Recent Publications

Weekly Highlighted Publication

Zooglider: An autonomous vehicle for optical and acoustic sensing of zooplankton

Impact:
In summary, Zooglider is a new instrument to optically image mesozooplankton and marine snow in situ, while simultaneously recording acoustic backscatter at two acoustic frequencies, Chl a, temperature, and salinity in the same water parcel. The instrument operates between 0 and 400 m depth and is completely autonomous but with remote two‐way communication and directed navigation via satellite. It is an endurance vehicle, capable of 50 d missions. It provides near‐real–time data and is suited to both prescribed sampling trajectories and adaptive feature‐based sampling for a broad spectrum of studies addressing the ecological interactions of zooplankton and their importance in ocean biogeochemical cycles.

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  • 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...

  • White-Gaynor A.L, Nyblade A.A, Aster R.C, Wiens D.A, Bromirski PD, Gerstoft P, Stephen R.A, Hansen S.E, Wilson T., Dalziel I.W et al..  2019.  Heterogeneous upper mantle structure beneath the Ross Sea Embayment and Marie Byrd Land, West Antarctica, revealed by P-wave tomography. Earth and Planetary Science Letters. 513:40-50.
    Abstract Summary:

    We present an upper mantle P-wave velocity model for the Ross Sea Embayment (RSE) region of West Antarctica, constructed by inverting relative P-wave travel-times from 1881 teleseismic earthquakes recorded by two temporary broadband seismograph deployments on the Ross Ice Shelf, as well as by regional ice- and rock-sited seismic stations surrounding the RSE. Faster upper mantle P-wave velocities (similar to +1%) characterize the eastern part...

  • Gutierrez-Rodriguez A., Stukel M.R, Santos A.L dos, Biard T., Scharek R., Vaulot D., Landry MR, Not F..  2019.  High contribution of Rhizaria (Radiolaria) to vertical export in the California Current Ecosystem revealed by DNA metabarcoding. Isme Journal. 13:964-976.
    Abstract Summary:

    Passive sinking of particulate organic matter (POM) is the main mechanism through which the biological pump transports surface primary production to the ocean interior. However, the contribution and variability of different biological sources to vertical export is not fully understood. Here, we use DNA metabarcoding of the 18S rRNA gene and particle interceptor traps (PITs) to characterize the taxonomic composition of particles sinking out of...

  • Spydell M.S, Feddersen F, Suanda S..  2019.  Inhomogeneous turbulent dispersion across the nearshore induced by surfzone eddies. Journal of Physical Oceanography. 49:1015-1034.
    Abstract Summary:

    In various oceanic regions, drifter-derived diffusivities reach a temporal maximum and subsequently decrease. Often, these are regions of inhomogeneous eddies, however, the effect of inhomogeneous turbulence on dispersion is poorly understood. The nearshore region (spanning from the surfzone to the inner shelf) also has strong cross-shore inhomogeneous turbulence. Nearshore Lagrangian statistics are estimated from drifter trajectories...

  • Negrete-Garcia G., Lovenduski N.S, Hauri C., Krumhardt K.M, Lauvset S.K.  2019.  Sudden emergence of a shallow aragonite saturation horizon in the Southern Ocean. Nature Climate Change. 9:313-+.
    Abstract Summary:

    Models project that with current CO2 emission rates, the Southern Ocean surface will be undersaturated with respect to aragonite by the end of this century(1-4). This will result in widespread impacts on biogeochemistry and ocean ecosystems(5-7), particularly the health of aragonitic organisms, such as pteropods(7), which can dominate polar surface water communities(6). Here, we quantify the depth of the present-day Southern Ocean aragonite...

  • Cape M.R, Vernet M, Pettit E.C, Wellner J., Truffer M., Akie G., Domack E., Leventer A., Smith C.R, Huber B.A.  2019.  Circumpolar deep water impacts glacial meltwater export and coastal biogeochemical cycling along the West Antarctic Peninsula. Frontiers in Marine Science. 6
    Abstract Summary:

    Warming along the Antarctic Peninsula has led to an increase in the export of glacial meltwater to the coastal ocean. While observations to date suggest that this freshwater export acts as an important forcing on the marine ecosystem, the processes linking ice-ocean interactions to lower trophic-level growth, particularly in coastal bays and fjords, are poorly understood. Here, we identify salient hydrographic features in Barilari Bay, a west...

