Samantha Siedlecki

(Ph.D., University of Chicago) Associate Professor of Marine Sciences

As an oceanographer, Dr. Siedlecki focuses on coastal regions where she implements numerical simulations to investigate and identify processes within that environment responsible for the biogeochemical dynamics in both the modern and future oceans. She received her PhD from the University of Chicago where she focused on largely on theoretical systems of the ocean. As a postdoctoral fellow at JISAO at the University of Washington, she began simulating Washington and Oregon waters using realistic simulations of ocean acidification variable and hypoxia developed as part of the Coastal Modeling Group there. At JISAO, she extended that work to include seasonal (J-SCOPE) and short term (LiveOcean) forecasts.  Now an assistant professor at the University of Connecticut, she has begun exploring regional climate projections of ocean conditions on both the west and east coast of the US. She has recently co-authored a chapter in the United States’ 4th National Climate Assessment and the 2nd State of the Carbon Cycle Report, and been named a Kavli Fellow.  Through work with colleagues on both coasts as well as new collaborators part of the Early Career Faculty Innovators Program at NCAR, she and her group at UConn are partnering with social scientists to bring these tools into decision making frameworks to aid coastal communities and the challenges they face with respect to marine resource planning.

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Current Projects:

NSF Convergence Accelerator Track E: Regional climate change projections to enable equitable ocean planning for the blue economy. (NSF)

Assessing vulnerability of the Atlantic Sea Scallop social- ecological system in the northeast waters of the US (NOAA OAP)

The predictability of oxygen and its metabolic consequences for fisheries on decadal time scales (NOAA MAPP)

Oxygen Dynamics in the Southern Benguela Upwelling system (NSF)

Assessment of the Observing Network to Identify Processes Relevant to the Predictability of the Coastal Ocean of the Northeast on Centennial Time Scales (NOAA OAP)

Enhancement of an existing ocean forecast system to include ocean acidification(NOAA OAP)

Experiments with Seasonal Forecasts of ocean conditions in the Pacific Northwest to aid the crab fishery (NOAA MAPP)

Oceanography Students

Kelly McGarry- PhD student

Halle Berger – PhD student (co-advised with Catherine Matassa)

Annette Carlson – M.Sc. student

Hung Nguyen – PhD student


Zhuomin Chen – Research Scientist

Felipe Soares – Research Assistant

Courses Taught:

Undergraduate: Reaction and Transport – MARN 3003Q (offered in the spring)

Reaction and Transport introduces methods for the quantification of chemical/biological reactions and transport dynamics of marine environmental systems through problem solving. Specifically, you’ll learn to:

  • Ask what processes dominate a signal in the marine environment – what is driving the signal? Give you the tools to start doing this quantitatively

  • Develop an ability to express quantitative results in language that conveys information

  • Connect mental analysis and assessment to the need to perform mathematical calculations

  • Think creatively about problems to analyze information

Key Tools/Concepts Developed include:

  • Steady state vs equilibrium

  • Rate vs flux

  • Residence time


  • mass balances, chemical reaction, advection, diffusion, steady state, transients state, boundary conditions, dynamic steady state

  • formalized process analysis including specific unit analysis

  • process description mathematically 

  • first order quantification of processes

To develop the skills mentioned above, Reaction and Transport balances lectures with hand on productive problem-solving sessions in small groups with plenty of access to the professor, and EXAMPLES!  By the end of the semester you will have completed 8 homeworks that include both short answer and interpretations of quantitative results as well as problems put forth to solve from the scientific literature.  I will guide you through each stage of the course to make sure you are ready in the end to begin applying these problems.

Graduate: Modeling Biogeochemical Tracers in the Coastal Ocean

Development of skills with modern and traditional methods of simulating biogeochemical cycles in the ocean. Specifically, lower trophic level ecosystem and biogeochemical models -nutrient, phytoplankton, zooplankton, and detritus (NPZD), oxygen, carbon, and carbonate cycling will be explored. We rely on a 1D ROMS simulation called BIOTOY -which we run on the HPC facilities at Storrs. Analysis is performed in Python.

