A new nitrate continuous observation sensor for autonomous sub-surface applications: Technical design and first results

Fiedler, Björn; Heuermann, R.; Körtzinger, Arne; Kopiske, E.; Meinecke, Gerrit; Munderloh, K.

doi:10.1109/oceanse.2007.4302300

Cited by 16 publications

(16 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relatively larger scatter in the nitrate absorbance is probably due to the wider wavelength range used. Laboratory measurements by Zielinski et al (2007) also found a similar strong temperature dependence of seawater absorbances.…”

Section: Assessmentsupporting

confidence: 54%

“…Once the temperature corrected ESW (λ,Tis) values are known, it should be possible to subtract the bromide component before computing nitrate as noted by Zielinski et al (2007). In this case, the expected spectral component due to sea salt at the in situ temperature (ASE (λ,Tis) ) can be calculated using the observed salinity S (acquired from associated CTD data) with the following equation:…”

Section: Assessmentmentioning

confidence: 99%

See 1 more Smart Citation

Improved algorithm for the computation of nitrate concentrations in seawater using an in situ ultraviolet spectrophotometer

Sakamoto

Johnson

Coletti

2009

Limnology & Ocean Methods

121

View full text Add to dashboard Cite

Improvements in the data processing algorithm and calibration procedures have greatly increased the accuracy of nitrate measurements using an in situ ultraviolet spectrophotometer (ISUS). Two major changes in the algorithm involve application of a temperature-dependent correction to the bromide spectrum and then using the observed temperature and salinity to subtract the bromide component before fitting nitrate. By reducing the degrees of freedom in calculating nitrate concentrations, the accuracy of the ISUS instrument is substantially improved. The new algorithm was tested in environments ranging from the Southern Ocean to oligotrophic eastern Pacific seawater and found to be applicable at all temperatures and depths. The standard error of the estimate for regression between ISUS nitrate values and discrete samples measured by standard wet chemistry methods for the combined data set is reduced by greater than 2-fold (1.4 down to 0.65 µM) using the new algorithm. This corresponds to a 5-fold reduction in variance (2.0 down to 0.4 µM 2 ). Although biofouling and calibration drift remain issues for any instrument deployed in situ for long periods of time, using the measured salinity and temperature to correct the ultraviolet spectra before the nitrate calculations will reduce the impacts of these confounding processes.

show abstract

Section: Assessmentsupporting

confidence: 54%

Section: Assessmentmentioning

confidence: 99%

Improved algorithm for the computation of nitrate concentrations in seawater using an in situ ultraviolet spectrophotometer

Sakamoto

Johnson

Coletti

2009

Limnology & Ocean Methods

121

View full text Add to dashboard Cite

show abstract

“…A Parameter such as salinity is derived from the CTD data and is necessary to calculate the oxygen content and the current oxygen saturation [10]. Also, by using CTD data, temperature dependent effects on the absorption spectrum of bromide ions, which absorb UV-light at a similar range as nitrate and thus interfere with the nitrate measurement, can be compensated ( [11], [12]). …”

Section: Data Fusionmentioning

confidence: 99%

Biogeochemical research with an Autonomous Underwater Vehicle: Payload structure and arctic operations

Wulff

Lehmenhecker

Bauerfeind

et al. 2013

2013 MTS/IEEE OCEANS - Bergen

View full text Add to dashboard Cite

“…Alternatives to wet chemical sensing techniques include nitrate analysis using UV absorbance [8][9][10] and surface ammonia measurements using a gas diffusion cell and potentiometric analysis [11]. The UV technique provides a very rapid response and does not require reagents or waste storage; however, sensitivity of the UV method is lower than that of wet chemical techniques.…”

Section: Current Techniquesmentioning

confidence: 99%

In Situ Nutrient Sensors for Ocean Observing Systems

Adornato

Cardenas-Valencia

Kaltenbacher

et al. 2010

Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society

View full text Add to dashboard Cite

New insights into global geochemical cycles can be realized through use of in situ nutrient sensors. Although a number of technological advances have been made, there remain challenges to synoptic, longterm nutrient sensing in marine systems. Resources must be expended to address critical sensor development needs that include reductions in size, cost, power consumption, reagent use, and waste generation, and increases in long-term reliability.

show abstract

A new nitrate continuous observation sensor for autonomous sub-surface applications: Technical design and first results

Cited by 16 publications

References 14 publications

Improved algorithm for the computation of nitrate concentrations in seawater using an in situ ultraviolet spectrophotometer

Improved algorithm for the computation of nitrate concentrations in seawater using an in situ ultraviolet spectrophotometer

Biogeochemical research with an Autonomous Underwater Vehicle: Payload structure and arctic operations

In Situ Nutrient Sensors for Ocean Observing Systems

Contact Info

Product

Resources

About