Recent Publications

Weekly Highlighted Publication

NADPH-dependent extracellular superoxide production is vital to photophysiology in the marine diatom Thalassiosira oceanica

Impact:
Batch cultures of T. oceanica were grown with replete initial nutrient concentrations under optimal light conditions, and whole cells were analyzed for net extracellular superoxide production by a flow-through chemiluminescence approach described previously. Results revealed that extracellular superoxide production rates were highest in exponential growth phase. As observed in other phytoplankton, this decline of net extracellular superoxide production with increasing age challenges the perception of superoxide as a stress-response molecule, given the continual drawdown of nutrients and the accumulation of cellular stress that occurs over time in batch cultures. These results therefore suggest that extracellular superoxide production may be a constitutive, or even beneficial physiological process in T. oceanica.

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  • Waters C.L, Day JMD, Watanabe S., Sayit K., Zanon V., Olson K.M, Hanan B.B, Widom E..  2020.  Sulfide mantle source heterogeneity recorded in basaltic lavas from the Azores. 268:422-445.
    Abstract Summary:

    New highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re) abundance and Os isotopic compositions, along with major- and trace-element abundance and Sr-Nd-Hf-Pb isotope data are reported for high-MgO (>8-17 wt.%) lavas from the islands of Sao Miguel, Terceira, Pico and Faial in the Azores archipelago. The lavas span the range of Sr-Nd-Hf-Pb isotope and trace-element abundance variability reported previously for the islands. Pico and...

  • Aarons S.M, Arvin L.J, Aciego S.M, Riebe C.S, Johnson K.R, Blakowski M.A, Koornneef J.M, Hart S.C, Barnes M.E, Dove N. et al..  2019.  Competing droughts affect dust delivery to Sierra Nevada. 41
    Abstract Summary:

    The generation and transport of mineral dust is strongly related to climate on seasonal, year-to-year, and glacial-interglacial timescales. The modern dust cycle is influenced by soil moisture, which is partly a function of drought duration and severity. The production and transport of dust can therefore be amplified by global and regional droughts, thereby moderating ecosystem vulnerability to disturbance through the influence of dust on...

  • Seltzer A.M, Ng J., Danskin W.R, Kulongoski JT, Gannon R.S, Stute M., Severinghaus JP.  2019.  Deglacial water-table decline in Southern California recorded by noble gas isotopes. 10
    Abstract Summary:

    Constraining the magnitude of past hydrological change may improve understanding and predictions of future shifts in water availability. Here we demonstrate that water-table depth, a sensitive indicator of hydroclimate, can be quantitatively reconstructed using Kr and Xe isotopes in groundwater. We present the first-ever measurements of these dissolved noble gas isotopes in groundwater at high precision (<= 0.005 parts per thousand amu(-1...

  • Tian Z., Chen H., Fegley B., Lodders K., Barrat J.A, Day JMD, Wang K..  2019.  Potassium isotopic compositions of howardite-eucrite-diogenite meteorites. 266:611-632.
    Abstract Summary:

    We report new high-precision stable K isotope data for three martian meteorites, one lunar meteorite, one ordinary chondrite, four terrestrial igneous United States Geological Survey (USGS) reference materials, and twenty howardite-eucrite-dio genite [HED] meteorites. The three martian meteorites define a relatively narrow delta K-41 range with an average of -0.36 +/- 0.12 parts per thousand (2 SD) that is slightly heavier than the Bulk...

  • Levy Y., Rockwell T.K, Shaw J.H, Plesch A., Driscoll NW, Perea H..  2019.  Structural modeling of the Western Transverse Ranges: An imbricated thrust ramp architecture. 11:868-883.
    Abstract Summary:

    Active fold-and-thrust belts can potentially accommodate large-magnitude earthquakes, so understanding the structure in such regions has both societal and scientific importance. Recent studies have provided evidence for large earthquakes in the Western Transverse Ranges of California, USA. However, the diverse set of conflicting structural models for this region highlights the lack of understanding of the subsurface geometry of faults. A more...

