I am an oceanographer.


Centered on Arctic Ocean dynamics, I study several trace elements to assess their utility as indicators of circulation and biogeochemical processes. At the International Arctic Research Center, I research sea-ice geochemistry and the connectivity between the sea ice system and the water column. I’m further interested in how the broad Arctic Ocean continental margins influence oceanographic biogeochemical cycles. I’m involved in several research programs including NABOS, GEOTRACES, MOSAiC, and ArCSII.

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Academic Summary

1113187
CRUISESPUBLICATIONSCONFERENCE PARTICIPATIONREVIEWER FOR (N) JOURNALS


Current Research

Arctic Ocean tracer studies. Arctic Ocean nutrient and trace element data are used to understand supply, circulation, cycling of materials in the Arctic.

Sea Ice. Sea ice is a habitat, ecosystem, and reservoir influenced by the ocean and the atmosphere. The processes controlling nutrients (and organisms) in sea ice are unclear. This work aims to develop methods for sea ice sample handling and to understand biogeochemical processes in sea ice.

Antarctic Geochemical Tracers. In upcoming expedition with U.S. GEOTRACES in Amundsen Sea region, I will be investigating a few trace metals to determine how they may be used as tracers to understand the supply of materials from ocean boundaries (like sediments, or sea ice melt) and the internal cycling in the water column (like biological uptake and export)


Sea-going and Field Experience

200 Sea Days11 Cruises3 Seas

Sample Collection Count

2000+1000+1000+633418742/61
NUTRIENTMETHANETRACE ELEMENTCFCDICN2/Ar & N2O

NABOS 2021 – Arctic Ocean

  • Collecting dissolved nutrient and barium from niskin bottles.
  • Managing water sampling from the rosette.

The Nansen, Amundsen, and Makarov Basins of the Arctic Ocean all boarder the broad Siberian shelf system (Laptev and East Siberian Arctic Seas). This region receives a large amount of freshwater from river runoff and sea ice melt. Previous NABOS work identified that shoaling warm Atlantic waters could lead to more heat flux reaching sea ice (increased sea ice melt). That said, variability between years leads to different amounts of stratification/mixing between the warm Atlantic waters and the cold surface ocean. The goals of the ongoing program are to determine controls on freshwater distribution in the surface ocean in this region.

MOSAiC Landfast Ice Study – Utqiaǵvik, AK

  • Collecting and sectioning sea ice cores for macronutrients, oxygen isotopes, salinity, temperature, and trace metals.
  • Collecting brine via sack holes, snow, and seawater for biogeochemical parameters (see above).

Sea-ice in the atmosphere is coupled to the atmosphere and ocean, yet our understanding of how is still developing. This specific study aimed to understand how sea-ice and seawater were coupled during the spring melt. During this time, sea ice drains and flushes materials into the surface ocean, do these materials quantitatively impact the surface ocean?

U.S. GEOTRACES – North Pacific Ocean

  • Water column dissolved methane sampling
  • Continuous underway surface methane measurement
  • Shipboard analysis: headspace equilibrium, Picarro CRDS

The North Pacific Ocean is of particular interest because it is host to the oldest waters in the world’s oceans. The transect included shelf waters in the Gulf of Alaska, transited through the North Pacific Current and into the North Pacific Gyre. The transect continues across the equator and into the South Pacific, although I was only aboard the ship for the first leg which retired in Hawaii.

U.S. GO-SHIP – Equatorial Pacific Ocean

  • Water column CFC & SF6 sampling
  • Shipboard analysis: purge-and-trap, Electron Capture-GC

The GO-SHIP program is an international effort to conduct regular hydrographic surveys around the global ocean. Data from GO-SHIP cruises contributes substantially to global ocean databases and, importantly, is enabling decadal scale studies to investigate longer term variations in the oceans.

CONCORDE – Mississippi Bight

  • Water column dissolved methane sampling
  • Shipboard analysis: headspace equilibrium, Picarro CRDS

CONCORDE scientists investigated the role of river influence on the chemistry and biology of the Northern Gulf of Mexico ecosystems. Utilizing a highly multidisciplinary platform, daily strategizing was conducted with on-shore scientists. The Shiller Lab collected samples for trace elements, radium, and methane in an effort to assess the regional influence of SGD (see publication/presentation).

