My PhD thesis focuses on deriving estimates of marine net community production (NCP) at high-resolution scales in the NE Pacific and Arctic Ocean. Net community production is a useful ecological metric that quantifies the balance between gross photosynthesis, and community-wide (i.e. heterotrophic and autotrophic) respiration in the ocean. As such, it represents the metabolic state of an ocean region, and helps to modulate key marine ecosystem services by, for example, setting upper limits on the ocean’s capacity for CO2 removal from the atmosphere and fisheries production. My research focuses on understanding the distribution of NCP on broad spatial and temporal scales. To achieve this, I combine a variety of approaches, including ship-based autonomous, underway sampling, chemical analyses, and modeling and statistical techniques. A key goal of my work is to produce a series of tools for deriving high-resolution, broad-coverage estimates of NCP, so that its distribution can be related to variability in climatic indices and fisheries production in the NE Pacific and Arctic Ocean.
Izett, R. W., and Tortell, P.D. The Pressure of In-situ Gases Instrument (PIGI) for autonomous ship-board measurement of dissolved O2 and N2 in surface ocean waters . Oceanography. Accepted.
Rosengard, S. Z., Izett, R. W., Burt, W. J., Schuback, N., and Tortell, P. D. Accepted May 2020. Decoupling of net community production and particulate
organic carbon dynamics in near shore surface ocean waters. Biogeosciences Discuss. https://doi.org/10.5194/bg-17-3277-2020.
Izett, R. W., Manning, C. C., Hamme, R. C., and Tortell, P. D. 2018. Refined Estimates of Net Community Production in the Subarctic Northeast Pacific Derived From ΔO2/Ar Measurements With N2O‐Based Corrections for Vertical Mixing. Global Biogeochemical Cycles. 32. 326-350. https://doi.org/10.1002/2017GB005792.
Burt, W. J., Westberry, T. K., Behrenfeld, M. J., Zeng, C., Izett, R. W., and Tortell, P. D. 2018. Carbon: Chlorophyll Ratios and Net Primary Productivity of Subarctic Pacific Surface Waters Derived From Autonomous Shipboard Sensors. Global Biogeochemical Cycles. 32. https://doi.org/10.1002/2017GB005783.