  • Day JMD, Sossi P.A, Shearer C.K, Moynier F..  2019.  Volatile distributions in and on the Moon revealed by Cu and Fe isotopes in the 'Rusty Rock' 66095. 266:131-143.
    Abstract Summary:

    The Apollo 16 'Rusty Rock' impact melt breccia 66095 is a volatile-rich sample, with the volatiles inherited through vapor condensation from an internal lunar source formed during thermo-magmatic evolution of the Moon. We report Cu and Fe isotope data for 66095 and find that bulk-rocks, residues and acid leaches span a relatively limited range of compositions (3.0 +/- 1.3 wt.% FeO [range = 2.0-4.8 wt.%], 5.4 +/- 3.1 ppm Cu [range = 3-12 ppm...

  • Delgado J.A, Sudre J., Tanahara S., Montes I., Hernandez-Ayon J.M, Zirino A..  2019.  Effect of Caribbean Water incursion into the Gulf of Mexico derived from absolute dynamic topography, satellite data, and remotely sensed chlorophyll a. 15:1561-1578.
    Abstract Summary:

    The dynamics of the Loop Current (LC) and the detached Loop Current eddies (LCEs) dominate the surface circulation of the Gulf of Mexico (GoM) and transport Caribbean Water (CW) into the gulf. In this work, 25 years (1993-2017) of daily satellite data are used to investigate the variability of these physical processes and their effect on chlorophyll a (Chl a) concentrations from 1998 to 2017, including temporal changes, mean differences, and...

  • Stephens BM, Wankel SD, J. Beman M, Rabines AJ, Allen AE, Aluwihare LI.  2019.  Euphotic zone nitrification in the California Current Ecosystem.
    Abstract Summary:

    Nitrification, the microbial conversion of ammonium to nitrite then to nitrate, occurs throughout the oceanic water column, yet the environmental factors influencing the production of nitrate in the euphotic zone (EZ) remain unclear. In this study, the natural abundances of N and O isotopes (δ15N and δ18O, respectively) in nitrate were used in an existing model framework to quantify nitrate contributed by EZ nitrification in the California...

  • Stephens B.M, Wankel S.D, Beman J.M, Rabines A.J, Allen A.E, Aluwihare LI.  2019.  Euphotic zone nitrification in the California Current Ecosystem.
    Abstract Summary:

    Nitrification, the microbial conversion of ammonium to nitrite then to nitrate, occurs throughout the oceanic water column, yet the environmental factors influencing the production of nitrate in the euphotic zone (EZ) remain unclear. In this study, the natural abundances of N and O isotopes (delta N-15 and delta O-18, respectively) in nitrate were used in an existing model framework to quantify nitrate contributed by EZ nitrification in the...

  • Asher E., Hornbrook R.S, Stephens B.B, Kinnison D., Morgan E.J, Keeling RF, Atlas E.L, Schauffler S.M, Tilmes S., Kort E.A et al..  2019.  Novel approaches to improve estimates of short-lived halocarbon emissions during summer from the Southern Ocean using airborne observations. 19:14071-14090.
    Abstract Summary:

    Fluxes of halogenated volatile organic compounds (VOCs) over the Southern Ocean remain poorly understood, and few atmospheric measurements exist to constrain modeled emissions of these compounds. We present observations of CHBr3, CH2Br2, CH3I, CHClBr2, CHBrCl2, and CH3Br during the O-2/N-2 Ratio and CO2 Airborne Southern Ocean (ORCAS) study and the second Atmospheric Tomography mission (ATom-2) in January and February of 2016 and 2017. Good...

  • Meskhidze N., Volker C., Al-Abadleh H.A, Barbeau K., Bressac M., Buck C., Bundy R.M, Croot P., Feng Y., Ito A. et al..  2019.  Perspective on identifying and characterizing the processes controlling iron speciation and residence time at the atmosphere-ocean interface. 217
    Abstract Summary:

    It is well recognized that the atmospheric deposition of iron (Fe) affects ocean productivity, atmospheric CO2 uptake, ecosystem diversity, and overall climate. Despite significant advances in measurement techniques and modeling efforts, discrepancies persist between observations and models that hinder accurate predictions of processes and their global effects. Here, we provide an assessment report on where the current state of knowledge is...

