umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Improved accuracy of optode‐based oxygen consumption measurements by removal of system drift and nonlinear derivation
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
(EcoChange; UMFpub)
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF). (EcoChange; UMFpub)
2019 (English)In: Limnology and Oceanography: Methods, ISSN 1541-5856, E-ISSN 1541-5856, Vol. 17, no 3, p. 179-189Article in journal (Refereed) Published
Abstract [en]

This method evaluation aimed to improve the accuracy and precision of the previously published method to measure oxygen consumption using optodes with integrated temperature and salinity correction in dark incubations. Significant short‐term system drift currently requires a correction to remove the drift, thus reducing the precision of the oxygen consumption rates. Frequent nonlinear declines in oxygen concentration with time also call for improved data analysis and identification of its origin. Optodes in titanium casings (Aanderaa™ model 4330) with low oxygen binding properties showed no significant system drift in autoclaved seawater. Nonlinear oxygen dynamics fitting a quadratic polynomial occurred in 28% of 230 field samples, independent of season and water depth. Polynomial curve fit resulted in 64% higher respiration rates when derived within 1 h of the quality assured incubation, than obtained when using linear fit. Carbon substrate limitation explained the nonlinearity of oxygen decline during dark incubations. Pretreatment of the optode attached to stoppers with 0.3 mol dm−3 hydrochloric acid resulted in the most stable performance of the sensor and simultaneously provided proper cleaning of the equipment. A conservative detection limit of 0.97 μmol O2 dm−3 d−1 was calculated for the titanium optodes, matching other methods for oxygen consumption reported in the literature. Thus, we recommend the use of model 4330 optode pretreated with HCl and the derivation of initial respiration rates by a quadratic polynomial function for best accuracy and precision of oxygen consumption in oxygenated surface waters.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019. Vol. 17, no 3, p. 179-189
National Category
Ecology
Identifiers
URN: urn:nbn:se:umu:diva-152581DOI: 10.1002/lom3.10297ISI: 000461209600001Scopus ID: 2-s2.0-85058957567OAI: oai:DiVA.org:umu-152581DiVA, id: diva2:1255803
Funder
Ecosystem dynamics in the Baltic Sea in a changing climate perspective - ECOCHANGEThe Kempe Foundations, JCK‐1716
Note

Originally included in thesis in manuscript form with title "Improved accuracy of optode-based oxygen consumption measurements by removal of system drift and non-linear derivation".

Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2019-04-05Bibliographically approved
In thesis
1. Importance of bacterial maintenance respiration and baseline respiration for development of coastal hypoxia
Open this publication in new window or tab >>Importance of bacterial maintenance respiration and baseline respiration for development of coastal hypoxia
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Reduced oxygen concentrations and increasing hypoxic zones havebecome more common in the sea due to climate change andeutrophication. The main cause of oxygen loss in oxygenatedenvironments is respiration. Respiration rates can be estimated usingoptode methodologies which utilize dynamic luminescence quenching toestimate the oxygen concentration declines in dark incubations. Apublished optode methodology was improved by using optodes withtitanium housing instead of plastic housing plausibly trapping oxygen.Drift was highly reduced by the titanium casings leading to a higherprecision and lower detection limit of 0.97 mmol O2 m-3 d-1. 28% ofmeasurements were shown to have non-linear oxygen concentrationdeclines. The rate of oxygen change was derived with a 2nd degreepolynomial at 1 hour from the incubation start. The majority of non-lineardeclines were concave and due to carbon substrate limitation. Analyzingnon-linear trends linearly, a common practice, leads to anunderestimation of respiration by up to 64%.

Bacterial maintenance respiration (Rm) was studied using anecophysiological model unverified in natural environments. The modelwas applicable at high productivities but a quadratic model wasdemonstrated to give a better fit. Rm was found to represent a significantpart in the sub-arctic estuary contributing to 58% of the annual specificbacterial respiration. Therefore, Rm may be more important in nature thanpreviously recognized. The ecophysiological model is driven solely by thebacterial specific growth rate (μ) where the relative influence of Rm iselevated as μ decreases. As a consequence, I hypothesize that a reductionin nutrients may not decrease the oxygen consumption but rather shiftbacterial growth based respiration to Rm as μ approaches zero.Baseline respiration (Rbl), defined as ecosystem respiration disconnectedfrom contemporary primary produced carbon, was also studied. Rbl wasshown to be largely supplied by allochthonous carbon in a coastalecosystem and had a contribution of 50% to the annual planktoncommunity respiration in the sub-arctic estuary studied. I claim that Rbland Rm are crucial to include for understanding and managingdevelopment of aquatic hypoxia in an effective and economic manner.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2018. p. 40
Keywords
Ecology, Respiration, Estuarine, Allochthonous, Maintenance, primary production, bacterial production
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-152587 (URN)978-91-7601-927-6 (ISBN)
Public defence
2018-11-09, N440, Naturvetarhuset, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2018-10-19 Created: 2018-10-15 Last updated: 2019-03-19Bibliographically approved

Open Access in DiVA

fulltext(390 kB)52 downloads
File information
File name FULLTEXT02.pdfFile size 390 kBChecksum SHA-512
edc9a43430981ea415dd09110444b17137d9c7e154a0d9844a31dcbec9cb5583533bb11a29c35781fa9297a0ac8e962f9acf8a7ca2c3ac6b8d3506b01a17f2ad
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopus

Authority records BETA

Vikström, KevinWikner, Johan

Search in DiVA

By author/editor
Vikström, KevinWikner, Johan
By organisation
Department of Ecology and Environmental SciencesUmeå Marine Sciences Centre (UMF)
In the same journal
Limnology and Oceanography: Methods
Ecology

Search outside of DiVA

GoogleGoogle Scholar
Total: 52 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 275 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf