cyanobacteria blooms in upper klamath lake esr 575 limnology november 23, 2009 lauren senkyr
Post on 21-Dec-2015
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Upper Klamath Lake
Oregon’s largest lake
Oregon’s largest lake:
•Volume ~ 536 x 1036
•Surface area ~275 km2
•Shallow, hypereutrophic
•Avg. depth 2.2 m
•Mean depth 2 m
•Max. depth 15.2 m
Management issues
ESA listed suckers
Water diversions
Agriculture- nutrient inputs + water useDams along Klamath River
↑ Phosphorus↑ Algal Blooms
↑ pH
↑ Unionized Ammonia
↓ Dissolved Oxygen
↓ Algal Blooms
↑ Nutrient Loading
Fish Die-offs
Cycle of Water Quality Degradation in Upper Klamath Lake
Cyanobacteria• “Blue green algae”• Aphanizomenon flos-aquae
dominant June-October• 1st appearance 1933• Collapse causes anoxic conditions that lead to
fish kills • Commercially harvested
• 1 toxic species in UKL (Microcystis aeruginosa)
Basic Biology of AFA
•Does not grow in pH < 7.1, water temperature < 11 degrees C
Yamamoto and Nakahara, Limnology (2005)
Current Conditions in Upper Klamath Lake Favor AFA
Eilers et. al. 2004
•High pH
•High water temperatures
Internal P Loading
• Internal load ~2/3 Total P in Upper Klamath Lake
• Decrease in total P in top
2 cm of sediment before/
after bloom
(Simon et. al. 2009)
The Role of Wind
• Very strong relationship between climate and water quality in Upper Klamath Lake
• ↑ wind speeds = ↓ water column stability
• Wind induced mixing of sediments= increased nutrient availability
• (Kann and Welch 2005)
Impacts of altered hydrology• Sedimentation• Nutrient retention• Greater internal loading• Wind control
accentuated by lower water levels
Eilers. E
t. al. 2004
Implications for wetland restoration and dam removal?
http://www.nature.org/wherewework/northamerica/states/oregon/about/art25169.html#