  • Coale T.H, Moosburner M., Horak A., Obornik M., Barbeau K.A, Allen A.E.  2019.  Reduction-dependent siderophore assimilation in a model pennate diatom. 116:23609-23617.
    Abstract Summary:

    Iron uptake by diatoms is a biochemical process with global biogeochemical implications. In large regions of the surface ocean diatoms are both responsible for the majority of primary production and frequently experiencing iron limitation of growth. The strategies used by these phytoplankton to extract iron from seawater constrain carbon flux into higher trophic levels and sequestration into sediments. In this study we use reverse genetic...

  • Morgan E.J, Stephens B.B, Long M.C, Keeling RF, Bent J.D, McKain K., Sweeney C, Hoecker-Martinez M.S, Kort E.A.  2019.  Summertime atmospheric boundary layer gradients of O-2 and CO2 over the Southern Ocean.
    Abstract Summary:

    We present airborne observations of the vertical gradient of atmospheric oxygen (delta(O-2/N-2)) and carbon dioxide (CO2) through the atmospheric boundary layer (BL) over the Drake Passage region of the Southern Ocean, during the O-2/N-2 Ratio and CO2 Airborne Southern Ocean Study, from 15 January to 29 February 2016. Gradients were predominately anticorrelated, with excesses of delta(O-2/N-2) and depletions of CO2 found within the boundary...

  • Johnson A.C, Aarons S.M, Dauphas N., Nie N.X, Zeng H., Helz R.T, Romaniello S.J, Anbar A.D.  2019.  Titanium isotopic fractionation in Kilauea Iki lava lake driven by oxide crystallization. 264:180-190.
    Abstract Summary:

    Recent work has demonstrated that titanium (Ti) isotopes undergo mass-dependent isotope fractionation during magmatic differentiation, leaving evolved silicic melts preferentially enriched in heavy Ti isotopes. Preferential incorporation of light Ti isotopes in crystallizing Fe-Ti oxides is thought to be the mechanism responsible for this fractionation in magmatic rocks. To test this hypothesis, we present Ti isotope measurements of Fe-Ti...

  • Wang J.A, Sulla-Menashe D., Woodcock C.E, Sonnentag O., Keeling RF, Friedl M.A.  2019.  Extensive land cover change across Arctic-Boreal Northwestern North America from disturbance and climate forcing.
    Abstract Summary:

    A multitude of disturbance agents, such as wildfires, land use, and climate-driven expansion of woody shrubs, is transforming the distribution of plant functional types across Arctic-Boreal ecosystems, which has significant implications for interactions and feedbacks between terrestrial ecosystems and climate in the northern high-latitude. However, because the spatial resolution of existing land cover datasets is too coarse, large-scale land...

  • Abstract Summary:

    Caribbean coral reefs have transformed into algal-dominated habitats over the past half-century, but the role of specific anthropogenic drivers is unresolved due to the lack of ecosystem-level data predating human disturbance. To better understand the extent and causes of long-term Caribbean reef declines, we produced a continuous 3000-yr record of the ecosystem state of three reefs in Bocas del Toro, Caribbean Panama. From fossils and...

  • Daniel P, J. MJeremiah, Emily K, Mingxun W, E. WMargot, E. AEric, I. ALihini, C. DPieter.  2019.  Non-targeted metabolomics enables the prioritization and tracking of anthropogenic pollutants in coastal seawater.
    Abstract Summary:

    Anthropogenic pollutants inundate marine ecosystems as human population growth and urbanization rapidly increase along the coast. Our analytical methods are typically aimed at measuring and monitoring a restricted number of compounds. To prioritize coastal anthropogenic impacts in a comprehensive fashion, we applied large-scale non-targeted liquid chromatography tandem mass spectrometry. We integrated an advanced data analysis pipeline that...

  • Sastri A.R, Christian J.R, Achterberg E.P, Atamanchuk D., Buck J.JH, Bresnahan P., Duke P.J, Evans W., Gonski S.F, Johnson B. et al..  2019.  Perspectives on in situ sensors for ocean acidification research. 6
    Abstract Summary:

    As ocean acidification (OA) sensor technology develops and improves, in situ deployment of such sensors is becoming more widespread. However, the scientific value of these data depends on the development and application of best practices for calibration, validation, and quality assurance as well as on further development and optimization of the measurement technologies themselves. Here, we summarize the results of a 2-day workshop on OA...

