bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the upward flux of sea‐spray spume droplets in high‐wind conditions
Authors: Wu Lin , Cheng Xueling , Zeng Qingcun , Jin Jiangbo , Huang Jian , Feng Yerong 
Published: May 2017

AbstractIt has been speculated that the spume droplets torn off from ocean waves in high wind speeds (larger than about 9 m s−1) enhance air‐sea fluxes. However, the vertical transport of spume droplets in the high‐wind atmospheric boundary layer (ABL) is little researched and lacks the support of numerical simulations. Based on observational data and the characteristics of high‐wind ABL above the ocean, the vertical transport of spume droplets is studied and simulated. It is revealed that the existence of gusty wind with coherent structure during high winds is favorable for the vertical transport of the large‐size droplets. The trajectories of 1000 spume droplets with different sizes under different wind speeds in the range 10–35 m s−1 are calculated, and the uplifting fraction of spume droplets that can reach the 100 m height in the ABL is parameterized by using a nondimensional factor U102/(r80g), where U10 is the wind speed at 10 m height, r80 the equilibrium radius of droplet at an equivalent 80% relative humidity, and g the gravitational acceleration. Then, the upward flux of large‐size spume droplets and the mass concentration at 100 m height are evaluated. These numerical results are comparable to some observational data and show that the large‐size spume droplets can be entrained into the ABL during high winds and then contribute to the air‐sea mass fluxes.
Geochemistry and microbial community composition across a range of acid mine drainage impact and implications for the Neoarchean‐Paleoproterozoic transition
Authors: Havig Jeff R. , Grettenberger Christen , Hamilton Trinity L. 
Published: May 2017

AbstractStreams impacted by acid mine drainage (AMD, also known as acid rock drainage) represent local environmental and ecological disasters; however, they may also present an opportunity to study microbial communities in environments analogous to past conditions. Neoarchean continents had streams and rivers replete with detrital pyrites. Following the emergence of oxygenic photosynthesis, Cyanobacteria colonized streams and rivers on continental surfaces. The combination of labile detrital pyrite grains and locally produced O2 generated by Cyanobacteria produced ideal conditions for pyrite oxidation similar to that found at modern AMD‐impacted sites. To explore the connection of modern sites to ancient conditions, we sampled sites that exhibited a range of AMD‐impact (e.g., pH from 2.1 to 7.9 [Fe2+] up to 5.2 mmol/L [SO42−] from 0.3 to 52.4 mmol/L) and found (i) nearly all analytes correlated to sulfate concentration; (ii) all sites exhibited the predominance of a single taxon most closely related to Ferrovum myxofaciens, an Fe‐oxidixing betaproteoabacterium capable of carbon and nitrogen fixation, and (iii) signs of potential inorganic carbon limitation and nitrogen cycling. From these findings and building on the work of others, we present a conceptual model of continental surfaces during the Neoarchean and Paleoproterozoic linking local O2 production to pyrite oxidation on continental surfaces to sulfate production and delivery to nearshore environments. The delivery of sulfate drives sulfate reduction and euxinia—favoring anoxygenic photosynthesis over cyanobacterial O2 generation in near‐continent/shelf marine environments.
Habitat and spatial thinning improve the Maxent models performed with incomplete data
Authors: Kiedrzyński Marcin , Zielińska Katarzyna M. , Rewicz Agnieszka , Kiedrzyńska Edyta 
Published: May 2017

AbstractSpecies distribution models need adequate sets of data, particularly in the case of range‐restricted species. The problem faced in the modeling of rare species is twofold: a small sample size and the occurrence of sampling biases. The present analysis combines spatial‐ and habitat‐thinning approaches to improve maximum entropy models based on geographically incomplete data of relict and subendemic Festuca amethystina L. grass on Polish territory. The results show that models based on strongly incomplete historic data did not predict the occurrence of all important areas where the species was found in the following decades. However, the introduction of species‐specific thinning allows for more precise prediction of the species range, i.e., the detection of suitable areas on a more local scale. The introduction of habitat thinning caused the diversity of important predictors in model to increase, but spatial thinning decreased the number of significant predictors and made interpretation easier. Additionally, a combination of thinning techniques allowed significant improvements to be made to the model predictions after the experimental addition of a lower number of localities to regions which had previously been poorly recognized. It can be concluded that in the case of incomplete data, the above corrections allow the true range of the species to be predicted after the discovery of a lower number and relatively dispersed new localities.
Investigating molecular changes in organic matter composition in two Holocene lake‐sediment records from central Sweden using pyrolysis‐GC/MS
Authors: Ninnes Sofia , Tolu Julie , Meyer‐Jacob Carsten , Mighall Tim M. , Bindler Richard 
Published: May 2017

