Recent Publications

  • Suanda SH, Barth JA.  2015.  Semidiurnal baroclinic tides on the central Oregon inner shelf. Journal of Physical Oceanography.
    Abstract Summary:

    Semidiurnal velocity and density oscillations are examined over the mid and inner continental shelf near Heceta Bank on the Oregon coast. Measurements from two long-term observation networks with sites on and off the submarine bank reveal that both baroclinic velocities and displacements are dominated by the first mode, with larger velocities on the mid shelf and northern parts of the bank. Mid-shelf sites have current ellipses that are near...

  • Ramirez-Llodra E., Trannum H.C, Evenset A., Levin L.A, Andersson M., Finne T.E, Hilario A., Flem B., Christensen G., Schaanning M. et al..  2015.  Submarine and deep-sea mine tailing placements: A review of current practices, environmental issues, natural analogs and knowledge gaps in Norway and internationally. Marine Pollution Bulletin. 97:13-35.
    Abstract Summary:

    The mining sector is growing in parallel with societal demands for minerals. One of the most important environmental issues and economic burdens of industrial mining on land is the safe storage of the vast amounts of waste produced. Traditionally, tailings have been stored in land dams, but the lack of land availability, potential risk of dam failure and topography in coastal areas in certain countries results in increasing disposal of...

  • Levin LA, Mendoza GF, Grupe BM, Gonzalez JP, Jellison B, Rouse G, Thurber AR, Waren A.  2015.  Biodiversity on the rocks: Macrofauna inhabiting authigenic carbonate at Costa Rica methane seeps. Plos One. 10:e0131080.
    Abstract Summary:

    The activity of anaerobic methane oxidizing microbes facilitates precipitation of vast quantities of authigenic carbonate at methane seeps. Here we demonstrate the significant role of carbonate rocks in promoting diversity by providing unique habitat and food resources for macrofaunal assemblages at seeps on the Costa Rica margin (400–1850 m). The attendant fauna is surprisingly similar to that in rocky intertidal shores, with numerous...

  • Asch R.G.  2015.  Climate change and decadal shifts in the phenology of larval fishes in the California Current ecosystem. Proceedings of the National Academy of Sciences of the United States of America. 112:E4065-E4074.
    Abstract Summary:

    Climate change has prompted an earlier arrival of spring in numerous ecosystems. It is uncertain whether such changes are occurring in Eastern Boundary Current Upwelling ecosystems, because these regions are subject to natural decadal climate variability, and regional climate models predict seasonal delays in upwelling. To answer this question, the phenology of 43 species of larval fishes was investigated between 1951 and 2008 off southern...

  • Brzezinski M.A, Krause J.W, Bundy R.M, Barbeau K.A, Franks P., Goericke R, Landry MR, Stukel M.R.  2015.  Enhanced silica ballasting from iron stress sustains carbon export in a frontal zone within the California Current. Journal of Geophysical Research-Oceans. 120:4654-4669.
    Abstract Summary:

    Nutrient dynamics, phytoplankton rate processes, and export were examined in a frontal region between an anticyclone and a pair of cyclones 120 km off the coast in the southern California Current System (sCCS). Low silicic acid: nitrate ratios (Si:N) and high nitrate to iron ratios (N: Fe) characteristic of Fe-limiting conditions in the sCCS were associated with the northern cyclone and with the transition zone between the cyclones and the...

  • Highlighted Publication Schematic viewof dielcycle of dissipation
    Franks PJS.  2015.  Has Sverdrup's critical depth hypothesis been tested? Mixed layers vs. turbulent layers Ices Journal of Marine Science. 72:1897-1907.
    Abstract Summary:

    Sverdrup (1953. On conditions for the vernal blooming of phytoplankton. Journal du Conseil International pour l'Exploration de la Mer, 18: 287295) was quite careful in formulating his critical depth hypothesis, specifying a "thoroughly mixed top layer" with mixing "strong enough to distribute the plankton organisms evenly through the layer". With a few notable exceptions, most subsequent tests of the critical depth hypothesis have ignored...

