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|Mahalakshmi, D. V., Paul, A., Dutta, D., Ali, M. M., Dadhwal, V. K., REddy, R. S., et al. (2016). Estimation of net surface radiation using eddy flux tower data over a tropical mangrove forest of Sundarban, West Bengal. Geofizika, 33(1), 1–14.|
|Morey, S. L., Bourassa, M. A., Dukhovskoy, D. S., & O'Brien, J. J. (2006). Modeling studies of the upper ocean response to a tropical cyclone. Ocean Dynamics, 56(5-6), 594–606.|
|Scott, J. P. (2011). An Intercomparison of Numerically Modeled Flux Data and Satellite-Derived Flux Data for Warm Seclusions. Master's thesis, Florida State University, Tallahassee, FL.|
|Smith, S. R., Lopez, N., & Bourassa, M. A. (2016). SAMOS air-sea fluxes: 2005-2014. Geosci. Data J., 3(1), 9–19.|
Stukel, M. R., Aluwihare, L. I., Barbeau, K. A., Chekalyuk, A. M., Goericke, R., Miller, A. J., et al. (2017). Mesoscale ocean fronts enhance carbon export due to gravitational sinking and subduction. Proc Natl Acad Sci U S A, 114(6), 1252–1257.
Abstract: Enhanced vertical carbon transport (gravitational sinking and subduction) at mesoscale ocean fronts may explain the demonstrated imbalance of new production and sinking particle export in coastal upwelling ecosystems. Based on flux assessments from 238U:234Th disequilibrium and sediment traps, we found 2 to 3 times higher rates of gravitational particle export near a deep-water front (305 mg Cm-2d-1) compared with adjacent water or to mean (nonfrontal) regional conditions. Elevated particle flux at the front was mechanistically linked to Fe-stressed diatoms and high mesozooplankton fecal pellet production. Using a data assimilative regional ocean model fit to measured conditions, we estimate that an additional approximately 225 mg Cm-2d-1 was exported as subduction of particle-rich water at the front, highlighting a transport mechanism that is not captured by sediment traps and is poorly quantified by most models and in situ measurements. Mesoscale fronts may be responsible for over a quarter of total organic carbon sequestration in the California Current and other coastal upwelling ecosystems.
Stukel, M. R., Benitez-Nelson, C. R., Decima, M., Taylor, A. G., Buchwald, C., & Landry, M. R. (2016). The biological pump in the Costa Rica Dome: an open-ocean upwelling system with high new production and low export. J Plankton Res, 38(2), 348–365.
Abstract: The Costa Rica Dome is a picophytoplankton-dominated, open-ocean upwelling system in the Eastern Tropical Pacific that overlies the ocean's largest oxygen minimum zone. To investigate the efficiency of the biological pump in this unique area, we used shallow (90-150 m) drifting sediment traps and 234Th:238U deficiency measurements to determine export fluxes of carbon, nitrogen and phosphorus in sinking particles. Simultaneous measurements of nitrate uptake and shallow water nitrification allowed us to assess the equilibrium balance of new and export production over a monthly timescale. While f-ratios (new:total production) were reasonably high (0.36 +/- 0.12, mean +/- standard deviation), export efficiencies were considerably lower. Sediment traps suggested e-ratios (export/14C-primary production) at 90-100 m ranging from 0.053 to 0.067. ThE-ratios (234Th disequilibrium-derived export) ranged from 0.038 to 0.088. C:N and N:P stoichiometries of sinking material were both greater than canonical (Redfield) ratios or measured C:N of suspended particulates, and they increased with depth, suggesting that both nitrogen and phosphorus were preferentially remineralized from sinking particles. Our results are consistent with an ecosystem in which mesozooplankton play a major role in energy transfer to higher trophic levels but are relatively inefficient in mediating vertical carbon flux to depth, leading to an imbalance between new production and sinking flux.
Keywords: Eastern Tropical Pacific; biogeochemistry; carbon flux; nutrients; plankton
|Stukel, M. R., Kahru, M., Benitez-Nelson, C. R., Décima, M., Goericke, R., Landry, M. R., et al. (2015). Using Lagrangian-based process studies to test satellite algorithms of vertical carbon flux in the eastern North Pacific Ocean. J. Geophys. Res. Oceans, 120(11), 7208–7222.|
|Wallcraft, A. J., Kara, A. B., Hurlburt, H. E., Chassignet, E. P., & Halliwell, G. H. (2008). Value of bulk heat flux parameterizations for ocean SST prediction. Journal of Marine Systems, 74(1-2), 241–258.|
Wang, S., Kranz, S. A., Kelly, T. B., Song, H., Stukel, M. R., & Cassar, N. (2020). Lagrangian Studies of Net Community Production: The Effect of Diel and Multiday Nonsteady State Factors and Vertical Fluxes on O2/Ar in a Dynamic Upwelling Region. J. Geophys. Res. Biogeosci., 125(6), e2019JG005569.
Abstract: The ratio of dissolved oxygen to argon in seawater is frequently employed to estimate rates of net community production (NCP) in the oceanic mixed layer. The in situ O2/Ar‐based method accounts for many physical factors that influence oxygen concentrations, permitting isolation of the biological oxygen signal produced by the balance of photosynthesis and respiration. However, this technique traditionally relies upon several assumptions when calculating the mixed‐layer O2/Ar budget, most notably the absence of vertical fluxes of O2/Ar and the principle that the air‐sea gas exchange of biological oxygen closely approximates net productivity rates. Employing a Lagrangian study design and leveraging data outputs from a regional physical oceanographic model, we conducted in situ measurements of O2/Ar in the California Current Ecosystem in spring 2016 and summer 2017 to evaluate these assumptions within a �worst‐case� field environment. Quantifying vertical fluxes, incorporating nonsteady state changes in O2/Ar, and comparing NCP estimates evaluated over several day versus longer timescales, we find differences in NCP metrics calculated over different time intervals to be considerable, also observing significant potential effects from vertical fluxes, particularly advection. Additionally, we observe strong diel variability in O2/Ar and NCP rates at multiple stations. Our results reemphasize the importance of accounting for vertical fluxes when interpreting O2/Ar‐derived NCP data and the potentially large effect of nonsteady state conditions on NCP evaluated over shorter timescales. In addition, diel cycles in surface O2/Ar can also bias interpretation of NCP data based on local productivity and the time of day when measurements were made.
Keywords: net community production; O2/Ar; California Current Ecosystem; Lagrangian measurements; vertical fluxes; nonsteady state
|Wei, J., Dirmeyer, P. A., Guo, Z., Zhang, L., & Misra, V. (2010). How Much Do Different Land Models Matter for Climate Simulation? Part I: Climatology and Variability. J. Climate, 23(11), 3120–3134.|