Download Cyanobacteria Blooms in Upper Klamath Lake

Cyanobacteria Blooms in
Upper Klamath Lake
Lauren Senkyr
ESR 575 Limnology
November 23, 2009
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
Water diversions
ESA listed suckers
Agriculture- nutrient inputs + water use
Dams along Klamath River
Cycle of Water Quality Degradation
in Upper Klamath Lake
↑ Phosphorus
↑ Algal Blooms
↑ pH
↑ Nutrient
Loading
↑ Unionized
Ammonia
Fish Dieoffs
↓ Dissolved
Oxygen
↓ Algal Blooms
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
•High pH
•High water temperatures
Eilers et. al. 2004
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
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Sedimentation
Nutrient retention
Greater internal loading
Wind control
accentuated by lower
water levels
Eilers. Et. al. 2004
Implications for wetland restoration
and dam removal?
http://www.nature.org/wherewework/northamerica/states/oregon/about/art25169.html#