Ecosystems Research

Nick Ward, PhD    

Other Publications

​​​Pacific Northwest National Laboratory (2019) STAR Workshop: Terrestrial-Aquatic Research in Coastal Systems. PNNL-28635. Pacific Northwest National Laboratory, Richland, Washington. Workshop Chairs: Megonigal, P. and Ward, N.D.

Ward, N.D., Bianchi, T.S., Medeiros, P.M., Seidel, M., Keil, R.G., Robinson, C. (2017) E-Book: Integrative research on organic matter cycling across aquatic gradients. Frontiers in Marine Science. Doi: 10.3389/978-2-88945-212-5



Schafer, T., Ward, N.D., Julian, P., Reddy, K.R., Osborne, T.Z. (2020) Impacts of hurricane disturbance on water quality across the aquatic continuum of a black-water river to estuary complexJournal of Marine Science and Engineering. 8 (12). doi:10.3390/jmse8060412 

Silva, G.C.X., Abreu, H.M., Ward, N.D., Cunha, H.F.A., Brito, D.C., Cunha, A.C. (2020) Environmental impacts of dam reservoir filling in the East Amazon.Frontiers in Water. 2 (11). doi: 10.3389/frwa.2020.00011

Ward, N.D., Megonigal, J.P., Bond-Lamberty, B.,L., Bailey, V.,  Butman, D., Canuel, E.A., Diefenderfer, H., Ganju, N.K., Goñi, M.A., Graham, E., Hopkinson, C.S., Khangaonkar, T., Langley, J.A., McDowell, N.G., Myers-Pigg, A.N., Neumann, R.B., Osburn, C.L., Price, R.M., Rowland, J., Sengupta, A., Simard, M., Thornton, P., Tzortziou, M., Vargas, R., Wesienhorn, P.B., Windham-Myers, L. (2020) Representing the function and sensitivity of coastal interfaces in Earth System Models. Nature Communications. 11 (2458).

Yabusaki, S., Myers-Pigg, A., Ward, N.D., Waichler, S.R., Sengupta, A., Hou, Z., Chen, X., Fang, Y., Duan, Z., Serkowski, Indivero, J., Weise-Moore, C., Gunn, C. (2020) Floodplain inundation and salinization from a recently restored first-order tidal stream. Water Resources Research.

Zayas-Santiago, C., Rivas-Ubach, A., Kuo, L.J., Ward, N.D., Zimmerman, R.C. (2020) Metabolic profiling reveals biochemical pathways responsible for eelgrass response to elevated CO2 and temperature. Scientific Reports. 10 (4693)

Araújo, K.R., Sawakuchi, H.O., Bertassoli Jr., D.J., Sawakuchi, A.O., da Silva, K.D., Bernardi, T.V., Ward, N.D., Pereira, T.S. (2019) The influence of reservoir traits on carbon dioxide emissions in the Belo Monte hydropower complex, Xingu River, Amazon-Brazil. Biogeosciences. 16 (18), 3527-3542.

Arellano, A.R., Bianchi, T.S., Osburn, C.L., D’Sa, E.J., Oviedo-Vargas, D., Ward, N.D., Joshi, I., Ko, D., Shields, M.R., Kurian, G., Green, J. (2019) Mechanisms of blue carbon export in estuaries with contrasting carbon sources. Journal of Geophysical Research: Biogeosciences. 124 (10), 3168-3188.

Bianchi, T.S. and Ward, N.D. (2019) Editorial: The Role of Priming in Terrestrial and Aquatic Ecosystems. Frontiers in Earth Science. 7 (321). doi: 10.3389/feart.2019.00321 

Bond-Lamberty, B., Pennington, S., Jian, J., Megonigal, P., Sengupta, A., Ward, N.D. (2019) Soil respiration variability and correlation across a wide range of temporal scales. Journal of Geophysical Research: Biogeosciences.

Chamberlain, C., Bianchi, T.S., Brown, A.L., Cohen, M.J., Dong, X., Flint, M.K., Martin, J.B., McLaughlin, D.L., Murray, A.B., Pain, A., Quintero, C., Ward, N.D., Zhang, X., Heffernan, J.B. (2019) Mass balance implies Holocene development of a low-relief karst patterned landscapeChemical Geology. 527 (20), 118782.
Coppola, A.I.,
Seidel, M., Ward, N.D., Viviroli, D., Haghipour, N., Nascimento, G.S., Jones, M., Revells, B.N., Abiven, S., Jones, M., Richey, J.E., Eglinton, T.I., Dittmar, T., Schmidt, M.W.I. (2019) Marked isotopic variability within and between the Amazon River and marine dissolved black carbon pools. Nature Communications. 10 (4018). doi: 10.1038/s41467-019-11543-9

