Recent Publications

Weekly Highlighted Publication

Synthesis of ocean observations using data assimilation for operational, real-time and reanalysis systems: A more complete picture of the state of the ocean

Impact:
There are many exciting new directions and future opportunities for discovery in ocean DA [data assimilation]. Perhaps the most immediate development borrowed from NWP [numerical weather prediction] is the merger of ensemble and variational methods that draws on the strengths of both approaches. Specifically, the static estimate of P used in Var and the flow-dependent estimate of P from an ensemble are combined to form a “hybrid” P that is employed in a DA system (e.g., Lorenc et al., 2015). In this way, the dynamical interpolation properties of the adjoint and the flow-dependent covariance information from the ensemble are simultaneously exploited. Experience in NWP suggests that the performance of hybrid approaches can improve the performance of an analysis-forecast system (Lorenc and Jardak, 2018), and efforts are underway to develop similar procedures for global (e.g., Penny et al., 2015; Frolov et al., 2016; Storto et al., 2018) and regional (e.g., Oddo et al., 2016) ocean prediction systems.

Search Recent Publications

  • Pham H.T, Sarkar S..  2018.  Ageostrophic secondary circulation at a submesoscale front and the formation of gravity currents. Journal of Physical Oceanography. 48:2507-2529.
    Abstract Summary:

    Large-eddy simulations are performed to investigate the development of the ageostrophic secondary circulation (ASC) and associated transport in a submesoscale front. Based on the observations in the northern Bay of Bengal and in the Pacific cold tongue, the model front has a large cross-front density difference that is partially compensated with lateral temperature and salinity gradients. Vertical stratification is varied in different cases...

  • Schulz C., Schneider J., Holanda B.A, Appel O., Costa A., de Sa S.S, Dreiling V., Futterer D., Jurkat-Witschas T., Klimach T. et al..  2018.  Aircraft-based observations of isoprene-epoxydiol-derived secondary organic aerosol (IEPOX-SOA) in the tropical upper troposphere over the Amazon region. Atmospheric Chemistry and Physics. 18:14979-15001.
    Abstract Summary:

    During the ACRIDICON-CHUVA field project (September-October 2014; based in Manaus, Brazil) aircraft-based in situ measurements of aerosol chemical composition were conducted in the tropical troposphere over the Amazon using the High Altitude and Long Range Research Aircraft (HALO), covering altitudes from the boundary layer (BL) height up to 14.4 km. The submicron non-refractory aerosol was characterized by flash-vaporization/electron impact-...

  • Ducasse T., Gourgiotis A., Pringle E., Moynier F., Frugier P., Jollivet P., Gin S..  2018.  Alteration of synthetic basaltic glass in silica saturated conditions: Analogy with nuclear glass. Applied Geochemistry. 97:19-31.
    Abstract Summary:

    This study investigates the analogy between basaltic and borosilicate glasses of nuclear interest, by focusing on mechanisms controlling glass dissolution under silica saturation conditions. These conditions are representative of a non-or slowly renewed contacting solution, favouring the formation of a potentially passivating silica rich gel layer and secondary phases. Laboratory batch experiments were performed with synthetic basaltic glass...

  • Zaba K, Rudnick DL, Cornuelle B, Gopalakrishnan G, Mazloff M.  2018.  Annual and interannual variability in the California Current System: Comparison of an ocean state estimate with a network of underwater gliders. Journal of Physical Oceanography.
    Abstract Summary:

    A data-constrained state estimate of the southern California Current System (CCS) is presented and compared against withheld CalCOFI data and assimilated glider data over the years 2007-2017. The objective of this comparison is to assess the ability of the California State Estimate (CASE) to reproduce the key physical features of the CCS mean state, annual cycles, and interannual variability along the three sections of the California...

