Net biological oxygen production in the ocean—II: Remote in situ measurements of O2 and N2 in subarctic pacific surface waters

Emerson, Steven; Stump, Charles

doi:10.1016/j.dsr.2010.06.001

Cited by 82 publications

(165 citation statements)

References 49 publications

Supporting

Mentioning

144

Contrasting

Order By: Relevance

“…In the absence of errors and processes such as salt fingers, we would expect that these values of diffusivity should be nearly the same. A reasonable agreement thus helps provide confidence that these diffusivity estimates can be used for other budgets, e.g., for carbon (Fassbender et al, submitted manuscript, 2015) or oxygen [Emerson and Stump, 2010]. As will be discussed, the diffusivity values at the base of the mixed layer have a seasonal cycle, have geographic variations, and are significantly larger than the values found in the thermocline and interior of the ocean.…”

Section: Introductionmentioning

confidence: 84%

Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific

et al. 2015

View full text Add to dashboard Cite

Data from two National Oceanographic and Atmospheric Administration (NOAA) surface moorings in the North Pacific, in combination with data from satellite, Argo floats and glider (when available), are used to evaluate the residual diffusive flux of heat across the base of the mixed layer from the surface mixed layer heat budget. The diffusion coefficient (i.e., diffusivity) is then computed by dividing the diffusive flux by the temperature gradient in the 20 m transition layer just below the base of the mixed layer. At Station Papa in the NE Pacific subpolar gyre, this diffusivity is 1 × 10−4 m2/s during summer, increasing to ∼3 × 10−4 m2/s during fall. During late winter and early spring, diffusivity has large errors. At other times, diffusivity computed from the mixed layer salt budget at Papa correlate with those from the heat budget, giving confidence that the results are robust for all seasons except late winter‐early spring and can be used for other tracers. In comparison, at the Kuroshio Extension Observatory (KEO) in the NW Pacific subtropical recirculation gyre, somewhat larger diffusivities are found based upon the mixed layer heat budget: ∼ 3 × 10−4 m2/s during the warm season and more than an order of magnitude larger during the winter, although again, wintertime errors are large. These larger values at KEO appear to be due to the increased turbulence associated with the summertime typhoons, and weaker wintertime stratification.

show abstract

Section: Introductionmentioning

confidence: 84%

Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific

et al. 2015

View full text Add to dashboard Cite

show abstract

“…All of these studies demonstrate that a parameterization with no bubble flux and too much bubble flux will both result in errors in the calculated air-water flux for low solubility gases. These and other studies provide insight into the most appropriate gas exchange parameterization to use in global biogeochemical models, and when interpreting data sets where inert gas measurements are not available, such as measurements of O 2 from moorings and BioArgo floats (Hamme and Emerson, 2006;Emerson and Stump, 2010;Plant et al, 2016).…”

Section: Broader Implicationsmentioning

confidence: 99%

Insight into chemical, biological, and physical processes in coastal waters from dissolved oxygen and inert gas tracers