  • Jeong H.J, Lim A.S, Franks PJS, Lee K.H, Kim J.H, Kang N.S, Lee M.J, Jang S.H, Lee S.Y, Yoon E.Y et al..  2015.  A hierarchy of conceptual models of red-tide generation: Nutrition, behavior, and biological interactions. Harmful Algae. 47:97-115.
    Abstract Summary:

    Red tides - discolorations of the sea surface due to dense plankton blooms - occur regularly in coastal and offshore waters along much of the world's coastline. Red tides often cause large-scale mortalities of fish and shellfish and significant losses to the aquaculture and tourist industries of many countries. Therefore, understanding and predicting the mechanisms controlling the outbreak, persistence, spread, and decline of red tides are...

  • Spydell M.S, Feddersen F, Olabarrieta M., Chen J.L, Guza RT, Raubenheimer B., Elgar S..  2015.  Observed and modeled drifters at a tidal inlet. Journal of Geophysical Research-Oceans. 120:4825-4844.
    Abstract Summary:

    Material transport and dispersion near the mouth of a tidal inlet (New River Inlet, NC) are investigated using GPS-tracked drifters and numerical models. For ebb tide releases, velocities are largest (> 1 ms(-1)) in two approximately 30 m wide channels that bisect the 1-3 m deep ebb shoal. In the channels, drifter and subsurface current meter velocities are similar, consistent with strong vertical mixing and 2-D hydrodynamics. Drifters...

  • Kahru M, Jacox M.G, Lee Z., Kudela R.M, Manzano-Sarabia M., Mitchell B.G.  2015.  Optimized multi-satellite merger of primary production estimates in the California Current using inherent optical properties. Journal of Marine Systems. 147:94-102.
    Abstract Summary:

    Building a multi-decadal time series of large-scale estimates of net primary production (NPP) requires merging data from multiple ocean color satellites. The primary product of ocean color sensors is spectral remote sensing reflectance (Rrs). We found significant differences (13-18% median absolute percent error) between Rrs estimates at 443 nm of different satellite sensors. These differences in Rrs are transferred to inherent optical...

  • de Verneil A., Franks PJS.  2015.  A pseudo-Lagrangian method for remapping ocean biogeochemical tracer data: Calculation of net Chl-a growth rates. Journal of Geophysical Research-Oceans. 120:4962-4979.
    Abstract Summary:

    A key goal in understanding the ocean's biogeochemical state is estimation of rates of change of critical tracers, particularly components of the planktonic ecosystem. Unfortunately, because ship survey data are not synoptic, it is difficult to obtain spatially resolved estimates of the rates of change of tracers sampled in a moving fluid. Here we present a pseudo-Lagrangian transformation to remap data from under-way surveys to a pseudo-...

  • Suanda SH, Feddersen F.  2015.  A self-similar scaling for cross-shelf exchange driven by transient rip currents. Geophysical Research Letters. 42:5427-5434.
    Abstract Summary:

    Transient rip currents, episodic offshore flows from the surf zone to the inner shelf, present a recreational beach hazard and exchange material across the nearshore ocean. The magnitude and offshore extent of transient rip-current-induced exchange and its relative importance to other inner shelf exchange processes are poorly understood. Here 120 model simulations with random, normally incident, directionally spread waves spanning a range of...

  • Highlighted Publication Unit source locations generating the largest amplitude waves at target sites on the U.S. West Coast.
    Rasmussen L., Bromirski PD, Miller AJ, Arcas D., Flick RE, Hendershott M.C.  2015.  Source location impact on relative tsunami strength along the US West Coast. Journal of Geophysical Research-Oceans. 120:4945-4961.
    Abstract Summary:

    Tsunami propagation simulations are used to identify which tsunami source locations would produce the highest amplitude waves on approach to key population centers along the U.S. West Coast. The reasons for preferential influence of certain remote excitation sites are explored by examining model time sequences of tsunami wave patterns emanating from the source. Distant bathymetric features in the West and Central Pacific can redirect tsunami...