  • Abstract Summary:

    Atmospheric rivers (ARs)-narrow corridors of high atmospheric water vapor transport-occur globally and are associated with flooding and maintenance of the water supply. Therefore, it is important to improve forecasts of AR occurrence and characteristics. Although prior work has examined the skill of numerical weather prediction (NWP) models in forecasting atmospheric rivers, these studies only cover several years of reforecasts from a handful...

  • Kelly T.B, Goericke R, Kahru M, Song H., Stukel M.R.  2018.  CCE II: Spatial and interannual variability in export efficiency and the biological pump in an eastern boundary current upwelling system with substantial lateral advection. Deep-Sea Research Part I-Oceanographic Research Papers. 140:14-25.
    Abstract Summary:
  • Highlighted Publication Chart superimposed on CCE-LTER photo of euphausiid
    Lilly L.E, Ohman MD.  2018.  CCE IV: El Nino-related zooplankton variability in the southern California Current System. Deep-Sea Research Part I-Oceanographic Research Papers. 140:36-51.
    Abstract Summary:

    We analyzed seven El Nino events (springs 1958-59, 1983, 1992-93, 1998, 2003, 2010, and 2016) and the 2014-15 Pacific Warm Anomaly (spring 2015) for their impacts on zooplankton biomass and community composition in the southern sector of the California Current System (CCS). Although total mesozooplankton carbon biomass was only modestly affected during El Nino springs, community composition changed substantially. Carbon biomass of five major...

  • Morrow R.M, Ohman MD, Goericke R, Kelly T.B, Stephens B.M, Stukel M.R.  2018.  CCE V: Primary production, mesozooplankton grazing, and the biological pump in the California Current Ecosystem: Variability and response to El Nino. Deep-Sea Research Part I-Oceanographic Research Papers. 140:52-62.
    Abstract Summary:

    Predicting marine carbon sequestration in a changing climate requires mechanistic understanding of the processes controlling sinking particle flux under different climatic conditions. The recent occurrence of a warm anomaly (2014-2015) followed by an El Nino (2015-2016) in the southern sector of the California Current System presented an opportunity to analyze changes in the biological carbon pump in response to altered climate forcing. We...

  • Abstract Summary:

    Oceanic fronts are sites of increased vertical exchange that are often associated with increased primary productivity, downward flux of organic carbon, and aggregation of plankton and higher trophic levels. Given the influence of fronts on the functioning of marine ecosystems, an improved understanding of the spatial and temporal variability of frontal activity is desirable. Here, we document changes in the frequency of sea-surface fronts and...

  • Abstract Summary:

    We hypothesized that copepod egg production rates would be suppressed relative to their normal functional relationships with food availability during the NE Pacific warm anomalies of 2014-2015 and the El Nino event of 2015-2016. We also hypothesized that copepods would show increased rates of egg production and recruitment in association with ocean fronts. Three species of copepods (Calanus pacificus, Metridia pacifica, and Eucalanus...

  • Whalen K.E, Kirby C., Nicholson R.M, O'Reilly M., Moore BS, Harvey E.L.  2018.  The chemical cue tetrabromopyrrole induces rapid cellular stress and mortality in phytoplankton. Scientific Reports. 8
    Abstract Summary:

    Eukaryotic phytoplankton contribute to the flow of elements through marine food webs, biogeochemical cycles, and Earth's climate. Therefore, how phytoplankton die is a critical determinate of the flow and fate of nutrients. While heterotroph grazing and viral infection contribute to phytoplankton mortality, recent evidence suggests that bacteria-derived cues also control phytoplankton lysis. Here, we report exposure to nanomolar...

  • Highlighted Publication Silhouette of grain plants in the shape of a mountain range
    Guedes Jd’Alpoim, R. Bocinsky K.  2018.  Climate change stimulated agricultural innovation and exchange across Asia. Science Advances. 4
    Abstract Summary:

    Ancient farmers experienced climate change at the local level through variations in the yields of their staple crops. However, archaeologists have had difficulty in determining where, when, and how changes in climate affected ancient farmers. We model how several key transitions in temperature affected the productivity of six grain crops across Eurasia. Cooling events between 3750 and 3000 cal. BP lead humans in parts of the Tibetan Plateau...

