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  • 1
    Online Resource
    Online Resource
    Dordrecht :Springer Netherlands,
    Keywords: Dust. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (526 pages)
    Edition: 1st ed.
    ISBN: 9789401789783
    DDC: 551.304
    Language: English
    Note: Intro -- Preface -- Personal Notes by the Editors -- Peter Knippertz -- Jan-Berend W. Stuut -- Acknowledgements -- Contents -- Contributors -- About the Editors -- 1 Introduction -- 1.1 Why Study Dust? -- 1.2 A Short History of Dust Research -- 1.3 Recent Developments: Timeliness of This Book -- 1.4 Outline and Structure of This Book -- References -- 2 On Composition, Morphology, and Size Distribution of Airborne Mineral Dust -- 2.1 Introduction -- 2.2 Composition -- 2.2.1 Mineralogical Data -- 2.2.2 Isotope Data -- 2.2.3 Elemental Data -- 2.3 Individual-Particle Analysis -- 2.3.1 Particle Shape and Morphology -- 2.4 Size Distributions -- 2.5 Discussion and Conclusions -- 2.5.1 Direct Radiative Forcing -- 2.5.2 Indirect Radiative Forcing -- 2.5.3 Ecosystem Nutrient Supply and Human Health Effects -- References -- 3 Identifying Sources of Aeolian Mineral Dust: Present and Past -- 3.1 Introduction -- 3.2 Processes of Dust Particle Formation -- 3.3 Methods of Identifying Contemporary Dust Sources -- 3.3.1 Geomorphic Perspectives on Dust Sources -- 3.3.2 Aerosol Indexes (AI) Derived from the Orbiting TOMS (Total Ozone Mapping Spectrometer) -- 3.3.3 MODIS and MISR Imagery from the Terra and Aqua Satellites -- 3.3.4 Back-Trajectory Analyses to Identify Dust Sources -- 3.4 Identification of Past Dust Sources -- 3.4.1 Geomorphic Evidence of Past Dust Sources -- 3.4.2 Physical Properties of Dust Deposits -- 3.4.3 Mineralogy as a Guide to Dust Sources -- 3.4.4 Geochemical Methods of Identifying Dust Sources -- 3.4.5 Isotopic Methods of Identifying Dust Sources -- 3.4.6 Biologic Methods of Identifying Dust Sources -- 3.5 Conclusion -- References -- 4 Processing and Ageing in the Atmosphere -- 4.1 Introduction -- 4.2 Physical Processing -- 4.3 Chemical Processing -- 4.3.1 Impacts on Physical Properties of Dust -- 4.3.2 Impacts on Dust Reactivity. , 4.3.3 Impacts on Atmospheric Composition -- Nitric Acid and Nitrogen Oxides -- Sulphur Species -- Ozone -- Other Inorganic and Organic Species -- 4.4 Conclusion -- References -- 5 Dust Production Mechanisms -- 5.1 Introduction -- 5.2 General Understanding -- 5.3 Erosion Threshold -- 5.3.1 Influence of Soil Particle Size -- 5.3.2 Influence of Soil Moisture -- 5.3.3 Influence of Surface Roughness -- 5.3.4 Other Factors -- 5.4 Saltation -- 5.5 Dust Emission -- 5.5.1 Empirical Approaches -- 5.5.2 Physically Based Models -- 5.5.3 Models Versus Observations -- 5.6 Conclusion -- References -- 6 Meteorological Aspects of Dust Storms -- 6.1 Introduction -- 6.2 Large-Scale Circulations -- 6.3 Synoptic-Scale Aspects -- 6.3.1 Cyclone Dominated Dust Events -- 6.3.2 Anticyclone Dominated Dust Events -- 6.3.3 Dynamics and Character of Dust Fronts -- 6.4 Moist Convection -- 6.5 Dry Convection -- 6.6 Diurnal Variations -- 6.7 Topographic Effects -- 6.8 Modelling -- 6.9 Conclusion -- References -- 7 Dust Observations and Climatology -- 7.1 