| Records |
| Author |
Mario Lebrato, Dieter Garbe-Schönberg, Marius N. Müller, Sonia Blanco-Ameijeiras, Richard A. Feely, Laura Lorenzoni, Juan-Carlos Molinero, Karen Bremer, Daniel O. B. Jones, Debora Iglesias-Rodriguez, Dana Greeley, Miles D. Lamare, Aurelien Paulmier, Michelle Graco, Joan Cartes, Joana Barcelos e Ramos, Ana de Lara, Ricardo Sanchez-Leal, Paz Jimenez, Flavio E. Paparazzo, Susan E. Hartman, Ulrike Westernströer, Marie Küter, Roberto Benavides, Armindo F. da Silva, Steven Bell, Chris Payne, Solveig Olafsdottir, Kelly Robinson, Liisa M. Jantunen, Alexander Korablev, Richard J. Webster, Elizabeth M. Jones, Olivier Gilg, Pascal Bailly du Bois, Jacek Beldowski, Carin Ashjian, Nejib D. Yahia, Benjamin Twining, Xue-Gang Chen, Li-Chun Tseng, Jiang-Shiou Hwang, Hans-Uwe Dahms, Andreas Oschlies |
| Title |
Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean |
Type |
Book Chapter |
| Year |
2020 |
Publication |
Proceedings of the National Academy of Sciences |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
36 |
Pages |
22281-22292 |
| Keywords |
|
| Abstract |
Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth–ocean–atmosphere dynamic exchange of elements. The ratios’ dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previous data, to test the assumption of limited seawater Mg:Ca and Sr:Ca variability across marine environments globally. High variability was found in open-ocean upwelling and polar regions, shelves/neritic and river-influenced areas, where seawater Mg:Ca and Sr:Ca ratios range from ∼4.40 to 6.40 mmol:mol and ∼6.95 to 9.80 mmol:mol, respectively. Open-ocean seawater Mg:Ca is semiconservative (∼4.90 to 5.30 mol:mol), while Sr:Ca is more variable and nonconservative (∼7.70 to 8.80 mmol:mol); both ratios are nonconservative in coastal seas. Further, the Ca, Mg, and Sr elemental fluxes are connected to large total alkalinity deviations from International Association for the Physical Sciences of the Oceans (IAPSO) standard values. Because there is significant modern seawater Mg:Ca and Sr:Ca ratios variability across marine environments we cannot absolutely assume that fossil archives using taxa-specific proxies reflect true global seawater chemistry but rather taxa- and process-specific ecosystem variations, reflecting regional conditions. This variability could reconcile secular seawater Mg:Ca and Sr:Ca ratio reconstructions using different taxa and techniques by assuming an error of 1 to 1.50 mol:mol, and 1 to 1.90 mmol:mol, respectively. The modern ratios’ variability is similar to the reconstructed rise over 20 Ma (Neogene Period), nurturing the question of seminonconservative behavior of Ca, Mg, and Sr over modern Earth geological history with an overlooked environmental effect. |
| Programme |
136 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0027-8424, 1091-6490 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7781 |
| Permanent link to this record |
| |
|
| |
| Author |
Frédéric Angelier, Olivier Chastel, Adam Z. Lendvai, Charline Parenteau, Henri Weimerskirch, John C. Wingfield |
| Title |
When do older birds better resist stress? A study of the corticosterone stress response in snow petrels |
Type |
Journal |
| Year |
2020 |
Publication |
Biology letters |
Abbreviated Journal |
|
| Volume |
16 |
Issue |
1 |
Pages |
20190733 |
| Keywords |
|
| Abstract |
Life-history theory predicts that, to optimize their fitness, individuals should increase their reproductive effort as their residual reproductive value decreases. Accordingly, several studies have shown that individuals downregulate their glucocorticoid stress response (a proxy of reproductive investment in vertebrates) as they age, and as the subsequent reproductive value decreases. However, and surprisingly, results appear inconsistent, suggesting that the environmental context or the individual state may affect the relationship between age and reproductive effort. Here, we tested for the first time this hypothesis, and more specifically, whether this attenuation of the corticosterone stress response with advancing age depends on the energetic status of individuals. We compared the influence of age on the corticosterone stress response between fasting and non-fasting breeding snow petrels (Pagodroma nivea), an extremely long-lived bird. As expected, we found that the corticosterone stress response was attenuated in old petrels, but only when they were not fasting. Interestingly, this pattern was not apparent in fasting petrels, suggesting that old birds downregulate their corticosterone stress response and increase their parental investment only when they are in good body condition. At the ultimate level, old individuals may maintain a strong corticosterone stress response when fasting because the survival costs of increased stress resistance and parental effort might then outweigh their reproductive benefits. |