  • Le C.F, Zhou X.Y, Hu C.M, Lee Z.P, Li L., Stramski D.  2018.  A color-index-based empirical algorithm for determining particulate organic carbon concentration in the ocean from satellite observations. Journal of Geophysical Research-Oceans. 123:7407-7419.
    Abstract Summary:

    An empirical algorithm for estimating particulate organic carbon (POC) concentration in the surface ocean from satellite observations is formulated and validated using in situ POC data and remote-sensing reflectance (R-rs) data obtained from match-up satellite ocean color measurements. The algorithm builds upon the band-difference algorithm concept, which was originally developed for estimating chlorophyll-a concentration in clear waters....

  • Highlighted Publication
    Sinnett G., Feddersen F.  2018.  The competing effects of breaking waves on surfzone heat fluxes: Albedo versus wave heating. Journal of Geophysical Research-Oceans. 123:7172-7184.
    Abstract Summary:

    Depth-limited wave breaking modifies the heat flux in the surfzone relative to the inner-shelf (where waves are not breaking). Surfzone wave breaking generates heat through viscous dissipation (wave heating), but also increases surface foam coverage and albedo, thereby reducing solar heating, that is, cooling relative to the inner-shelf. These two competing breaking wave effects are quantified with a yearlong experiment at the Scripps...

  • Jones C.S, Cessi P.  2018.  Components of upper-ocean salt transport by the gyres and the meridional overturning circulation. Journal of Physical Oceanography. 48:2445-2456.
    Abstract Summary:

    The salt transport by the wind-driven gyres and the meridional overturning circulation (MOC) is studied in an idealized-geometry primitive equation ocean model. Two narrow continents, running along meridians, divide the model domain into two basins of different widths connected by a re-entrant channel south of 52.5 degrees S. One of the continents, representing the Americas, is longer than the other, representing Europe/Africa. Two different...

  • Ballance LT.  2018.  Contributions of photographs to cetacean science. Aquatic Mammals. 44:668-682.
    Abstract Summary:

    Over four decades ago, a short paper demonstrated how photographs of free-swimming dolphins could be used to reveal scientific information about cetaceans. That paper, and a few others published during the same time period, illustrated a research technique that has become foundational in the field of marine mammalogy and resulted in a cascade of science. Photographs can be used to identify individuals, providing insights into movements,...

  • Abstract Summary:

    The Eocene volcanic rocks from the Kahrizak Mountains in north-central Iran are part of the Urumieh-Dokhtar magmatic arc, which runs parallel to the Main Zagros Thrust segment of the Neo-Tethys suture. These volcanic rocks, similar to those from eastern Pontides and northern Anatolia, Turkey, were mainly produced during the Eocene magmatic flare-up associated with the Arabia-Eurasia convergence. The rock suite includes basalt, trachyandesite/...

  • Sahakian V., Baltay A., Hanks T., Buehler J., Vernon F, Kilb D., Abrahamson N..  2018.  Decomposing leftovers: Event, path, and site residuals for a small-magnitude Anza Region GMPE. Bulletin of the Seismological Society of America. 108:2478-2492.
    Abstract Summary:

    Ground-motion prediction equations (GMPEs) are critical elements of probabilistic seismic hazard analysis (PSHA), as well as for other applications of ground motions. To isolate the path component for the purpose of building nonergodic GMPEs, we compute a regional GMPE using a large dataset of peak ground accelerations (PGAs) from small-magnitude earthquakes (0.5 <= M <= 4.5 with > 10; 000 events, yielding similar to 120; 000...