  • Kim S, Hammerstrom K, Dayton P..  2019.  Epifaunal community response to iceberg-mediated environmental change in McMurdo Sound, Antarctica. Marine Ecology Progress Series. 613:1-14.
    Abstract Summary:

    High-latitude marine communities are dependent on sea ice patterns. Sea ice cover limits light, and hence primary production and food supply. Plankton, carried by currents from open water to areas under the sea ice, provides a transitory food resource that is spatially and temporally variable. We recorded epifaunal abundances at 17 sites in McMurdo Sound, Antarctica, over 12 yr, and found differences in communities based on location and time...

  • Stark J.S, Peltzer E.T, Kline DI, Queiros A.M, Cox T.E, Headley K., Barry J, Gazeau F., Runcie J.W, Widdicombe S. et al..  2019.  Free Ocean CO2 Enrichment (FOCE) experiments: Scientific and technical recommendations for future in situ ocean acidification projects. Progress in Oceanography. 172:89-107.
    Abstract Summary:

    Free Ocean CO2 Enrichment (FOCE) experiments are a relatively recent development in ocean acidification research, designed to address the need for in situ, long-term, community level experiments. FOCE studies have been conducted across different marine benthic habitats and regions, from Antarctica to the tropics. Based on this previous research we have formed some core operating principles that will aid those embarking on future FOCE...

  • de Verneil A., Franks PJS, Ohman MD.  2019.  Frontogenesis and the creation of fine-scale vertical phytoplankton structure. Journal of Geophysical Research-Oceans. 124:1509-1523.
    Abstract Summary:

    Fine-scale spatial structuring of phytoplankton patches has significant consequences for the marine food web, from altering phytoplankton exposure to surface light and limiting nutrients, to influencing the foraging of zooplankton, modifying carbon export, and impacting patterns of diversity. Hence, it is important to identify these fine-scale features and determine what generates their variability. Here we present evidence of fine-scale,...

  • Decima M, Stukel M.R, Lopez-Lopez L., Landry MR.  2019.  The unique ecological role of pyrosomes in the Eastern Tropical Pacific. Limnology and Oceanography. 64:728-743.
    Abstract Summary:

    Pyrosomes are an important but often overlooked component of marine zooplankton communities, with limited existing information regarding their ecological and trophic roles in pelagic ecosystems. We present the first estimates of grazing and trophic interactions of the large tropical pyrosome, Pyrostremma spinosum, in the Eastern Tropical Pacific. While patchy in distribution, Pyrostremma spinosum's grazing impact was substantial, up to 17.5%...

  • Dayton PK, Oliver JS, Thrush S.F, Hammerstrom K.  2019.  Bacteria defend carrion from scavengers. Antarctic Science. 31:13-15.
    Abstract Summary:

    Carrion in the form of dead seal pups and algal mats placed on soft bottom habitats at Explorers Cove and Salmon Bay, McMurdo Sound, attract scavenging invertebrates that are driven away by hydrogen sulphide produced by sulphate-reducing bacteria sequestered below a layer of Beggiatoa/Thioploca-like filamentous bacteria. This system is usually found for lipid-rich marine mammal carrion, but also occurred with natural algal mats.


  • Abstract Summary:

    The green microalga, Tetraselmis suecica, is commonly used in scientific, industrial, and aquacultural purposes because of its high stress tolerance and ease of culture in wide spectrums of environments. We hypothesized that carotenoids help to protect Tetraselmis cells from environmental stress by regulating genes in biosynthetic pathways. Here, we determined three major carotenogenic genes, phytoene synthase (PSY), phytoene desaturase (PDS...

  • Yarimizu K., Cruz-Lopez R., Garcia-Mendoza E., Edwards M., Carter ML, Carrano C.J.  2019.  Distribution of dissolved iron and bacteria producing the photoactive siderophore, vibrioferrin, in waters off Southern California and Northern Baja. 32:139-154.
    Abstract Summary:

    Phytoplankton blooms can cause acute effects on marine ecosystems due either to their production of endogenous toxins or to their enormous biomass leading to major impacts on local economies and public health. Despite years of effort, the causes of these Harmful Algal Blooms are still not fully understood. Our hypothesis is that bacteria that produce photoactive siderophores may provide a bioavailable source of iron for phytoplankton which...

