Influence of plant habitats on denitrification in lowland agricultural streams

TY - JOUR

T1 - Influence of plant habitats on denitrification in lowland agricultural streams

AU - Audet, Joachim

AU - Olsen, Trine Mariane

AU - Elsborg, Thomas

AU - Baattrup-Pedersen, Annette

AU - Riis, Tenna

PY - 2021/5

Y1 - 2021/5

N2 - The aim of this study was to assess potential differences in denitrification in contrasting stream habitats in agricultural lowland streams located in Denmark. The study focused on three types of habitats i) vegetated habitats with emergent plants, ii) vegetated habitats with submerged plants, iii) bare sediments. Denitrification rates were measured in situ using denitrification chambers and nitrogen isotope pairing technique three times during a growing season. Denitrification rates across all habitats and samplings were 73 ± 116 μmol N m−2 h−1 (mean ± sd) with greater denitrification rates in vegetated habitats compared to bare sediments. Habitats with emergent plants had significantly higher denitrification rates than habitats with submerged plants. The habitats exhibited differences in oxygen and carbon availability probably connected to differences in flow velocity and physical effect of the vegetation (if present) which likely acted as a trap for finer organic-rich particles. Placing these results in the context of stream and river restoration highlights the potential of in-stream vegetation to mitigate nitrogen pollution, especially by restoring plant habitats in degraded and channelized streams to sustain vegetation promoting higher denitrification rates.

AB - The aim of this study was to assess potential differences in denitrification in contrasting stream habitats in agricultural lowland streams located in Denmark. The study focused on three types of habitats i) vegetated habitats with emergent plants, ii) vegetated habitats with submerged plants, iii) bare sediments. Denitrification rates were measured in situ using denitrification chambers and nitrogen isotope pairing technique three times during a growing season. Denitrification rates across all habitats and samplings were 73 ± 116 μmol N m−2 h−1 (mean ± sd) with greater denitrification rates in vegetated habitats compared to bare sediments. Habitats with emergent plants had significantly higher denitrification rates than habitats with submerged plants. The habitats exhibited differences in oxygen and carbon availability probably connected to differences in flow velocity and physical effect of the vegetation (if present) which likely acted as a trap for finer organic-rich particles. Placing these results in the context of stream and river restoration highlights the potential of in-stream vegetation to mitigate nitrogen pollution, especially by restoring plant habitats in degraded and channelized streams to sustain vegetation promoting higher denitrification rates.

KW - Aquatic vegetation

KW - Eutrophication

KW - Isotope partitioning technique

KW - Macrophytes

KW - Nitrogen

KW - Restoration

UR - http://www.scopus.com/inward/record.url?scp=85101351221&partnerID=8YFLogxK

U2 - 10.1016/j.jenvman.2021.112193

DO - 10.1016/j.jenvman.2021.112193

M3 - Journal article

C2 - 33636626

SN - 0301-4797

VL - 286

JO - Journal of Environmental Management

JF - Journal of Environmental Management

M1 - 112193

ER -