By the end of the semester, students should be able to:

  1. Understand the basic structure of a NPZD model and a more complicated version with gas exchange

  2. Compile the regional ocean modeling system (ROMS) with a biogeochemistry module turned on

  3. Plot the output from the ROMS model

  4. Perform simple sensitivity tests of an NPZD model

  5. Add a new tracer to a 1D ROMS simulation

Graduate: Connecting urban estuaries to the sea: Coastal oceanography of Long Island Sound and the shelf of the Mid-Atlantic Bight

Four (4) credits. May be repeated for credit with change in content. 2 day ship expedition and 13, two-hour seminar sessions required. 

The course would involve working in small interdisciplinary teams toward a common theme, hypothesis or problem that the cruise plan would be designed to address. Some potential interdisciplinary themes discussed include:

  1. Carbon and/or pollutant transfer from estuaries to the open ocean

  2. Frontal processes (shelf break front) – interesting productivity, gas exchange, etc

  3. Lower trophic level food web structure changes as you move offshore – trends and patterns

  4. Benthic pelagic coupling of organic material in various physical settings from shallow shelf to deep shelf

Through this activity they would learn the basic skills needed to (in no particular order): 

1) constrain a problem/question like this with the tools/techniques and resources at hand

3) test hypotheses

4) sample collection techniques in the ocean

5) quality control skills in data collection techniques

6) estimate fluxes across interfaces (air-water; sediment-water)

7) work together as an interdisciplinary team toward a common goal 

The course for the fall of 2020 will include classes that would meet for 1.5 hours twice a week. The class/lab sessions would include readings, discussions and lectures and cover (1) oceanography of the study area; (2) plans and procedures for the measurements, sampling and data collection techniques on the cruise; (4) Quality control methods; (5) Synthesis of the cruise data; (6) Writing up a final proposal for the following cruise. The bulk of the analysis will be done on the cruise with limited analysis time required of the students when back from their cruise. One possible final project idea is that they write a proposal for the next course offered as their final project. This way the group with the strongest proposal could “win” the opportunity to go on the cruise a second time in a more senior role, and we may end up with projects for the students to focus on the next year the course is offered


Siedlecki, S. A., Pilcher, D., Howard, E. M., Deutsch, C., MacCready, P., Norton, E. L., Frenzel, H., Newton, J., Feely, R. A., Alin, S. R., and Klinger, T.: Coastal processes modify projections of some climate-driven stressors in the California Current System, Biogeosciences, 18, 2871–2890,, 2021.

SA Siedlecki, J Salisbury, DK Gledhill, C Bastidas, S Meseck, K McGarry, CW Hunt, M Alexander, D Lavoie, ZA Wang, J Scott, DC Brady, I Mlsna, K Azetsu-Scott, CM Liberti, DC Melrose, MM White, A Pershing, D Vandemark, DW Townsend, C Chen, W Mook, R Morrison; Projecting ocean acidification impacts for the Gulf of Maine to 2050: New tools and expectations. Elementa: Science of the Anthropocene 21 January 2021; 9 (1): 00062. doi:

McGarry, K.*, S.A. Siedlecki, J. Salisbury, and S. R. Alin (2021) Multiple linear regression models for reconstructing and exploring processes controlling the carbonate system of the northeast US from basic hydrographic data. JGR-Oceans, 126, e2020JC016480.

MacCready, P.,  McCabe, R. M.,  Siedlecki, S. A.,  Lorenz, M.,  Giddings, S. N.,  Bos, J., et al. (2021).  Estuarine circulation, mixing, and residence times in the Salish Sea. Journal of Geophysical Research: Oceans,  126, e2020JC016738.