Introduction -- 7.2 Observational Systems -- 7.3 Applications -- 7.3.1 Source Regions -- Regional Data from Geostationary Satellite -- Global Data from Polar-Orbiting Satellite -- 7.3.2 Transport -- General Features -- AOD, Dust Discrimination and Dust Above Clouds -- 7.3.3 Interannual Variability and Trends -- 7.3.4 Vertical Structure -- 7.4 Conclusion -- References -- 8 Dust Deposition -- 8.1 Introduction -- 8.2 Deposition Processes -- 8.2.1 Dry Deposition -- Gravitational Settling Velocity -- Aerodynamic and Quasi-laminar Resistances -- 8.2.2 Wet Deposition -- Brownian Diffusion -- Interception -- Inertial Impaction -- 8.2.3 Particle Size Distribution and Deposition in Dust Models -- 8.3 Dust Deposition Measurements -- 8.4 The Uncertainties in the Simulated Dust Mass Budget -- 8.5 Conclusion -- References. , 9 Numerical Dust Models -- 9.1 Introduction -- 9.2 Dust Emission Modelling -- 9.3 Model Representation of Dust Source Properties -- 9.4 Role of Meteorology in Dust Emission and Transport -- 9.5 Deposition -- 9.6 Optical Properties of Dust Used in Dust Models -- 9.7 Regional Dust Models -- 9.8 Global Dust Models -- 9.9 Conclusion -- References -- 10 Operational Dust Prediction -- 10.1 Introduction -- 10.1.1 Motivation for Dust Forecasting -- 10.1.2 A Brief History of Dust Forecasting -- 10.1.3 Specific Challenges in Dust Prediction -- 10.2 Dust Prediction Models -- 10.2.1 Global Models -- ECMWF/MACC Aerosol Prediction System -- FNMOC Navy Aerosol Analysis and Prediction System -- JMA Operational Dust Forecast Model -- Met Office Dust Prediction System -- NASA GEOS-5 Aerosol Forecasting System -- NCEP/NGAC Global Aerosol Forecasting System -- NMMB/BSC-Dust Model -- 10.2.2 Regional Models -- CHIMERE Model -- CUACE/Dust -- The DREAM/BSC-DREAM8b Models -- FNMOC Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) -- Regional Mineral Dust Forecast Model in Taiwan -- 10.3 Multi-model Ensembles -- 10.3.1 The International Cooperative for Aerosol Prediction (ICAP) Multi-model Ensemble -- 10.3.2 WMO SDS Regional Dust Prediction Multi-model Ensemble -- 10.4 Data Assimilation for Dust Prediction -- 10.4.1 Introduction -- 10.4.2 Main Concepts -- 10.5 Evaluation of Atmospheric Dust Prediction Models -- 10.5.1 General Concepts -- 10.5.2 Observational Data for Evaluation -- 10.5.3 Metrics -- 10.5.4 Examples of Near Real-Time Evaluation -- The WMO SDS-WAS Dust Model Evaluation Initiative -- The MACC-II Evaluation -- Case Study Evaluation -- 10.6 Conclusion -- Appendix A: Technical Aspects of Data Assimilationfor Dust Prediction -- A10.1 Assimilation Techniques -- Variational Methods (CMA, ECMWF, FNMOC/NRL, Met Office, NASA GMAO). , Kalman Filter and Ensemble Kalman Filter Methods (MRI/JMA, NRL) -- A10.2 Observations Used for the Dust Analyses -- Main Products -- Data Quality Aspects and Bias Correction -- A10.3 Definitions of Background and Observational Errors -- Background Error Covariance Matrices -- Flow-Dependent Background Error Covariance Matrix -- Observation Errors -- References -- 11 Radiative Effects of Dust -- 11.1 Introduction -- 11.2 Optical Properties of Dust -- 11.2.1 Definition of Optical Properties -- 11.2.2 Methods of Characterising Dust Optical Properties -- 11.2.3 Sensitivity of Optical Properties to Size and Composition: An Illustrative Example -- 11.2.4 Measurements of Single-Scattering Albedo -- 11.3 Measurements and Estimates of Radiative Effect -- 11.4 Implications of Dust-Radiation Interactions for Satellite Retrievals -- 11.5 Dust and Visibility -- 11.6 Implications for Including the Radiative Impact of Dust in Models -- References -- 12 Mineral Dust and its Microphysical Interactions with Clouds -- 12.1 CCN, IN, and Their Impacts on Clouds, the Hydrological Cycle, and Climate -- 12.2 The CCN Activity of Mineral Dust -- 12.3 The IN Activity of Mineral Dust -- 12.4 Field Observations of Dust CCN Activity/Hygroscopicity -- 12.5 Field Observations of Mineral Dust as IN -- 12.6 Laboratory Experiments on Mineral Dust CCN -- 12.7 Laboratory Experiments on Mineral Dust IN -- 12.8 Modeling Studies on the Interaction of Dust with Clouds -- 12.9 Conclusion -- References -- 13 Impact of Dust Radiative Forcing upon Climate -- 13.1 Introduction -- 13.2 Radiative Forcing by Dust Aerosols -- 13.3 Dust Radiative Impacts upon Climate -- 13.3.1 Temperature -- 13.3.1.1 Temperature Adjustment in Convectively Mixed Regions -- 13.3.1.2 Temperature Adjustment in Subsiding Regions -- 13.3.2 Precipitation -- 13.3.2.1 The Global Anomaly -- 13.3.2.2 Regional Anomalies. , 13.4 Feedback of Climate Anomalies upon the Dust Cycle -- 13.4.1 Surface Wind Speed and Dust Mobilization -- 13.4.2 Vegetation and Dust Source Extent -- 13.5 Conclusion -- References -- 14 Biogeochemical Impacts of Dust on the Global Carbon Cycle -- 14.1 Introduction -- 14.2 Biogeochemical Impacts of Dust on Terrestrial Systems -- 14.2.1 Soil Formation -- 14.2.2 Nutrient Supply -- 14.3 Biogeochemical Impacts of Dust Deposition on the Oceans -- 14.4 Conclusion -- References -- 15 Dust and Human Health -- 15.1 Introduction -- 15.2 Review of Air Pollution Basics -- 15.3 Human Exposure Pathways -- 15.4 Characteristics That Contribute to Observed Health Effects -- 15.4.1 Particle Size and Composition -- 15.4.2 Microorganisms in Dust -- 15.4.3 Mechanisms of Action -- 15.4.4 Exposure and Susceptibility -- 15.5 Ailments Associated with Airborne Dusts -- 15.5.1 Asthma -- 15.5.2 Meningitis -- 15.5.3 Hospitalization and Mortality Related to Intercontinental Dust -- 15.5.4 Exposures to Agricultural Dusts -- 15.5.5 Other Potential Risks Related to MD Exposures: Pneumoconioses -- 15.6 Conclusion -- References -- 16 Loess Records -- 16.1 Introduction -- 16.2 Definition of Loess -- 16.3 Mineralogy and Geochemistry of Loess -- 16.4 Genesis of Loess Deposits -- 16.5 Loess Stratigraphy -- 16.6 Loess Geochronology -- 16.7 Paleoclimatic and Paleoenvironmental Interpretation of Loess Deposits -- 16.8 Global Loess Deposits -- 16.8.1 Europe -- 16.8.2 Africa and the Middle East -- 16.8.3 Asia -- 16.8.4 Australia and New Zealand -- 16.8.5 South America -- 16.8.6 North America -- 16.9 Conclusion -- References -- 17 Subaquatic Dust Deposits -- 17.1 Introduction -- 17.2 From Desert Source to Subaquatic Sink: Dust Transport Processes -- 17.3 Wind-blown Dust in Subaqueous Sedimentary Archives: A Recorder of Environmental Changes -- 17.3.1 Lacustrine Dust Archives. , 17.3.2 Marine Dust Archives.