  • Chin E.J.  2018.  Deep crustal cumulates reflect patterns of continental rift volcanism beneath Tanzania. Contributions to Mineralogy and Petrology. 173
    Abstract Summary:

    Magmatism on Earth is most abundantly expressed by surface volcanic activity, but all volcanism has roots deep in the crust, lithosphere, and mantle. Intraplate magmatism, in particular, has remained enigmatic as the plate tectonic paradigm cannot easily explain phenomena such as large flood basalt provinces and lithospheric rupture within continental interiors. Here, I explore the role of deep crustal magmatic processes and their connection...

  • Su W.Y, Liang L.S, Doelling D.R, Minnis P, Duda D.P, Khlopenkov K., Thieman M.M, Loeb N.G, Kato S., Valero F.PJ et al..  2018.  Determining the shortwave radiative flux from Earth Polychromatic Imaging Camera. Journal of Geophysical Research-Atmospheres. 123:11479-11491.
    Abstract Summary:

    The Earth Polychromatic Imaging Camera (EPIC) onboard Deep Space Climate Observatory provides 10 narrowband spectral images of the sunlit side of the Earth. The blue (443 nm), green (551 nm), and red (680 nm) channels are used to derive EPIC broadband radiances based upon narrowband-to-broadband regressions developed using collocated MODIS equivalent channels and Clouds and the Earth's Radiant Energy System (CERES) broadband measurements. The...

  • Suanda S.H, Feddersen F, Spydell M.S, Kumar N..  2018.  The effect of barotropic and baroclinic tides on three-dimensional coastal dispersion. Geophysical Research Letters. 45:11235-11246.
    Abstract Summary:

    The effects of barotropic and baroclinic tides on three-dimensional (3-D) coastal dispersion are examined with realistic, 200-m horizontal resolution simulations of the Central Californian continental shelf during upwelling. Over multiple tidal cycles, the horizontal relative dispersion and vertical dispersion of 3-D drifters are similar between simulations with no tides and with barotropic tides. In contrast, baroclinic tides, which...

  • Cessi P.  2018.  The effect of Northern Hemisphere winds on the meridional overturning circulation and stratification. Journal of Physical Oceanography. 48:2495-2506.
    Abstract Summary:

    The current paradigm for the meridional overturning cell and the associated middepth stratification is that the wind stress in the subpolar region of the Southern Ocean drives a northward Ekman flow, which, together with the global diapycnal mixing across the lower boundary of the middepth waters, feeds the upper branch of the interhemispheric overturning. The resulting mass transport proceeds to the Northern Hemisphere of the North Atlantic...

  • Pusok A.E, Kaus B.JP, Popov A.A.  2018.  The effect of rheological approximations in 3-D numerical simulations of subduction and collision. Tectonophysics. 746:296-311.
    Abstract Summary:

    Subduction and collision zones evolve differently from one another due to different rheological properties, different amounts of regional isostatic compensation, and the different mechanisms by which forces are applied to the convergent plates. The rheology of mantle and lithosphere is known to have the largest influence on the dynamics of subduction and continental collision. However, previous 3-D geodynamic models of subduction/ collision...

  • Zhang J.J, Moore BS, Tang X.Y.  2018.  Engineering Salinispora tropica for heterologous expression of natural product biosynthetic gene clusters. Applied Microbiology and Biotechnology. 102:8437-8446.
    Abstract Summary:

    The marine actinomycete genus Salinispora is a remarkably prolific source of structurally diverse and biologically active secondary metabolites. Herein, we select the model organism Salinispora tropica CNB-440 for development as a heterologous host for the expression of biosynthetic gene clusters (BGCs) to complement well-established Streptomyces host strains. In order to create an integratable host with a clean background of secondary...

  • Salmon R.  2018.  Entropy budget and coherent structures associated with a spectral closure model of turbulence. Journal of Fluid Mechanics. 857:806-822.
    Abstract Summary:

    We 'derive' the eddy-damped quasi-normal Markovian model (EDQNM) by a method that replaces the exact equation for the Fourier phases with a solvable stochastic model, and we analyse the entropy budget of the EDQNM. We show that a quantity that appears in the probability distribution of the phases may be interpreted as the rate at which entropy is transferred from the Fourier phases to the Fourier amplitudes. In this interpretation, the...

