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Marine Sciences Division

Nicholas Ward

Nicholas Ward

Marine Sciences Laboratory
Pacific Northwest National Laboratory
1529 West Sequim Bay Road
Sequim, Washington 98382


Nick joined the Pacific Northwest National Laboratory in 2016 as a Research Scientist at the Marine Sciences Laboratory in Sequim, Washington. Nick manages the Mercury Analytical Laboratory and associated projects focused on monitoring trace metal and mercury levels and speciation in a variety of environmental and man-made settings (e.g. rivers/oceans/reservoirs, factories, mines, and wastewater plants) and matrices (e.g. water, soils/sediments, and biological tissue). Nick is also responsible for leading research aimed at understanding how biogeochemical and biological processes interact along the interface of terrestrial and aquatic ecosystems, particularly with respect to global carbon cycling. More information about Nick’s research can be found here:

Research Interests

  • Biogeochemistry and environmental “omics”
  • Ecosystem dynamics, sensitivity, and resilience
  • Sustainable natural resource management
  • Hydrology and hydrodynamics

Education and Credentials

  • 2018-present Faculty Fellow, School of Oceanography, University of Washington, Seattle, WA
  • 2017-2018 Affiliate Assistant Professor, University of Washington, School of Oceanography, Seattle, WA
  • 2016-present Earth Scientist, Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim, WA
  • 2016 Research Scientist, University of Florida, Whitney Lab for Marine Bioscience, St. Augustine, FL
  • 2014-2016 Postdoctoral Associate, University of Florida, Dept. of Geological Sciences, Gainesville, FL
  • 2014 Ph.D. Chemical Oceanography, University of Washington, School of Oceanography, Seattle, WA
  • 2010 M.S. Chemical Oceanography, University of Washington, School of Oceanography, Seattle, WA
  • 2008 B.S. Environmental Systems, University of California San Diego, La Jolla, CA
  • 2007 Summer Student Fellow, Woods Hole Oceanographic Institution, Woods Hole, MA
  • 2006-2008 Research Assistant, Scripps Institution of Oceanography, La Jolla, CA

Affiliations and Professional Service

  • American Association for the Advancement of Science
  • American Geophysical Union
  • Association for the Sciences of Limnology and Oceanography
  • National Science Teachers Association (2012-2016)

Awards and Recognitions

  • 2018 PNNL STEM Ambassador Fellow
  • 2018 AGU Editor's Citation for Excellence in Refereeing (JGR: Biogeosciences)
  • 2017 PNNL Energy and Environment Directorate Publication of the Year
  • 2017 ASLO Aquatic Sciences Meeting Early Career Scientist Travel Grant
  • 2012 National Science Foundation GK-12 teaching fellowship
  • 2008 UCSD Sports Clubs Male Athlete of the Year
  • 2007 UCSD Dean of Physical Sciences Undergraduate Award for Excellence
  • 2007 National Science Foundation REU Summer Student Fellowship
  • 2004 Antone Ara Bia Scholarship

PNNL Publications


  • Tagestad J.D., N.D. Ward, D. Butman, and J.C. Stegen. 2021. "Small Streams Dominate US Tidal Reaches and Will be Disproportionately Impacted by Sea-level Rise." Science of the Total Environment 753. PNNL-SA-145873. doi:10.1016/j.scitotenv.2020.141944