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  • 2
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: The terrigenous fraction of seabed sediments recovered along the north-west African continental margin illustrates spatial variability in grain size attributed to different transport mechanisms. Three subpopulations are determined from the grain-size analyses (n = 78) of the carbonate-free silt fraction applying an end-member modelling algorithm (G. J. Weltje, 1997). The two coarsest end-members are interpreted as representing aeolian dust, and the fine-grained end-member is related to fluvial supply. The end-member model thus allows aeolian fallout to be distinguished from fluvial-sourced mud in this area. The relative contributions of the end-members show distinct regional variations that can be related to different transport processes and pathways. Understanding present-day sediment dispersal and mixing is important for a better understanding of older sedimentary records and palaeoclimate reconstructions in the region.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2020-02-06
    Description: Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12° N, 49° W and M2 at 14° N, 37° W) collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic. The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus) but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241×107 ± 76×107 coccoliths m−2 d−1 at station M4 compared to only 66×107 ± 31×107 coccoliths m−2 d−1 at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, favoured by the westward deepening of the thermocline and nutricline. Still, most UPZ species also contributed to higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. Such was the case of two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi in January and April 2013 at M4, indicating a fast response to the nutrient enrichment of the UPZ, probably by wind-forced mixing. Later, increased fluxes of G. oceanica and E. huxleyi in October–November 2013 coincided with the occurrence of Amazon-River-affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust flux peaks, we propose a scenario in which atmospheric dust also provided fertilizing nutrients to this area. Enhanced surface buoyancy associated with the river plume indicates that the Amazon acted not only as a nutrient source, but also as a surface density retainer for nutrients supplied from the atmosphere. Nevertheless, lower total coccolith fluxes during these events compared to the maxima recorded in November 2012 and July 2013 indicate that transient productivity by opportunistic species was less important than "background" tropical productivity in the equatorial North Atlantic. This study illustrates how two apparently similar sites in the tropical open ocean actually differ greatly in ecological and oceanographic terms. The results presented here provide valuable insights into the processes governing the ecological dynamics and the downward export of coccolithophores in the tropical North Atlantic.
    Type: Article , PeerReviewed
    Format: text
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  • 4
    Publication Date: 2023-02-08
    Description: Mineral dust plays an important role in the atmospheric radiation budget as well as in the ocean carbon cycle through fertilization and by ballasting of settling organic matter. However, observational records of open‐ocean dust deposition are sparse. Here, we present the spatial and temporal evolution of Saharan dust deposition over 2 years from marine sediment traps across the North Atlantic, directly below the core of the Saharan dust plume, with highest dust fluxes observed in summer. We combined the observed deposition fluxes with model simulations and satellite observations and argue that dust deposition in the Atlantic is predominantly controlled by summer rains. The dominant depositional pathway changes from wet deposition in summer to dry deposition in winter. Wet deposition has previously been suggested to increase the release of dust‐derived nutrients and their bioavailability, which may be a key contributor to surface‐ocean productivity in remote and oligotrophic parts of the oceans.
    Type: Article , PeerReviewed
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  • 5
    Publication Date: 2020-05-13
    Description: Mineral dust plays an important role in the atmospheric radiation budget as well as in the ocean carbon cycle through fertilization and by ballasting of settling organic matter. However, observational records of open‐ocean dust deposition are sparse. Here, we present the spatial and temporal evolution of Saharan dust deposition over 2 years from marine sediment traps across the North Atlantic, directly below the core of the Saharan dust plume, with highest dust fluxes observed in summer. We combined the observed deposition fluxes with model simulations and satellite observations and argue that dust deposition in the Atlantic is predominantly controlled by summer rains. The dominant depositional pathway changes from wet deposition in summer to dry deposition in winter. Wet deposition has previously been suggested to increase the release of dust‐derived nutrients and their bioavailability, which may be a key contributor to surface‐ocean productivity in remote and oligotrophic parts of the oceans.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
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  • 6
    Publication Date: 2022-05-25
    Description: © The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Climate of the Past 8 (2012): 519-534, doi:10.5194/cp-8-519-2012.