  • Sperling E.A, Wolock C.J, Morgan A.S, Gill B.C, Kunzmann M., Halverson G.P, Macdonald F.A, Knoll A.H, Johnston D.T.  2015.  Statistical analysis of iron geochemical data suggests limited late Proterozoic oxygenation. Nature. 523:451-454.
    Abstract Summary:

    Sedimentary rocks deposited across the Proterozoic-Phanerozoic transition record extreme climate fluctuations, a potential rise in atmospheric oxygen or re-organization of the seafloor redox landscape, and the initial diversification of animals(1,2). It is widely assumed that the inferred redox change facilitated the observed trends in biodiversity. Establishing this palaeoenvironmental context, however, requires that changes in marine redox...

  • Beijbom O., Edmunds P.J, Roelfsema C., Smith J., Kline DI, Neal B.P, Dunlap M.J, Moriarty V., Fan TY, Tan C.J et al..  2015.  Towards automated annotation of benthic survey images: Variability of human experts and operational modes of automation. Plos One. 10
    Abstract Summary:

    Global climate change and other anthropogenic stressors have heightened the need to rapidly characterize ecological changes in marine benthic communities across large scales. Digital photography enables rapid collection of survey images to meet this need, but the subsequent image annotation is typically a time consuming, manual task. We investigated the feasibility of using automated point-annotation to expedite cover estimation of the 17...

  • Breitburg D.L, Salisbury J., Bernhard J.M, Cai W.J, Dupont S., Doney SC, Kroeker K.J, Levin L.A, Long W.C, Milke L.M et al..  2015.  And on top of all that... Coping with ocean acidification in the midst of many stressors. Oceanography. 28:48-61.
    Abstract Summary:

    Oceanic and coastal waters are acidifying due to processes dominated in the open ocean by increasing atmospheric CO2 and dominated in estuaries and some coastal waters by nutrient-fueled respiration. The patterns and severity of acidification, as well as its effects, are modified by the host of stressors related to human activities that also influence these habitats. Temperature, deoxygenation, and changes in food webs are particularly...

  • Levin L.A, Honisch B., Frieder C.A.  2015.  Geochemical proxies for estimating faunal exposure to ocean acidification. Oceanography. 28:62-73.
    Abstract Summary:

    Growing concern over the impacts of modern ocean acidification (OA) and interest in historical pH excursions have intensified the development of geochemical proxies for organism exposure to acidification and other components of the carbonate system. The use of carbonate structures produced by foraminifers, coccolithophores, corals, mollusks, brachiopods, echinoderms, ostracods, and fish for paleoreconstructions is an active area of study, and...

  • Mehring A.S, Kuehn K.A, Thompson A., Pringle C.M, Rosemond A.D, First M.R, Lowrance R.R, Vellidis G..  2015.  Leaf litter nutrient uptake in an intermittent blackwater river: influence of tree species and associated biotic and abiotic drivers. Functional Ecology. 29:849-860.
    Abstract Summary:

    1. Organic matter may sequester nutrients as it decomposes, increasing in total N and P mass via multiple uptake pathways. During leaf litter decomposition, microbial biomass and accumulated inorganic materials immobilize and retain nutrients, and therefore, both biotic and abiotic drivers may influence detrital nutrient content. We examined the relative importance of these types of nutrient immobilization and compared patterns of nutrient...

  • Kumar N., Feddersen F, Uchiyama Y., McWilliams J., O'Reilly W..  2015.  Midshelf to surfzone coupled ROMS-SWAN model data comparison of waves, currents, and temperature: Diagnosis of subtidal forcings and response. Journal of Physical Oceanography. 45:1464-1490.
    Abstract Summary:

    A coupled wave and circulation model that includes tide, wind, buoyancy, and wave processes is necessary to investigate tracer exchange in the shelf region. Here, a coupled Regional Ocean Model System (ROMS)-Simulating Waves Nearshore (SWAN) model, resolving midshelf to the surfzone region of the San Pedro Bay, California, is compared to observations from the 2006 Huntington Beach experiment. Waves are well modeled, and surfzone cross- and...