| Programme |
109 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
Royal Society |
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7669 |
| Permanent link to this record |
| |
|
| |
| Author |
Boulinier, T., Betoulle, S., Caza, F., St Pierre, Y., Tornos, J., Gamble, A. &Amp; Tasiemski, A |
| Title |
Panorama des recherches et des derniers résultats sur les pathogènes en milieu polaire |
Type |
Book Chapter |
| Year |
2020 |
Publication |
Ipev 2020: rapport d'activité − campagne 2018 2019 |
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
54-65 |
| Keywords |
|
| Abstract |
Approches complémentaires des interactions hôte-parasite en zones polaire: de la détection de parasites et agents infectieux à l'étude fonctionnelle, écologique et évolutive de leurs interactions avec leurs hôtes. |
| Programme |
333,1151 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1246-7375 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
6951 |
| Permanent link to this record |
| |
|
| |
| Author |
Tijl Verhoelst, Steven Compernolle, Gaia Pinardi, Jean-Christopher Lambert, Henk J. Eskes, Kai-Uwe Eichmann, Ann Mari Fjæraa, José Granville, Sander Niemeijer, Alexander Cede, Martin Tiefengraber, François Hendrick, Andrea Pazmiño, Alkiviadis Bais, Ariane Bazureau, K. Folkert Boersma, Kristof Bognar, Angelika Dehn, Sebastian Donner, Aleksandr Elokhov, Manuel Gebetsberger, Florence Goutail, Michel Grutter de la Mora, Aleksandr Gruzdev, Myrto Gratsea, Georg H. Hansen, Hitoshi Irie, Nis Jepsen, Yugo Kanaya, Dimitris Karagkiozidis, Rigel Kivi, Karin Kreher, Pieternel F. Levelt, Cheng Liu, Moritz Müller, Monica Navarro Comas, Ankie J. M. Piters, Jean-Pierre Pommereau, Thierry Portafaix, Olga Puentedura, Richard Querel, Julia Remmers, Andreas Richter, John Rimmer, Claudia Rivera Cárdenas, Lidia Saavedra de Miguel, Valery P. Sinyakov, Kimberley Strong, Michel Van Roozendael, J. Pepijn Veefkind, Thomas Wagner, Folkard Wittrock, Margarita Yela González, Claus Zehner |
| Title |
Ground-based validation of the Copernicus Sentinel-5p TROPOMI NO2 measurements with the NDACC ZSL-DOAS, MAX-DOAS and Pandonia global networks |
Type |
Journal |
| Year |
2020 |
Publication |
Atmospheric Measurement Techniques Discussions |
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
1-40 |
| Keywords |
|
| Abstract |
This Paper Reports On Consolidated Ground-based Validation Results Of The Atmospheric No2 Data Produced Operationally Since April 2018 By The Tropomi Instrument On Board Of The Esa/eu Copernicus Sentinel-5 Precursor (S5p) Satellite. Tropospheric, Stratospheric, And Total No2 Column Data From S5p Are Compared To Correlative Measurements Collected From, Respectively, 19 Multi-axis Doas (Max-doas), 26 Ndacc Zenith-scattered-light Doas (Zsl-doas), And 25 Pgn/pandora Instruments Distributed Globally. The Validation Methodology Gives Special Care To Minimizing Mismatch Errors Due To Imperfect Spatio-temporal Co-location Of The Satellite And Correlative Data, E.g., By Using Tailored Observation Operators To Account For Differences In Smoothing And In Sampling Of Atmospheric Structures And Variability, And Photochemical Modelling To Reduce Diurnal Cycle Effects. Compared To The Ground-based Measurements, S5p Data Show, On An Average: (I) A Negative Bias For The Tropospheric Column Data, Of Typically −23 To −37 % In Clean To Slightly Polluted Conditions, But Reaching Values As High As −51 % Over Highly Polluted Areas; (Ii) A Slight Negative Bias For The Stratospheric Column Data, Of About −0.2 Pmolec/cm2, I.e. Approx. −2 % In Summer To −15 % In Winter; And (Iii) A Bias Ranging From Zero To −50 % For The Total Column Data, Found To Depend On The Amplitude Of The Total No2 Column, With Small To Slightly Positive Bias Values For Columns Below 6 Pmolec/cm2 And Negative Values Above. The Dispersion Between S5p And Correlative Measurements Contains Mostly Random Components, Which Remain Within Mission Requirements For The Stratospheric Column Data (0.5 Pmolec/cm2), But Exceed Those For The Tropospheric Column Data (0.7 Pmolec/cm2). While A Part Of The Biases And Dispersion May Be Due To Representativeness Differences, It Is Known That Errors In The S5p Tropospheric Columns Exist Due To Shortcomings In The (Horizontally Coarse) A-priori Profile Representation In The Tm5-mp Chemistry Transport Model Used In The S5p Retrieval, And To A Lesser Extent, To The Treatment Of Cloud Effects. Although Considerable Differences (Up To 2 Pmolec/cm2 And More) Are Observed At Single Ground-pixel Level, The Near-real-time (Nrti) And Off-line (Offl) Versions Of The S5p No2 Operational Data Processor Provide Similar No2 Column Values And Validation Results When Globally Averaged, With The Nrti Values Being On Average 0.79 % Larger Than The Offl Values. |