AbstractOrganic matter (OM) is a key component of lake sediments, affecting carbon, nutrient, and trace metal cycling at local and global scales. Yet little is known about long‐term (millennial) changes in OM composition due to the inherent chemical complexity arising from multiple OM sources and from secondary transformations. In this study we explore how the molecular composition of OM changes throughout the Holocene in two adjacent boreal lakes in central Sweden and compare molecular‐level information with conventional OM variables, including total carbon, total nitrogen, C:N ratios, δ13C, and δ15N. To characterize the molecular OM composition, we employed a new method based on pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS), which yields semiquantitative data on >100 organic compounds of different origin and degradation status. We identify large changes in OM composition after deglaciation (circa 8500 ± 500 B.C.), associated with early landscape development, and during the most recent 40–50 years, driven by degradation processes. With molecular‐level information we can also distinguish between natural landscape development and human catchment disturbance during the last 1700 years. Our study demonstrates that characterization of the molecular OM composition by the high‐throughput Py‐GC/MS method is an efficient complement to conventional OM variables for identification and understanding of past OM dynamics in lake‐sediment records. Holocene changes observed for pyrolytic compounds and compound classes known for having different reactivity indicate the need for further paleo‐reconstruction of the molecular OM composition to better understand both past and future OM dynamics and associated environmental changes.
Closing an early Miocene astronomical gap with Southern Ocean δ18O and δ13C records: Implications for sea level change
Authors: Miller Kenneth G. , Baluyot Ronidell , Wright James D. , Kopp Robert E. , Browning James V. 
Published: May 2017

AbstractWe present orbital‐scale resolution (~10 kyr) benthic foraminiferal δ18O and δ13C records from the Kerguelen Plateau (Ocean Drilling Program Sites 751 and 747) from 14.5 to 20.0 Ma spanning the Miocene climate optimum (15–17 Ma). Our records fill a critical gap from ~17 to 18 Ma, a time when many other deep‐sea records are affected by dissolution. We tested the fidelity of published magnetobiostratigraphic age models for these sites by astronomically tuning to the 405 kyr eccentricity cycle. A comparison of spectral estimates between the untuned and tuned records, as well as coherency with Laskar's (2004) eccentricity solution, revealed quasi‐100 kyr cyclicity in δ18O and δ13C. There is only a weak signal associated with the 41 kyr obliquity cycle, likely due to the 10 kyr sampling limiting resolution. The δ18O variations point to persistent 405 and quasi‐100 kyr modulations of temperature and sea level changes through the early to middle Miocene as predicted by astronomical solutions, with changing dominance of the 100 and 41 kyr beat. Comparison of δ18O records with early to middle Miocene sequences from the New Jersey shelf, northeast Australian margin, Bahamas, and Maldives suggests that the dominant sea level period preserved is the 1.2 Myr obliquity cycle, with sequence boundaries associated with δ18O increases or maxima. On the New Jersey margin, higher‐order sequences reflect the quasi‐100 kyr eccentricity cycles as modulated by 405 kyr cycles. We suggest that “nesting” of stratigraphic cycles is a function of the following: (1) pervasive (though changing) Milankovitch forcing of global mean sea level change and (2) preservation that depends on sufficient sediment supply and accommodation.
An evaporite‐bearing accretionary complex in the northern front of the Betic‐Rif orogen
Authors: Pérez‐Valera Fernando , Sánchez‐Gómez Mario , Pérez‐López Alberto , Pérez‐Valera Luis Alfonso 
Published: May 2017