  • Murik O., Tirichine L., Prihoda J., Thomas Y., Araujo W.L, Allen A.E, Fernie A.R, Bowler C..  2019.  Downregulation of mitochondrial alternative oxidase affects chloroplast function, redox status and stress response in a marine diatom. New Phytologist. 221:1303-1316.
    Abstract Summary:

    Diatom dominance in contemporary aquatic environments indicates that they have developed unique and effective mechanisms to cope with the rapid and considerable fluctuations that characterize these environments. In view of their evolutionary history from a secondary endosymbiosis, inter-organellar regulation of biochemical activities may be of particular relevance. Diatom mitochondrial alternative oxidase (AOX) is believed to play a...

  • Mullineaux L.S, Metaxas A., Beaulieu S.E, Bright M., Gollner S., Grupe B.M, Herrera S., Kellner J.B, Levin L.A, Mitarai S. et al..  2018.  Exploring the ecology of deep-sea hydrothermal vents in a metacommunity framework. Frontiers in Marine Science. 5
    Abstract Summary:

    Species inhabiting deep-sea hydrothermal vents are strongly influenced by the geological setting, as it provides the chemical-rich fluids supporting the food web, creates the patchwork of seafloor habitat, and generates catastrophic disturbances that can eradicate entire communities. The patches of vent habitat host a network of communities (a metacommunity) connected by dispersal of planktonic larvae. The dynamics of the metacommunity are...

  • Webb S.J, Rabsattt T., Erazo N., Bowman J.S.  2019.  Impacts of Zostera eelgrasses on microbial community structure in San Diego coastal waters. 7
    Abstract Summary:

    Marine eelgrasses are influential to their surrounding environments through their many ecosystem services, ranging from the provisioning of food and shelter for marine life to serving as a natural defense against pollution and pathogenic bacteria. In the marine waters of San Diego, CA, USA, eelgrass beds comprised of Zostera spp. are an integral part of the coastal ecosystem. To evaluate the impact of eelgrass on bacterial and archaeal...

  • Abstract Summary:

    Temperature and light are fundamental environmental variables which regulate phytoplankton growth rates when nutrients are in excess. For polar coastal oceans that are undergoing changes in sea ice cover and warming, light, and temperature are particularly important for bloom dynamics. Using colonial Phaeocystis antarctica cultures grown at steady-state, we assessed the combined effect of these two environmental controls on net growth rate (...

  • B. Pan J, Vernet M, Reynolds RA, B. Mitchell G.  2019.  The optical and biological properties of glacial meltwater in an Antarctic fjord. Plos One. 14
    Abstract Summary:

    As the Western Antarctic Peninsula (WAP) region responds to a warmer climate, the impacts of glacial meltwater on the Southern Ocean are expected to intensify. The Antarctic Peninsula fjord system offers an ideal system to understand meltwater’s properties, providing an extreme in the meltwater’s spatial gradient from the glacio-marine boundary to the WAP continental shelf. Glacial meltwater discharge in Arctic and Greenland fjords is...

  • Crosby S.C, Kumar N., O'Reilly W.C, Guza RT.  2019.  Regional swell transformation by backward ray tracing and SWAN. Journal of Atmospheric and Oceanic Technology. 36:217-229.
    Abstract Summary:

    Beach erosion and wave-induced flooding models are often initialized in O(10)-m depth, seaward of the surfzone, with wave conditions estimated from regional nonlinear spectral wave models [e.g., Simulating Waves Nearshore (SWAN)]. These models are computationally expensive for high-resolution, long-term regional O(100)-km hindcasts, and they limit examination of the effect of different climate scenarios on nearshore processes. Alternatively,...

  • Lee K.H, Jeong H.J, Lee K., Franks PJS, Seong K.A, Lee S.Y, Lee M.J, Jang S.H, Potvin E., Lim A.S et al..  2019.  Effects of warming and eutrophication on coastal phytoplankton production. Harmful Algae. 81:106-118.
    Abstract Summary:

    Phytoplankton production in coastal waters influences seafood production and human health and can lead to harmful algal blooms. Water temperature and eutrophication are critical factors affecting phytoplankton production, although the combined effects of warming and nutrient changes on phytoplankton production in coastal waters are not well understood. To address this, phytoplankton production changes in natural waters were investigated using...