  • Kline DI, Teneva L., Hauri C., Schneider K., Miard T., Chai A., Marker M., Dunbar R., Caldeira K., Lazar B. et al..  2015.  Six month in situ high-resolution carbonate chemistry and temperature study on a coral reef flat reveals asynchronous pH and temperature anomalies. Plos One. 10
    Abstract Summary:

    Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically...

  • Winters KB.  2015.  Tidally-forced flow in a rotating, stratified, shoaling basin. Ocean Modelling. 90:72-81.
    Abstract Summary:

    Baroclinic flow of a rotating, stratified fluid in a parabolic basin is computed in response to barotropic tidal forcing using the nonlinear, non-hydrostatic, Boussinesq equations of motion. The tidal forcing is derived from an imposed, boundary-enhanced free-surface deflection that advances cyclonically around a central amphidrome. The tidal forcing perturbs a shallow pycnocline, sloshing it up and down over the shoaling bottom....

  • Davison P.C, Koslow JA, Kloser R.J.  2015.  Acoustic biomass estimation of mesopelagic fish: backscattering from individuals, populations, and communities. Ices Journal of Marine Science. 72:1413-1424.
    Abstract Summary:

    Acoustic survey methods are useful to estimate the distribution, abundance, and biomass of mesopelagic fish, a key component of open ocean ecosystems. However, mesopelagic fish pose several challenges for acoustic biomass estimation based on their small size, wide depth range, mixed aggregations, and length-dependent acoustic reflectance, which differentiate them from the larger epipelagic and neritic fish for which these methods were...

  • Abstract Summary:

    We report cross-frontal changes in the characteristics of plankton proxy variables measured by autonomous Spray ocean gliders operating within the Southern California Current System (SCCS). A comparison of conditions across the 154 positive frontal gradients (i.e., where density of the surface layer decreased in the offshore direction) identified from six years of continuous measurements showed that waters on the denser side of the fronts...

  • Jackson G.A, Checkley DM, Dagg M..  2015.  Settling of particles in the upper 100 m of the ocean detected with autonomous profiling floats off California. Deep-Sea Research Part I-Oceanographic Research Papers. 99:75-86.
    Abstract Summary:

    We have deployed an autonomous profiling float, the SOLOPC, to sample the concentration of particles larger than 100 mu m off the California coast at approximately hourly intervals down to at least 100 m for periods as long as 12 d. We used the data to estimate total aggregate concentrations hourly at 2-m depth intervals, studying the dynamics of particle sedimentation in this difficult-to-sample region. We find that even over time scales of...

  • Gallo N.D, Cameron J., Hardy K., Fryer P., Bartlett DH, Levin L.A.  2015.  Submersible- and lander-observed community patterns in the Mariana and New Britain trenches: Influence of productivity and depth on epibenthic and scavenging communities. Deep-Sea Research Part I-Oceanographic Research Papers. 99:119-133.
    Abstract Summary:

    Deep-sea trenches remain one of the least explored ocean ecosystems due to the unique challenges of sampling at great depths. Five submersible dives conducted using the DEEPSEA CHALLENGER submersible generated video of undisturbed deep-sea communities at bathyal (994 m), abyssal (3755 m), and hadal (8228 m) depths in the New Britain Trench, bathyal depths near the Ulithi atoll (1192 m), and hadal depths in the Mariana Trench Challenger Deep (...

  • Maloney J.M, Grupe B.M, Pasulka A.L, Dawson K.S, Case D.H, Frieder C.A, Levin L.A, Driscoll NW.  2015.  Transpressional segment boundaries in strike-slip fault systems offshore southern California: Implications for fluid expulsion and cold seep habitats. Geophysical Research Letters. 42:4080-4088.
    Abstract Summary:

    The importance of tectonics and fluid flow in controlling cold seep habitats has long been appreciated at convergent margins but remains poorly understood in strike-slip systems. Here we present geophysical, geochemical, and biological data from an active methane seep offshore from Del Mar, California, in the inner California borderlands (ICB). The location of this seep appears controlled by localized transpression associated with a step in...