AbstractThe Guadalquivir Accretionary Complex forms a largely oblique prism at the northern edge of the Betic‐Rif orogen, where Miocene sediments plus allochthonous evaporite‐bearing units were accreted during the displacement of the Alborán Domain toward the west. Traditional interpretations end the tectonic structuring of the Betic Cordillera at the present topographic front, beyond which gravitational and/or diapiric processes would predominate. However, this study shows pervasive tectonic deformation in the outer prism with coherent oblique shortening kinematics, which is achieved through an alternation of roughly N‐S arcuate thrust systems connected by E‐W transfer fault zones. These structures accord well with the geophysical models that propose westward rollback subduction. The main stage of tectonic activity occurred in the early‐middle Miocene, but deformation lasted until the Quaternary with the same kinematics. Evaporite rocks played a leading role in the deformation as evidenced by the suite of ductile structures in gypsum distributed throughout the area. S‐ and L‐ gypsum tectonites, scaly clay fabrics, and brittle fabrics coexist and consistently indicate westward motion (top to 290°), with subordinate N‐S contraction almost perpendicular to the transfer zones. This work reveals ductile tectonic fabrics in gypsum as a valuable tool to elucidate the structure and deformational history of complex tectonic mélanges involving evaporites above the décollement level of accretionary wedges.
Replenishing an unconfined coastal aquifer to control seawater intrusion: Injection or infiltration?
Authors: Lu Chunhui , Shi Wenlong , Xin Pei , Wu Jichun , Werner Adrian D. 
Published: May 2017

AbstractIn this study, we compare the performances of well injection and pond infiltration in controlling seawater intrusion in an unconfined coastal aquifer through two scenario groups: (1) a single injection well versus an elliptic infiltration pond and (2) an injection‐extraction well pair system versus an elliptic infiltration pond‐extraction well system. Comparison is based on quantitative indicators that include the interface toe location, saltwater volume, and maximum net extraction rate (for scenario 2). We introduce a method to determine the maximum net extraction rate for cases where the locations of stagnation points cannot be easily derived. Analytical analysis shows that the performances of injection and infiltration are the same, provided that the pond shape is circular. The examination of scenario group 1 suggests that the shape of the infiltration pond has a minor effect on the interface toe location as well as the reduction in the saltwater volume, given the same total recharge rate. The investigation of scenario group 2 indicates, by contrast, that the maximum net extraction rate increases significantly with the increasing ratio of b to a, where a and b are semiaxes of the ellipse parallel and perpendicular to the coastline, respectively. Specifically, for a typical aquifer assumed, an increase of 40% is obtained for the maximum net extraction when b/a increases from 1/200 to 200. Despite that the study is based on a simplified model, the results provide initial guidance for practitioners when planning to use an aquifer recharge strategy to restore a salinized unconfined coastal aquifer.
Concentration‐discharge relationships during an extreme event: Contrasting behavior of solutes and changes to chemical quality of dissolved organic material in the Boulder Creek Watershed during the September 2013 flood
Authors: Rue Garrett P. , Rock Nathan D. , Gabor Rachel S. , Pitlick John , Tfaily Malak , McKnight Diane M. 
Published: May 2017

AbstractDuring the week of 9–15 September 2013, about 44 cm of rain fell across Boulder County, Colorado, USA, representing a very rare precipitation event. The resultant streamflows corresponded to an extreme event not seen since the historical flood of 1894. For the Boulder Creek Critical Zone Observatory (BcCZO), this event provided an opportunity to study the effect of extreme rainfall on solute concentration‐discharge relationships and biogeochemical processes. We measured weathering‐derived lithologic solutes (Ca, Mg, Na, K, and Si) and dissolved organic carbon (DOC) concentrations at two sites on Boulder Creek during the recession of peak flow. We also isolated four distinct fractions of dissolved organic matter (DOM) for chemical characterization. At the upper and lower sites, all solutes had their highest concentration at peak flow. At the upper site, which represented a mostly forested catchment, the concentrations of lithologic solutes decreased slightly during flood recession. In contrast, DOC and K concentrations decreased by a factor of three. At the lower site within the urban corridor, concentration of lithologic solutes decreased substantially for a few days before rebounding, whereas the DOC and K concentrations continued to decrease. Additionally, we found spatiotemporal trends in the chemical quality of DOM that were consistent with a limited reservoir of soluble organic matter in surficial soils becoming depleted and deeper layers of the Critical Zone contributing DOM during the flood recession. Overall, these results suggest that despite the extreme flood event, concentration‐discharge relationships were similar to typical snowmelt periods in this Rocky Mountain region.
Observations of the impact of rock heterogeneity on solute spreading and mixing
Authors: Boon Maartje , Bijeljic Branko , Krevor Samuel 
Published: May 2017