Malick MJ, Siedlecki SA, Norton EL, Kaplan IC, Haltuch MA, Hunsicker ME, Parker-Stetter SL, Marshall KN, Berger AM, Hermann AJ, Bond NA and Gauthier S (2020) Environmentally Driven Seasonal Forecasts of Pacific Hake Distribution. Front. Mar. Sci. 7:578490. doi: 10.3389/fmars.2020.578490

Ray, S., Siedlecki, S. A., Alexander, M. A., Bond, N. A., & Hermann, A. J. (2020). Drivers of subsurface temperature variability in the Northern California Current. Journal of Geophysical Research: Oceans, 125, e2020JC016227.

Flynn, R. F.,  Granger, J.,  Veitch, J. A.,  Siedlecki, S.,  Burger, J. M.,  Pillay, K., &  Fawcett, S. E. ( 2020).  On‐shelf nutrient trapping enhances the fertility of the southern Benguela upwelling system. Journal of Geophysical Research: Oceans,  125, e2019JC015948.

Jacox, M. G., Alexander, M. A., Siedlecki, S., Chen, K., Kwon, Y.-O., Brodie, S., … Rykaczewski, R. (2020). Seasonal-to-interannual prediction of North American coastal marine ecosystems: Forecast methods, mechanisms of predictability, and priority developments. Progress in Oceanography, 183, 102307.

Norton, E., Siedlecki, S.A., Kaplan, I.C., Hermann, A.J., Fisher, J., Morgan, C., Officer, S., Saenger, C., Alin, S.A., Newton, J., Bednarsek, N., and R.A. Feely (2020) The Importance of Environmental Exposure History in Forecasting Dungeness Crab Megalopae, Occurrence Using J-SCOPE, a High-Resolution Model for the US Pacific Northwest. Frontiers in Marine Science, 7, 102.

Bednaršek, N., Feely, R. A., Beck, M. W., Alin, S. R., Siedlecki, S. A., Calosi, P., … Spicer, J. I. (2020). Exoskeleton dissolution with mechanoreceptor damage in larval Dungeness crab related to severity of present-day ocean acidification vertical gradients. Science of The Total Environment, 716, 136610.

Capotondi, A., Jacox, M., Bowler, C., Kavanaugh, M.,  Lehodey, P., Barrie, D., Brodie, S., Chaffron, S., Cheng, W., Faggiani Dias, D., Eveillard, D., Guidi, L., Iudicone, D., Lovenduski, N., Nye, J.A., Ortiz, I., Pirhalla, D.E., Pozo Buil, M., Saba, V., Sheridan, S.C., Siedlecki, S.A., Subramanian, A., De Vargas, C., Di Lorenzo, E., Doney, S.C., Hermann, A.J., Joyce, T., Merrifield, M., Miller, A.J., Not, F., & S. Pesant (2019). Observational Needs Supporting Marine Ecosystems Modeling and Forecasting: From the Global Ocean to Regional and Coastal Systems  . Frontiers in Marine Science.

L. Schmeisser, N. A. Bond, S. A. Siedlecki, & T. P. Ackerman, (2019) The role of clouds and surface heat fluxes in the maintenance of the 2013-2016 Northeast Pacific marine heatwave.  JGR-Atmospheres,, 124, 10, 772-10, 783.

Tilbrook, B., Jewett, E. B., DeGrandpre, M. D., Hernandez-Ayon, J. M., Feely, R. A., Gledhill, D. K., Hansson, L., Isensee, K., Kurz, M.L., Netwon, J.A., Siedlecki, S.A., Chai, F., Dupont, S., Graco, M., Calvo, E., Greeley, D., Kapsenberg, L., Lebrec, M., Pelejero, C., Schoo, K.L., and Telszewski, M. (2019). An Enhanced Ocean Acidification Observing Network: From People to Technology to Data Synthesis and Information Exchange. Frontiers in Marine Science, 6, 337.

