Air-Sea Ammonia Fluxes Calculated from High-Resolution Summertime Observations Across the Atlantic Southern Ocean

2021 ◽  
Author(s):  
Katye Altieri ◽  
Kurt Spence ◽  
Shantelle Smith
Keyword(s):  
Sensitivity Analysis ◽  
High Resolution ◽  
Southern Ocean ◽  
Major Influence ◽  
Ammonia Emissions ◽  
Human Influence ◽  
Ammonia Gas ◽  
Surface Ocean ◽  
Latitudinal Transect ◽  
Ammonia Flux

<p>Oceanic ammonia emissions are the largest natural source of ammonia globally, but the magnitude of the air-sea flux in remote regions absent human influence remains uncertain. Here, we measured the concentration of surface ocean ammonium and atmospheric ammonia gas every two hours across a latitudinal transect (34.5ºS to 61ºS) of the Atlantic Southern Ocean during summer. Surface ocean ammonium concentrations ranged from undetectable to 0.36 µM and ammonia gas concentrations ranged from 0.6 to 5.1 nmol m<sup>-3</sup>. Calculated ammonia fluxes ranged from -2.5 to -91 pmol m<sup>-2</sup> s<sup>-1</sup>, and were consistently from the atmosphere into the ocean, even in regions where surface ocean ammonium concentrations were relatively high. As expected, temperature was the dominant control on the air-sea ammonia flux across the latitudinal transect. However, a sensitivity analysis suggests that seasonality in the surface Southern Ocean nitrogen cycle may have a major influence on the direction of the ammonia flux.</p>

On new developments in accelerator mass spectrometry and how they promote our understanding of global carbon cycle dynamics during the last deglaciation

2020 ◽  
Author(s):  
Julia Gottschalk ◽  
Robert F. Anderson ◽  
David A. Hodell ◽  
Alfredo Martinez-Garcia ◽  
Alain Mazaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Bottom Water ◽  
Deep Ocean ◽  
Global Ocean ◽  
Last Deglaciation ◽  
Surface Ocean ◽  
Ocean Atmosphere ◽  
The Last Deglaciation ◽  
Reservoir Age

<p>Ocean-atmosphere <sup>14</sup>C disequilibria of the surface and deep ocean reflect past changes in the efficiency of ocean-atmosphere CO<sub>2</sub> exchange and ocean mixing, while it may also be related to variations in global-ocean respired carbon content. A full assessment of the oceanic mechanisms controlling deglacial changes in atmospheric CO<sub>2</sub> is complicated by a lack of high-resolution <sup>14</sup>C ventilation age estimates from the Southern Ocean and other key regions due to low foraminiferal abundances in marine sediments in those areas. Here we present high-resolution deglacial <sup>14</sup>C ventilation age records from key sites in the Atlantic and Indian Sector of the Southern Ocean obtained by radiocarbon analyses of small benthic and planktic foraminiferal samples (<1 mg CaCO<sub>3</sub>) with the UniBe Mini-Carbon Dating System (MICADAS). Our analyses specifically circumvent foraminiferal sample size requirements related to “conventional” accelerator mass spectrometer analyses involving sample graphitization (>1 mg CaCO<sub>3</sub> in most laboratories). Complementing multi-proxy analyses of sea surface temperature (SST) changes at these sites allow the construction of a radiocarbon-independent age model through a stratigraphic alignment of SST changes to Antarctic (ice core) temperature variations. We demonstrate the value of refining the age models of our study cores on the basis of high-resolution sedimentary U- and Th flux estimates, which allows an improved quantification of surface ocean reservoir age variations in the past. The resulting deep-ocean ventilation age changes are compared against qualitative and quantitative indicators of bottom water [O<sub>2</sub>] variations, in order to assess the role of Southern Ocean overturning dynamics in respired carbon changes at our study sites. We discuss the implications of our new radiocarbon- and bottom water [O<sub>2</sub>] data for the ocean’s role in atmospheric CO<sub>2</sub> changes throughout the last deglaciation, and evaluate down-stream effects of southern high-latitude surface ocean reservoir age anomalies.</p>