U.S. GEOTRACES – Arctic Ocean

  • Water column dissolved methane sampling
  • Water column gaseous dissolved nitrogen species sampling
  • Water column dissolved inorganic carbon sampling
  • Shipboard analysis: headspace equilibrium, Picarro CRDS

The Arctic Ocean is particularly responsive to variations in climate. A small change in seawater temperatures can destabilize sea ice, or even the sea-floor (methane hydrates!). The 2015 GEOTRACES Arctic campaigns were a multi-national effort to characterize trace metals in the Arctic and to set an important “baseline” by which future studies can be referenced to. Prior to this campaign, few studies had assessed trace elements in the Arctic and those that did focused largely on bioactive trace metals, or trace metals that could be easily sampled (i.e., don’t require trace metal clean equipment). The effort set out in 2015 engaged 3 ships to gather a pan-Arctic coverage at roughly the same time (all cruises occurred between July and October).

Educational Cruises

I have participated as both a student and an educator on multiple cruises aboard the R/V Point Sur in the Northern Gulf of Mexico and Mississippi Bight.

YearRoleCruise Purpose
2017EducatorGraduate Student Teaching Cruise
2017Co-PI/EducatorOutreach
2016EducatorGraduate Student Teaching Cruise
2016Student/TechnicianMooring Recovery
2016StudentMarine Instrumentation

Local Field Experience

A benefit to being near the coast is the bounty of research opportunity in our backyard. The Shiller Lab, under the leadership of Amy Moody, conducts monthly beach surveys to assess the role of submarine groundwater discharge in the coastal environment and ecosystem. We collect both surface water samples and ground water samples for a variety of parameters including nutrients, radium, trace metals, and methane. We utilize the local pier system to sample surface waters, as well as a raft as needed. To collect ground water we use a push-point sampler coupled with a peristaltic pump.


Technical Skills

Analytical Chemistry
Picarro CRDS
ICP-MS
SeaFast Preconcentration
EA-IRMS
GC
Data Analysis
R
Ocean Data View


Leadership

Ocean Decade Early Career Ocean Professional, Representative for GEOTRACES
2020-2023
Marine Technology Society Gulf Coast Student Section
Chair, 2016 2017
Student Oceanographic Society
Vice-President, 2016-2017

Awards

USM Graduate Student Hall of Fame2019
MTS Gulf Coast Section Scholarship2017
The MTS Student Scholarship for Graduate Students2016
USM College of Science and Technology – Masters Student of the Year2016
USM Department of Marine Science – Marine Science Scholar2016
Thermal Biology Institute – Workforce Development Grant2013
Howard Hughes Medical Institute Student Fellowship2012-2013
Howard Hughes Medical Institute SURP2012

Publications and Presentations

Recent Conferences and Workshops

  • Alaska Tribal Conference for Environmental Management, 2023
  • International Symposium for Arctic Research, 2023
  • Alaska Marine Science Symposium, 2023
  • MOSAiC Science Conference, 2022
  • Ocean Sciences Meeting, 2022
  • Ocean Sciences Meeting, 2020. Presentation.