  • Venturelli R.A, Rathburn A.E, Burkett A.M, Ziebis W..  2018.  Epifaunal foraminifera in an infaunal world: Insights into the influence of heterogeneity on the benthic ecology of oxygen-poor, deep-sea habitats. Frontiers in Marine Science. 5
    Abstract Summary:

    A reduction in dissolved oxygen availability in marine habitats is among the predicted consequences of increasing global temperatures. An understanding of past oxygenation is critical for predictions of future changes in the extent and distribution of oxygen minimum zones (OMZs). Benthic foraminifera have been used to assess changes in paleo-oxygenation, and according to prevailing thought, oxygen-poor marine benthic habitats are dominated by...

  • Konovalov I.B, Lvova D.A, Beekmann M., Jethva H., Mikhailov E.F, Paris J.D, Belan B.D, Kozlov V.S, Ciais P., Andreae M.O.  2018.  Estimation of black carbon emissions from Siberian fires using satellite observations of absorption and extinction optical depths. Atmospheric Chemistry and Physics. 18:14889-14924.
    Abstract Summary:

    Black carbon (BC) emissions from open biomass burning (BB) are known to have a considerable impact on the radiative budget of the atmosphere at both global and regional scales; however, these emissions are poorly constrained in models by atmospheric observations, especially in remote regions. Here, we investigate the feasibility of constraining BC emissions from BB using satellite observations of the aerosol absorption optical depth (AAOD)...

  • Koweek D.A, Zimmerman R.C, Hewett K.M, Gaylord B., Giddings S.N, Nickols K.J, Ruesink J.L, Stachowicz J.J, Takeshita Y, Caldeira K..  2018.  Expected limits on the ocean acidification buffering potential of a temperate seagrass meadow. Ecological Applications. 28:1694-1714.
    Abstract Summary:

    Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global-scale solution to ocean acidification remains rapid reduction in CO2 emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass meadows has been considered as a possible...

  • Deike L., Melville W.K.  2018.  Gas transfer by breaking waves. Geophysical Research Letters. 45:10482-10492.
    Abstract Summary:

    The transfer of gases at the ocean-atmosphere interface impacts weather and climate from local to global scales, with carbon dioxide (CO2) key to marine life and ecosystems, and dimethyl sulfide affecting aerosols and atmospheric processes. However, the bubble-mediated gas transfer, associated with breaking waves has remained poorly constrained. We present a spectral framework for bubble-mediated gas transfer, computed from a mechanistic...

  • Hodge L.EW, Baumann-Pickering S., Hildebrand JA, Bell J.T, Cummings E.W, Foley H.J, McAlarney R.J, McLellan W.A, Pabst D.A, Swaim Z.T et al..  2018.  Heard but not seen: Occurrence of Kogia spp. along the western North Atlantic shelf break. Marine Mammal Science. 34:1141-1153.
    Abstract Summary:
  • Abstract Summary:

    This study investigates the impact of dynamical downscaling on historical and future projections of winter extratropical cyclones over eastern North America and the western Atlantic Ocean. Six-hourly output from two global circulation models (GCMs), CCSM4 and GFDL-ESM2M, from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are used to create the initial and boundary conditions for 20 historical (1986-2005) and 20 future (2080-99...

  • Diaz-Isaac L.I, Lauvaux T., Davis K.J.  2018.  Impact of physical parameterizations and initial conditions on simulated atmospheric transport and CO2 mole fractions in the US Midwest. Atmospheric Chemistry and Physics. 18:14813-14835.
    Abstract Summary:

    Atmospheric transport model errors are one of the main contributors to the uncertainty affecting CO2 inverse flux estimates. In this study, we determine the leading causes of transport errors over the US upper Midwest with a large set of simulations generated with the Weather Research and Forecasting (WRF) mesoscale model. The various WRF simulations are performed using different meteorological driver datasets and physical parameterizations...

