Stukel, M. R., Décima, M., Landry, M. R., & Selph, K. E. (2018). Nitrogen and isotope flows through the Costa Rica Dome upwelling ecosystem: The crucial mesozooplankton role in export flux. Global Biogeochemical Cycles, 32(12), 1815–1832.
Abstract: The Costa Rica Dome (CRD) is an open-ocean upwelling ecosystem, with high biomasses of picophytoplankton (especially Synechococcus), mesozooplankton, and higher trophic levels. To elucidate the food web pathways supporting the trophic structure and carbon export in this unique ecosystem, we used Markov Chain Monte Carlo techniques to assimilate data from four independent realizations of δ15N and planktonic rate measurements from the CRD into steady state, multicompartment ecosystem box models (linear inverse models). Model results present well-constrained snapshots of ecosystem nitrogen and stable isotope fluxes. New production is supported by upwelled nitrate, not nitrogen fixation. Protistivory (rather than herbivory) was the most important feeding mode for mesozooplankton, which rely heavily on microzooplankton prey. Mesozooplankton play a central role in vertical nitrogen export, primarily through active transport of nitrogen consumed in the surface layer and excreted at depth, which comprised an average 36-46% of total export. Detritus or aggregate feeding is also an important mode of resource acquisition by mesozooplankton and regeneration of nutrients within the euphotic zone. As a consequence, the ratio of passively sinking particle export to phytoplankton production is very low in the CRD. Comparisons to similar models constrained with data from the nearby equatorial Pacific demonstrate that the dominant role of vertical migrators to the biological pump is a unique feature of the CRD. However, both regions show efficient nitrogen transfer from mesozooplankton to higher trophic levels (as expected for regions with large fish, cetacean, and seabird populations) despite the dominance of protists as major grazers of phytoplankton.
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Morey, S. L., Zavala-Hidalgo, J., & O'Brien, J. J. (2005). The seasonal variability of continental shelf circulation in the northern and western Gulf of Mexico from a high-resolution numerical model. In W. Sturges, & A. Lugo-Fernandez (Eds.), New Developments in the Circulation of the Gulf of Mexico. Geophys. Mongr. Ser., (161).
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Kranz, S. A., Wang, S., Kelly, T. B., Stukel, M. R., Goericke, R., Landry, M. R., et al. (2020). Lagrangian Studies of Marine Production: A Multimethod Assessment of Productivity Relationships in the California Current Ecosystem Upwelling Region. J. Geophys. Res. Oceans, 125(6).
Abstract: A multimethod process‐oriented investigation of diverse productivity measures in the California Current Ecosystem (CCE) Long‐Term Ecological Research study region, a complex physical environment, is presented. Seven multiday deployments covering a transition region from high to low productivity were conducted over two field expeditions (spring 2016 and summer 2017). Employing a Lagrangian study design, water parcels were followed over several days, comparing 24‐h in situ measurements (14C and 15NO3 ‐uptake, dilution estimates of phytoplankton growth, and microzooplankton grazing) with high‐resolution productivity measurements by fast repetition rate fluorometry (FRRF) and equilibrium inlet mass spectrometry (EIMS), and integrated carbon export measuremnts using sediment traps. Results show the importance of accounting for temporal and fine spatial scale variability when estimating ecosystem production. FRRF and EIMS measurements resolved diel patterns in gross primary and net community production. Diel productivity changes agreed well with comparably more traditional measurements. While differences in productivity metrics calculated over different time intervals were considerable, as those methods rely on different base assumptions, the data can be used to explain ecosystem processes which would otherwise have gone unnoticed. The processes resolved from this method comparison further understanding of temporal and spatial coupling and decoupling of surface productivity and potential carbon burial in a gradient from coastal to offshore ecosystems.
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Hou, T. Y., Yan, M. P., & Wu, Z. (2009). A Variant Of The Emd Method For Multi-Scale Data. Adv. Adapt. Data Anal., 01(04), 483–516.
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Wu, Z., Huang, N. E., & Chen, X. (2009). The Multi-Dimensional Ensemble Empirical Mode Decomposition Method. Adv. Adapt. Data Anal., 01(03), 339–372.
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Huang, N. E., Wu, Z., Pinzón, J. E., Parkinson, C. L., Long, S. R., Blank, K., et al. (2009). Reductions Of Noise And Uncertainty In Annual Global Surface Temperature Anomaly Data. Adv. Adapt. Data Anal., 01(03), 447–460.
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Huang, N. E., Wu, Z., Long, S. R., Arnold, K. C., Chen, X., & Blank, K. (2009). On Instantaneous Frequency. Adv. Adapt. Data Anal., 01(02), 177–229.
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Wu, Z., & Huang, N. E. (2009). Ensemble Empirical Mode Decomposition: A Noise-Assisted Data Analysis Method. Adv. Adapt. Data Anal., 01(01), 1–41.
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Lim, Y. - K., D. W. Shin, T. E. LaRow, and S. Cocke. (2007). Categorical predictability of regionalized surface temperature and precipitation over the southeast United States. CAS/JSC Working Group on Numerical Experimentation.
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LaRow, T. E., Y.-K. Lim, D. W. Shin, S. D. Cocke, and E. Chassignet. (2007). High resolution ensemble west Atlantic basin seasonal hurricane simulations. CAS/JSC Working Group on Numerical Experimentation.
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