AbstractRock heterogeneity plays an important role in solute spreading and mixing in hydrogeologic systems. Few observations, however, have been made that can spatially resolve these processes in 3‐D, in consolidated rocks. We make observations of the spatially resolved steady state concentration of a sodium iodide solute while flowing brine through cylindrical rock cores using X‐ray CT imaging. Three rocks with an increasing level of heterogeneity are chosen: a Berea sandstone, a Ketton carbonate, and an Indiana carbonate. The impact of heterogeneity on solute transport is analyzed by: (1) quantifying spreading and mixing using metrics such as the transverse dispersion coefficient, the dilution index, the reactor ratio, and the scalar dissipation rate and (2) visualizing and analyzing flow structures such as meandering, flow‐focusing, and flow‐splitting using isoconcentration contour maps. The transverse dispersion coefficient, Dt, and the variation in Dt throughout the rock core, increases with Peclét number (Pe) and rock heterogeneity. The reactor ratio indicates that mixing is Fickian for the Berea sandstone and Ketton carbonate, but diverges for the Indiana carbonate. The temporal evolution of the scalar dissipation rate, a measure of the mixing rate, remains close to that of Fickian mixing for the Berea and Ketton rocks but not for the Indiana. Heterogeneous rock features are observed to cause meandering, focusing, or splitting of the plume depending on Pe.
Understanding the unique biogeochemistry of the Mediterranean Sea: Insights from a coupled phosphorus and nitrogen model
Authors: Powley Helen R. , Krom Michael D. , Van Cappellen Philippe 
Published: May 2017

AbstractThe Mediterranean Sea (MS) is an oligotrophic basin whose offshore water column exhibits low dissolved inorganic phosphorus (P) and nitrogen (N) concentrations, unusually high nitrate (NO3) to phosphate (PO4) ratios, and distinct biogeochemical differences between the Western Mediterranean Sea (WMS) and Eastern Mediterranean Sea (EMS). A new mass balance model of P and N cycling in the WMS is coupled to a pre‐existing EMS model to understand these biogeochemical features. Estimated land‐derived inputs of reactive P and N to the WMS and EMS are similar per unit surface area, but marine inputs are 4 to 5 times greater for the WMS, which helps explain the approximately 3 times higher primary productivity of the WMS. The lateral inputs of marine sourced inorganic and organic P support significant fractions of new production in the WMS and EMS, similar to subtropical gyres. The mass balance calculations imply that the MS is net heterotrophic: dissolved organic P and N entering the WMS and EMS, primarily via the Straits of Gibraltar and Sicily, are mineralized to PO4 and NO3 and subsequently exported out of the basin by the prevailing anti‐estuarine circulation. The high deepwater (DW) molar NO3:PO4 ratios reflect the high reactive N:P ratio of inputs to the WMS and EMS, combined with low denitrification rates. The lower DW NO3:PO4 ratio of the WMS (21) compared to the EMS (28) reflects lower reactive N:P ratios of inputs to the WMS, including the relatively low N:P ratio of Atlantic surface water flowing into the WMS.
Pervasive silicification and hanging wall overplating along the 13°20′N oceanic detachment fault (Mid‐Atlantic Ridge)
Authors: Bonnemains D. , Escartín J. , Mével C. , Andreani M. , Verlaguet A. 
Published: May 2017

