An experiment with forced oxygenation of the deepwater of the anoxic By Fjord, western Sweden.
In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.
Department of Geosciences, University of Gothenburg, Box 460, 405 30, Göteborg, Sweden, anst@gvc.gu.se.
Anders
A
Stigebrandt
Bengt
B
Liljebladh
Loreto
L
de Brabandere
Michael
M
Forth
Åke
Å
Granmo
Per
P
Hall
Jonatan
J
Hammar
Daniel
D
Hansson
Mikhail
M
Kononets
Marina
M
Magnusson
Fredrik
F
Norén
Lars
L
Rahm
Alexander H
AH
Treusch
Lena
L
Viktorsson
D003247:Conservation of Natural Resources / Q000191:economics / Q000379:methods*; D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000032:analysis; D009566:Nitrates / Q000032:analysis*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D012621:Seasons; D012623:Seawater / Q000382:microbiology; D013548:Sweden; D014874:Water Pollutants, Chemical / Q000032:analysis
D009566:Nitrates; D014874:Water Pollutants, Chemical; D010100:Oxygen