Publications

  • Ö. Mete, A. Subhas, H. Kim, A. Dunlea, L. Whitmore, A. Shiller, M. Gilbert, W. Leavitt, T. Horner. (2023). Barium in seawater: Dissolved distribution, relationship to silicon, and barite saturation state determined using machine learning. Earth System Science Data. DOI: 10.5194/essd-2023-67
  • M. Gilbert, P. Ho, L. Whitmore, A. Shiller. (2023). Automated determination of gallium in seawater using seaFAST pre-concentration and high-resolution inductively-coupled plasma mass spectrometry. Analytica Chimica Acta. DOI: 10.1016/j.aca.2023.340799
  • L.M. Whitmore, A. Shiller, T. Horner, Y. Xiang, M. Auro, D. Bauch, F. Dehairs, P. Lam, J. Li, M. Maldonado, C. Mears, R. Newton, A. Pasqualini, H. Planquette, R. Rember, H. Thomas. (2022) Strong margin influence on the Arctic Ocean barium cycle revealed by Pan-Arctic Synthesis. Journal of Geophysical Research: Oceans. DOI: 10.1029/2021JC017417
  • L.M. Whitmore, A. Pasqualini, B. Newton, A.M. Shiller. (2020). Gallium: A new tracer of Pacific water in the Arctic Ocean. Journal of Geophysical Research: Oceans. DOI: 10.1029/2019JC015842
  • M.A. Charette, L.E. Kipp, L.T. Jensen, J.S. Dabrowski, L.M. Whitmore, J.N. Fitzsimmons, et al. (2020). The Transpolar Drift as a source of riverine and shelf derived trace elements to the central Arctic Ocean. Journal of Geophysical Research: Oceans DOI: 10.1029/2019jc015920
  • W.J. Jenkins, M. Hatta, J.N. Fitzsimmons, R. Schlitzer, A. Shiller, C.R. German, D.E. Lott III, G. Weiss, L. Whitmore, N.T. Lanning, K. Casciotti, P.J. Lam, G.A. Cutter, K.L Cahill. (2020). An intermediate-depth source of hydrothermal 3He and dissolved iron in the North Pacific. Earth and Planetary Sciences. DOI: 10.1016/j.epsl.2020.116223
  • L.M. Whitmore, P.L. Morton, B.S. Twining, A.M. Shiller. (2019) Vanadium cycling in the Western Arctic Ocean and shelf-basin connectivity. Marine Chemistry. DOI: 10.1016/j.marchem.2019.103701
  • D. Kadko, A. Aguilar-Islas, C. Bolt, C.S. Buck., J.N. Fitzsimmons, L.T. Jensen, W.M. Landing, C.M. Marsay, R. Rember, A.M. Shiller, L.M. Whitmore, R.F. Anderson. 2019. The residence times of trace elements determined in the surface Arctic Ocean during the 2015 US Arctic GEOTRACES expedition. Marine Chemistry.  DOI: 10.1016/j.marchem.2018.10.011
  • C.M. Marsay, A. Aguilar-Islas, J.N. Fitzsimmons, M. Hatta, L.T. Jensen, S.G. John, D. Kadko, W.M. Landing, N.T. Lanning, P.L. Morton, A. Pasqualini, S. Rauschenberg, R.M. Sherrell, A.M. Shiller, B.S. Twining, L.M. Whitmore, Ruifeng Zhan, C.S. Buck. 2018. Dissolved and particulate trace elements in late summer Arctic melt ponds. Marine Chemistry, DOI: 10.1016/j.marchem.2018.06.002
  • J.J. Moran, L.M. Whitmore, Z.J. Jay, R.deM. Jennings, J.P. Beam, H.W. Kreuzer, W.P. Inskeep. 2017. Dual stable isotopes of CH4 from Yellowstone hot-springs suggest hydrothermal processes involving magmatic CO2.  J. of Volcan. & Geophys. Res., DOI: 10.1016/j.volgeores.2017.05.011
  • R. deM. Jennings, J.J. Moran, Z.J. Jay, J.P. Beam, L.M. Whitmore, M.A. Kozubal, H.W. Kreuzer, W.P. Inskeep. 2017. Integration of metagenomic and stable carbon isotope evidence reveals the extent and mechanisms of carbon dioxide fixation in high-temperature microbial communities. Front. Microbiol. DOI: 10.3389/fmicb.2017.00088
  • J.J. Moran, L.M. Whitmore, N.G. Isern, M.F. Romine, K.M. Riha, W.P. Inskeep, H.W. Kreuzer. 2016. Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of the Norris Geyser Basin, Yellowstone National Park. Extremophiles. DOI: 10.1007/s00792-016-0821-2
  • R. deM. Jennings, L.M. Whitmore, J.J. Moran, H.W. Kreuzer, W.P. Inskeep. 2014. Carbon dioxide fixation by Metallosphaera yellowstonensis and acidothermophilic iron-oxidizing microbial communities from Yellowstone National Park. Applied and Environmental Microbiology, DOI: 10.1128/AEM.03416-13