Dong, X., Cohen, M.J., Martin, J.B., McLaughlin, D.L., Murray, A.B., Ward, N.D., Flint, M.K., Heffernan, J.B. (2019) Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscapeChemical Geology. 527 (20), 118774 

Kuhn, C., Valerio, A., Ward, N.D., Loken, L., Sawakuchi, H.O., Kampel, M., Richey, J.E., Stadler, P., Crawford, J., Striegl, R.G., Vermote, E., Pahlevan, N. Butman, D. (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. 224, 104-118

Sengupta, A., Indivero, J., Gunn, C., Tfaily, M., Chu, R., Toyoda, J., Bailey, V., Ward, N.D., Stegen, J.C. (2019) Spatial gradients in soil-carbon character of a coastal forested floodplain are associated with abiotic features, but not microbial communities. Biogeosciences. 16 (19), 3911-3928.

Wang, W., McDowell, N.G., Ward, N.D., Indivero, J., Gunn, C., Bailey, V. (2019) Constrained tree growth and gas exchange of seawater‐exposed forests in the Pacific Northwest, USAJournal of Ecology. 107 (6), 2541-2552. doi: 10.1111/1365-2745.13225

Ward, N.D., Indivero, J., Gunn, Wang, W., Bailey, V., McDowell, N.G. (2019) Longitudinal gradients in tree stem greenhouse gas concentrations across six Pacific Northwest coastal forests. Journal of Geophysical Research: Biogeosciences. 124.doi: 10.1029/2019JG005064

Ward, N.D., Morrison, E., Liu, Y., Rivas-Ubach, A., Osborne, T.Z., Ogram, A., Bianchi, T.S. (2019) Marine microbial responses related to wetland carbon mobilization in the coastal zone. Limnology & Oceanography: Letters. 4, 25-33, doi: 10.1002/lol2.10101

Ward, N.D., Sawakuchi, H.O., Richey, J.E., Keil, R.G., Bianchi, T.S. (2019) Enhanced aquatic respiration rates associated with mixing of clearwater tributary and turbid Amazon River waters. Frontiers in Earth Science. 7 (101). doi: 10.3389/feart.2019.00101

Zhang, X., Bianchi, T.S., Cohen, Martin, J.B., Quintero, C.J., Brown, A.L., Ares, A.M., Ward, N.D., Osborne, T.Z., Heffernan, J.B. (2019) Development of wetlands in southern Florida karst landscape associated with accumulation of organic matter and its cycling. Journal of Geophysical Research: Biogeosciences. 124. doi: 10.1029/2018JG004921

Galeron, M.-A., Radakovitch, O., Charrière, B., Volkman, J.K., Bianchi, T.S., Ward, N.D., Medeiros, P.M., Sawakuchi, H.O., Tank, S., Rontani, J.-F. (2018) Lipoxygenase-induced autoxidative degradation of terrestrial particulate organic matter in estuaries: a widespread process enhanced at high and low latitudes. Organic Geochemistry. 115, 78-92

Joshi, I., Ward, N.D., D’Sa, E.J., Osburn, C.L., Bianchi, T.S., Oviedo-Vargas, D. (2018) Seasonal trends in surface pCO2 and air-sea CO2 fluxes in Apalachicola Bay, Florida from VIIRS ocean color. Journal of Geophysical Research: Biogeosciences. 123 (8), 2466-2484.

Valerio, A.M., Kampel, M., Vantrepotte, V., Ward, N.D., Sawakuchi, H.O., Less, D.F., Neu, V., Cunha, A., Richey, J.E. (2018) Using CDOM optical properties for estimating DOC concentrations and pCO2 in the Lower Amazon River. Optics Express. 26 (14), A657

Ward, N.D., Sawakuchi, H.O., Richey, J.E. (2018) The Amazon River’s ecosystem—where land meets the sea. Eos. 99. 

Ward, N.D., Sawakuchi, H.O., Neu, V., Less, D., Valerio, A.M., Cunha, A.C., Kampel, M., Bianchi, T.S., Krusche, A.V., Richey, J.E., Keil, R.G. (2018) Velocity-amplified microbial respiration rates in the lower Amazon River. Limnology & Oceanography: Letters. 3, 265-274. doi: 10.1002/lol2.10062

Bianchi, T.S., Butman, D., Raymond, P., Ward, N.D., Kates, R., Flessa, K.W., Zamora, H., Arellano, A., Ramirez, J., Rodriguez, E. (2017) The experimental flow to the Colorado River delta: effects on carbon cycling in a dry watercourse. Journal of Geophysical Research: Biogeosciences. 122 (3), 607-627.