  • Schafer T., N.D. Ward, P. Julian, K. Reddy, and T. Osborne. 2020. "Impacts of hurricane disturbance on water quality across the aquatic continuum of a black-water river to estuary complex." Journal of Marine Science and Engineering 8, no. 6:Article No. 412. PNNL-SA-137849. doi:10.3390/jmse8060412
  • Wang W., N.G. McDowell, S.C. Pennington, C. Grossiord, R.T. Leff, A. Sengupta, and N.D. Ward, et al. 2020. "Tree growth, transpiration, and water-use efficiency between shoreline and upland red maple (Acer rubrum) trees in a coastal forest." Agricultural and Forest Meteorology 295. PNNL-SA-153708. doi:10.1016/j.agrformet.2020.108163
  • Ward N.D., J.L. Indivero, C.M. Gunn, W. Wang, V.L. Bailey, and N.G. McDowell. 2020. Longitudinal gradients in tree stem greenhouse gas concentrations across six Pacific Northwest coastal forests. PNNL-30257. Richland, WA: Pacific Northwest National Laboratory. Longitudinal gradients in tree stem greenhouse gas concentrations across six Pacific Northwest coastal forests
  • Ward N.D., P. Megonigal, B. Bond-Lamberty, V.L. Bailey, D. Butman, E. Canuel, and H.L. Diefenderfer, et al. 2020. "Representing the Function and Sensitivity of Coastal Interfaces in Earth System Models." Nature Communications 11. PNNL-SA-147328. doi:10.1038/s41467-020-16236-2
  • Yabusaki S.B., A.N. Myers-Pigg, N.D. Ward, S.R. Waichler, A. Sengupta, Z. Hou, and X. Chen, et al. 2020. "Floodplain inundation and salinization from a recently restored first-order tidal stream." Water Resources Research 56, no. 7:Article No. e2019WR026850. PNNL-SA-149723. doi:10.1029/2019WR026850
  • Zayas-Santiago C., A. Rivas-Ubach, L. Kuo, N.D. Ward, and R.C. Zimmerman. 2020. "Metabolic profiling reveals biochemical pathways responsible for eelgrass response to elevated CO2 and temperature." Scientific Reports 10, no. 1:Article No. 4693. PNNL-SA-142954. doi:10.1038/s41598-020-61684-x


