Comparison of DET, DGT and conventional porewater extractions for determining nutrient profiles and cycling in stream sediments

Jianyin Huang, Hannah Franklin, Peter R. Teasdale*, Michele A. Burford, Nadeeka Rathnayake Kankanamge, William W. Bennett, David T. Welsh

*Kontaktforfatter for dette arbejde

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

Determining inorganic nutrient profiles to support understanding of nitrogen transformations in stream sediments is challenging, due to nitrification and denitrification being confined to particular conditions in potentially heterogeneous sediment influenced by benthic microalgae, rooted aquatic plants and/or diel light cycles. The diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques allow in situ determination of porewater concentration profiles, and distributions for some solutes. In this study, DGT, DET and conventional porewater extraction (sectioning and centrifugation) methods were compared for ammonium and nitrate in stream sediments under light and dark conditions. Two-dimensional distributions of Fe(ii) and PO4-P were also provided to indicate the degree of spatial and temporal heterogeneity in sediment porewater, which can explain the sources and sinks of ammonium at various depths in the sediments. Although the conventional porewater extraction method consistently measured higher NH4-N concentrations than the DGT and DET techniques, the study showed that the DET measurements were the most reliable indicator of porewater NH4-N concentrations, with the DGT data being usefully supplementary. However, a large proportion of the NO3-N concentrations measured by DGT and DET were close to or below the method detection limits. Therefore, further development of these techniques is required to reduce the blanks and detection limits to allow natural low sediment porewater NO3-N concentrations to be accurately monitored using DGT and DET. The study indicated that benthic microalgae had direct and indirect influences on porewater nutrient distributions over light-dark cycles. Overall, DGT and DET techniques can be useful for monitoring porewater nutrient concentrations and profiles and for determining how biological processes drive changes in sediment nutrient concentrations and distributions.

OriginalsprogEngelsk
TidsskriftEnvironmental Science: Processes and Impacts
Vol/bind21
Udgave nummer12
Sider (fra-til)2128-2140
Antal sider13
ISSN2050-7887
DOI
StatusUdgivet - dec. 2019
Udgivet eksterntJa

Fingeraftryk

fluvial deposit
Nutrients
porewater
Sediments
Microalgae
Food
Thin films
nutrient
Photoperiod
Limit of Detection
Centrifugation
Ammonium Compounds
Nitrogen
sediment
comparison
ammonium
Nitrification
Denitrification
aquatic plant
detection method

Citer dette

Huang, Jianyin ; Franklin, Hannah ; Teasdale, Peter R. ; Burford, Michele A. ; Kankanamge, Nadeeka Rathnayake ; Bennett, William W. ; Welsh, David T. / Comparison of DET, DGT and conventional porewater extractions for determining nutrient profiles and cycling in stream sediments. I: Environmental Science: Processes and Impacts. 2019 ; Bind 21, Nr. 12. s. 2128-2140.
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title = "Comparison of DET, DGT and conventional porewater extractions for determining nutrient profiles and cycling in stream sediments",
abstract = "Determining inorganic nutrient profiles to support understanding of nitrogen transformations in stream sediments is challenging, due to nitrification and denitrification being confined to particular conditions in potentially heterogeneous sediment influenced by benthic microalgae, rooted aquatic plants and/or diel light cycles. The diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques allow in situ determination of porewater concentration profiles, and distributions for some solutes. In this study, DGT, DET and conventional porewater extraction (sectioning and centrifugation) methods were compared for ammonium and nitrate in stream sediments under light and dark conditions. Two-dimensional distributions of Fe(ii) and PO4-P were also provided to indicate the degree of spatial and temporal heterogeneity in sediment porewater, which can explain the sources and sinks of ammonium at various depths in the sediments. Although the conventional porewater extraction method consistently measured higher NH4-N concentrations than the DGT and DET techniques, the study showed that the DET measurements were the most reliable indicator of porewater NH4-N concentrations, with the DGT data being usefully supplementary. However, a large proportion of the NO3-N concentrations measured by DGT and DET were close to or below the method detection limits. Therefore, further development of these techniques is required to reduce the blanks and detection limits to allow natural low sediment porewater NO3-N concentrations to be accurately monitored using DGT and DET. The study indicated that benthic microalgae had direct and indirect influences on porewater nutrient distributions over light-dark cycles. Overall, DGT and DET techniques can be useful for monitoring porewater nutrient concentrations and profiles and for determining how biological processes drive changes in sediment nutrient concentrations and distributions.",
author = "Jianyin Huang and Hannah Franklin and Teasdale, {Peter R.} and Burford, {Michele A.} and Kankanamge, {Nadeeka Rathnayake} and Bennett, {William W.} and Welsh, {David T.}",
year = "2019",
month = "12",
doi = "10.1039/c9em00312f",
language = "English",
volume = "21",
pages = "2128--2140",
journal = "Environmental Science Processes & Impacts",
issn = "2050-7887",
publisher = "Royal Society of Chemistry",
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Comparison of DET, DGT and conventional porewater extractions for determining nutrient profiles and cycling in stream sediments. / Huang, Jianyin; Franklin, Hannah; Teasdale, Peter R.; Burford, Michele A.; Kankanamge, Nadeeka Rathnayake; Bennett, William W.; Welsh, David T.

