Simultaneous vertical measurements of in situ pH and CO2 in the sea using spectrophotometric profilers

Nakano, Yoshiyuki; Kimoto, Hideshi; Watanabe, Shuichi; Harada, Koh; Watanabe, Yutaka

doi:10.1007/s10872-006-0033-y

Cited by 40 publications

(35 citation statements)

References 27 publications

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“…The spectrophotometric pH measurement technique, refined by Robert Byrne and coworkers (1993) at the University of South Florida is now the basis of nearly all pH measurements made for studying the seawater CO 2 system. Discrete (Friis et al 2004), underway (Bellerby et al 2002), and profiling (Nakano et al 2006) spectrophotometric pH instruments are increasingly common. Autonomous spectrophotometric pH analyzers (Liu et al 2006;Martz et al 2003;Seidel et al 2008) that can operate in situ for months without calibration are now beginning to be used.…”

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confidence: 99%

Testing the Honeywell Durafet® for seawater pH applications

Martz

Connery²,

Johnson

2010

Limnology & Ocean Methods

253

244

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We report on the first seawater tests at 1 atm of the Honeywell Durafet ® pH sensor, a commercially available ion sensitive field effect transistor (ISFET). Performance of this sensor was evaluated in a number of different situations including a temperature-controlled calibration vessel, the MBARI test tank, shipboard underway mapping, and a surface mooring. Many of these tests included a secondary reference electrode in addition to the internal reference supplied with the stock Durafet sensor. We present a theoretical overview of sensor response using both types of reference electrode. The Durafet sensor operates with a short term precision of ± 0.0005 pH over periods of several hours and exhibits stability of better than 0.005 pH over periods of weeks to months. Our tests indicate that the Durafet pH sensor operates at a level of performance satisfactory for many types of biogeochemical studies at low pressure. *Corresponding author: E-mail: trmartz@ucsd.edu AcknowledgmentsThis work was supported by grants from the David and Lucile Packard Foundation and the National Science Foundation through the Biocomplexity in the Environment Program Grant ECS-0308070 and the Ocean Technology and Interdisciplinary Coordination Program Grant OTIC-0844394. We thank Bob Carlson at Honeywell Laboratories for many helpful discussions throughout this work and for a critical review of the manuscript. Gernot Friederich provided underway TCO 2 and pCO 2 data. Hans Jannasch, Luke Coletti, Tom Marion, and Jim Montgomery facilitated construction of the autonomous Durafet sensor. Ginger Elrod, Steve Fitzwater, and Carole Sakamoto performed spectrophotometric pH measurements on test tank samples.

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confidence: 99%

Testing the Honeywell Durafet® for seawater pH applications

Martz

Connery²,

Johnson

2010

Limnology & Ocean Methods

253

244

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“…[48][49][50] Of these, colorimetry -in which the sample is mixed with an analyte-specific reagent to produce a measurable colour -has proved to be by far the most popular method and has been used for in situ analysis of a range of chemical parameters including nitrate and nitrite, [21,22,24,29,31,34,35,38] phosphate, [27,38] iron, [23,26,28,36,39,[42][43][44] manganese, [25,26,28,37,40] sulfide [32,33,35,39,41] silicate [30,32,33,38] and pH. [51][52][53][54][55] Colorimetry lends itself well to microfluidic in situ analysers as it is chemically robust, offers excellent analytical performance (limits of detection typically in the order of 10 nM [21,25,36]) and requires relatively small, cheap and easily-sourced components.…”

Section: In Situ Chemical Sensorsmentioning

confidence: 99%

Trends in microfluidic systems for in situ chemical analysis of natural waters

Nightingale

Beaton

Mowlem

2015

Sensors and Actuators B: Chemical

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Spatially and temporally detailed measurement of ocean, river and lake chemistry is key to fully understanding the biogeochemical processes at work within them. To obtain these valuable data, miniaturised in situ chemical analysers have recently become an attractive alternative to traditional manual sampling, with microfluidic technology at the forefront of recent advances. In this short critical review we discuss the role, operation and application of in situ microfluidic analysers to measure biogeochemical parameters in natural waters. We describe recent technical developments, most notably how pumping technology has evolved to allow long-term deployments, and describe how they have been deployed in real-world situations to yield detailed, scientifically useful data. Finally, we discuss the technical challenges that still remain and the key obstacles that must be negotiated if these promising systems are to be widely adopted and used, for example, in large environmental sensor networks and on low-power underwater vehicles.

