Cyanobacterial Toxins in the Red Cedar Basin
Chlorophyll a
Microcystin toxin
100
0.8
50
0.4
July 14
July 7
July 28
Chlorophyll a (µg·l-1)
200
To measure microcystin toxin,
we used an Enzyme-Linked
Immunosorbent Assay
(ELISA) (Fig. 2, Table 1).
1.6
150
1.2
100
0.8
50
0.4
0
July 7
July 14
July 28
0.0
0.0
Hay River,
Wheeler, WI
Red Cedar River,
Colfax, WI
200
Chlorophyll a (µg·l-1)
1.6
150
1.2
100
0.8
50
0.4
0
0.0
July 14
July 7
July 28
Microcystin toxin (µg·l-1)
T4 Transect
200
1.6
150
1.2
100
0.8
50
0.4
0
0.0
July 7
July 14
Chlorophyll a (µg·l-1)
1.6
150
1.2
0.8
50
0.4
0
0.0
July 10
July 17
July 30
Microcystin toxin (µg·l-1)
200
100
1.2
100
0.8
50
0.4
0
0.0
July 7
July 14
July 28
July 28
Boat Dock, Men
Boat Dock, Taint
Wakanda Beach
Butch‘s Bay
MC (µg·l-1 )
Mid-July
Late-July
1.1
4.7
0.8
9.1
0.9
7.1
2.4
19.1
26% of 72 samples analyzed for
microcystin toxin were above 0.5 µg·l-1.
The current WHO limit for safe drinking
water is 1 µg·l-1.3
CONCLUSIONS
Red Cedar River,
Menomonie, WI
Chlorophyll a (µg·l-1)
Chlorophyll a concentrations can be
used to estimate cyanobacterial
abundance. We determined
chlorophyll a via fluorescence
spectroscopy2 (Fig. 3).
150
T5
200
Fig 2. Illustration of competitive ELISA
procedure1
1.6
Table 1. Representative microcystin toxin
levels in samples from near-shore sites.
Microcystin toxin (µg·l-1)
0
Chlorophyll a (µg·l-1)
1.2
1.6
150
1.2
100
0.8
50
0.4
0
0.0
July 10
July 17
July 30
Microcystin toxin (µg·l-1)
Harmful algal blooms are a global concern
due to environmental and human health
impacts. Blooms in the Red Cedar Basin
primarly consist of Microcystis aeruginosa
(Fig. 1), a cyanobacterium that produces the
liver toxin microcystin.
150
Chlorophyll a (µg·l-1)
OVERVIEW
1.6
Microcystin toxin (µg·l-1)
Chlorophyll a (µg·l-1)
200
Microcystin toxin (µg·l-1)
Fig 1. Microcystis bloom, Tainter Lake
200
Microcystin toxin (µg·l-1)
Courtney Worthington (Coe College), Peng Vang (St. Cloud State University) and Dr. Stephen Nold
(University of Wisconsin-Stout)
• Chlorophyll a and microcystin toxin levels
increase over time in the lakes.
• Toxicity is higher in areas of greater human
and animal contact with the water.
• Unsafe toxicity levels are already present and
will increase as the bloom progresses.
REFERENCES
1http://www.elisa-antibody.com/ELISA-Introduction/ELISA-types/competitive-elisa
Figure 3. A temporal and spatial study of the chlorophyll a and microcystin toxin concentrations in Lake Tainter,
Lake Menomin, and rivers of the Red Cedar Watershed in Western Wisconsin during the summer of 2014.
2Welschmeyer
NA. 1994. Limnology and Oceanography 39:1985-1992.
3Gurbuz, F., et. Al. 2012. Environmental Forensics 13:105-109.
4Davis, Christopher T., et. Al. 2009. Harmful Algae 8:5:715-725.
This work supported by grant #SMA 1357387
from the National Science Foundation