Fennel, K., Alin, S., Barbero, L., Evans, W., Bourgeois, T., Cooley, S., Dunne, J., Feely, R. A., Martin Hernandez-Ayon, J., Hu, X., Lohrenz, S., Muller-Karger, F., Najjar, R., Robbins, L., Shadwick, E., Siedlecki, S. A., Steiner, N., Sutton, A., Turk, D., Vlahos, P., & Aleck Wang, Z. (2019). Carbon cycling in the North American coastal ocean: A synthesis. Biogeosciences, (6 ed., vol. 16, pp. 1281-1304).

Barth, J. A., Allen, S. E., Dever, E. P., Dewey, R. K., Evans, W., Feely, R. A., Fisher, J. L., Fram, J. P., Hales, B., Ianson, D., Jackson, J., Juniper, K., Kawka, O., Kelley, D., Klymak, J. M., Konovsky, J., Kosro, P. M., Kurapov, A., Mayorga, E., MacCready, P., Newton, J., Ian Perry, R., Risien, C. M., Robert, M., Ross, T., Kipp Shearman, R., Schumacker, J., Siedlecki, S. A., Trainer, V. L., Waterman, S., &  Wingard, C. E. (2019). Better Regional Ocean Observing Through Cross-National Cooperation: A Case Study From the Northeast Pacific. Frontiers in Marine Science, 6, 93.

Alistair J Hobday, Jason R Hartog, John P Manderson, Katherine E Mills, Matthew J Oliver, Andrew J Pershing, Samantha Siedlecki, Handling editor: Howard Browman, (2019) Ethical considerations and unanticipated consequences associated with ecological forecasting for marine resources, ICES Journal of Marine Science, , fsy210,

Pilcher DJ, Naiman DM, Cross JN, Hermann AJ, Siedlecki SA, Gibson GA and Mathis JT (2019) Modeled Effect of Coastal Biogeochemical Processes, Climate Variability, and Ocean Acidification on Aragonite Saturation State in the Bering Sea. Front. Mar. Sci. 5:508. doi: 10.3389/fmars.2018.00508

Pershing, A.J., R.B. Griffis, E.B. Jewett, C.T. Armstrong, J.F. Bruno, D.S. Busch, A.C. Haynie, S.A. Siedlecki, and D. Tommasi, 2018: Oceans and Marine Resources. In Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA. doi: 10.7930/NCA4.2018.CH9

Pilcher, D. J., Siedlecki, S. A., Hermann, A. J., Coyle, K. O., Mathis, J. T., & Evans, W. (2018). Simulated impact of glacial runoff on CO2 uptake in the Gulf of Alaska. Geophysical Research Letters, 45, 880–890. 2017GL075910

Siedlecki, S. A., Pilcher, D. J., Hermann, A. J., Coyle, K., & Mathis, J. (2017). The importance of freshwater to spatial variability of aragonite saturation state in the Gulf of Alaska. Journal of Geophysical Research: Oceans, 122.                

Bednaršek, N., R.A. Feely, N. Tolimieri, A.J. Hermann, S.A. Siedlecki, H.O. Pörtner, G.G. Waldbusser, P. McElhany, S.R. Alin, and J. Menkel (2017): Exposure history determines pteropod vulnerability to ocean acidification along the US West Coast. Scientific Reports 7, Article number: 4526,  doi:10.1038/s41598-017-03934-z

Carter, B.R., Feely, R.A., Mecking, S., Cross, J. N., Macdonald, A.M., Siedlecki, S.A. Talley, L., Sabine, C. L., Millero, R., Swift, J.H. , and Dickson, A. G.,  (2017) Two Decades of Pacific Anthropogenic Carbon Storage and Ocean Acidification Along GO-SHIP Sections P16 and P02, Global Biogeochem. Cycles, 31, doi:10.1002/2016GB005485.