  • Viale M., Valenzuela R., Garreaud R.D, Ralph FM.  2018.  Impacts of atmospheric rivers on precipitation in southern South America. Journal of Hydrometeorology. 19:1671-1687.
    Abstract Summary:

    This study quantifies the impact of atmospheric rivers (ARs) on precipitation in southern South America. An AR detection algorithm was developed based on integrated water vapor transport (IVT) from 6-hourly CFSR reanalysis data over a 16-yr period (2001-16). AR landfalls were linked to precipitation using a comprehensive observing network that spanned large variations in terrain along and across the Andes from 27 degrees to 55 degrees S,...

  • Sumargo E., Cayan DR.  2018.  The influence of cloudiness on hydrologic fluctuations in the mountains of the western United States. Water Resources Research. 54:8478-8499.
    Abstract Summary:

    This study investigates snowmelt and streamflow responses to cloudiness variability across the mountainous parts of the western United States. Twenty years (1996-2015) of Geostationary Operational Environmental Satellite-derived cloud cover indices (CC) with 4-km spatial and daily temporal resolutions are used as a proxy for cloudiness. The primary driver of nonseasonal fluctuations in daily mean solar insolation is the fluctuating cloudiness...

  • Cruz-Gomez R.C, Vazquez H.J.  2018.  Interaction of North Brazil Current rings with the Lesser Antilles Arc and Barbados Island: laboratory experiments and observations. Environmental Fluid Mechanics. 18:1203-1226.
    Abstract Summary:

    The interaction of North Brazil Current (NBC) rings with the Lesser Antilles Arc (LAA) and the Barbados Island (BI) is addressed by experimental modeling and observations. Our results compare well with previous experimental results and numerical simulations. Several sizes, intensities and two different vorticity profiles (non-isolated and initially isolated vortices) were tested. Three regimes were found namely: (1) the vortex surrounds the...

  • Drenkard E.J, Cohen A.L, McCorkle D.C, de Putron S.J, Starczak V.R, Repeta D.J.  2018.  Juveniles of the Atlantic coral, Favia fragum (Esper, 1797) do not invest energy to maintain calcification under ocean acidification. Journal of Experimental Marine Biology and Ecology. 507:61-69.
    Abstract Summary:

    Ocean acidification (OA) threatens coral reef ecosystems by slowing calcification and enhancing dissolution of calcifying organisms and sediments. Nevertheless, multiple factors have been shown to modulate OA's impact on calcification, including the nutritional status of the coral host. In three separate experiments, we exposed juveniles of the Atlantic golf ball coral, Favia fragum, to elevated CO2 and varied nutritional (light or feeding)...

  • Sasagawa G.S, Zumberge M.A, Cook M.J.  2018.  Laboratory simulation and measurement of instrument drift in quartz-resonant pressure gauges. 6:57334-57340.
    Abstract Summary:

    Seafloor pressure gauges are used in marine geodesy to detect vertical displacement of the seafloor. Instrumental gauge drift is often larger than the sought after geophysical and oceanographic signals. We performed a 12 month laboratory test on two new methods that aim to reduce pressure gauge drift in Paroscientific Digiquartz and other pressure transducers. In one method, a reference quartz oscillator (RQO) is installed adjacent to but...

  • Duke E.M, Harada A.E, Burton RS.  2018.  Large interannual variation in spawning in San Diego marine protected areas captured by molecular identification of fish eggs. Marine Ecology Progress Series. 604:199-210.
    Abstract Summary:

    Long-term monitoring of marine ecosystems is critical to assessing how global processes such as natural environmental variation and climate change affect marine populations. Ichthyoplankton surveys provide one approach to such monitoring. We conducted weekly fish egg collections off the Scripps Institution of Oceanography (SIO) Pier (La Jolla, CA, USA) for 3 yr (2014 to 2017) and added a second sampling site near the La Jolla kelp forest for...

