Biogeochemistry and community ecology in a spring-fed urban river following a major earthquake.
In February 2011 a MW 6.3 earthquake in Christchurch, New Zealand inundated urban waterways with sediment from liquefaction and triggered sewage spills. The impacts of, and recovery from, this natural disaster on the stream biogeochemistry and biology were assessed over six months along a longitudinal impact gradient in an urban river. The impact of liquefaction was masked by earthquake triggered sewage spills (~20,000 m(3) day(-1) entering the river for one month). Within 10 days of the earthquake dissolved oxygen in the lowest reaches was <1 mg l(-1), in-stream denitrification accelerated (attenuating 40-80% of sewage nitrogen), microbial biofilm communities changed, and several benthic invertebrate taxa disappeared. Following sewage system repairs, the river recovered in a reverse cascade, and within six months there were no differences in water chemistry, nutrient cycling, or benthic communities between severely and minimally impacted reaches. This study highlights the importance of assessing environmental impact following urban natural disasters.
Department of Soil & Physical Sciences, Faculty of Agriculture & Life Sciences, P.O. Box 84, Lincoln 7674, New Zealand. Electronic address: naomi.wells@ufz.de.
Naomi S
NS
Wells
Tim J
TJ
Clough
Leo M
LM
Condron
W Troy
WT
Baisden
Jon S
JS
Harding
Y
Y
Dong
G D
GD
Lewis
Gavin
G
Lear
D000818:Animals; D055866:Earthquakes; D017753:Ecosystem; D004784:Environmental Monitoring; D007448:Invertebrates / Q000145:classification; D009520:New Zealand; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical
Liquefaction; Natural disaster recovery; Sewage contamination; Stable isotopes; Stream biofilm