel spatial variability of ground movements, a validation scheme needs to be developed and implemented for future DInSAR studies in permafrost environments.
Other research product . Other ORP type . Collection . 2018
Here we quantify the abundance and distribution of three primary permafrost region disturbances (PRD; lakes and their dynamics, wildfires, retrogressive thaw slumps) using trend analysis of 30-m resolution Landsat imagery from 1999-2014 and auxiliary datasets. The dataset spans four continental-scale transects in North America (Alaska, Eastern Canada) and Eurasia (Western Siberia, Eastern Siberia), covering 2.3M km² or ~10% of the permafrost region. This data publication contains geospatial vector files (polygons) of the perimeters of PRD.The data are subdivided by PRD type (lakes, wildfire, retrogressive thaw slumps) and further subdivided by study region (T1_WS, T2_ES, T3_AK, T4_EC).T1_WS: Western SIberiaT2_ES: Eastern SiberiaT3_AK: AlaskaT4_EC: Eastern CanadaThe datasets are documented in detail in the linked document (Nitze_etal_2018: Data Documentation v1.0). Vector format: ESRI ShapefileProjection: Geographic WGS84 (EPSG:4326)Vector type: Polygon