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“…Gas permeable interface indicator solution fluorescence Goyet et al (1992); Tabacco et al (1999); Rubin and Ping Wu (2000) Gas permeable interface indicator solution spectrophotometry Degrandpre (1993); Lefévre et al (1993); Degrandpre et al (1995Degrandpre et al ( , 1999; Wang et al (2002);Wang et al (2003); Nakano et al (2006); Lu et al (2008) culate the internal gas around a closed circuit connecting the equilibrator and detector (flow path: valve 2-circulation pump-optical cell-valve 3-valve 4-equilibrator-valve 1-valve 2, Fig. 1).…”

Section: Measured Phase Determination Referencesmentioning

confidence: 99%

“…The knowledge of surface ocean CO 2 variability is important for understanding the marine carbon cycle and its future response to the absorption of anthropogenic CO 2 (Doney et al 2009). In the past few decades, high-accuracy seawater pCO 2 measuring systems (Körtzinger et al 1996;Pierrot et al 2009) have been widely used on research vessels providing high quality pCO 2 data, which leads to the generation of a global atlas of the surface ocean pCO 2 (Surface Ocean CO 2 Atlas, http://www.socat.info/, Bakker et al 2013) and CO 2 flux (Takahashi et al 2009). However, there is still a lack of data from large areas of the globe, especially in the shelf seas, Southern Ocean, and southern-hemisphere subtropical gyres (Doney et al 2009).…”

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confidence: 99%

Application and assessment of a membrane‐based pCO₂ sensor under field and laboratory conditions

Jiang

Hydes

Hartman

et al. 2014

Limnology & Ocean Methods

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The principle, application, and assessment of the membrane-based ProOceanus CO 2 -Pro sensor for partial pressure of CO 2 (pCO 2 ) are presented. The performance of the sensor is evaluated extensively under field and laboratory conditions by comparing the sensor outputs with direct measurements from calibrated pCO 2 measuring systems and the thermodynamic carbonate calculation of pCO 2 from discrete samples. Under stable laboratory condition, the sensor agreed with a calibrated water-air equilibrator system at -3.0 ± 4.4 μatm during a 2-month intercomparison experiment. When applied in field deployments, the larger differences between measurements and the calculated pCO 2 references (6.4 ± 12.3 μatm on a ship of opportunity and 8.7 ± 14.1 μatm on a mooring) are related not only to sensor error, but also to the uncertainties of the references and the comparison process, as well as changes in the working environments of the sensor. When corrected against references, the overall uncertainties of the sensor results are largely determined by those of the pCO 2 references (± 2 and ± 8 μatm for direct measurements and calculated pCO 2 , respectively). Our study suggests accuracy of the sensor can be affected by temperature fluctuations of the detector optical cell and calibration error. These problems have been addressed in more recent models of the instrument through improving detector temperature control and through using more accurate standard gases. Another interesting result in our laboratory test is the unexpected change in alkalinity which results in significant underestimation in the pCO 2 calculation as compared to the direct measurement (up to 90 μatm).

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Simultaneous vertical measurements of in situ pH and CO2 in the sea using spectrophotometric profilers

Cited by 40 publications

References 27 publications

Testing the Honeywell Durafet® for seawater pH applications

Testing the Honeywell Durafet® for seawater pH applications

Trends in microfluidic systems for in situ chemical analysis of natural waters

Application and assessment of a membrane‐based pCO₂ sensor under field and laboratory conditions

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Simultaneous vertical measurements of in situ pH and CO2 in the sea using spectrophotometric profilers

Cited by 40 publications

References 27 publications

Testing the Honeywell Durafet® for seawater pH applications

Testing the Honeywell Durafet® for seawater pH applications

Trends in microfluidic systems for in situ chemical analysis of natural waters

Application and assessment of a membrane‐based pCO2 sensor under field and laboratory conditions

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Product

Resources

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Application and assessment of a membrane‐based pCO₂ sensor under field and laboratory conditions