Biological production rates off the Southern California coast estimated from triple O<sub>2</sub> isotopes and O<sub>2</sub> : Ar gas ratios

Munro, David R.; Quay, Paul D.; Juranek, L. W.; Goericke, Ralf

doi:10.4319/lo.2013.58.4.1312

Cited by 40 publications

(75 citation statements)

References 42 publications

(124 reference statements)

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“…The GOP/NPP ratio in Phase 1 is similar to the GOP/ 14 C-PP ratio of 3.3 for phytoplankton growing on nitrate measured by Halsey et al (2010), but somewhat higher than the ratio of 2.7 for gross O 2 production to net C uptake observed in incubations from a global compilation of all JGOFS sites . Munro et al (2013) calculated a GOP/NPP ratio of ∼4.8-8.1 in the north inshore region, using 6 h daytime 14 C incubations scaled to 24 h by multiplying by 1.81 (Eppley, 1992). Some of the discrepancy between the GOP/NPP ratio determined in our study and Munro et al (2013) may be due to uncertainty in scaling the incubations from 6 h to 24 h.…”

Section: Synthesis and Comparison With Prior Workmentioning

confidence: 79%

“…Munro et al (2013) calculated a GOP/NPP ratio of ∼4.8-8.1 in the north inshore region, using 6 h daytime 14 C incubations scaled to 24 h by multiplying by 1.81 (Eppley, 1992). Some of the discrepancy between the GOP/NPP ratio determined in our study and Munro et al (2013) may be due to uncertainty in scaling the incubations from 6 h to 24 h.…”

Section: Synthesis and Comparison With Prior Workmentioning

confidence: 79%

“…transect cruises) or sampling at the same location occurs very far apart in time (much longer than the residence time of O 2 in the mixed layer, which is typically on the order of two weeks), making it necessary to assume the gases are at steady state in order to calculate NCP and GPP (Stanley et al, 2010;Giesbrecht et al, 2012;Munro et al, 2013). When a higher-frequency time-series of measurements is obtained (as occurred during this cruise), investigators can quantify the change in [O 2 ] and 17 ∆ with time and include these terms in the productivity estimates when appropriate (Hamme et al, 2012;Tortell et al, 2014;Wilson et al, 2015).…”

Section: O 2 Mass Balancementioning

confidence: 99%

“…Monthly, multiyear time-series of productivity, based on incubations measuring the uptake of 14 C-labeled dissolved inorganic carbon (DIC) and 15 NO − 3 have been reported previously (Pennington and Chavez, 2000;Wilkerson et al, 2000), and numerous process-oriented biological studies have been conducted (Pilskaln et al, 1996;Kudela and Dugdale, 2000;Ward, 2005;Ryan et al, 2009;Johnson, 2010;Smith et al, 2014aSmith et al, , 2016 , but can be challenging to apply in systems where recently-upwelled water is observed at the surface; this low O 2 water may bias estimates low if not accurately accounted for (Munro et al, 2013;Teeter, 2014;Haskell et al, 2016b). Furthermore, inferring carbon export below the mixed layer from techniques within the mixed layer is complicated by the fact that lateral transport of surface waters and oceanic fronts may cause a spatial and/or temporal decoupling between carbon fixation and export (Olivieri and Chavez, 2000;Estapa et al, 2015;Nagai et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…We also use the terms gross oxygen production (GOP) to refer to the gross amount of O 2 produced by photosynthesis, and net oxygen production (NOP) to refer to the net amount of O 2 produced (Munro et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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

Manning¹

2017

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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.

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Section: Synthesis and Comparison With Prior Workmentioning

confidence: 79%

Section: Synthesis and Comparison With Prior Workmentioning

confidence: 79%

Section: O 2 Mass Balancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Manning¹

2017

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Annual net community production and the biological carbon flux in the ocean

Emerson

2014

Global Biogeochemical Cycles

178

218

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The flux of biologically produced organic matter from the surface ocean (the biological pump), over an annual cycle, is equal to the annual net community production (ANCP). Experimental determinations of ANCP at ocean time series sites using a variety of different metabolite mass balances have made it possible to evaluate the accuracy of sediment trap fluxes and satellite-determined ocean carbon export. ANCP values at the Hawaii Ocean Time-series (HOT), the Bermuda Atlantic Time-series Study (BATS), Ocean Station Papa (OSP) are 3 ± 1 mol C m À2 yr À1 -much less variable than presently suggested by satellite remote sensing measurements and global circulation models. ANCP determined from mass balances at these locations are 3-4 times particulate organic carbon fluxes measured in sediment traps. When the roles of dissolved organic carbon (DOC) flux, zooplankton migration, and depth-dependent respiration are considered these differences are reconciled at HOT and OSP but not at BATS, where measured particulate fluxes are about 3 times lower than expected. Even in the cases where sediment trap fluxes are accurate, it is not possible to "scale up" these measurements to determine ANCP without independent determinations of geographically variable DOC flux and zooplankton migration. Estimates of ANCP from satellite remote sensing using net primary production determined by the carbon-based productivity model suggests less geographic variability than its predecessor (the vertically generalized productivity model) and brings predictions at HOT and OSP closer to measurements; however, satellite-predicted ANCP at BATS is still 3 times too low.

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The triple oxygen isotope tracer of primary productivity in a dynamic ocean model

Nicholson

Stanley

Doney

2014

Global Biogeochemical Cycles

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The triple oxygen isotopic composition of dissolved oxygen ( 17 Δ dis ) was added to the ocean ecosystem and biogeochemistry component of the Community Earth System Model, version 1.1.1. Model simulations were used to investigate the biological and physical dynamics of 17 Δ dis and assess its application as a tracer of gross photosynthetic production (gross oxygen production (GOP)) of O 2 in the ocean mixed layer. The model reproduced large-scale patterns of 17 Δ dis found in observational data across diverse biogeographical provinces. Mixed layer model performance was best in the Pacific and had a negative bias in the North Atlantic and a positive bias in the Southern Ocean. Based on model results, the steady state equation commonly used to calculate GOP from tracer values overestimated the globally averaged model GOP by 29%. Vertical entrainment/mixing and the time rate of change of 17 Δ dis were the two largest sources of bias when applying the steady state method to calculate GOP. Entrainment/mixing resulted in the largest overestimation in midlatitudes and during summer and fall and almost never caused an underestimation of GOP. The tracer time rate of change bias resulted both in underestimation of GOP (e.g., during spring blooms at high latitudes) and overestimation (e.g., during the summer following a bloom). Seasonally, bias was highest in the fall (September-October-November in the Northern Hemisphere, March-April-May in the Southern), overestimating GOP by 62%, globally averaged. Overall, the steady state method was most accurate in equatorial and low-latitude regions where it estimated GOP to within ±10%. Field applicable correction terms are derived for entrainment and mixing that capture 86% of model vertical bias and require only mixed layer depth history and triple oxygen isotope measurements from two depths.

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Biological production rates off the Southern California coast estimated from triple O₂ isotopes and O₂ : Ar gas ratios

Cited by 40 publications

References 42 publications

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

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

Annual net community production and the biological carbon flux in the ocean

The triple oxygen isotope tracer of primary productivity in a dynamic ocean model

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Biological production rates off the Southern California coast estimated from triple O2 isotopes and O2 : Ar gas ratios

Cited by 40 publications

References 42 publications

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

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

Annual net community production and the biological carbon flux in the ocean

The triple oxygen isotope tracer of primary productivity in a dynamic ocean model

Contact Info

Product

Resources

About

Biological production rates off the Southern California coast estimated from triple O₂ isotopes and O₂ : Ar gas ratios