HIGH-RESOLUTION SEDIMENTARY [HG] RECORDS ACROSS THE PETM FROM A TERRESTRIAL LATITUDINAL TRANSECT IN NORTH AMERICA

2020 ◽  
Author(s):  
Natalie Sorrem ◽  
◽  
Clara L. Meier ◽  
Gabriel J. Bowen ◽  
Brady Z. Foreman ◽  
...  
Keyword(s):  
High Resolution ◽  
North America ◽  
Latitudinal Transect

A methodology for optimizing modeling configuration in the numerical modeling of oil concentrations in underwater blowouts: a North Sea case study

2021 ◽  
Author(s):  
Andrés Martínez
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Modeling ◽  
High Resolution ◽  
North Sea ◽  
Oil And Gas ◽  
Data Bases ◽  
Lagrangian Trajectory ◽  
Number Of Particles

<p><strong>A METHODOLOGY FOR OPTIMIZING MODELING CONFIGURATION IN THE NUMERICAL MODELING OF OIL CONCENTRATIONS IN UNDERWATER BLOWOUTS: A NORTH SEA CASE STUDY</strong></p><p>Andrés Martínez<sup>a,*</sup>, Ana J. Abascal<sup>a</sup>, Andrés García<sup>a</sup>, Beatriz Pérez-Díaz<sup>a</sup>, Germán Aragón<sup>a</sup>, Raúl Medina<sup>a</sup></p><p><sup>a</sup>IHCantabria - Instituto de Hidráulica Ambiental de la Universidad de Cantabria, Avda. Isabel Torres, 15, 39011 Santander, Spain</p><p><sup>* </sup>Corresponding author: [email protected]</p><p>Underwater oil and gas blowouts are not easy to repair. It may take months before the well is finally capped, releasing large amounts of oil into the marine environment. In addition, persistent oils (crude oil, fuel oil, etc.) break up and dissipate slowly, so they often reach the shore before the cleanup is completed, affecting vasts extension of seas-oceans, just as posing a major threat to marine organisms.</p><p>On account of the above, numerical modeling of underwater blowouts demands great computing power. High-resolution, long-term data bases of wind-ocean currents are needed to be able to properly model the trajectory of the spill at both regional (open sea) and local level (coastline), just as to account for temporal variability. Moreover, a large number of particles, just as a high-resolution grid, are unavoidable in order to ensure accurate modeling of oil concentrations, of utmost importance in risk assessment, so that threshold concentrations can be established (threshold concentrations tell you what level of exposure to a compound could harm marine organisms).</p><p>In this study, an innovative methodology has been accomplished for the purpose of optimizing modeling configuration: number of particles and grid resolution, in the modeling of an underwater blowout, with a view to accurately represent oil concentrations, especially when threshold concentrations are considered. In doing so, statistical analyses (dimensionality reduction and clustering techniques), just as numerical modeling, have been applied.</p><p>It is composed of the following partial steps: (i) classification of i representative clusters of forcing patterns (based on PCA and K-means algorithms) from long-term wind-ocean current hindcast data bases, so that forcing variability in the study area is accounted for; (ii) definition of j modeling scenarios, based on key blowout parameters (oil type, flow rate, etc.) and modeling configuration (number of particles and grid resolution); (iii) Lagrangian trajectory modeling of the combination of the i clusters of forcing patterns and the j modeling scenarios; (iv) sensitivity analysis of the Lagrangian trajectory model output: oil concentrations,  to modeling configuration; (v) finally, as a result, the optimal modeling configuration, given a certain underwater blowout (its key parameters), is provided.</p><p>It has been applied to a hypothetical underwater blowout in the North Sea, one of the world’s most active seas in terms of offshore oil and gas exploration and production. A 5,000 cubic meter per day-flow rate oil spill, flowing from the well over a 15-day period, has been modeled (assuming a 31-day period of subsequent drift for a 46-day modeling). Moreover, threshold concentrations of 0.1, 0.25, 1 and 10 grams per square meter have been applied in the sensitivity analysis. The findings of this study stress the importance of modeling configuration in accurate modeling of oil concentrations, in particular if lower threshold concentrations are considered.</p>

scholarly journals Centennial mineral dust variability in high-resolution ice core data from Dome C, Antarctica