| Programme |
209 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1867-1381 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7782 |
| Permanent link to this record |
| |
|
| |
| Author |
Franz Slemr, Lynwill Martin, Casper Labuschagne, Thumeka Mkololo, Hélène Angot, Olivier Magand, Aurélien Dommergue, Philippe Garat, Michel Ramonet, Johannes Bieser |
| Title |
Atmospheric mercury in the Southern Hemisphere – Part 1: Trend and inter-annual variations in atmospheric mercury at Cape Point, South Africa, in 2007–2017, and on Amsterdam Island in 2012–2017 |
Type |
Journal |
| Year |
2020 |
Publication |
Atmospheric Chemistry and Physics |
Abbreviated Journal |
|
| Volume |
20 |
Issue |
13 |
Pages |
7683-7692 |
| Keywords |
|
| Abstract |
The Minamata Convention On Mercury (Hg) Entered Into Force In 2017, Committing Its 116 Parties (As Of January 2019) To Curb Anthropogenic Emissions. Monitoring Of Atmospheric Concentrations And Trends Is An Important Part Of The Effectiveness Evaluation Of The Convention. A Few Years Ago (In 2017) We Reported An Increasing Trend In Atmospheric Hg Concentrations At The Cape Point Global Atmosphere Watch (Gaw) Station In South Africa (34.3535∘ S, 18.4897∘ E) For The 2007–2015 Period. With 2 More Years Of Measurements At Cape Point And The 2012–2017 Data From Amsterdam Island (37.7983∘ S, 77.5378∘ E) In The Remote Southern Indian Ocean, A More Complex Picture Emerges: At Cape Point The Upward Trend For The 2007–2017 Period Is Still Significant, But No Trend Or A Slightly Downward Trend Was Detected For The Period 2012–2017 At Both Cape Point And Amsterdam Island. The Upward Trend At Cape Point Is Driven Mainly By The Hg Concentration Minimum In 2009 And Maxima In 2014 And 2012. Using Ancillary Data On 222rn, Co, O3, Co2, And Ch4 From Cape Point And Amsterdam Island, The Possible Reasons For The Trend And Its Change Are Investigated. In A Companion Paper This Analysis Is Extended For The Cape Point Station By Calculations Of Source And Sink Regions Using Backward-trajectory Analysis. |
| Programme |
416,1028 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1680-7316 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7736 |
| Permanent link to this record |
| |
|
| |
| Author |
Amandine Gamble, Henri Weimerskirch, Thierry Boulinier |
| Title |
Seabirds blinded by ticks |
Type |
Journal |
| Year |
2020 |
Publication |
Frontiers in Ecology and the Environment |
Abbreviated Journal |
|
| Volume |
18 |
Issue |
6 |
Pages |
322-322 |
| Keywords |
|
| Abstract |
In December 2017, on Possession Island (part of the Crozet Archipelago in the southern Indian Ocean), we observed two breeding white‐chinned petrels (Procellaria aequinoctialis ) with very high levels of tick (Ixodes kerguelenensis ) infestation on both eyes. This degree of infestation was likely responsible for the birds’ death. Although this rare observation may seem anecdotal, it reveals that ticks can be fatal for a long‐lived colonial seabird species, in this case one that is already under pressure from fisheries bycatch and predation by introduced black rats (Rattus rattus ). It also raises questions about the frequency and spatial distribution of such a phenomenon and the conditions that may have been responsible for its occurrence. Such high parasite loads imply high local tick abundances but also a lack of preening by the partner. Could this be linked to the recent death of the partner? Infestations by ticks can affect the health of hosts through blood loss, the injection of toxins, and the transmission of infectious agents. In this instance, the mechanical blocking of eyesight may also have affected the birds’ behavior. The potential impact of climate change on local parasitic infestation levels is another important question. Parasites and diseases can harm endangered species in polar and subpolar areas, and could play critical roles in some circumstances. |
| Programme |
