Yager Patricia L.

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Yager
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Patricia L.
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  • Article
    Bacterial biogeography across the Amazon river-ocean continuum
    (Frontiers Media, 2017-05-23) Doherty, Mary ; Yager, Patricia L. ; Moran, Mary Ann ; Coles, Victoria J. ; Fortunato, Caroline S. ; Krusche, Alex V. ; Medeiros, Patricia M. ; Payet, Jérôme P. ; Richey, Jeffrey E. ; Satinsky, Brandon ; Sawakuchi, Henrique O. ; Ward, Nicholas D. ; Crump, Byron C.
    Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ∼675 km of the lower Amazon River mainstem, in the Tapajós River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2–2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitional assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity near-shore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and coastal oceans. Comparison of Amazon continuum microbial communities to those from temperate and arctic systems suggest that river discharge and salinity are master variables structuring a range of environmental conditions that control bacterial communities across the river-ocean continuum.
  • Dataset
    Surface pCO2, bottle-corrected Chl a, and shipboard wind speed from cruises conducted during 2010, 2011, and 2012 off the Northeast coast of Brazil in the Amazon River Plume as part of the ANACONDAS project
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-04-21) Yager, Patricia L.
    Surface pCO2, bottle-corrected Chl a, and shipboard wind speed from three cruises conducted off the Northeast coast of Brazil in the Amazon River Plume as part of the ANACONDAS project. Cruise AN10 took place on R/V Knorr (KN197-08) from May-June 2010; cruise AN11 took place on R/V Melville (MV1110) from September-October 2011; and cruise AN12 took place on R/V Atlantis (AT21-04) during July 2012. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/849870
  • Dataset
    1-D vertical mixing/biogeochemical Regional Ocean Modeling System (ROMS) output of October 2010 - March 2011 of the Amundsen Sea Polynya, modeled at twelve bloom stations.
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-07-24) Yager, Patricia L. ; Sherrell, Robert M.
    1-D vertical mixing/biogeochemical Regional Ocean Modeling System (ROMS) output of October 2010 - March 2011 of the Amundsen Sea Polynya, modeled at twelve bloom stations. Data are 3-hourly averages, and saved in NetCDF files. In the NetCDF files, data are distributed over a 6x6 grid with 30 depths (ranging from the surface down to 210 m, with higher resolution near the surface). ocean_avg.nc files are the standard model output, while files named ocean_avg_sensitivity_lowWW.nc are from runs using a lower winter water initial dissolved iron concentration. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/765252
  • Dataset
    ASPIRE station data used to develop 1-D and 3-D numerical models from the Nathaniel B. Palmer in the Amundsen Sea from 2010-12-14 through 2011-01-05
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-04-17) Yager, Patricia L. ; Sherrell, Robert M.
    Hydrographic profiles and discrete water samples were collected from each station using a conventional shipboard conductivity-temperature-depth (CTD; Sea-Bird 911+) sensor and a 24 × 10 L Niskin bottle rosette sampler (General Oceanics). Potential temperature (θ) and salinity (S) were recorded continuously as a function of depth and at the moment of Niskin bottle closure (see Yager et al., 2016). Trace-metal samples were collected similarly using a trace-metal-clean CTD-rosette system (see Sherrell et al., 2015) that was deployed at the same location just before or after the conventional CTD. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/765081
  • Dataset
    Nitrogen fixation rates from samples collected in the Chukchi Sea, Arctic Ocean near Barrow, Alaska in August of 2011 (ArcticNITRO project)
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2017-06-08) Sipler, Rachel E. ; Bronk, Deborah ; Yager, Patricia L.