    Description: Glaciers are frequently used as indicators of climate change. However, the link between past glacier fluctuations and climate variability is still highly debated. Here, we investigate the mid- to late-Holocene fluctuations of Gualas Glacier, one of the northernmost outlet glaciers of the Northern Patagonian Icefield, using a multi-proxy sedimentological and geochemical analysis of a 15 m long fjord sediment core from Golfo Elefantes, Chile, and historical documents from early Spanish explorers. Our results show that the core can be sub-divided into three main lithological units that were deposited under very different hydrodynamic conditions. Between 5400 and 4180 cal yr BP and after 750 cal yr BP, sedimentation in Golfo Elefantes was characterized by the rapid deposition of fine silt, most likely transported by fluvio-glacial processes. By contrast, the sediment deposited between 4130 and 850 cal yr BP is composed of poorly sorted sand that is free of shells. This interval is particularly marked by high magnetic susceptibility values and Zr concentrations, and likely reflects a major advance of Gualas glacier towards Golfo Elefantes during the Neoglaciation. Several thin silt layers observed in the upper part of the core are interpreted as secondary fluctuations of Gualas glacier during the Little Ice Age, in agreement with historical and dendrochronological data. Our interpretation of the Golfo Elefantes glaciomarine sediment record in terms of fluctuations of Gualas glacier is in excellent agreement with the glacier chronology proposed for the Southern Patagonian Icefield, which is based on terrestrial (moraine) deposits. By comparing our results with independent proxy records of precipitation and sea surface temperature, we suggest that the fluctuations of Gualas glacier during the last 5400 yr were mainly driven by changes in precipitation in the North Patagonian Andes.
    Description: This research was supported by an EU FP6 Marie Curie Outgoing Fellowship to S.B. Cruise NBP0505 was funded by the US National Science Foundation, Office of Polar Programs grant number NSF/OPP 03-38137 to J. Anderson (Rice University) and J. Smith Wellner (University of Houston). The Cimar-7 Program was supported by the Chilean National Oceanographic Committee (CONA, Grant C7F 01-10 to S. Pantoja).
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 7
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Geoscience 4 (2011): 540–544, doi:10.1038/ngeo1209.
    Description: The Australian-Indonesian monsoon is an important component of the climate system in the tropical Indo-Pacific region. However, its past variability, relation with northern and southern high latitude climate and connection to the other Asian monsoon systems are poorly understood. Here we present high-resolution records of monsoon-controlled austral winter upwelling during the past 22,000 years, based on planktic foraminiferal oxygen isotope and faunal composition in a sedimentary archive collected offshore southern Java. We show that glacial-interglacial variations in the Australian-Indonesian winter monsoon were in phase with the Indian summer monsoon system, consistent with their modern linkage through cross-equatorial surface winds. Likewise, millennial-scale variability of upwelling shares similar sign and timing with upwelling variability in the Arabian Sea. On the basis of element composition and grain-size distribution as precipitation-sensitive proxies in the same archive, we infer that (austral) summer monsoon rainfall was highest during the Bølling-Allerød period and the past 2,500 years. Our results indicate drier conditions during Heinrich Stadial 1 due to a southward shift of summer rainfall and a relatively weak Hadley Cell south of the Equator. We suggest that the Australian-Indonesian summer and winter monsoon variability were closely linked to summer insolation and abrupt climate changes in the northern hemisphere.
    Description: This study was funded by the German Bundesministerium für Bildung und Forschung (PABESIA) and the Deutsche Forschungsgemeinschaft (DFG, HE 3412/15-1). DWO’s participation was funded by the U.S. National Science Foundation.
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
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  • 8
    Publication Date: 2022-10-19
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 37(1), (2022): e020PA004137, https://doi.org/10.1029/2020PA004137.
    Description: Reconstructions of aeolian dust flux to West African margin sediments can be used to explore changing atmospheric circulation and hydroclimate over North Africa on millennial to orbital timescales. Here, we extend West African margin dust flux records back to 37 ka in a transect of sites from 19° to 27°N, and back to 67 ka at Ocean Drilling Program (ODP) Hole 658C, in order to explore the interplay of orbital and high-latitude forcings on North African climate and make quantitative estimates of dust flux during the core of the Last Glacial Maximum (LGM). The ODP 658C record shows a Green Sahara interval from 60 to 50 ka during a time of high Northern Hemisphere summer insolation, with dust fluxes similar to levels during the early Holocene African Humid Period, and an abrupt peak in flux during Heinrich event 5a (H5a). Dust fluxes increase from 50 to 35 ka while the high-latitude Northern Hemisphere cools, with peaks in dust flux associated with North Atlantic cool events. From 35 ka through the LGM dust deposition decreases in all cores, and little response is observed to low-latitude insolation changes. Dust fluxes at sites from 21° to 27°N were near late Holocene levels during the LGM time slice, suggesting a more muted LGM response than observed from mid-latitude dust sources. Records along the northwest African margin suggest important differences in wind responses during different stadials, with maximum dust flux anomalies centered south of 20°N during H1 and north of 20°N during the Younger Dryas.
