O2, Ar, N2, and 222Rn in surface waters of the subarctic Ocean: Net biological O2 production

Emerson, Steven; Quay, Paul D.; Stump, Charles; Wilbur, David; Knox, Molly

doi:10.1029/90gb02656

Cited by 166 publications

(131 citation statements)

References 41 publications

(6 reference statements)

Supporting

Mentioning

125

Contrasting

Order By: Relevance

“…Following Emerson et al (1991), with small modifications, the water and headspace in the sampling flasks were equilibrated for 24 h at room temperature. After equilibration, the water was sucked out of the flasks leaving only headspace gases.…”

Section: Field and Laboratory Methodsmentioning

confidence: 99%

Evaluation of community respiratory mechanisms with oxygen isotopes: A case study in Lake Kinneret

Luz

Barkan

Sagi

et al. 2002

Limnology & Oceanography

125

View full text Add to dashboard Cite

Gross and net O 2 production between May 1996 and February 1999 was determined in bottle incubation experiments with H 2 18 O spike and from the change in O 2 concentration. Carbon fixation rates were obtained from 14 C incubations. In general, production rates determined using the H 2 18 O-spike were about twice the primary production determined by the 14 C method, where the latter was close to net oxygen evolution. These relationships are similar to results for the open ocean. During the spring bloom, when the dinoflagellate Peridinium was abundant, the ratio of gross O 2 production to carbon fixation was about 7.5, and net O 2 production was greater than carbon fixation. The difference between O 2 gross production and carbon fixation results, at least in part, from uptake by Mehler reaction and from recycling of the 14 C tracer by dark respiration and the alternative oxidase (AOX). We used the difference in isotopic discrimination against 18 O, occurring during O 2 consumption by various biological pathways, to place constraints on the relative engagement of these pathways. We estimated the overall discrimination against 18 O in the lake from O 2 isotopic mass balance as 20.5-29‰. The only mechanism that can explain the strong overall fractionation in the lake is AOX, which strongly discriminates against 18 O (ϳ31‰). Our results show, for the first time, that uptake by AOX is widespread and quantitatively important to oxygen consumption in aquatic systems.Oxygen exchange by photosynthesis and respiration is the largest biogeochemical cycle in aquatic systems. In order to understand this cycle, it is necessary to know the gross rates of the major processes involved in oxygen production and uptake. Production of O 2 is known to occur in one process in photosystem II, but O 2 consumption in aquatic organisms is possible by several reactions. These include ordinary respiration through the cytochrome oxidase pathway, respiration by the alternative oxidase pathway, Mehler reaction, and photorespiration. The first two processes take place in light as well as in dark conditions, whereas the latter two occur only under illumination. Although the presence of the above mechanisms has been established in different studies, their quantitative importance in the overall O 2 uptake in aquatic systems is not well known, and it is necessary to assess their role in natural environments. In this respect, ordinary O 2 incubation methods, which are very useful for the assessment of photosynthetic production from light-and dark-incubation experiments (e.g., Williams and Purdie 1991), do not provide the necessary information. The main drawback of these methods is their inability to measure the rate of O 2 AcknowledgmentsWe thank Y. Geiffman and the Mekorot Watershed Unit for provision of wind data and extend special thanks to the Kinneret Limnological Laboratory skipper M. Hatab. We are grateful

show abstract

Section: Field and Laboratory Methodsmentioning

confidence: 99%

Evaluation of community respiratory mechanisms with oxygen isotopes: A case study in Lake Kinneret

Luz

Barkan

Sagi

et al. 2002

Limnology & Oceanography

125

View full text Add to dashboard Cite

show abstract

“…Therefore, entrainment of these waters into the mixed layer would tend to decrease NOP and GOP estimates. Respiration increases with depth, causing [O 2 ] and ∆(O 2 /Ar) to decrease with depth in oceanic systems (Spitzer and Jenkins, 1989;Emerson et al, 1991). In some oceanic regions, photosynthesis below the mixed layer generates excess 17 ∆ (because there is no process decreasing 17 ∆ below the mixed layer), which can then be entrained into the euphotic zone, where 17 ∆ is lower because some of the photosynthetic O 2 is ventilated to the atmosphere (Hendricks et al, 2004;Sarma et al, 2005;Juranek and Quay, 2013).…”

Section: Effect Of Physical Processes On Productivity Estimatesmentioning

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

“…over long enough time scales (many months to years) so that changes in the integrated biogeochemical stocks can be compared with the summed pathway fluxes is also required. These long-term stock measurements can be made from autonomous profiling floats or from periodic discrete water profiles taken from ships of opportunities (e.g., Emerson et al, 1991;Riser and Johnson, 2008).…”

Section: Experimental Approachmentioning

confidence: 99%

Prediction of the Export and Fate of Global Ocean Net Primary Production: The EXPORTS Science Plan

et al. 2016

View full text Add to dashboard Cite

Ocean ecosystems play a critical role in the Earth's carbon cycle and the quantification of their impacts for both present conditions and for predictions into the future remains one of the greatest challenges in oceanography. The goal of the EXport Processes in the Ocean from Remote Sensing (EXPORTS) Science Plan is to develop a predictive understanding of the export and fate of global ocean net primary production (NPP) and its implications for present and future climates. The achievement of this goal requires a quantification of the mechanisms that control the export of carbon from the euphotic zone as well as its fate in the underlying "twilight zone" where some fraction of exported carbon will be sequestered in the ocean's interior on time scales of months to millennia. Here we present a measurement/synthesis/modeling framework aimed at quantifying the fates of upper ocean NPP and its impacts on the global carbon cycle based upon the EXPORTS Science Plan. The proposed approach will diagnose relationships among the ecological, biogeochemical, and physical oceanographic processes that control carbon cycling across a range of ecosystem and carbon cycling states leading to advances in satellite diagnostic and numerical prognostic models. To collect these data, a combination of ship and robotic field sampling, satellite remote sensing, and numerical modeling is proposed which enables the sampling of the many pathways of NPP export and fates. This coordinated, process-oriented approach has the potential to foster new insights on ocean carbon cycling that maximizes its societal relevance through the achievement of research goals of many international research agencies and will be a key step toward our understanding of the Earth as an integrated system.

show abstract

O₂, Ar, N₂, and ²²²Rn in surface waters of the subarctic Ocean: Net biological O₂ production

Cited by 166 publications

References 41 publications

Evaluation of community respiratory mechanisms with oxygen isotopes: A case study in Lake Kinneret

Evaluation of community respiratory mechanisms with oxygen isotopes: A case study in Lake Kinneret

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

Prediction of the Export and Fate of Global Ocean Net Primary Production: The EXPORTS Science Plan

Contact Info

Product

Resources

About