    This dataset provides rates of nitrogen fixation for the coastal Chukchi Sea near Barrow, Alaska. Nitrogen fixation supplies ‘new’ nitrogen to the global ocean and supports primary production and impacts global biogeochemical cycles. Historically, nitrogen fixation in marine waters was considered a predominantly warm water process but this and other recent studies have shown that nitrogen fixation is occurring at low rates in polar waters. This dataset reports rates of 3.5 – 17.2 nmol N L-1 d-1 in the ice-free coastal Alaskan Arctic. Additional investigations of high-latitude marine diazotrophic physiology are required to refine these N2 fixation estimates. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/701789
  • Article
    ASPIRE : the Amundsen Sea Polynya International Research Expedition
    (The Oceanography Society, 2012-09) Yager, Patricia L. ; Sherrell, Robert M. ; Stammerjohn, Sharon E. ; Alderkamp, Anne-Carlijn ; Schofield, Oscar M. E. ; Abrahamsen, E. Povl ; Arrigo, Kevin R. ; Bertilsson, Stefan ; Garay, D. Lollie ; Guerrero, Raul ; Lowry, Kate E. ; Moksnes, Per-Olav ; Ndungu, Kuria ; Post, Anton F. ; Randall-Goodwin, Evan ; Riemann, Lasse ; Severmann, Silke ; Thatje, Sven ; van Dijken, Gert L. ; Wilson, Stephanie
    In search of an explanation for some of the greenest waters ever seen in coastal Antarctica and their possible link to some of the fastest melting glaciers and declining summer sea ice, the Amundsen Sea Polynya International Research Expedition (ASPIRE) challenged the capabilities of the US Antarctic Program and RVIB Nathaniel B. Palmer during Austral summer 2010–2011. We were well rewarded by both an extraordinary research platform and a truly remarkable oceanic setting. Here we provide further insights into the key questions that motivated our sampling approach during ASPIRE and present some preliminary findings, while highlighting the value of the Palmer for accomplishing complex, multifaceted oceanographic research in such a challenging environment.
  • Working Paper
    US SOLAS Science Report
    (Woods Hole Oceanographic Institution, 2021-12) Stanley, Rachel H. R. ; Bell, Tom G. ; Gao, Yuan ; Gaston, Cassandra J. ; Ho, David T. ; Kieber, David J. ; Mackey, Katherine R. M. ; Meskhidze, Nicholas ; Miller, William L. ; Potter, Henry ; Vlahos, Penny ; Yager, Patricia L. ; Alexander, Becky ; Beaupre, Steven R. ; Craig, Susanne E. ; Cutter, Gregory A. ; Emerson, Steven ; Frossard, Amanda A. ; Gasso, Santiago ; Haus, Brian K. ; Keene, William C. ; Landing, William M. ; Moore, Richard H. ; Ortiz-Suslow, David ; Palter, Jaime B. ; Paulot, Fabien ; Saltzman, Eric ; Thornton, Daniel ; Wozniak, Andrew S. ; Zamora, Lauren M. ; Benway, Heather M.
    The Surface Ocean – Lower Atmosphere Study (SOLAS) (http://www.solas-int.org/) is an international research initiative focused on understanding the key biogeochemical-physical interactions and feedbacks between the ocean and atmosphere that are critical elements of climate and global biogeochemical cycles. Following the release of the SOLAS Decadal Science Plan (2015-2025) (Brévière et al., 2016), the Ocean-Atmosphere Interaction Committee (OAIC) was formed as a subcommittee of the Ocean Carbon and Biogeochemistry (OCB) Scientific Steering Committee to coordinate US SOLAS efforts and activities, facilitate interactions among atmospheric and ocean scientists, and strengthen US contributions to international SOLAS. In October 2019, with support from OCB, the OAIC convened an open community workshop, Ocean-Atmosphere Interactions: Scoping directions for new research with the goal of fostering new collaborations and identifying knowledge gaps and high-priority science questions to formulate a US SOLAS Science Plan. Based on presentations and discussions at the workshop, the OAIC and workshop participants have developed this US SOLAS Science Plan. The first part of the workshop and this Science Plan were purposefully designed around the five themes of the SOLAS Decadal Science Plan (2015-2025) (Brévière et al., 2016) to provide a common set of research priorities and ensure a more cohesive US contribution to international SOLAS.
  • Article
    Meltwater-enhanced nutrient export from Greenland's Glacial Fjords: a sensitivity analysis
    (American Geophysical Union, 2020-06-22) Oliver, Hilde ; Castelao, Renato M. ; Wang, Chuning ; Yager, Patricia L.
    As mass loss from the Greenland Ice Sheet accelerates, this modeling study considers how meltwater inputs to the ocean can impact marine ecosystems using a simplified fjord scenario. At marine‐terminating glaciers in Greenland fjords, meltwater can be delivered far below the sea surface, both as subglacial runoff (from atmosphere‐driven surface melt) and as basal melt (from ocean heat). Such delivery can result in buoyancy‐driven upwelling and the upward entrainment of nutrient‐rich deep water, which can support phytoplankton growth in fjord surface waters. For this study, we use an idealized fjord‐scale model to investigate which properties of glaciers and fjords govern the transport of buoyantly upwelled nutrients from fjords. We model the influence of fjord geometry, hydrology, wind, tides, and phytoplankton growth within the fjord on meltwater‐driven nutrient export to the ocean. We use the Regional Ocean Modeling System (ROMS) coupled to a buoyant plume model and a biogeochemical model to simulate physical and biogeochemical processes within an idealized tidewater glacial fjord. Results show that meltwater‐driven nutrient export increases with larger subglacial discharge rates and deeper grounding lines, features that are both likely to change with continued ice sheet melting. Nutrient export decreases with longer residence times, allowing greater biological drawdown. While the absence of a coastal current in the model setup prevents the downstream advection of exported nutrients, results suggest that shelf‐forced flows could influence nutrient residence time within fjords. This simplified model highlights key uncertainties requiring further observation to understand ecological impacts of Greenland mass loss.