  • Bromirski PD, Cayan DR.  2015.  Wave power variability and trends across the North Atlantic influenced by decadal climate patterns. Journal of Geophysical Research-Oceans. 120:3419-3443.
    Abstract Summary:

    Climate variations influence North Atlantic winter storm intensity and resultant variations in wave energy levels. A 60 year hindcast allows investigation of the influence of decadal climate variability on long-term trends of North Atlantic wave power, P-W, spanning the 1948-2008 epoch. P-W variations over much of the eastern North Atlantic are strongly influenced by the fluctuating North Atlantic Oscillation (NAO) atmospheric circulation...

  • Karas BJ, Diner RE, Lefebvre SC, McQuaid J, Phillips APR, Noddings CM, Brunson JK, Valas RE, Deerinck TJ, Jablanovic J et al..  2015.  Designer diatom episomes delivered by bacterial conjugation. Nat Commun. 6
    Abstract Summary:

    Eukaryotic microalgae hold great promise for the bioproduction of fuels and higher value chemicals. However, compared with model genetic organisms such as Escherichia coli and Saccharomyces cerevisiae, characterization of the complex biology and biochemistry of algae and strain improvement has been hampered by the inefficient genetic tools. To date, many algal species are transformable only via particle bombardment, and the introduced DNA is...

  • Parnell P.E.  2015.  The effects of seascape pattern on algal patch structure, sea urchin barrens, and ecological processes. Journal of Experimental Marine Biology and Ecology. 465:64-76.
    Abstract Summary:

    Seascapes are the marine analog of terrestrial landscapes, and their importance for ecological processes in marine ecosystems is generally poorly known. This is especially true for giant kelp (Macrocystis pyrifera) forests for which the acquisition of high resolution acoustic terrain data is problematic due to canopy cover. The goal of this study was to determine the effects of geologically forced seascape structure on algal patch structure,...

  • Highlighted Publication Scanning electronic micrographs illustrating different types of shell dissolution.
    Bednarsek N., Ohman MD.  2015.  Changes in pteropod distributions and shell dissolution across a frontal system in the California Current System. Marine Ecology Progress Series. 523:93-103.
    Abstract Summary:

    We tested the sensitivity of the vertical distributions and shell dissolution patterns of thecosome pteropods to spatial gradients associated with an eddy-associated front in the southern California Current System. The aragonite saturation horizon (Omega(arag) = 1.0) shoaled from > 200 to <75 m depth across the front. The vertical distribution of thecosome pteropods tracked these changes, with all 5 species showing reduced occurrence at...

  • Helly J.J, Vernet M, Murray A.E, Stephenson G.R.  2015.  Characteristics of the meltwater field from a large Antarctic iceberg using delta O-18. Journal of Geophysical Research-Oceans. 120:2259-2269.
    Abstract Summary:

    Large tabular icebergs represent a disruptive influence on a stable water column when drifting in the open ocean. This is a study of one iceberg, C18A, encountered in the Powell Basin in the Weddell Sea in March 2009, formed from iceberg C18 ( 76x7km) originating from the Ross Ice Shelf in May 2002. C18A was lunate in shape with longest dimensions of 31kmx7kmx184m. The meltwater field from C18A was characterized using 18O from water samples...

  • Luo M, Dale AW, Wallmann K, Hensen C, Gieskes J, Yan W, Chen D.  2015.  Estimating the time of pockmark formation in the SW Xisha Uplift (South China Sea) using reaction-transport modeling. Marine Geology. 364:21-31.
    Abstract Summary:

    Carbon cycling and fluid seepage in marine sediments over the late Quaternary were investigated at a now-extinct pockmark located in a mega-pockmark field in the SW Xisha Uplift (NW South China Sea). Measured particulate organic carbon (POC) content, and porewater sulfate (SO42 −), dissolved inorganic carbon (DIC) concentrations and δ34S-SO42 − distributions were used to constrain a non-steady-state reaction-transport model and quantify POC...