  • Coale TH, Moosburner M, Horák A, Oborník M, Barbeau KA, Allen AE.  2019.  Reduction-dependent siderophore assimilation in a model pennate diatom.
    Abstract Summary:

    Diatoms can access inorganic iron with remarkable efficiency, but this process is contingent on carbonate ion concentration. As ocean acidification reduces carbonate concentration, inorganic iron uptake may be discouraged in favor of carbonate-independent uptake. We report details of an iron assimilation process that needs no carbonate but requires exogenous compounds produced by cooccurring organisms. We show this process to be critical for...

  • Winski D.A, Fudge T.J, Ferris D.G, Osterberg E.C, Fegyveresi J.M, Cole-Dai J., Thundercloud Z., Cox T.S, Kreutz K.J, Ortman N. et al..  2019.  The SP19 chronology for the South Pole Ice Core - Part 1: volcanic matching and annual layer counting. 15:1793-1808.
    Abstract Summary:

    The South Pole Ice Core (SPICEcore) was drilled in 2014-2016 to provide a detailed multi-proxy archive of paleoclimate conditions in East Antarctica during the Holocene and late Pleistocene. Interpretation of these records requires an accurate depth-age relationship. Here, we present the SPICEcore (SP19) timescale for the age of the ice of SPICEcore. SP19 is synchronized to the WD2014 chronology from theWest Antarctic Ice Sheet Divide (WAIS...

  • Yan Y.Z, Bender M.L, Brook E.J, Clifford H.M, Kemeny P.C, Kurbatov A.V, Mackay S., Mayewski P.A, Ng J., Severinghaus JP et al..  2019.  Two-million-year-old snapshots of atmospheric gases from Antarctic ice. 574:663-+.
    Abstract Summary:

    Over the past eight hundred thousand years, glacial-interglacial cycles oscillated with a period of one hundred thousand years ('100k world'1). Ice core and ocean sediment data have shown that atmospheric carbon dioxide, Antarctic temperature, deep ocean temperature, and global ice volume correlated strongly with each other in the 100k world(2-6). Between about 2.8 and 1.2 million years ago, glacial cycles were smaller in magnitude and...

  • Guedes J.D, Hanson S., Higham C., Higham T., Lertcharnrit T..  2019.  The wet and the dry, the wild and the cultivated: subsistence and risk management in ancient Central Thailand.
    Abstract Summary:

    Increasing the productivity and yield of rice in Central Thailand has been a key focus of international and local government policy. Efforts have centered around producing a second winter season of irrigated rice. However, a series of droughts in the region have led to widespread crop failure. We carry out a re-evaluation of weather station and environmental data and combine this with new information from a key archeological site in Central...

  • Gracia E., Grevemeyer I., Bartolome R., Perea H., Martinez-Loriente S., de la Pena L.G, Villasenor A., Klinger Y., C. Iacono L, Diez S. et al..  2019.  Earthquake crisis unveils the growth of an incipient continental fault system. 10
    Abstract Summary:

    Large continental faults extend for thousands of kilometres to form boundaries between rigid tectonic blocks. These faults are associated with prominent topographic features and can produce large earthquakes. Here we show the first evidence of a major tectonic structure in its initial-stage, the Al-Idrissi Fault System (AIFS), in the Alboran Sea. Combining bathymetric and seismic reflection data, together with seismological analyses of the...

  • Highlighted Publication Map of Juan Fernandez Ridge
    Abstract Summary:

    Mantle plume models have been widely applied to explain the formation of ocean island basalts (OIB), with high-3He/4He in their lavas being explained by sampling of a primitive deep mantle source. The Juan Fernandez Islands have 3He/4He (7.8–18 RA) similar to or higher than in mid-ocean ridge basalts (MORB; 8 ± 1 RA) and have been used to both support and refute the mantle plume hypothesis. Ambiguity regarding the origin of the Juan Fernandez...