1151 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1540-9309 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7797 |
| Permanent link to this record |
| |
|
| |
| Author |
Louis Le Toumelin, Charles Amory, Vincent Favier, Christoph Kittel, Stefan Hofer, Xavier Fettweis, Hubert Gallée, Vinay Kayetha |
| Title |
Sensitivity of the surface energy budget to drifting snow as simulated by MAR in coastal Adelie Land, Antarctica |
Type |
Journal |
| Year |
2020 |
Publication |
The Cryosphere |
Abbreviated Journal |
|
| Volume |
15 |
Issue |
8 |
Pages |
3595-3614 |
| Keywords |
|
| Abstract |
|
| Programme |
411,1013 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1994-0416 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7946 |
| Permanent link to this record |
| |
|
| |
| Author |
Detlev Helmig, Daniel Liptzin, Jacques Hueber, Joel Savarino |
| Title |
Impact of exhaust emissions on chemical snowpack composition at Concordia Station, Antarctica |
Type |
Journal |
| Year |
2020 |
Publication |
The Cryosphere |
Abbreviated Journal |
|
| Volume |
14 |
Issue |
1 |
Pages |
199-209 |
| Keywords |
|
| Abstract |
The chemistry of reactive gases inside the snowpack and in the lower atmosphere was investigated at Concordia Station (Dome C), Antarctica, from December 2012 to January 2014. Measured species included ozone, nitrogen oxides, gaseous elemental mercury (GEM), and formaldehyde, for study of photochemical reactions, surface exchange, and the seasonal cycles and atmospheric chemistry of these gases. The experiment was installed ≈1 km from the station main infrastructure inside the station clean air sector and within the station electrical power grid boundary. Ambient air was sampled continuously from inlets mounted above the surface on a 10 m meteorological tower. In addition, snowpack air was collected at 30 cm intervals to 1.2 m depth from two manifolds that had both above- and below-surface sampling inlets. Despite being in the clean air sector, over the course of the 1.2-year study, we observed on the order of 50 occasions when exhaust plumes from the camp, most notably from the power generation system, were transported to the study site. Continuous monitoring of nitrogen oxides (NOx) provided a measurement of a chemical tracer for exhaust plumes. Highly elevated levels of NOx (up to 1000 × background) and lowered ozone (down to ≈50 %), most likely from reaction of ozone with nitric oxide, were measured in air from above and within the snowpack. Within 5–15 min from observing elevated pollutant levels above the snow, rapidly increasing and long-lasting concentration enhancements were measured in snowpack air. While pollution events typically lasted only a few minutes to an hour above the snow surface, elevated NOx levels were observed in the snowpack lasting from a few days to ≈ 1 week. GEM and formaldehyde measurements were less sensitive and covered a shorter measurement period; neither of these species' data showed noticeable concentration changes during these events that were above the normal variability seen in the data. Nonetheless, the clarity of the NOx and ozone observations adds important new insight into the discussion of if and how snow photochemical experiments within reach of the power grid of polar research sites are possibly compromised by the snowpack being chemically influenced (contaminated) by gaseous and particulate emissions from the research camp activities. This question is critical for evaluating if snowpack trace chemical measurements from within the camp boundaries are representative for the vast polar ice sheets. |
| Programme |
1177 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1994-0416 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7853 |
| Permanent link to this record |
| |
|
| |
| Author |
Albane Barbero, Camille Blouzon, Joël Savarino, Nicolas Caillon, Aurélien Dommergue, Roberto Grilli |
| Title |
A compact incoherent broadband cavity-enhanced absorption spectrometer for trace detection of nitrogen oxides, iodine oxide and glyoxal at levels below parts per billion for field applications |
Type |
Journal |
| Year |
2020 |
Publication |
Atmospheric Measurement Techniques |
Abbreviated Journal |
|
| Volume |
13 |
Issue |
8 |
Pages |
4317-4331 |
| Keywords |
|
| Abstract |
|
| Programme |
1028,1177 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1867-1381 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7854 |
| Permanent link to this record |
| |
|
| |
| Author |