  • Gallien T.W, O'Reilly W.C, Flick RE, Guza RT.  2015.  Geometric properties of anthropogenic flood control berms on southern California beaches. Ocean & Coastal Management. 105:35-47.
    Abstract Summary:

    Coastal flood riskfrom coincident high tides' and energetic waves is concentrated around low-lying urban areas. Municipalities construct temporary sand berms (also known as sacrificial dunes) to manage potential flooding, however the relationships between berm geometry (e.g., height, width and length) and performance are not understood. Concomitant pressures of sea level rise and urbanization will increase active beach berming. Effective...

  • Highlighted Publication Satellite image of near-surface chlorophyll a
    Pasulka A.L, Samo T.J, Landry MR.  2015.  Grazer and viral impacts on microbial growth and mortality in the southern California Current Ecosystem. Journal of Plankton Research. 37:320-336.
    Abstract Summary:

    Protistan grazers and viruses are major agents of mortality in marine microbial communities with substantially different implications for food-web dynamics, carbon cycling and diversity maintenance. While grazers and viruses are typically studied independently, their impacts on microbial communities may be complicated by direct and indirect interactions of their mortality effects. Using a modification of the seawater dilution approach, we...

  • Abstract Summary:

    A preferred orientation of the anisotropic ice crystals influences the viscosity of the ice bulk and the dynamic behaviour of glaciers and ice sheets. Knowledge about the distribution of crystal anisotropy is mainly provided by crystal orientation fabric (COF) data from ice cores. However, the developed anisotropic fabric influences not only the flow behaviour of ice but also the propagation of seismic waves. Two effects are important: (i)...

  • Diez A., Eisen O., Hofstede C., Lambrecht A., Mayer C., Miller H., Steinhage D., Binder T., Weikusat I..  2015.  Seismic wave propagation in anisotropic ice - Part 2: Effects of crystal anisotropy in geophysical data. Cryosphere. 9:385-398.
    Abstract Summary:

    We investigate the propagation of seismic waves in anisotropic ice. Two effects are important: (i) sudden changes in crystal orientation fabric (COF) lead to englacial reflections; (ii) the anisotropic fabric induces an angle dependency on the seismic velocities and, thus, recorded travel times. Velocities calculated from the polycrystal elasticity tensor derived for the anisotropic fabric from measured COF eigen-values of the EDML ice core,...

  • Highlighted Publication Global ocean heat gain
    Roemmich D., Church J., Gilson J., Monselesan D., Sutton P., Wijffels S..  2015.  Unabated planetary warming and its ocean structure since 2006. Nature Climate Change. 5:240-245.
    Abstract Summary:

    Increasing heat content of the global ocean dominates the energy imbalance in the climate system(1). Here we show that ocean heat gain over the 0-2,000 m layer continued at a rate of 0.4-0.6 W m(-2) during 2006-2013. The depth dependence and spatial structure of temperature changes are described on the basis of the Argo Program's(2) accurate and spatially homogeneous data set, through comparison of three Argo-only analyses. Heat gain was...

  • Bograd SJ, Buil M.P, Di Lorenzo E, Castro C.G, Schroeder I.D, Goericke R, Anderson C.R, Benitez-Nelson C., Whitney F.A.  2015.  Changes in source waters to the Southern California Bight. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:42-52.
    Abstract Summary:

    Historical hydrographic data (1984-2012) from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program and global reanalysis products were used to quantify recent water mass variability off the coast of Southern California. Dissolved oxygen concentrations continued to decline within the lower pycnocline, concurrent with strong increases in nitrate and phosphate that have spatial patterns matching those of dissolved oxygen...