  • Sanchez S.C, Amaya D.J, Miller AJ, Xie SP, Charles CD.  2019.  The Pacific Meridional Mode over the last millennium. 53:3547-3560.
    Abstract Summary:

    The Pacific Meridional Mode, a coupled ocean-atmospheric interaction responsible for propagating subtropical anomalies to the tropics via thermodynamic mechanisms, features prominently in discussions of the response of climate variability to climate change. However, it is presently unclear how and why the variance in PMM might change, or even if greenhouse gas forcing might lead to heightened activity. Here, PMM variance over the last...

  • Behar N., Shaar R, Tauxe L, Asefaw H., Ebert Y., Heimann A., Koppers A.AP, Ron H.G.  2019.  Paleomagnetism and paleosecular variations from the Plio-Pleistocene Golan Heights volcanic plateau, Israel. 20:4319-4335.
    Abstract Summary:

    Statistical analysis of geomagnetic paleosecular variation (PSV) and time-averaged field has been largely based on global compilations of paleomagnetic data from lava flows. These show different trends in the averaged inclination anomaly (Delta I) between the two hemispheres, with small positive (<2 degrees) anomalies in midsouthern latitudes and large negative (> -5 degrees) anomalies in midnorthern latitudes. To inspect the large...

  • Chen H., Meshik A.P, Pravdivtseva O.V, Day JMD, Wang K..  2019.  Potassium isotope fractionation during high-temperature evaporation determined from the Trinity nuclear test. 522:84-92.
    Abstract Summary:

    Trinitite materials are the post-detonation glassy residues formed from melting and evaporation of arkosic sands during the first nuclear detonation at the Trinity test site, New Mexico on 16th July, 1945. These trinitites provide useful materials for studying elemental and isotopic behaviors associated with high temperature melting and evaporation that is otherwise difficult to achieve under laboratory conditions. Using a high-precision...

  • Abstract Summary:

    The origin of variations in Os-186/Os-188 ratios amongst mantle-derived basaltic and komatiitic lavas remains controversial, with opposing models arguing for deep core-mantle versus shallow mantle sources. Crustal contamination has generally not been favored due to the low Os contents of such sources, meaning that variations in Os-186/Os-188 would require involvement of extremely high proportions of crustal material. Here we re-examine...

  • Say D., Ganesan A.L, Lunt M.F, Rigby M, O'Doherty S, Harth C, Manning A.J, Krummel PB, Bauguitte S..  2019.  Emissions of halocarbons from India inferred through atmospheric measurements. 19:9865-9885.
    Abstract Summary:

    As the second most populous country and third fastest growing economy, India has emerged as a global economic power. As such, its emissions of greenhouse and ozone-depleting gases are of global significance. However, unlike neighbouring China, the Indian sub-continent is very poorly monitored by atmospheric measurement networks. India's halocarbon emissions, here defined as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs),...

  • Jiang M., Measures C.I, Barbeau K.A, Charette MA, Gille ST, Hatta M., Kahru M, Mitchell B.G, Garabato A.CN, Reiss C et al..  2019.  Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea. 150
    Abstract Summary:

    The Antarctic Peninsula (AP) shelf is an important source of dissolved iron (Fe) to the upper ocean in the southern Scotia Sea, one of the most productive regions of the Southern Ocean. Here we present results from a four-year (2003-2006) numerical simulation using a regional coupled physical-biogeochemical model to assess the Fe sources and transport on the AP shelf and toward the southern Scotia Sea. The model was validated with a suite of...

  • Seltzer A.M, Pavia F.J, Ng J., Severinghaus JP.  2019.  Heavy noble gas isotopes as new constraints on the ventilation of the deep ocean. 46:8926-8932.
    Abstract Summary:

    Past studies of noble gas concentrations in the deep ocean have revealed widespread, several percent undersaturation of Ar, Kr, and Xe. However, the physical explanation for these disequilibria remains unclear. To gain insight into undersaturation set by deep-water formation, we measured heavy noble gas isotope and elemental ratios from the deep North Pacific using a new analytical technique. To our knowledge, these are the first high-...