  • Nickels C.F, Sala L.M, Ohman MD.  2019.  The euphausiid prey field for blue whales around a steep bathymetric feature in the southern California current system. Limnology and Oceanography. 64:390-405.
    Abstract Summary:

    Euphausiids are important prey for many marine organisms and often occur in patchy aggregations. Euphausiid predators, such as blue whales, may become concentrated in the vicinity of these aggregations. We investigated an area called Nine Mile Bank (NMB) near San Diego, California, defined by an area of steep bathymetry, to determine whether the frequent whale sightings in that locality can be explained by the distribution of euphausiids...

  • Till C.P, Solomon J.R, Cohen N.R, Lampe R.H, Marchetti A., Coale T.H, Bruland K.W.  2019.  The iron limitation mosaic in the California Current System: Factors governing Fe availability in the shelf/near-shelf region. Limnology and Oceanography. 64:109-123.
    Abstract Summary:

    The California Current System is a productive eastern boundary region off the coasts of Washington, Oregon, and California. There is strong seasonality to the region, with high levels of rainfall and river input to the coastal ocean during the winter season, and coastal and Ekman upwelling during the spring and summer. Iron (Fe) input to the coastal ocean during the winter months can be stored in the continental shelf mud belts and then be...

  • Swalethorp R., Dinasquet J., Logares R., Bertilsson S., Kjellerup S., Krabberod A.K, Moksnes P.O, Nielsen T.G, Riemann L..  2019.  Microzooplankton distribution in the Amundsen Sea Polynya (Antarctica) during an extensive Phaeocystis antarctica bloom. Progress in Oceanography. 170:1-10.
    Abstract Summary:

    In Antarctica, summer is a time of extreme environmental shifts resulting in large coastal phytoplankton blooms fueling the food web. Despite the importance of the microbial loop in remineralizing biomass from primary production, studies of how microzooplankton communities respond to such blooms in the Southern Ocean are rather scarce. Microzooplankton (ciliate and dinoflagellate) communities were investigated combining microscopy and 18S...

  • Hendrix A.R, Hurford T.A, Barge L.M, Bland M.T, Bowman J.S, Brinckerhoff W., Buratti B.J, Cable M.L, Castillo-Rogez J., Collins G.C et al..  2019.  The NASA Roadmap to Ocean Worlds. Astrobiology. 19:1-27.
    Abstract Summary:

    In this article, we summarize the work of the NASA Outer Planets Assessment Group (OPAG) Roadmaps to Ocean Worlds (ROW) group. The aim of this group is to assemble the scientific framework that will guide the exploration of ocean worlds, and to identify and prioritize science objectives for ocean worlds over the next several decades. The overarching goal of an Ocean Worlds exploration program as defined by ROW is to "identify ocean worlds,...

  • Fiedler J.W, Smit P.B, Brodie K.L, McNinch J., Guza RT.  2019.  The offshore boundary condition in surf zone modeling. Coastal Engineering. 143:12-20.
    Abstract Summary:

    Numerical models predicting surfzone waves and shoreline runup in field situations are often initialized with shoreward propagating (sea-swell, and infragravity) waves at an offshore boundary in 10-30 m water depth. We develop an offshore boundary condition, based on Fourier analysis of observations with co-located current and pressure sensors, that accounts for reflection and includes nonlinear phase-coupling. The performance of additional...

  • Taboada F.G, Barton A.D, Stock C.A, Dunne J., John J.G.  2019.  Seasonal to interannual predictability of oceanic net primary production inferred from satellite observations. Progress in Oceanography. 170:28-39.
    Abstract Summary:

    Seasonal to interannual predictions of ecosystem dynamics have the potential to improve the management of living marine resources. Prediction of oceanic net primary production (NPP), the foundation of marine food webs and the biological carbon pump, is particularly promising, with recent analysis suggesting that ecosystem feedback processes may lead to higher predictability of NPP at interannual scales than for physical variables like sea...