Doherty, M., Yager, P.L., Moran, M.A., Satinsky, B.M., Payet, J.P., Ward, N.D., Sawakuchi, H.O., Fortunato, C., Richey, J.E., Crump, B.C. (2017) Bacterial biogeography across the Amazon river-to-ocean continuum. Frontiers in Microbiology. 8 (882). doi: 10.3389/fmicb.2017.00882

Duan, S.W., He, Y., Kaushal, S.S., Bianchi, T.S., Ward, N.D., Guo, L., Findlay, S.E.G. (2017) Wetland controls on dissolved organic carbon concentrations along the Mississippi River continuum. Frontiers in Marine Science. 3 (280)

Gagne-Maynard, W., Ward, N.D., Keil, R.G., Sawakuchi, H.O., Cunha, A.C., Neu, V., Brito, D.C., Less, D., Diniz, J., Valerio, A.M., Kampel, M., Krusche, A.V., Richey, J.E. (2017) Evaluation of primary production in the lower Amazon River based on a dissolved oxygen stable isotopic mass balance.Frontiers in Marine Science. 4 (26)

Joshi, I., D’Sa, E.J., Osburn, C.L., Bianchi, T.S., Ko, D., Oviedo-Vargas, D., Arellano, A., Ward, N.D. (2017) Assessing chromophoric dissolved organic matter (CDOM) distributions, stocks, and fluxes in Apalachicola Bay using combined field, VIIRS ocean color, and model observations. Remote Sensing of Environment. 191, 359-372

Sawakuchi, H.O., Neu, V., Ward, N.D., Barros, M.L.C., Valerio, A.M., Gagne-Maynard, W., Cunha, A.C., Less, D.F., Diniz, J.E., Brito, D.C., Krusche, A.V., Richey, J.E. (2017) Carbon dioxide emissions along the lower Amazon River. Frontiers in Marine Science​. 4 (76)

Satinsky, B., Smith, C.B., Sharma, S., Ward, N.D., Krusche, A.V., Richey, J.E., Yager, P.L., Crump, B.C., Moran, M.A. (2017) Patterns of bacterial and archaeal gene expression through the lower Amazon River.Frontiers in Marine Science. 4 (253)

Silva, B.S.O., Coutinho, F.H., Gregoracci, G.B., Leomil, L., Oliveira, L.S.d.O., Froes, A.M., Tschoeke, D., Soares, A.C., Cabral, A.S., Ward, N.D., Richey, J.E., Krusche, A.V., Yager, P.L., Rezende, C.E. (2017) Virioplankton Assemblage Structure in the Lower River and Ocean Continuum of the AmazonmSphere. 2 (5), e00366-17

Ward, N.D. (2017) Editorial: Integrative research on organic matter cycling across aquatic gradients. Frontiers in Marine Science. 4 (131)

Ward, N.D., Bianchi, T.S., Medeiros, P.M., Seidel, M., Richey, J.E., Keil, R.G., Sawakuchi, H.O. (2017) Where carbon goes when water flows: Carbon cycling across the aqautic continuumFrontiers in Marine Science. 4 (7)

​​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)

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., de Matos, A., 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 systemGeophysical 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 2011Microbiome. 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 AmazonMarine Chemistry. 177 (2), 218-231

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—Obidos to the oceanMarine Chemistry. 177 (2), 244-256

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., 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

Manuscripts in review


Norwood, M.J., Ward, N.D., McDowell, N.G., Myers-Pigg, A.N., Bond-Lamberty, B., Pennington, S., Wang, W., Kirwan, M., Hopple, A.M., Megonigal, J.P. (in review) Accumulation of tree stem methane in association with diverse disturbance regimes. Submitted to Journal of Geophysical Research: Biogeosciences

Richey, J.E., Spencer, R., Drake, T.W., Ward, N.D. (in review) Fluvial carbon dynamics across the land to ocean continuum of great tropical rivers: the Amazon and Congo. AGU Monograph Series. In Congo Basin Hydrology, Climate, and Biogeochemistry: A Foundation for the Future. Edited by Alsdorf, D.E., Tshimanga, R., Moukandi, G.

Sawakuchi, H.O., Bastviken, D., Enrich-Prast, A., Ward, N.D., Rodrigues Bastos, W., Richey, J.E., Ballester, M.V.R., Krusche, A.V. (in review) Low methane emissions from the main channel of a large Amazonian run-of-the-river reservoir attributed to high methane oxidation. Submitted to Frontiers in Earth Science

Valerio, A.M., Kampel, M., Ward, N.D., Sawakuchi, H.O., Cunha, A.C., Krusche, A.V., Richey, J.E. (in review) Assessment of partial pressure of carbon dioxide in the Amazon River plume using in situ and remote sensing data. Submitted to Continental Shelf Research

Wang, W., McDowell, N., Pennington, S., Grossiord, C., Leff, R., Ward, N.D., Megonigal, J.P., Bond-Lamberty, B., Bailey, V. (in review). Homeostatic tree growth, transpiration, and water-use efficiency between shoreline and upland red maple (Acer rubrum) trees in a coastal forest. Submitted to Agricultural and Forest Meteorology

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