    Description: This research was supported by NSF #OCE-1103262 to L. Bradtmiller, NSF #OCE-1030784 to D. McGee, P. deMenocal, and G. Winckler, and by internal grants from Macalester College and MIT.
    Description: 2022-06-07
    Keywords: North Africa ; Dust flux ; Aeolian dust ; Green Sahara ; Stadials
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 9
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    American Geophysical Union (AGU)
    In:  EPIC3Geochemistry Geophysics Geosystems, American Geophysical Union (AGU), 25(1), ISSN: 1525-2027
    Publication Date: 2024-03-04
    Description: Mineral dust accumulated on the ocean floor is an important archive for reconstructing past atmospheric circulation changes and climatological conditions in the source areas. Dust emitted from Southern Hemisphere dust sources is widely deposited over the oceans. However, there are few records of dust deposition over the open ocean, and a large need for extended geographical coverage exists. We present a large data set (134 surface sediment samples) of Late Holocene dust deposition from seafloor surface sediments covering the entire South Atlantic Ocean. Polymodal grain-size distributions of the lithogenic fraction indicate that the sediments are composed of multiple sediment components. By using end-member modeling, we attempt to disentangle the dust signal from non-aeolian sediments. Combined with 230Th-normalized lithogenic fluxes, we quantified the specific deposition fluxes for mineral dust, crrent-sorted sediments and ice-rafted debris (IRD). Although the method could not completely separate the different components in every region, it shows that dust deposition off the most prominent dust source for the South Atlantic Ocean—southern South America—amounts up to approximately 0.7 g cm−2 Kyr−1 and decreases downwind. Bottom-current-sorted sediments and IRD are mostly concentrated around the continental margins. The ratio of the coarse to fine dust end members reveals input from north African dust sources to the South Atlantic. The majority of the observations are in good agreement with new model simulations. This extensive and relevant data set of dust grain size and deposition fluxes to the South Atlantic could be used to calibrate and validate further model simulations.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 10
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    PANGAEA
    In:  Supplement to: van der Jagt, Helga; Friese, Carmen A; Stuut, Jan-Berend W; Fischer, Gerhard; Iversen, Morten Hvitfeldt (2018): The ballasting effect of Saharan dust deposition on aggregate dynamics and carbon export: Aggregation, settling, and scavenging potential of marine snow. Limnology and Oceanography, 63(3), 1386-1394, https://doi.org/10.1002/lno.10779
    Publication Date: 2023-03-16
    Description: Lithogenic material such as Saharan dust can be incorporated into organic aggregates and act as ballast, potentially enhancing the marine carbon export via increased sinking velocities of aggregates. We studied the ballasting effects of Saharan dust on the aggregate dynamics in the upwelling region off Cape Blanc (Mauritania). Aggregate formation from a natural plankton community exposed to Saharan dust deposition resulted in higher abundance of aggregates with higher sinking velocities compared to aggregate formation with low dust. This higher aggregate abundance and sinking velocities potentially increased the carbon export 10-fold when the aggregates were ballasted by Saharan dust. After aggregate formation in the surface waters, subsequent sinking through suspended Saharan dust minerals had no influence on aggregate sizes, abundance, and sinking velocities. We found that aggregates formed in the surface ocean off Mauritania were already heavily ballasted with lithogenic material and could therefore not scavenge any additional minerals during their descent. This suggests that carbon export to the deep ocean in regions with high dust deposition is strongly controlled by dust input to the surface ocean while suspended dust particles in deeper water layers do not significantly interact with sinking aggregates.
    Keywords: Center for Marine Environmental Sciences; MARUM; SeaPump; Seasonal and regional food web interactions with the biological pump
    Type: Dataset
    Format: application/zip, 3 datasets
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