  • Arajo K., H.O. Sawakuchi, D. Bertassoli, A.O. Sawakuchi, K. da Silva, T.B. Vieira, and N.D. Ward, et al. 2019. "Carbon dioxide (CO2) concentrations and emission in the newly constructed Belo Monte hydropower complex in the Xingu River, Amazonia." Biogeosciences 16, no. 18:3527-3542. PNNL-SA-140925. doi:10.5194/bg-16-3527-2019
  • Arellano A., T.S. Bianchi, C. Osburn, E. D'Sa, N.D. Ward, D. Oveido-Vargas, and I. Joshi, et al. 2019. "Mechanisms of Organic Matter Export in Estuaries with Contrasting Carbon Sources." Journal of Geophysical Research. Biogeosciences 124, no. 10:3168-3188. PNNL-SA-137885. doi:10.1029/2018JG004868
  • Bianchi T.S., and N.D. Ward. 2019. "Editorial: The Role of Priming in Terrestrial and Aquatic Ecosystems." Frontiers in Earth Science 7. PNNL-SA-148208. doi:10.3389/feart.2019.00321
  • Bond-Lamberty B., S.C. Pennington, J. Jian, P. Megonigal, A. Sengupta, and N.D. Ward. 2019. "Soil respiration variability and correlation across a wide range of temporal scales." Journal of Geophysical Research. Biogeosciences 124, no. 11:3672-3685. PNNL-SA-143258. doi:10.1029/2019JG005265
  • Chamberlain C., T.S. Bianchi, A. Brown, M. Cohen, X. Dong, M. Flint, and J. Martin, et al. 2019. "Mass Balance Implies Holocene Development of a Low-Relief Karst Patterned Landscape." Chemical Geology 527. PNNL-SA-128697. doi:10.1016/j.chemgeo.2018.05.029
  • Coppola A., M. Seidel, N.D. Ward, D. Viviroli, G. Nascimento, N. Haghipour, and B. Revels, et al. 2019. "Marked isotopic variability within and between the Amazon River and marine dissolved black carbon pools." Nature Communications 10, no. 1:Article Number 4018. PNNL-SA-144923. doi:10.1038/s41467-019-11543-9
  • Kuhn C., A. Valerio, N.D. Ward, L. Loken, H.O. Sawakuchi, M. Kampel, and J.E. Richey, et al. 2019. "Performance of Landsat-8 and Sentinel-2 surface reflectance products for river remote sensing retrievals of chlorophyll-a and turbidity." Remote Sensing of Environment. PNNL-SA-141044. doi:10.1016/j.rse.2019.01.023
  • Valerio A., M. Kampel, V. Vantrepotte, N.D. Ward, H.O. Sawakuchi, D. Less, and V. Neu, et al. 2019. "Algoritmo regional para estimativa do material particulado em suspenso no baixo Amazonas." In Proceedings of XIX Brazilian Symposium on Remote Sensing, April 14-17, 2019, Santos, Sao Paulo, Brazil, 17, 636-639. PNNL-SA-138628.
  • Wang W., N.G. McDowell, N.D. Ward, J.L. Indivero, C.M. Gunn, and V.L. Bailey. 2019. "Constrained tree growth and gas-exchange of seawater-exposed forests in the Pacific Northwest, USA." Journal of Ecology 107, no. 6:2541-2552. PNNL-SA-144278. doi:10.1111/1365-2745.13225
  • Ward N.D., E. Morrison, Y. Liu, A. Rivas-Ubach, T. Osborne, A. Ogram, and T.S. Bianchi. 2019. "Marine microbial community responses related to wetland carbon mobilization in the coastal zone." Limnology and Oceanography: Letters 4, no. 1:25-33. PNNL-SA-134462. doi:10.1002/lol2.10101
  • Ward N.D., H.O. Sawakuchi, J.E. Richey, R.G. Keil, and T.S. Bianchi. 2019. "Enhanced aquatic respiration associated with mixing of clearwater tributary and turbid Amazon River waters." Frontiers in Earth Science 7. PNNL-SA-140620. doi:10.3389/feart.2019.00101
  • Ward N.D., J.L. Indivero, C.M. Gunn, W. Wang, V.L. Bailey, and N.G. McDowell. 2019. "Longitudinal gradients in tree stem greenhouse gas concentrations across six Pacific Northwest coastal forests." Journal of Geophysical Research. Biogeosciences 124, no. 6:1401-1412. PNNL-SA-138892. doi:10.1029/2019JG005064
  • Zhang X., T.S. Bianchi, M. Cohen, J. Martin, C. Quintero, A. Brown, and A. Ares, et al. 2019. "Initiation and development of wetlands in southern Florida karst landscape associated with accumulation of organic matter and vegetation evolution." Journal of Geophysical Research. Biogeosciences 124, no. 6:1604-1617. PNNL-SA-136524. doi:10.1029/2018JG004921


  • Dong X., M. Cohen, J. Martin, D. Mclaughlin, A. Murray, N.D. Ward, and M. Flint, et al. 2018. "Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape." Chemical Geology 527, no. 2019:Article No. 118774. PNNL-SA-132178. doi:10.1016/j.chemgeo.2018.05.021
  • Galeron M., O. Radakovitch, B. Charrire, F. Vaultier, J. Volkman, T.S. Bianchi, and N.D. Ward, et al. 2018. "Lipoxygenase-induced autoxidative degradation of terrestrial particulate organic matter in estuaries: A widespread process enhanced at high and low latitude." Organic Geochemistry 115. PNNL-SA-130078. doi:10.1016/j.orggeochem.2017.10.013
  • Valerio A., M. Kampel, V. Vantrepotte, N.D. Ward, H.O. Sawakuchi, D. Less, and V. Neu, et al. 2018. "Using CDOM optical properties for estimating DOC concentrations and pCO2 in the Lower Amazon River." Optics Express 26, no. 14:A657-A677. PNNL-SA-131638. doi:10.1364/OE.26.00A657
  • Ward N.D., H.O. Sawakuchi, and J.E. Richey. 2018. "The Amazon River's Ecosystem-Where Land Meets the Sea." Eos 99, no. January 18, 2018. PNNL-SA-128535. doi:10.1029/2018EO088573
  • Ward N.D., H.O. Sawakuchi, V. Neu, D. Less, A. Valerio, A. Cunha, and M. Kampel, et al. 2018. "Velocity-amplified microbial respiration rates in the lower Amazon River." Limnology and Oceanography: Letters 3, no. 3:265-274. PNNL-SA-123173. doi:10.1002/lol2.10062