  • Pernet-Fisher JF, Barry PH, Day JMD, D. Pearson G, Woodland S, Agashev AM, Pokhilenko LN, Pokhilenko NP.  2019.  Heterogeneous kimberlite metasomatism revealed from a combined He-Os isotope study of Siberian megacrystalline dunite xenoliths.
    Abstract Summary:

    The Siberian sub-continental lithospheric mantle (SCLM) is regionally heterogeneous due to the complex modification of ancient cratonic material by various metasomatic fluids and interaction with the Siberian plume at ∼250 Ma. Here, we assess the extent and origin of this heterogeneity by analysis of helium isotopes, rhenium-osmium isotopes, trace-element, and highly siderophile element [HSE: Os, Ir, Ru, Pt, Pd, Re] abundances in a suite of...

  • Cui Y.Y, Vijayan A., Falk M., Hsu Y.K, Yin D.Z, Chen X.M, Zhao Z., Avise J., Chen Y.J, Verhulst K. et al..  2019.  A multiplatform inversion estimation of statewide and regional methane emissions in California during 2014-2016. 53:9636-9645.
    Abstract Summary:

    California methane (CH4) emissions are quantified for three years from two tower networks and one aircraft campaign. We used backward trajectory simulations and a mesoscale Bayesian inverse model, Mbring ratios (VI ' initialized by three inventories, to achieve the emission quantification. Results show total statewide CH4 emissions of 2.05 +/- 0.26 (at 95% confidence) Tg/yr, which is 1.14 to 1.47 times greater than the anthropogenic emission...

  • Highlighted Publication Distribution of putative homologs of T. oceanica GR in representative phytoplankton genomes and the global ocean.
    Diaz JM, Plummer S, Hansel CM, Andeer PF, Saito MA, McIlvin MR.  2019.  NADPH-dependent extracellular superoxide production is vital to photophysiology in the marine diatom Thalassiosira oceanica. 116:16448-16453.
    Abstract Summary:

    Superoxide and other reactive oxygen species (ROS) are commonly regarded as harmful progenitors of biological stress and death, but this view has been changing. Indeed, many phytoplankton actively generate extracellular superoxide under ideal growth conditions for reasons that are mysterious. Results from this study suggest that extracellular superoxide production by the marine diatom Thalassiosira oceanica may promote photosynthetic health...

  • Mühle J, Trudinger C.M, Western L.M, Rigby M, Vollmer M.K, Park S., Manning A.J, Say D., Ganesan A., Steele LP et al..  2019.  Perfluorocyclobutane (PFC-318, c-C4F8) in the global atmosphere. 19:10335-10359.
    Abstract Summary:

    We reconstruct atmospheric abundances of the potent greenhouse gas c-C4F8 (perfluorocyclobutane, perfluorocarbon PFC-318) from measurements of in situ, archived, firn, and aircraft air samples with precisions of ∼1 %–2 % reported on the SIO-14 gravimetric calibration scale. Combined with inverse methods, we found near-zero atmospheric abundances from the early 1900s to the early 1960s, after which they rose sharply, reaching 1.66 ppt (parts...

  • Wan B., Huang R.X, Diaz J.M, Tang Y.Z.  2019.  Polyphosphate adsorption and hydrolysis on aluminum oxides. 53:9542-9552.
    Abstract Summary:

    The geochemical behaviors of phosphate-containing species at mineral-water interfaces are of fundamental importance for controlling phosphorus mobility, fate, and bioavailability. This study investigates the sorption and hydrolysis of polyphosphate (a group of important long-chained phosphate molecules) on aluminum oxides in the presence of divalent metal cations (Ca2+, Cu-,(2+) Mg2+, Mn2+, and Zn2+) at pH 6-8. gamma-Al2O3 with three particle...