Manning¹

2017

View full text Add to dashboard Cite

In this thesis, I use coastal measurements of dissolved O 2 and inert gases to provide insight into the chemical, biological, and physical processes that impact the oceanic cycles of carbon and dissolved gases. Dissolved O 2 concentration and triple isotopic composition trace net and gross biological productivity. The saturation states of inert gases trace physical processes, such as air-water gas exchange, temperature change, and mixing, that affect all gases.First, I developed a field-deployable system that measures Ne, Ar, Kr, and Xe gas ratios in water. It has precision and accuracy of 1 % or better, enables near-continuous measurements, and has much lower cost compared to existing laboratory-based methods. The system will increase the scientific community's access to use dissolved noble gases as environmental tracers.Second, I measured O 2 and five noble gases during a cruise in Monterey Bay, California. I developed a vertical model and found that accurately parameterizing bubble-mediated gas exchange was necessary to accurately simulate the He and Ne measurements. I present the first comparison of multiple gas tracer, incubation, and sediment trap-based productivity estimates in the coastal ocean. Net community production estimated from 15 NO -3 uptake and O 2 /Ar gave equivalent results at steady state. Underway O 2 /Ar measurements revealed submesoscale variability that was not apparent from daily incubations.Third, I quantified productivity by O 2 mass balance and air-water gas exchange by dual tracer ( 3 He/SF 6 ) release during ice melt in the Bras d'Or Lakes, a Canadian estuary. The gas transfer velocity at >90 % ice cover was 6 % of the rate for nearly ice-free conditions. Rates of volumetric gross primary production were similar when the estuary was completely ice-covered and ice-free, and the ecosystem was on average net autotrophic during ice melt and net heterotrophic following ice melt. I present a method for incorporating the isotopic composition of H 2 O into the O 2 isotope-based productivity calculations, which increases the estimated gross primary production in this study by 46-97 %.In summary, I describe a new noble gas analysis system and apply O 2 and inert gas observations in new ways to study chemical, biological, and physical processes in coastal waters.

show abstract

“…DO sensors are also frequently used on autonomous platforms (e.g., moorings, floats, gliders, profilers, AUVs, benthic landers) to study a variety of processes and environments. Some examples of studies that use DO sensors include net ecosystem metabolism (Emerson and Stump 2010;Fiedler et al 2012;Martz et al 2008;Riser and Johnson 2008), air-sea gas exchange (D'Asaro and McNeil 2007;Körtzinger et al 2004), oxygen minimum zones (Revsbech et al 2009), phytoplankton blooms (Perry et al 2008), benthic respiration rates (Frederiksen and Glud 2006;Wikner et al 2013), and lake/reservoir benthic O 2 flux (McGinnis et al 2008).…”

mentioning

confidence: 99%

A calibration equation for oxygen optodes based on physical properties of the sensing foil

McNeil

D’Asaro

2014

Limnology & Ocean Methods

View full text Add to dashboard Cite

We present a new physically based calibration equation for Aanderaa Inc. oxygen sensing optodes. We use the two site fluorescence quenching model of Demas et al. (1995) to describe the nonlinear Stern-Volmer response of the optode foil to oxygen partial pressure. Seven (minimally six) coefficients quantify foil response to oxygen and temperature; another quantifies response to hydrostatic pressure. These eight coefficients are related, theoretically, to basic physical properties of the foil. The equation provides a framework to study causes of variability and drift in optodes and to develop better quality control and handling procedures. We tested the equation using factory calibrations of 24 optode foils. When accurate multi-point calibration data are unavailable, two additional coefficients empirically correct the usually large differences observed between factory foil calibrations and post-factory laboratory/field calibrations; we cannot eliminate this major cause of uncertainty in optode calibrations. Excluding two potentially anomalous foils, the calibration equation fits 13 similarly calibrated foils, totaling 455 calibration points over 3 -40°C to -0.57 ± 1.48 mbar. Analysis of the resulting best fit coefficients reveals an underlying variability in optodes associated with variability in site 2 and site 1 Stern-Volmer coefficients of 32% and 20%, respectively. The fraction of unquenched fluorophores responding with the more accessible site 1 quenching characteristics varies by only 3%. The equation fits multi-point data for two optodes within manufacturer's specifications, the greater of ± 2.5 μmol . kg -1 and ± 1.5%. Detailed measurements of calibration changes over time will be required to understand the causes of optode drift.

show abstract

Net biological oxygen production in the ocean—II: Remote in situ measurements of O2 and N2 in subarctic pacific surface waters

Cited by 82 publications

References 49 publications

Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific

Estimating diffusivity from the mixed layer heat and salt balances in the North Pacific

Insight into chemical, biological, and physical processes in coastal waters from dissolved oxygen and inert gas tracers

A calibration equation for oxygen optodes based on physical properties of the sensing foil

Contact Info

Product

Resources

About