  • Bianchi T.S., D. Butman, P.A. Raymond, N.D. Ward, R. Kates, K. Flessa, and H. Zamora, et al. 2017. "The Experimental Flow to the Colorado River Delta: Effects on Carbon Mobilization in a Dry Watercourse." Journal of Geophysical Research. Biogeosciences 122, no. 3:607-327. PNNL-SA-124474. doi:10.1002/2016JG003555
  • Doherty M., P. Yager, M. Moran, V. Coles, C.S. Fortunato, A. Krusche, and P.M. Medeiros, et al. 2017. "Bacterial biogeography across the Amazon river-ocean continuum." Frontiers in Microbiology 8. PNNL-SA-125962. doi:10.3389/fmicb.2017.00882
  • Duan S., Y. He, S.S. Kaushal, T.S. Bianchi, N.D. Ward, and L. Guo. 2017. "Impact of wetland decline on decreasing dissolved organic carbon concentrations along the Mississippi River continuum." Frontiers in Marine Science 3. PNNL-SA-124217. doi:10.3389/fmars.2016.00280
  • Gagne-Maynard W., N.D. Ward, R.G. Keil, H.O. Sawakuchi, A. Cunha, V. Neu, and D. Brito, et al. 2017. "Evaluation of primary production in the lower Amazon River based on a dissolved oxygen stable isotopic mass balance." Frontiers in Marine Science 4. PNNL-SA-123464.
  • Joshi I., E. D'Sa, C. Osburn, T.S. Bianchi, D. Ko, D. Oveido-Vargas, and A. Arellano, et al. 2017. "Assessing chromophoric dissolved organic matter (CDOM) distribution, stocks, and fluxes in Apalachicola Bay using combined field, VIIRS ocean color, and model observations." Remote Sensing of Environment 191. PNNL-SA-124218. doi:10.1016/j.rse.2017.01.039
  • Satinsky B., C. Smith, S. Sharma, N.D. Ward, A. Krusche, J.E. Richey, and P. Yager, et al. 2017. "Patterns of Bacterial and Archaeal Gene Expression Through the Lower Amazon River." Frontiers in Marine Science 4. PNNL-SA-128662. doi:10.3389/fmars.2017.00253
  • Sawakuchi H.O., V. Neu, N.D. Ward, M.C. Barros, A. Valerio, W. Gagne-Maynard, and A. Cunha, et al. 2017. "Carbon dioxide emissions along the lower Amazon River." Frontiers in Marine Science 4. PNNL-SA-124475.
  • Silva B., F. Coutinho, G. Gregoracci, L. Leomil, L. Oliveira, A. Fres, and D. Tschoeke, et al. 2017. "Virioplankton assemblage structure in the lower river and ocean continuum of the Amazon." mSphere 2, no. 5:e00366-17. PNNL-SA-128630. doi:10.1128/mSphere.00366-17
  • Ward N.D. 2017. "Editorial: Integrative Research on Organic Matter Cycling Across Aquatic Gradients." Frontiers in Marine Science 4. PNNL-SA-124200.
  • Ward N.D., T.S. Bianchi, P.M. Medeiros, M. Seidel, J.E. Richey, R.G. Keil, and H.O. Sawakuchi. 2017. "Where carbon goes when water flows: Carbon cycling across the aquatic continuum." Frontiers in Marine Science 4. PNNL-SA-122717.
  • Ward N.D., T.S. Bianchi, P.M. Medeiros, M. Seidel, R.G. Keil, and C. Robinson. 2017. Integrative Research on Organic Matter Cycling Across Aquatic Gradients. Lausanne:Frontiers Media SA. PNNL-SA-127485. doi:10.3389/978-2-88945-212-5