  • Menking J.A, Brook E.J, Shackleton S.A, Severinghaus JP, Dyonisius M.N, Petrenko V., McConnell J.R, Rhodes R.H, Bauska T.K, Baggenstos D et al..  2019.  Spatial pattern of accumulation at Taylor Dome during Marine Isotope Stage 4: stratigraphic constraints from Taylor Glacier. 15:1537-1556.
    Abstract Summary:

    New ice cores retrieved from the Taylor Glacier (Antarctica) blue ice area contain ice and air spanning the Marine Isotope Stage (MIS) 5-4 transition, a period of global cooling and ice sheet expansion. We determine chronologies for the ice and air bubbles in the new ice cores by visually matching variations in gas-and ice-phase tracers to pre-existing ice core records. The chronologies reveal an ice age-gas age difference (1 age) approaching...

  • Baggenstos D, Haberli M., Schmitt J., Shackleton S.A, Birner B., Severinghaus JP, Kellerhals T., Fischer H..  2019.  Earth's radiative imbalance from the Last Glacial Maximum to the present. 116:14881-14886.
    Abstract Summary:

    The energy imbalance at the top of the atmosphere determines the temporal evolution of the global climate, and vice versa changes in the climate system can alter the planetary energy fluxes. This interplay is fundamental to our understanding of Earth's heat budget and the climate system. However, even today, the direct measurement of global radiative fluxes is difficult, such that most assessments are based on changes in the total energy...

  • Rahib RR, Udry A, Howarth GH, Gross J, Paquet M, Combs LM, Laczniak DL, Day JMD.  2019.  Mantle source to near-surface emplacement of enriched and intermediate poikilitic shergottites in Mars.
    Abstract Summary:

    Poikilitic shergottites make up >20% of the current martian meteorite collection, with a total of 27 samples. These meteorites are intrusive gabbroic to lherzolitic rocks and represent igneous materials recording important processes in the martian crust. To further constrain petrogenetic relationships amongst enriched and intermediate poikilitic shergottites, we studied a comprehensive suite of poikilitic shergottites — including four...

  • Benway H.M, Lorenzoni L., White A.E, Fiedler B., Levine N.M, Nicholson D.P, DeGrandpre M.D, Sosik H.M, Church M.J, O'Brien T.D et al..  2019.  Ocean time series observations of changing marine ecosystems: An era of integration, synthesis, and societal applications. 6
    Abstract Summary:

    Sustained ocean time series are critical for characterizing marine ecosystem shifts in a time of accelerating, and at times unpredictable, changes. They represent the only means to distinguish between natural and anthropogenic forcings, and are the best tools to explore causal links and implications for human communities that depend on ocean resources. Since the inception of sustained ocean observations, ocean time series have withstood many...

  • Combs LM, Udry A, Howarth GH, Righter M, Lapen TJ, Gross J, Ross DK, Rahib RR, Day JMD.  2019.   Petrology of the enriched poikilitic shergottite Northwest Africa 10169: Insight into the martian interior.
    Abstract Summary:

    The martian meteorite Northwest Africa (NWA) 10169 is classified as a member of the geochemically enriched poikilitic shergottites, based on mineral composition, Lu-Hf and Sm-Nd isotope systematics, and rare earth element (REE) concentrations. Similar to other enriched and intermediate poikilitic shergottites, NWA 10169 is a cumulate rock that exhibits a bimodal texture characterized by large pyroxene oikocrysts (poikilitic texture)...

  • Abstract Summary:

    Polyphosphates and phosphomonoesters are dominant components of marine dissolved organic phosphorus (DOP). Collectively, DOP represents an important nutritional phosphorus (P) source for phytoplankton growth in the ocean, but the contribution of specific DOP sources to microbial community P demand is not fully understood. In a prior study, it was reported that inorganic polyphosphate was not bioavailable to the model diatoms Thalassiosira...

  • Abstract Summary:

    In this study, we investigated the geomorphic and incision history for an similar to 5 km reach of the northern Rio Grande gorge in New Mexico using field and LiDAR-based geomorphic mapping and cosmogenic 3 He surface exposure dating. This wide (>1.5 km) and deep (similar to 240 m) section of the gorge exhibits Toreva blocks, incoherent landslides, rock falls, and slumps developed within Servilleta Basalts and intercalated weakly...