  • Huang X.M, Hu C.Q, Huang X., Chu Y., Tseng Y.H, Zhang GJ, Lin Y.L.  2018.  A long-term tropical mesoscale convective systems dataset based on a novel objective automatic tracking algorithm. Climate Dynamics. 51:3145-3159.
    Abstract Summary:

    Mesoscale convective systems (MCSs) are important components of tropical weather systems and the climate system. Long-term data of MCS are of great significance in weather and climate research. Using long-term (1985-2008) global satellite infrared (IR) data, we developed a novel objective automatic tracking algorithm, which combines a Kalman filter (KF) with the conventional area-overlapping method, to generate a comprehensive MCS dataset....

  • Watanabe M., Kamae Y., Shiogama H., DeAngelis A.M, Suzuki K..  2018.  Low clouds link equilibrium climate sensitivity to hydrological sensitivity. Nature Climate Change. 8:901-+.
    Abstract Summary:

    Equilibrium climate sensitivity (ECS) and hydrological sensitivity describe the global mean surface temperature and precipitation responses to a doubling of atmospheric CO2. Despite their connection via the Earth's energy budget, the physical linkage between these two metrics remains controversial. Here, using a global climate model with a perturbed mean hydrological cycle, we show that ECS and hydrological sensitivity per unit warming are...

  • Huang K.J, Teng F.Z, Plank T., Staudigel H., Hu Y., Bao Z.Y.  2018.  Magnesium isotopic composition of altered oceanic crust and the global Mg cycle. Geochimica Et Cosmochimica Acta. 238:357-373.
    Abstract Summary:

    To investigate the behavior of Mg isotopes during low-temperature alteration of oceanic crust and to further under- stand its role in the global Mg cycle, we measured the Mg isotopic compositions (Mg-25/Mg-24 and Mg-26/Mg-24) of a set of samples of altered oceanic crust (AOC) recovered from the Ocean Drilling Program Hole 801C, the reference site for old crust (similar to 170 Ma) subducting in the Pacific. The measured delta Mg-26 values...

  • Highlighted Publication Pillow lava photo by Hubert Staudigel
    Castillo P.R, MacIsaac C., Perry S., Veizer J..  2018.  Marine carbonates in the mantle source of oceanic basalts: Pb isotopic constraints. Scientific Reports. 8
    Abstract Summary:

    For almost fifty years, geochemists have been interpreting the clues from Pb isotopic ratios concerning mantle composition and evolution separately. The Pb isotopes of ocean island basalts (OIB) indicate that their mantle source is heterogeneous, most likely due to the presence of end-components derived from recycled crust and sediment. Some OIB have unusually high Pb-206/Pb-204 coming from one of the end-components with a long time-...

  • Constable S, Kowalczyk P., Bloomer S..  2018.  Measuring marine self-potential using an autonomous underwater vehicle. Geophysical Journal International. 215:49-60.
    Abstract Summary:

    The marine self-potential (SP) method is used to explore for hydrothermal venting and associated seafloor mineralization. Measurements are commonly made in deep water using instruments towed close to the seafloor, which requires dedicated ship time, is limited to slow speeds, and is subject to navigation errors. Instead, we mounted a three-axis electric field receiver on an autonomous underwater vehicle (AUV), and tested the method with data...

  • Fine E.C, MacKinnon JA, Alford MH, Mickett J.B.  2018.  Microstructure observations of turbulent heat fluxes in a warm-core Canada Basin eddy. Journal of Physical Oceanography. 48:2397-2418.
    Abstract Summary:

    An intrahalocline eddy was observed on the Chukchi slope in September of 2015 using both towed CTD and microstructure temperature and shear sections. The core of the eddy was 6 degrees C, significantly warmer than the surrounding -1 degrees C water and far exceeding typical temperatures of warm-core Arctic eddies. Microstructure sections indicated that outside of the eddy the rate of dissipation of turbulent kinetic energy epsilon was quite...