Tommasi, D., Stock, C., Hobday, A., Methot, R., Kaplan, I., Eveson, P., Holsman, K., Miller, T., Gaichas, S.,  Gehlen, M.,  Pershing, A., Vecchi, G.,  Msadek, R., Delworth, T., Eakin, M., Haltuch, M., Sefarian, R., Spillman, C., Hartog, J., Siedlecki, S.,Samhouri, J., Muhling, B., Asch, R., Pinsky, M.,  Saba, V., Kapnick, S., Gaitan, C.,  Rykaczewski, R., Alexander, M., Xue, Y., Pegion, K.,  Lynch, P.,  Payne, M., Kristiansen, T., Lehodey, P., and C. Werner. (accepted) Managing living marine resources in a dynamic environment: the role of seasonal to decadal climate forecasts, Progress in Oceanography

S. McClatchie, A. R. Thompson, S. R. Alin, S. J. Bograd, S.A. Siedlecki, W. Watson, (2016) The influence of Pacific Equatorial Water on fish diversity in the southern California Current System, JGR-Oceans, doi:10.1002/2016JC011672

Siedlecki, S.A., Kaplan, I.C., Hermann, A., Nguyen, T., Bond, N., Williams, G., Newton, J., Peterson, W. T., Alin, S., and R.A. Feely (2016) Experiments with Seasonal Forecasts of ocean conditions for the Northern region of the California Current upwelling system, Nature: Scientific Reports 6, doi:10.1038/srep27203

Harrison, C.S., Hales, B., Siedlecki, S.A., and Samelson, R.M., Potential and timescales for oxygen depletion in coastal upwelling systems: Idealized model analysis (2016) JGR-Oceans 121, doi:10.1002/2015JC011328.

Kaplan, I. C., Williams, G. D., Bond, N. A., Hermann, A. J. and Siedlecki, S. A. (2016), Cloudy with a chance of sardines: forecasting sardine distributions using regional climate models. Fisheries Oceanography, 25: 15–27. doi: 10.1111/fog.12131

Siedlecki, S.A., Banas, N., Davis, K.A., Giddings, S., Hickey, B.M., MacCready, P., Connolly, T., and S. Geier, Seasonal and interannual oxygen variability on the Washington and Oregon continental shelves, (2015), J. Geophys. Res. Oceans, 120, DOI: 10.1002/2014JC010254

Davis, K. A., N. S. Banas, S. N. Giddings, S. A. Siedlecki, P. MacCready, E. J. Lessard, R. M. Kudela, and B. M. Hickey (2014), Estuary-enhanced upwelling of marine nutrients fuels coastal productivity in the U.S. Pacific Northwest, J. Geophys. Res. Oceans, 119, 8778–8799, doi:10.1002/2014JC010248.

Giddings, SN, MacCready, P, Hickey, BM, Banas, NS, Davis, KA, Siedlecki, SA, Trainer, VL, Kudela, RM, Pelland, NA, and Connolly, TP. (2014) Hindcasts of harmful algal bloom transport on the Pacific Northwest coast, JGR-oceans, 119(4), 2439-2461. doi: 10.1002/2013/JC009622.

Siedlecki, SA, Mahadevan, A, and Archer, DE (2012) The Coastal Ocean as a Supplier of Global Iron: Mechanisms for Iron Export in an Upwelling Regime, Geophysical Research Letters 39, DOI:10.1029/2011GL050366

Siedlecki SA, Archer, DE, and Mahadevan, A (2011) Mechanisms for nutrient exchange and ventilation in the coastal ocean: an idealized model for the East Coast of the US, Journal of Geophysical Research – Oceans 116

Loubere P, Siedlecki SA, and Bradtmiller LI (2007) Organic carbon and carbonate fluxes: Links to climate change DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY 54 (5-7): 437-446

Brunner, C.A., Andres, M., Holbourn, A.E., Siedlecki, S., Brooks, G.R., Molina Garza, R.S, Fuller, M.D., Ladner, B.C., Hine, A.C., and Li, Q., 2002. Quaternary planktonic foraminiferal biostratigraphy, ODP Leg 182 sites. In Hine, A.C., Feary, D.A., and Malone, M.J. (Eds.), Proc. ODP, Sci. Results, 182 [Online]. Available from World Wide Web: <>.