  • Article
    Phaeocystis antarctica blooms strongly influence bacterial community structures in the Amundsen Sea polynya
    (Frontiers Media, 2014-12-19) Delmont, Tom O. ; Hammar, Katherine M. ; Ducklow, Hugh W. ; Yager, Patricia L. ; Post, Anton F.
    Rising temperatures and changing winds drive the expansion of the highly productive polynyas (open water areas surrounded by sea ice) abutting the Antarctic continent. Phytoplankton blooms in polynyas are often dominated by the haptophyte Phaeocystis antarctica, and they generate the organic carbon that enters the resident microbial food web. Yet, little is known about how Phaeocystis blooms shape bacterial community structures and carbon fluxes in these systems. We identified the bacterial communities that accompanied a Phaeocystis bloom in the Amundsen Sea polynya during the austral summers of 2007–2008 and 2010–2011. These communities are distinct from those determined for the Antarctic Circumpolar Current (ACC) and off the Palmer Peninsula. Diversity patterns for most microbial taxa in the Amundsen Sea depended on location (e.g., waters abutting the pack ice near the shelf break and at the edge of the Dotson glacier) and depth, reflecting different niche adaptations within the confines of this isolated ecosystem. Inside the polynya, P. antarctica coexisted with the bacterial taxa Polaribacter sensu lato, a cryptic Oceanospirillum, SAR92 and Pelagibacter. These taxa were dominated by a single oligotype (genotypes partitioned by Shannon entropy analysis) and together contributed up to 73% of the bacterial community. Size fractionation of the bacterial community [<3 μm (free-living bacteria) vs. >3 μm (particle-associated bacteria)] identified several taxa (especially SAR92) that were preferentially associated with Phaeocystis colonies, indicative of a distinct role in Phaeocystis bloom ecology. In contrast, particle-associated bacteria at 250 m depth were enriched in Colwellia and members of the Cryomorphaceae suggesting that they play important roles in the decay of Phaeocystis blooms.
  • Dataset
    Numerical model simulating the sea ice and ocean conditions in the Amundsen Sea over the period Jan. 1, 2006 to Dec. 31, 2013
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2017-08-03) St-Laurent, Pierre ; Hofmann, Eileen E. ; Sherrell, Robert M. ; Stammerjohn, Sharon E. ; Yager, Patricia L. ; Biddle, Mathew ; York, Amber D.
    Numerous coastal polynyas fringe the Antarctic continent and strongly influence the productivity of Antarctic shelf systems. Of the 46 Antarctic coastal polynyas documented in a recent study, the Amundsen Sea Polynya (ASP) stands out as having the highest net primary production per unit area. Incubation experiments suggest that this productivity is partly controlled by the availability of dissolved iron (dFe). As a first step toward understanding the iron supply of the ASP, we introduce four plausible sources of dFe and simulate their steady spatial distribution using conservative numerical tracers. The modeled distributions replicate important features from observations including dFe maxima at the bottom of deep troughs and enhanced concentrations near the ice shelf fronts. A perturbation experiment with an idealized drawdown mimicking summertime biological uptake and subsequent resupply suggests that glacial meltwater and sediment-derived dFe are the main contributors to the prebloom dFe inventory in the top 100 m of the ASP. The sediment-derived dFe depends strongly on the buoyancy-driven overturning circulation associated with the melting ice shelves (the “meltwater pump”) to add dFe to the upper 300 m of the water column. The results support the view that ice shelf melting plays an important direct and indirect role in the dFe supply and delivery to polynyas such as the ASP. The data are from a numerical model simulating the sea ice and ocean conditions in the Amundsen Sea over the period Jan. 1, 2006 to Dec. 31, 2013. The data files provide the daily averaged model fields during this period. The numerical model and experiment are thoroughly described in St-Laurent et al., J. Geophys. Res. Oceans, doi:10.1002/2017jc013162.