  • Chang C., Smith SGL.  2018.  The motion of a buoyant vortex filament. Journal of Fluid Mechanics. 857
    Abstract Summary:

    We investigate the motion of a thin vortex filament in the presence of buoyancy. The asymptotic model of Moore & Saffman (Phil. Trans. R. Soc. bond. A, vol. 272, 1972, pp. 403-429) is extended to take account of buoyancy forces in the force balance on a vortex element. The motion of a buoyant vortex is given by the transverse component of force balance, while the tangential component governs the dynamics of the structure in the core. We...

  • Chaput J., Aster R.C, McGrath D., Baker M., Anthony R.E, Gerstoft P, Bromirski P., Nyblade A., Stephen R.A, Wiens D.A et al..  2018.  Near-surface environmentally forced changes in the Ross Ice Shelf observed with ambient seismic noise. Geophysical Research Letters. 45:11187-11196.
    Abstract Summary:

    Continuous seismic observations across the Ross Ice Shelf reveal ubiquitous ambient resonances at frequencies >5 Hz. These firn-trapped surface wave signals arise through wind and snow bedform interactions coupled with very low velocity structures. Progressive and long-term spectral changes are associated with surface snow redistribution by wind and with a January 2016 regional melt event. Modeling demonstrates high spectral sensitivity to...

  • Nevison C., Munro D., Lovenduski N., Cassar N., Keeling R., Krummel P., Tjiputra J..  2018.  Net community production in the Southern Ocean: Insights from comparing atmospheric potential oxygen to satellite ocean color algorithms and ocean models. Geophysical Research Letters. 45:10549-10559.
    Abstract Summary:

    The contribution of oceanic net community production (NCP) to the observed seasonal cycle in atmospheric potential oxygen (APO) is estimated at Cape Grim, Tasmania. The resulting APO(NCP) signal is compared to satellite and ocean model-based estimates of POC export and NCP across the Southern Ocean. The satellite products underestimate the amplitude of the observed APONCP seasonal cycle by more than a factor of 2. Ocean models suggest two...

  • Abstract Summary:

    Lamellibrachia Webb, 1969 has eight currently recognized species reported from chemosynthetic environments in the Pacific, Atlantic, and Mediterranean. Of these, Lamellibrachia barhami Webb, 1969 has been reported in the eastern Pacific from Canada to Costa Rica. In this study, phylogenetic analyses of Lamellibrachia tubeworms sampled from the Costa Rica margin confirm the large geographic range of L. barhami and reveal a new Lamellibrachia...

  • Martin J.W, Wall A.R, Shank T., Cha H., Seid C.A, Rouse GW.  2018.  A new species of Alvinocaris (Crustacea: Decapoda: Caridea: Alvinocarididae) from Costa Rican methane seeps. Zootaxa. 4504:418-430.
    Abstract Summary:

    A new caridean shrimp, Alvinocaris costaricensis, is described from methane seeps in the eastern Pacific off Costa Rica. The new species is the 16th described species of the genus, and by molecular analysis appears closest to Alvinocaris komaii from the Lau Basin, southwestern Pacific, but shares certain morphological characters with A. lusca from the Galapagos Rift and A. muricola from the West Florida Escarpment, as well as with A. kexueae...

  • Johnson G.C, Pezner A.K, Sura S.A, Fong P..  2018.  Nutrients and herbivory, but not sediments, have opposite and independent effects on the tropical macroalga, Padina boryana. Journal of Experimental Marine Biology and Ecology. 507:17-22.
    Abstract Summary:

    Multiple anthropogenic stressors including overfishing, nutrient loading, and sediments are major drivers that may support the proliferation of macroalgae on coral reefs; however, few studies have investigated all three simultaneously. We evaluated the effects of all three stressors (nutrient enrichment, small and large sediment grain sizes, and herbivory) on biomass accumulation of the dominant coral reef macroalga Padina boryana in a...

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