2012 ◽  
Vol 8 (2) ◽  
pp. 609-623 ◽  
Author(s):  
F. Lambert ◽  
M. Bigler ◽  
J. P. Steffensen ◽  
M. Hutterli ◽  
H. Fischer
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Mineral Dust ◽  
Ice Core ◽  
Principal Component ◽  
Dominant Factor ◽  
Core Data ◽  
The Past ◽  
Dust Flux ◽  
Soluble Calcium

Abstract. Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca2+), non-sea-salt soluble calcium (nssCa2+), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO2 changes during glacial-interglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.

scholarly journals Seasonal variations and drivers of surface ocean pCO 2 in the Seasonal Ice Zone of the Eastern Indian Sector, Southern Ocean

2021 ◽  
Author(s):  
Manami Tozawa ◽  
Daiki Nomura ◽  
Shin−ichiro Nakaoka ◽  
Masaaki Kiuchi ◽  
Kaihe Yamazaki ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Seasonal Variations ◽  
Surface Ocean ◽  
Indian Sector ◽  
Seasonal Ice Zone

scholarly journals REDUCTION OF AMMONIA EMISSIONS FROM THE COMPOSTING OF SLAUGHTERHOUSE SOLID WASTE USING ZEOLITE

2020 ◽  
Vol 3 (2) ◽  
pp. 164
Author(s):  
Rhenny Ratnawati ◽  
Sugito Sugito
Keyword(s):  
Solid Waste ◽  
High Capacity ◽  
Raw Material ◽  
Ammonia Emission ◽  
Ammonia Emissions ◽  
Impact Study ◽  
Aerobic Composting ◽  
Ammonia Gas ◽  
Gas Emissions ◽  
Composting Process

The process of aerobic composting the slaughterhouse (SH) solid waste generate ammonia emissions. Aim: The objective of this research to study the ability of the adsorbent to use zeolite to reduce ammonia gas emissions during the composting process of SH solid waste. Methodology and Results: Reduction of ammonia emission is conducted during the aerobic composting process which is 50 days. The raw material composition of the composting process used was 100% rumen contents, 60% rumen contents: 40% straw, 50% rumen contents: 50% straw, and 40% rumen contents: 60% straw. Zeolite used in the form of granular size 100 mesh. The result of the research showed that the level of release of ammonia gas emissions during the composting process could be reduced by zeolite. Conclusion, significance, and impact study: The efficiency of reducing ammonia gas emissions using zeolite adsorbents in the composting process of SH solid waste ranges from 98.09 - 99.40% on average. Zeolite is an adsorbent that has high adsorption power because it has many pores and has a high ion exchange high capacity and serves as an absorbent cation that can cause environmental pollution.

scholarly journals Atmospheric iron delivery and surface ocean biological activity in the Southern Ocean and Patagonian region

2003 ◽  
Vol 30 (12) ◽  
Author(s):  
David J. Erickson ◽  
Jose L. Hernandez ◽  
P. Ginoux ◽  
W. W. Gregg ◽  
C. McClain ◽  
...  
Keyword(s):  
Biological Activity ◽  
Southern Ocean ◽  
Surface Ocean ◽  
Iron Delivery

The Southern Ocean and its interaction with the Antarctic Ice Sheet

Science ◽  
2020 ◽  
Vol 367 (6484) ◽  
pp. 1326-1330
Author(s):  
David M. Holland ◽  
Keith W. Nicholls ◽  
Aurora Basinski
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Thermal Structure ◽  
Ice Sheet ◽  
Major Influence ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Air Temperatures ◽  
The Antarctic ◽  
Circulation Changes

The Southern Ocean exerts a major influence on the mass balance of the Antarctic Ice Sheet, either indirectly, by its influence on air temperatures and winds, or directly, mostly through its effects on ice shelves. How much melting the ocean causes depends on the temperature of the water, which in turn is controlled by the combination of the thermal structure of the surrounding ocean and local ocean circulation, which in turn is determined largely by winds and bathymetry. As climate warms and atmospheric circulation changes, there will be follow-on changes in the ocean circulation and temperature. These consequences will affect the pace of mass loss of the Antarctic Ice Sheet.

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