Effects of Nitrogen Dilution
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Transcript of Effects of Nitrogen Dilution
Effects of Nitrogen Dilution on Algal Growth in Lake Erie Water Samples
Nathan Arroyo Summer REU 2011
Acknowledgements Stone Lab REU
Program Dr. Bade Matt Thomas
NOAA/Ohio Sea Grant
Summer 2011 Limnology Class
Introduction Lake Erie plagued with late summer algal
blooms Thick mats of algae are unappealing hurt tourism cause fish kills toxic to animals and humans
Background
Eutrophication studied for over a century
Schindler- 1970’s Phosphorous Paradigm
Recently challenged with idea of nitrogen limitation
Questions Asked
What is the best strategy to remediate the Lake?
Can the growth of algae in Lake Erie be curbed by limiting nitrogen?
Hypothesis: By removing nitrogen, the growth of algae in Lake Erie can be reduced.
Nutrient Dilutions Samples from Gibraltar Island and Sandusky
Bay Samples diluted with artificial Lake Water
Gibraltar Island - no Ca+2 or Si+4 Sandusky Bay - no Ca+2
Nutrient Dilutions
Lake Water 100% 80% 60% 40% Artificial Water 0% 20% 40% 60%
Nutrient Dilutions Samples incubated at alligator bar for a week Algal biomass estimated from Chlorophyll a using fluorometer
Gibraltar Dilutions
0
5
10
15
20
25
30
35
Rela
tive
Gro
wth
(µg
Chl
. a/L
)
C + P
Gibraltar Dilutions
-10
0
10
20
30
40
50
1C 0.8C 0.6C 0.4C 1+P 0.8+P 0.6+P 0.4+P
Rela
tive
Gro
wth
(µg
Chl
. a/L
)
Gibraltar Dilutions
Sandusky Bay Dilutions
-35
-30
-25
-20
-15
-10
-5
0
Rela
tive
Gro
wth
(µg
chl.
a/L)
C + P Sandusky Bay Dilutions
-60
-50
-40
-30
-20
-10
0
10 1C 0.8C 0.6C 0.4C 1+P 0.8+P 0.6+P 0.4+P
Rela
tive
Gro
wth
(µg
chl.
a/L)
Sandusky Bay Dilutions
Summary
Gibraltar dilution- some limitation from nitrogen dilution, overwhelming phosphorous limitation
Sandusky Bay Dilution-slightly phosphorous limited, results point to possible other nutrient limitation (Si)
Conclusion