Winton V.H.L., Ming A., Caillon N., Hauge L. Jones A.E., Savarino J., Yang X., Frey M.M. |
| Title |
Deposition, recycling, and archival of nitrate stable isotopes between the air–snow interface: comparison between Dronning Maud Land and Dome C, Antarctica |
Type |
Journal |
| Year |
2020 |
Publication |
Atmospheric Chemistry and Physics |
Abbreviated Journal |
|
| Volume |
20 |
Issue |
9 |
Pages |
5861–5885 |
| Keywords |
|
| Abstract |
The nitrogen stable isotopic composition in nitrate (δ15N-NO−3) measured in ice cores from low-snow-accumulation regions in East Antarctica has the potential to provide constraints on past ultraviolet (UV) radiation and thereby total column ozone (TCO) due to the sensitivity of nitrate (NO−3) photolysis to UV radiation. However, understanding the transfer of reactive nitrogen at the air–snow interface in polar regions is paramount for the interpretation of ice core records of δ15N-NO−3 and NO−3 mass concentrations. As NO−3 undergoes a number of post-depositional processes before it is archived in ice cores, site-specific observations of δ15N-NO−3 and air–snow transfer modelling are necessary to understand and quantify the complex photochemical processes at play. As part of the Isotopic Constraints on Past Ozone Layer Thickness in Polar Ice (ISOL-ICE) project, we report new measurements of NO−3 mass concentration and δ15N-NO−3 in the atmosphere, skin layer (operationally defined as the top 5 mm of the snowpack), and snow pit depth profiles at Kohnen Station, Dronning Maud Land (DML), Antarctica. We compare the results to previous studies and new data, presented here, from Dome C on the East Antarctic Plateau. Additionally, we apply the conceptual 1D model of TRansfer of Atmospheric Nitrate Stable Isotopes To the Snow (TRANSITS) to assess the impact of NO−3 recycling on δ15N-NO−3 and NO−3 mass concentrations archived in snow and firn. We find clear evidence of NO−3 photolysis at DML and confirmation of previous theoretical, field, and laboratory studies that UV photolysis is driving NO−3 recycling and redistribution at DML. Firstly, strong denitrification of the snowpack is observed through the δ15N-NO−3 signature, which evolves from the enriched snowpack (−3 ‰ to 100 ‰), to the skin layer (−20 ‰ to 3 ‰), to the depleted atmosphere (−50 ‰ to −20 ‰), corresponding to mass loss of NO−3 from the snowpack. Based on the TRANSITS model, we find that NO−3 is recycled two times, on average, before it is archived in the snowpack below 15 cm and within 0.75 years (i.e. below the photic zone). Mean annual archived δ15N-NO−3 and NO−3 mass concentration values are 50 ‰ and 60 ng g−1, respectively, at the DML site. We report an e-folding depth (light attenuation) of 2–5 cm for the DML site, which is considerably lower than Dome C. A reduced photolytic loss of NO−3 at DML results in less enrichment of δ15N-NO−3 than at Dome C mainly due to the shallower e-folding depth but also due to the higher snow accumulation rate based on TRANSITS-modelled sensitivities. Even at a relatively low snow accumulation rate of 6 cm yr−1 (water equivalent; w.e.), the snow accumulation rate at DML is great enough to preserve the seasonal cycle of NO−3 mass concentration and δ15N-NO−3, in contrast to Dome C where the depth profiles are smoothed due to longer exposure of surface snow layers to incoming UV radiation before burial. TRANSITS sensitivity analysis of δ15N-NO−3 at DML highlights that the dominant factors controlling the archived δ15N-NO−3 signature are the e-folding depth and snow accumulation rate, with a smaller role from changes in the snowfall timing and TCO. Mean TRANSITS model sensitivities of archived δ15N-NO−3 at the DML site are 100 ‰ for an e-folding depth change of 8 cm, 110 ‰ for an annual snow accumulation rate change of 8.5 cm yr−1 w.e., 10 ‰ for a change in the dominant snow deposition season between winter and summer, and 10 ‰ for a TCO change of 100 DU (Dobson units). Here we set the framework for the interpretation of a 1000-year ice core record of δ15N-NO−3 from DML. Ice core δ15N-NO−3 records at DML will be less sensitive to changes in UV than at Dome C; however the higher snow accumulation rate and more accurate dating at DML allows for higher-resolution δ15N-NO−3 records. |
| Programme |
1177 |
| Campaign |
|
| Address |
|
| Corporate Author |
|
Thesis |
Bachelor's thesis |
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1680-7316 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
yes |
| Call Number |
|
Serial |
7855 |
| Permanent link to this record |