  • Highlighted Publication
    Dayton PK, Jarrell SC, Kim S, Parnell P.E, Thrush S.F, Hammerstrom K, Leichter J.J.  2019.  Benthic responses to an Antarctic regime shift: food particle size and recruitment biology. Ecological Applications. 29
    Abstract Summary:

    Polar ecosystems are bellwether indicators of climate change and offer insights into ecological resilience. In this study, we describe contrasting responses to an apparent regime shift of two very different benthic communities in McMurdo Sound, Antarctica. We compared species-specific patterns of benthic invertebrate abundance and size between the west (low productivity) and east (higher productivity) sides of McMurdo Sound across multiple...

  • Lampe R.H, Mann E.L, Cohen N.R, Till C.P, Thamatrakoln K., Brzezinski M.A, Bruland K.W, Twining B.S, Marchetti A..  2018.  Different iron storage strategies among bloom-forming diatoms. Proceedings of the National Academy of Sciences of the United States of America. 115:E12275-E12284.
    Abstract Summary:

    Diatoms are prominent eukaryotic phytoplankton despite being limited by the micronutrient iron in vast expanses of the ocean. As iron inputs are often sporadic, diatoms have evolved mechanisms such as the ability to store iron that enable them to bloom when iron is resupplied and then persist when low iron levels are reinstated. Two iron storage mechanisms have been previously described: the protein ferritin and vacuolar storage. To...

  • Neira C., Ingels J., Mendoza G., Hernandez-Lopez E., Levin L.A.  2018.  Distribution of meiofauna in bathyal sediments influenced by the oxygen minimum zone off Costa Rica. Frontiers in Marine Science. 5
    Abstract Summary:

    Ocean deoxygenation has become a topic of increasing concern because of its potential impacts on marine ecosystems, including oxygen minimum zone (OMZ) expansion and subsequent benthic effects. We investigated the influence of oxygen concentration and organic matter (OM) availability on metazoan meiofauna within and below an OMZ in bathyal sediments off Costa Rica, testing the hypothesis that oxygen and OM levels are reflected in meiofaunal...

  • Bowman J.S.  2018.  Identification of microbial dark matter in Antarctic environments. Frontiers in Microbiology. 9
    Abstract Summary:

    Numerous studies have applied molecular techniques to understand the diversity, evolution, and ecological function of Antarctic bacteria and archaea. One common technique is sequencing of the 16S rRNA gene, which produces a nearly quantitative profile of community membership. However, the utility of this and similar approaches is limited by what is known about the evolution, physiology, and ecology of surveyed taxa. When representative...

  • Dayton PK, Robilliard G.A, Oliver JS, Kim S, Hammerstrom K, O'Connor K, Fisher J., Barber J., Jarrell S..  2018.  Long-term persistence of wood on the sea floor at McMurdo Sound, Antarctica. Antarctic Science. 30:355-356.
    Abstract Summary:
  • Kuhn A.M, Fennel K., Berman-Frank I..  2018.  Modelling the biogeochemical effects of heterotrophic and autotrophic N-2 fixation in the Gulf of Aqaba (Israel), Red Sea. Biogeosciences. 15:7379-7401.
    Abstract Summary:

    Recent studies demonstrate that marine N-2 fixation can be carried out without light by heterotrophic N-2 fixers (diazotrophs). However, direct measurements of N-2 fixation in aphotic environments are relatively scarce. Heterotrophic as well as unicellular and colonial photoautotrophic diazotrophs are present in the oligotrophic Gulf of Aqaba (northern Red Sea). This study evaluates the relative importance of these different diazotrophs by...

  • Stukel M.R, Decima M, Landry MR, Selph K.E.  2018.  Nitrogen and Isotope Flows Through the Costa Rica Dome Upwelling Ecosystem: The Crucial Mesozooplankton Role in Export Flux. Global Biogeochemical Cycles. 32:1815-1832.
    Abstract Summary:

    The Costa Rica Dome (CRD) is an open-ocean upwelling ecosystem, with high biomasses of picophytoplankton (especially Synechococcus), mesozooplankton, and higher trophic levels. To elucidate the food web pathways supporting the trophic structure and carbon export in this unique ecosystem, we used Markov Chain Monte Carlo techniques to assimilate data from four independent realizations of N-15 and planktonic rate measurements from the CRD into...