  • Sydeman WJ, Thompson S.A, Santora J.A, Koslow JA, Goericke R, Ohman MD.  2015.  Climate-ecosystem change off southern California: Time-dependent seabird predator-prey numerical responses. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:158-170.
    Abstract Summary:

    Climate change may increase both stratification and upwelling in marine ecosystems, but these processes may affect productivity in opposing or complementary ways. For the Southern California region of the California Current Ecosystem (CCE), we hypothesized that changes in stratification and upwelling have affected marine bird populations indirectly through changes in prey availability. To test this hypothesis, we derived trends and...

  • Earlie CS, Young AP, Masselink G, Russell PE.  2015.  Coastal cliff ground motions and response to extreme storm waves. Geophysical Research Letters. :2014GL062534.
    Abstract Summary:

    Coastal cliff erosion from storm waves is observed worldwide but the processes are notoriously difficult to measure during extreme storm wave conditions when most erosion normally occurs, limiting our understanding of cliff processes. Over January-February 2014, during the largest Atlantic storms in at least 60 years with deep water significant wave heights of 6 – 8 m, cliff-top ground motions showed vertical ground displacements in excess of...

  • Powell J.R, Ohman MD.  2015.  Covariability of zooplankton gradients with glider-detected density fronts in the Southern California Current System. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:79-90.
    Abstract Summary:

    Fronts represent sharp boundaries between water masses, but seasonal and interannual variation in their occurrence and effects on the distributions of pelagic organisms are poorly understood. This study reports results from six years of ocean front observations (2006-2011) along two transect lines across the Southern California Current System (SCCS) using autonomous Spray ocean gliders. During this time, 154 positive near-surface density...

  • Goericke R, Bograd SJ, Grundle D.S.  2015.  Denitrification and flushing of the Santa Barbara Basin bottom waters. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:53-60.
    Abstract Summary:

    The sediments of the Santa Barbara Basin (SBB) are an important paleoecological resource since their structure reflects the oxygenation of the bottom waters and the quality and quantity of the particulate matter which is sequestered to the bottom of the basin. These properties are controlled by regional atmospheric and oceanic climate. The California Cooperative Oceanic Fisheries Investigations (CalCOFI) program has been monitoring the bottom...

  • Davison P, Lara-Lopez A, J. Koslow A.  2015.  Mesopelagic fish biomass in the southern California current ecosystem. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:129-142.
    Abstract Summary:

    Mesopelagic fishes are the most common vertebrates on Earth, forming an important link between lower trophic levels and higher predators, and also between surface production and the deep sea. The biomass of these fishes is a key parameter for ecological modeling of oceanic ecosystems, but it is poorly known. The two most common methods to estimate the biomass of these fishes, acoustic and trawl surveys, are both sensitive to the ability of...

  • Kahru M, Lee Z, Kudela RM, Manzano-Sarabia M, B. Mitchell G.  2015.  Multi-satellite time series of inherent optical properties in the California Current. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:91-106.
    Abstract Summary:

    Satellite ocean color radiometry is a powerful method to study ocean biology but the relationships between satellite measurements and the in situ ocean properties are not well understood. Moreover, the measurements made with one satellite sensor may not be directly compatible with similar measurements from another sensor. We estimate inherent optical properties (IOPs) in the California Current by applying empirically optimized versions of the...

  • Morrissey J, Sutak R, Paz-Yepes J, Tanaka A, Moustafa A, Veluchamy A, Thomas Y, Botebol H, Bouget F-Y, McQuaid J B et al..  2015.  A novel protein, ubiquitous in marine phytoplankton, concentrates iron at the cell surface and facilitates uptake. Current Biology. 25:364-371.
    Abstract Summary:

    Numerous cellular functions including respiration require iron. Plants and phytoplankton must also maintain the iron-rich photosynthetic electron transport chain, which most likely evolved in the iron-replete reducing environments of the Proterozoic ocean [1]. Iron bioavailability has drastically decreased in the contemporary ocean [1], most likely selecting for the evolution of efficient iron acquisition mechanisms among modern phytoplankton...

  • Saba V.S, Hyde K.JW, Rebuck N.D, Friedland K.D, Hare J.A, Kahru M, Fogarty M.J.  2015.  Physical associations to spring phytoplankton biomass interannual variability in the US Northeast Continental Shelf. Journal of Geophysical Research-Biogeosciences. 120:205-220.
    Abstract Summary:

    The continental shelf of the Northeast United States and Nova Scotia is a productive marine ecosystem that supports a robust biomass of living marine resources. Understanding marine ecosystem sensitivity to changes in the physical environment can start with the first-order response of phytoplankton (i.e., chlorophyll a), the base of the marine food web. However, the primary physical associations to the interannual variability of chlorophyll a...

  • Jacox M.G, Edwards C.A, Kahru M, Rudnick D.L, Kudela R.M.  2015.  The potential for improving remote primary productivity estimates through subsurface chlorophyll and irradiance measurement. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:107-116.
    Abstract Summary:

    A 26-year record of depth integrated primary productivity (PP) in the Southern California Current System (SCCS) is analyzed with the goal of improving satellite net primary productivity (PP) estimates. Modest improvements in PP model performance are achieved by tuning existing algorithms for the SCCS, particularly by parameterizing carbon fixation rate in the vertically generalized production model as a function of surface chlorophyll...

  • Siedlecki S.A, Banas N.S, Davis K.A, Giddings S., Hickey B.M, MacCready P., Connolly T., Geier S..  2015.  Seasonal and interannual oxygen variability on the Washington and Oregon continental shelves. Journal of Geophysical Research: Oceans. 120:608-633.
    Abstract Summary:

    The coastal waters of the northern portion of the California Current System experience a seasonal decline in oxygen concentrations and hypoxia over the summer upwelling season that results in negative impacts on habitat for many organisms. Using a regional model extending from 43°N to 50°N, with an oxygen component developed in this study, drivers of seasonal and regional oxygen variability are identified. The model includes two pools of...

  • Taylor A.G, Landry MR, Selph K.E, Wokuluk J.J.  2015.  Temporal and spatial patterns of microbial community biomass and composition in the Southern California Current Ecosystem. Deep-Sea Research Part Ii-Topical Studies in Oceanography. 112:117-128.
    Abstract Summary:

    As part of the California Current Ecosystem Long Term Ecological Research (CCE-LTER) Program, samples for epifluorescence microscopy and flow cytometry (FCM) were collected at ten 'cardinal' stations on the California Cooperative Oceanic Fisheries Investigations (CalCOFI) grid during 25 quarterly cruises from 2004 to 2010 to investigate the biomass, composition and size-structure of microbial communities within the southern CCE. Based on our...

  • Levin L.A, Liu K.K, Emeis K.C, Breitburg D.L, Cloern J., Deutsch C., Giani M., Goffart A., Hofmann E.E, Lachkar Z. et al..  2015.  Comparative biogeochemistry-ecosystem-human interactions on dynamic continental margins. Journal of Marine Systems. 141:3-17.
    Abstract Summary:

    The oceans' continental margins face strong and rapid change, forced by a combination of direct human activity, anthropogenic CO2-induced climate change, and natural variability. Stimulated by discussions in Goa, India at the IMBER IMBIZO III, we (1) provide an overview of the drivers of biogeochemical variation and change on margins, (2) compare temporal trends in hydrographic and biogeochemical data across different margins, (3) review...

  • Barkan R, Winters KB, Smith SGL.  2015.  Energy cascades and loss of balance in a reentrant channel forced by wind stress and buoyancy fluxes. Journal of Physical Oceanography. 45:272-293.
    Abstract Summary:

    A large fraction of the kinetic energy in the ocean is stored in the "quasigeostrophic" eddy field. This "balanced" eddy field is expected, according to geostrophic turbulence theory, to transfer energy to larger scales. In order for the general circulation to remain approximately steady, instability mechanisms leading to loss of balance (LOB) have been hypothesized to take place so that the eddy kinetic energy (EKE) may be transferred to...

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