AbstractThe corrugated detachment fault zone of the active 13°20′N oceanic core complex (Mid‐Atlantic Ridge) was investigated with a deep‐sea vehicle to assess the links between deformation, alteration, and magmatism at detachment fault zones. We present a study of 18 in situ fault rock samples from striated fault outcrops on the flanks of microbathymetric corrugations. All the samples are mafic breccias that are mostly derived from a diabase protolith, with two of them also showing mixing with ultramafic clasts. Breccias are cataclastic and display variable deformation textures, recording numerous slip events, and showing pervasive silicification throughout the fault zone. Deformation‐silicification relationships are also complex, showing both static and syntectonic quartz precipitation; undeformed quartz overprints the fault breccia textures, and reflective and striated fault surfaces cross‐cut silicified rocks. In situ detachment fault rocks are mainly fault breccias with almost exclusively basaltic clasts, with rare ultramafic ones, a lithology and texture never observed previously at other oceanic detachment fault zones. We propose the lower dyke complex in the hanging wall crust at the volcanic rift valley floor is the most plausible diabase source. Mechanical mixing of predominantly mafic and rare ultramafic clasts suggests an underlying ultramafic footwall and that mafic accretion operates in the shallowest crust (1–2 km), at the base of the dyke complex at temperatures >400°C. Silicification is produced by silica‐rich fluids syntectonically channeled along the fault zone, and likely derived from hydrothermal alteration of basaltic rocks, likely mixed with serpentinization‐derived fluids.
An Argo mixed layer climatology and database
Authors: Holte James , Talley Lynne D. , Gilson John , Roemmich Dean 
Published: May 2017

AbstractA global climatology and database of mixed layer properties are computed from nearly 1,250,000 Argo profiles. The climatology is calculated with both a hybrid algorithm for detecting the mixed layer depth (MLD) and a standard threshold method. The climatology provides accurate information about the depth, properties, extent, and seasonal patterns of global mixed layers. The individual profile results in the database can be used to construct time series of mixed layer properties in specific regions of interest. The climatology and database are available online at http://mixedlayer.ucsd.edu. The MLDs calculated by the hybrid algorithm are shallower and generally more accurate than those of the threshold method, particularly in regions of deep winter mixed layers; the new climatology differs the most from existing mixed layer climatologies in these regions. Examples are presented from the Labrador and Irminger Seas, the Southern Ocean, and the North Atlantic Ocean near the Gulf Stream. In these regions the threshold method tends to overestimate winter MLDs by approximately 10% compared to the algorithm.
Convective aggregation in realistic convective‐scale simulations
Authors: Holloway Christopher E. 
Published: May 2017

AbstractTo investigate the real‐world relevance of idealized‐model convective self‐aggregation, five 15 day cases of real organized convection in the tropics are simulated. These include multiple simulations of each case to test sensitivities of the convective organization and mean states to interactive radiation, interactive surface fluxes, and evaporation of rain. These simulations are compared to self‐aggregation seen in the same model configured to run in idealized radiative‐convective equilibrium. Analysis of the budget of the spatial variance of column‐integrated frozen moist static energy shows that control runs have significant positive contributions to organization from radiation and negative contributions from surface fluxes and transport, similar to idealized runs once they become aggregated. Despite identical lateral boundary conditions for all experiments in each case, systematic differences in mean column water vapor (CWV), CWV distribution shape, and CWV autocorrelation length scale are found between the different sensitivity runs, particularly for those without interactive radiation, showing that there are at least some similarities in sensitivities to these feedbacks in both idealized and realistic simulations (although the organization of precipitation shows less sensitivity to interactive radiation). The magnitudes and signs of these systematic differences are consistent with a rough equilibrium between (1) equalization due to advection from the lateral boundaries and (2) disaggregation due to the absence of interactive radiation, implying disaggregation rates comparable to those in idealized runs with aggregated initial conditions and noninteractive radiation. This points to a plausible similarity in the way that radiation feedbacks maintain aggregated convection in both idealized simulations and the real world.
Design of the printing pattern on film for three‐dimensional molded interconnect devices
Authors: Liu Ren Hao , Young Wen‐Bin , Ming Hsu Pe 
Published: May 2017

AbstractThis article discusses the application of an in‐mold decoration (IMD) technology for the development of three‐dimensional molded interconnect devices (3D‐MID). The 3D‐MID process uses the film printing technology to print the circuit pattern on a plastic film, and then deform it to the shape of the component by thermoforming. Then, the plastic film is placed inside the mold cavity for injection molding, and is attached to the surface of the component after molding. Experiments were performed for the 3D‐MID process using a semisphere shape. A simple geometric model was also proposed to correlate the printed film patterns before and after the thermoforming. The geometric model will be used to design the required printing pattern on a 2D film for a given 3D pattern on a component.