I: Environmental Science: Processes and Impacts, Bind 21, Nr. 12, 12.2019, s. 2128-2140.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Comparison of DET, DGT and conventional porewater extractions for determining nutrient profiles and cycling in stream sediments

AU - Huang, Jianyin

AU - Franklin, Hannah

AU - Teasdale, Peter R.

AU - Burford, Michele A.

AU - Kankanamge, Nadeeka Rathnayake

AU - Bennett, William W.

AU - Welsh, David T.

PY - 2019/12

Y1 - 2019/12

N2 - Determining inorganic nutrient profiles to support understanding of nitrogen transformations in stream sediments is challenging, due to nitrification and denitrification being confined to particular conditions in potentially heterogeneous sediment influenced by benthic microalgae, rooted aquatic plants and/or diel light cycles. The diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques allow in situ determination of porewater concentration profiles, and distributions for some solutes. In this study, DGT, DET and conventional porewater extraction (sectioning and centrifugation) methods were compared for ammonium and nitrate in stream sediments under light and dark conditions. Two-dimensional distributions of Fe(ii) and PO4-P were also provided to indicate the degree of spatial and temporal heterogeneity in sediment porewater, which can explain the sources and sinks of ammonium at various depths in the sediments. Although the conventional porewater extraction method consistently measured higher NH4-N concentrations than the DGT and DET techniques, the study showed that the DET measurements were the most reliable indicator of porewater NH4-N concentrations, with the DGT data being usefully supplementary. However, a large proportion of the NO3-N concentrations measured by DGT and DET were close to or below the method detection limits. Therefore, further development of these techniques is required to reduce the blanks and detection limits to allow natural low sediment porewater NO3-N concentrations to be accurately monitored using DGT and DET. The study indicated that benthic microalgae had direct and indirect influences on porewater nutrient distributions over light-dark cycles. Overall, DGT and DET techniques can be useful for monitoring porewater nutrient concentrations and profiles and for determining how biological processes drive changes in sediment nutrient concentrations and distributions.

AB - Determining inorganic nutrient profiles to support understanding of nitrogen transformations in stream sediments is challenging, due to nitrification and denitrification being confined to particular conditions in potentially heterogeneous sediment influenced by benthic microalgae, rooted aquatic plants and/or diel light cycles. The diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques allow in situ determination of porewater concentration profiles, and distributions for some solutes. In this study, DGT, DET and conventional porewater extraction (sectioning and centrifugation) methods were compared for ammonium and nitrate in stream sediments under light and dark conditions. Two-dimensional distributions of Fe(ii) and PO4-P were also provided to indicate the degree of spatial and temporal heterogeneity in sediment porewater, which can explain the sources and sinks of ammonium at various depths in the sediments. Although the conventional porewater extraction method consistently measured higher NH4-N concentrations than the DGT and DET techniques, the study showed that the DET measurements were the most reliable indicator of porewater NH4-N concentrations, with the DGT data being usefully supplementary. However, a large proportion of the NO3-N concentrations measured by DGT and DET were close to or below the method detection limits. Therefore, further development of these techniques is required to reduce the blanks and detection limits to allow natural low sediment porewater NO3-N concentrations to be accurately monitored using DGT and DET. The study indicated that benthic microalgae had direct and indirect influences on porewater nutrient distributions over light-dark cycles. Overall, DGT and DET techniques can be useful for monitoring porewater nutrient concentrations and profiles and for determining how biological processes drive changes in sediment nutrient concentrations and distributions.

U2 - 10.1039/c9em00312f

DO - 10.1039/c9em00312f

M3 - Journal article

C2 - 31681920

AN - SCOPUS:85076383893

VL - 21

SP - 2128

EP - 2140

JO - Environmental Science Processes & Impacts

JF - Environmental Science Processes & Impacts

SN - 2050-7887

IS - 12

ER -