  • Hogle S.L, Dupont C.L, Hopkinson B.M, King A.L, Buck K.N, Roe K.L, Stuart RK, Allen A.E, Mann E.L, Johnson Z.I et al..  2018.  Pervasive iron limitation at subsurface chlorophyll maxima of the California Current. Proceedings of the National Academy of Sciences of the United States of America. 115:13300-13305.
    Abstract Summary:

    Subsurface chlorophyll maximum layers (SCMLs) are nearly ubiquitous in stratified water columns and exist at horizontal scales ranging from the submesoscale to the extent of oligotrophic gyres. These layers of heightened chlorophyll and/or phytoplankton concentrations are generally thought to be a consequence of a balance between light energy from above and a limiting nutrient flux from below, typically nitrate (NO3). Here we present multiple...

  • Van Cise A.M, Mahaffy S.D, Baird R.W, Mooney T.A, Barlow J.  2018.  Song of my people: dialect differences among sympatric social groups of short-finned pilot whales in Hawai'i. Behavioral Ecology and Sociobiology. 72
    Abstract Summary:

    In many social species, acoustic dialects are used to differentiate among social groups within a local population. These acoustic dialects and their corresponding social groups are often related to distinct foraging behaviors or spatial movement patterns, and it is possible that vocal repertoire variability is one of the proximate mechanisms driving or maintaining genetic and ecological diversity at a subspecies level in social species. Short...

  • Highlighted Publication
    Ohman MD, Davis RE, Sherman JT, Grindley KR, Whitmore BM, Nickels CF, Ellen JS.  2018.  Zooglider: An autonomous vehicle for optical and acoustic sensing of zooplankton.
    Abstract Summary:

    We present the design and preliminary results from ocean deployments of Zooglider, a new autonomous zooplankton-sensing glider. Zooglider is a modified Spray glider that includes a low-power camera (Zoocam) with telecentric lens and a custom dual frequency Zonar (200 and 1000 kHz). The Zoocam quantifies zooplankton and marine snow as they flow through a defined volume inside a sampling tunnel. Images are acquired on average every 5 cm from a...

  • Arzeno I.B, Collignon A., Merrifield M., Giddings S.N, Pawlak G..  2018.  An alongshore momentum budget over a fringing tropical fore-reef. Journal of Geophysical Research-Oceans. 123:7839-7855.
    Abstract Summary:

    Existing momentum budgets over coral reefs have predominantly focused on cross-reef dynamics, lacking analysis of alongshore processes. To complement existing cross-reef research and enhance our understanding of forcing variability at the semidiurnal period, this study examines the sigma-coordinate, depth-averaged alongshore momentum budget over a fore-reef as a function of tidal phase. The observations were gathered over a 3-week timespan,...

  • Paulsen M.L, Seuthe L., Reigstad M., Larsen A., Cape M.R, Vernet M.  2018.  Asynchronous accumulation of organic carbon and nitrogen in the Atlantic gateway to the Arctic Ocean. Frontiers in Marine Science. 5
    Abstract Summary:

    Nitrogen (N) is the main limiting nutrient for biological production in the Arctic Ocean. While dissolved inorganic N (DIN) is well studied, the substantial pool of N bound in organic matter (OM) and its bioavailability in the system is rarely considered. Covering a full annual cycle, we here follow N and carbon (C) content in particulate (P) and dissolved (D) OM within the Atlantic water inflow to the Arctic Ocean. While particulate organic...

  • Politikos D.V, Curchitser E.N, Rose K.A, Checkley DM, Fiechter J..  2018.  Climate variability and sardine recruitment in the California Current: A mechanistic analysis of an ecosystem model. Fisheries Oceanography. 27:602-622.
    Abstract Summary:

    Recruitment varies substantially in small pelagic fish populations. Understanding of the mechanisms linking environment to recruitment is essential for the effective management of fisheries resources. In this study, we used a fully coupled end-to-end ecosystem model to study the effect of climate variability on sardine recruitment in the California Current System during 1965-2006. Ocean variability was represented by ROMS hydrodynamic and...

  • Smith KL, Ruhl H.A, Huffard C.L, Messie M., Kahru M.  2018.  Episodic organic carbon fluxes from surface ocean to abyssal depths during long-term monitoring in NE Pacific. Proceedings of the National Academy of Sciences of the United States of America. 115:12235-12240.
    Abstract Summary:

    Growing evidence suggests substantial quantities of particulate organic carbon (POC) produced in surface waters reach abyssal depths within days during episodic flux events. A 29-year record of in situ observations was used to examine episodic peaks in POC fluxes and sediment community oxygen consumption (SCOC) at Station M (NE Pacific, 4,000-m depth). From 1989 to 2017, 19% of POC flux at 3,400 m arrived during high-magnitude episodic events...