Selected Publications


  • Neu, V., Ward, N.D., Krusche, A.V., Neill, C. 2016. Dissolved organic and inorganic carbon flow paths in an Amazonian transitional forest. Frontiers in Marine Science 3 (114). DOI: 10.3389/fmars.2016.00114.
  • Sawakuchi, H.O., Bastviken, D., Sawakuchi, A.O., Ward, N.D., Borges, C., Tsai, S.M., Richey, J.E., Ballester, M.V.R., Krusche, A.V. 2016. Oxidative mitigation of methane evasion in large Amazonian rivers. Global Change Biology 22 (3), 1075-1085.
  • Seidel, M., Dittmar, T., Ward, N.D., Krusche, A.V., Richey, J.E., Yager, P.L., Medeiros, P.M. 2016. Seasonal and spatial variability of dissolved organic matter in the lower Amazon River. Biogeochemistry 131 (3), 281-302.
  • Ward, N.D., Bianchi, T.S., Sawakuchi, H.O., Gagne-Maynard, W., Cunha, A.C., Brito, D.C., Neu, V., Valerio, A.M., da Silva, R., Krusche, A.V., Richey, J.E., Keil, R.G. 2016. The reactivity of plant-derived organic matter and the potential importance of priming effects in the lower Amazon River. Journal of Geophysical Research: Biogeosciences 121, 1522-1539.


  • Bianchi, T.S., Thornton, D., Yvon-Lewis, S., King, G., Eglinton, T., Shields, M., Ward, N.D., Curtis, J. 2015. Positive priming of terrestrially-derived dissolved organic matter in a freshwater microcosm system. Geophysical Research Letters 42 (13), 5460-5467.
  • Medeiros, P.M., Seidel, M., Ward, N.D., Carpenter, E.J., do Rosário Gomes, H., Niggemann, J., Krusche, A.V., Richey, J.E., Yager, P.L., Dittmar, T. 2015. Fate of Amazon River dissolved organic matter in the Tropical Atlantic Ocean. Global Biogeochemical Cycles 29 (5), 677-690.
  • Satinsky, B.M., Fortunato, C.S., Doherty, M., Smith, C.B., Sharma, S., Richey, J.E., Ward, N.D., Krusche, A.V., Moran, M.A., Crump, B.C. 2015. Metagenomic and metatranscriptomic inventories of the Amazon River, May 2011. Microbiome 3 (39).
  • Seidel, M., Yager, P.L., Ward, N.D., Carpenter, E.J., Gomes, H.R., de Rezende, C.E., Krusche, A.V., Richey, J.E., Dittmar, T., Medeiros, P.M. 2015. Molecular level transformations of dissolved organic matter in the river to ocean continuum of the Amazon. Marine Chemistry 177 (2), 218-231.
  • Ward, N.D. and Petrik-Finley, R.J. 2015. Integrating local environmental research into an inquiry-based unit on biogeochemical principles in a high school science classroom. The Earth Scientist-NESTA 31(2), 21-28.
  • Ward, N.D., Krusche, A.V., Sawakuchi, H.O., Brito, D.C., Cunha, A.C., Moura, J.M.S., da Silva, R., Yager, P.L., Keil, R.G., Richey, J.E. 2015. The compositional evolution of dissolved and particulate organic matter along the lower Amazon River-Óbidos to the ocean. Marine Chemistry 177 (2), 244-256.


  • Ward, N.D., Finley, R.J., Keil, R.G., Clay, T.G. 2013. Benefits and limitations of iPads in the high school science classroom and a trophic cascade lesson plan. Journal of Geoscience Education 61(4), 378-384.
  • Ward, N.D., Keil, R.G., Medeiros, P.M., Brito, D.C., Cunha, A.C., Dittmar, T., Yager, P.L., Krusche, A.V., Richey, J.E. 2013. Degradation of terrestrially derived macromolecules in the Amazon River. Nature Geoscience 6 (7), 530-533.


  • Ward, N.D., Keil, R.G., Richey, J.E. 2012. Temporal variation in river nutrient and dissolved lignin phenol concentrations and the impact of storm events on nutrient loading to Hood Canal, Washington, USA. Biogeochemistry 111 (1-3), 629-645.

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Marine Sciences Laboratory
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