  • House B.M, Bebout G.E, Hilton DR.  2019.  Carbon cycling at the Sunda margin, Indonesia: A regional study with global implications. Geology. 47:483-486.
    Abstract Summary:

    The subduction and release of carbon at convergent margins is a primary mechanism by which tectonic processes influence atmospheric pCO(2), but the balance between the amount of carbon subducting and the CO2 flux from volcanic arcs remains poorly constrained. Estimating CO2 recycling efficiency in complex regions like the Sunda margin, Indonesia, is particularly difficult due to the lateral variability in sediment thickness, composition, and...

  • Stukel M.R, Kelly T.B, Aluwihare LI, Barbeau K.A, Goericke R, Krause J.W, Landry MR, Ohman MD.  2019.  The Carbon:(234)Thorium ratios of sinking particles in the California current ecosystem 1: relationships with plankton ecosystem dynamics. Marine Chemistry. 212:1-15.
    Abstract Summary:

    We investigated variability in the C:Th-234 ratio of sinking particles and its relationship to changing water column characteristics and plankton ecological dynamics during 29 Lagrangian experiments conducted on six cruises of the California Current Ecosystem Long-Term Ecological Research (CCE-LTER) Program. C:Th-234 ratios of sinking particles collected by a surface-tethered sediment trap ((CThST)-Th-:234) varied from 2.3 to 20.5 mu mol C...

  • Andersson AJ, Venn A.A, Pendleton L., Brathwaite A., Camp E.F, Cooley S., Gledhill D., Koch M., Maliki S., Manfrino C..  2019.  Ecological and socioeconomic strategies to sustain Caribbean coral reefs in a high-CO2 world. 29
    Abstract Summary:

    The Caribbean and Western Atlantic region hosts one of the world's most diverse geopolitical regions and a unique marine biota distinct from tropical seas in the Pacific and Indian Oceans. While this region varies in human population density, GDP and wealth, coral reefs, and their associated ecosystem services, are central to people's livelihoods. Unfortunately, the region's reefs have experienced extensive degradation over the last several...

  • Eddebbar Y.A, Rodgers K.B, Long M.C, Subramanian AC, Xie SP, Keeling RF.  2019.  El Nino-like physical and biogeochemical ocean response to tropical eruptions. Journal of Climate. 32:2627-2649.
    Abstract Summary:

    The oceanic response to recent tropical eruptions is examined in Large Ensemble (LE) experiments from two fully coupled global climate models, the Community Earth System Model (CESM) and the Geophysical Fluid Dynamics Laboratory Earth System Model (ESM2M), each forced by a distinct volcanic forcing dataset. Following the simulated eruptions of Agung, El Chichon, and Pinatubo, the ocean loses heat and gains oxygen and carbon, in general...

  • Young A.P, Carilli JE.  2019.  Global distribution of coastal cliffs. 44:1309-1316.
    Abstract Summary:

    Previous studies have estimated that coastal cliffs exist on about 80% of the global shoreline, but have not been validated on a global scale. This study uses two approaches to capture information on the worldwide existence and erosion of coastal cliffs: a detailed literature survey and imagery search, and a GIS-based global mapping analysis. The literature and imagery review show coastal cliffs exist in 93% of the combined recognized...

  • Rigby M, Park S., Saito T., Western L.M, Redington A.L, Fang X., Henne S., Manning A.J, Prinn RG, Dutton GS et al..  2019.  Increase in CFC-11 emissions from eastern China based on atmospheric observations. 569:546-+.
    Abstract Summary:

    The recovery of the stratospheric ozone layer relies on the continued decline in the atmospheric concentrations of ozone-depleting gases such as chlorofluorocarbons(1). The atmospheric concentration of trichlorofluoromethane (CFC-11), the second-most abundant chlorofluorocarbon, has declined substantially since the mid-1990s(2). A recently reported slowdown in the decline of the atmospheric concentration of CFC-11 after 2012, however,...

  • Abstract Summary:

    Dissolved noble gases are ideal conservative tracers of physical processes in the Earth system due to their chemical and biological inertness. Although bulk concentrations of dissolved Ar, Kr, and Xe are commonly measured to constrain physical models of atmosphere, ocean, and terrestrial hydrosphere processes, stable isotope ratios of these gases (e.g. Xe-136/Xe-129) are seldom used because of low signal-to-noise ratios. Here we present the...

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