  • Minich J.J, Humphrey G., Benitez R.AS, Sanders J., Swofford A., Allen EE, Knight R..  2018.  High-throughput miniaturized 16S rRNA amplicon library preparation reduces costs while preserving microbiome integrity. mSystems. 3
    Abstract Summary:

    Next generation sequencing technologies have enabled many advances across biology, with microbial ecology benefiting primarily through expanded sample sizes. Although the cost of running sequencing instruments has decreased substantially over time, the price of library preparation methods has largely remained unchanged. In this study, we developed a low-cost miniaturized (5-mu l volume) high-throughput (384-sample) amplicon library...

  • Spackeen J.L, Sipler R.E, Bertrand E.M, Xu K., McQuaid J.B, Walworth N.G, Hutchins D.A, Allen A.E, Bronk D.A.  2019.  Impact of temperature, CO2, and iron on nutrient uptake by a late-season microbial community from the Ross Sea, Antarctica. Aquatic Microbial Ecology. 82:145-159.
    Abstract Summary:

    The Southern Ocean is rapidly changing as a result of rising sea surface temperatures, elevated CO2 concentrations, and modifications to iron sources and sinks. The Southern Ocean has seasonally high rates of primary production, making it critical to determine how changes will impact biogeochemical rate processes in this important sink for CO2. During the austral summer, we measured nitrogen and carbon uptake rates by a late-season Ross Sea...

  • Stukel M.R, Biard T., Krause J., Ohman MD.  2018.  Large Phaeodaria in the twilight zone: Their role in the carbon cycle. Limnology and Oceanography. 63:2579-2594.
    Abstract Summary:

    Advances in in situ imaging allow enumeration of abundant populations of large Rhizarians that compose a substantial proportion of total mesozooplankton biovolume. Using a quasi-Lagrangian sampling scheme, we quantified the abundance, vertical distributions, and sinking-related mortality of Aulosphaeridae, an abundant family of Phaeodaria in the California Current Ecosystem. Inter-cruise variability was high, with average concentrations at...

  • Levy M., Franks PJS, Smith K.S.  2018.  The role of submesoscale currents in structuring marine ecosystems. Nature Communications. 9
    Abstract Summary:

    From microbes to large predators, there is increasing evidence that marine life is shaped by short-lived submesoscales currents that are difficult to observe, model, and explain theoretically. Whether and how these intense three-dimensional currents structure the productivity and diversity of marine ecosystems is a subject of active debate. Our synthesis of observations and models suggests that the shallow penetration of submesoscale vertical...

  • Van Oostende N., Dussin R., Stock C.A, Barton A.D, Curchitser E., Dunne J.P, Ward B.B.  2018.  Simulating the ocean's chlorophyll dynamic range from coastal upwelling to oligotrophy. Progress in Oceanography. 168:232-247.
    Abstract Summary:

    The measured concentration of chlorophyll a in the surface ocean spans four orders of magnitude, from similar to 0.01 mg m(-3) in the oligotrophic gyres to > 10 mg m(-3) in coastal zones. Productive regions encompass only a small fraction of the global ocean area yet they contribute disproportionately to marine resources and biogeo-chemical processes, such as fish catch and coastal hypoxia. These regions and/or the full observed range of...

  • Young AP, Flick RE, Gallien TW, Giddings SN, Guza RT, Harvey M., Lenain L, Ludka B.C, W. Melville K, O'Reilly W.C.  2018.  Southern California coastal response to the 2015–2016 El Niño. Journal of Geophysical Research: Earth Surface. 123:3069-3083.
    Abstract Summary:

    Widespread erosion associated with energetic waves of the strong 2015–2016 El Niño on the U.S. West Coast has been reported widely. However, Southern California was often sheltered from the northerly approach direction of the offshore waves. The few large swells that reached Southern California were not synchronous with the highest tides. Although west coast-wide tidal anomalies were relatively large in 2015–2016, in Southern California,...

  • 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...

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