Interaction effects of flow velocity and oxygen metabolism on nitrification and denitrification in biofilms on submersed macrophytes

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Abstract

Effects of water flow velocityon nitrification, denitrification, andthe metabolism of dissolved oxygen andinorganic carbon in macrophyte-epiphytoncomplexes were investigated in the presentstudy. The metabolic rates were measured inmicrocosms containing shoots of Potamogeton pectinatus L. with epiphyticbiofilms in the light and dark with no flow orwith the flow velocities of 0.03 and 9 cms–1. Photosynthesis and respirationincreased with increasing water flow velocity.Rates of oxygen respiration were positivelycorrelated to the oxygen concentration of thewater. Nitrification was not significantlyaffected by flow velocity, but nitrificationwas higher in light than in dark at 0.03 cms–1, but not at 9 cm s–1.Denitrification was higher in stagnant waterand at 9 cm s–1 than at 0.03 cm s–1 inthe absence of oxygen, possibly due to complexeffects of water flow velocity on the supply oforganic matter to the denitrifying bacteria.Denitrification was always inhibited in light,and negatively correlated to the oxygenconcentration in dark. Epiphyticdenitrification occurred only at low oxygenconcentrations in flowing water, whereas instagnant water, denitrification was present inalmost oxygen saturated water. Therefore,because there are little of water movements andhigh oxygen consumption in dense stands ofsubmersed macrophytes, significant rates ofepiphytic denitrification can probably be foundwithin submersed vegetation despite high oxygenconcentrations in the surrounding water. Inconclusion, this study shows that the waterflow and oxygen metabolism within submersedvegetation have minor effects on nitrification,but significantly affect denitrification inbiofilms on submersed macrophytes.

Detaljer

Författare
  • Peder Eriksson
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Ekologi
  • Miljövetenskap
Originalspråkengelska
Sidor (från-till)29-44
TidskriftBiogeochemistry
Volym55
Utgivningsnummer1
StatusPublished - 2001
PublikationskategoriForskning
Peer review utfördJa