Hypoxia in
Estuarine and Coastal
Waters
by
Y. Peter Sheng, Taeyun Kim, and Kijin Park
Civil & Coastal Engineering Department
University of Florida
Content
• What Cause Hypoxia?
• Hypoxia in Gulf of Mexico & Chesapeake Bay
• Hypoxia in Florida
• Simulation of Hypoxia in Florida
• How do External Loading and Climate Change
Affect Hypoxia?
What Cause Hypoxia?
S tra tific a tio n + S O D
External Loading
F re s h w a te r
Nutrients
CBOD
H y p o x ia
Wind Mixing
Tidal
Mixing
DO
V e rtic a l
S tra tific a tio n
H y p o x ia
SOD
Sediment Oxygen Demand
S e a w a te r
Mississippi Dead Zone
4500-7000 sq mi
NASA
Satellite
Imagery
NOAA Ship Survey
Chesapeake Bay Dead Zone
2.98E+06
Time =
194.2917 day
July 2000
DO (mg/l)
2.97E+06
Northing (UTM,meter)
2.99E+06
Bottom-water Hypoxia in Charlotte Harbor, FL
375000
8
7.5
7
6.5
6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
380000
385000
390000
395000
Easting (UTM,meter)
400000
Hypoxia in Charlotte Harbor
After Charley (8/13/2004)
D. Tomasko
Bottom hypoxia
Surface+Bottom
hypoxia
~38 sq mi on
8/27/04
Hypoxia in Peace River Watershed
8/21/2004
Northing (UTM, meter)
2.9E+06
2.95E+06
3E+06
Simulation of Hypoxia Using an
Integrated Modeling System for
Estuarine and Coastal Ecosystems
350000
400000
Easting (UTM, meter)
CH3D-IMS (Sheng et al. 2002)
Model Grid
450000
River Discharge (m3/s)
Hypoxia in Charlotte Harbor during 2000
100
Peace River
Myakka River
80
60
40
20
0
50
100
150
200
250
300
Year Day 2000
DO (mg/l)
10
5
0
50
100
150
200
250
300
CH006
Simulated Surface DO
Simulated Bottom DO
Measured Surface DO
Measured Bottom DO
15
DO (mg/l)
CH005
Simulated Surface DO
Simulated Bottom DO
Measured Surface DO
Measured Bottom DO
15
10
5
0
50
100
150
200
250
300
Sediment Oxygen Demand
Station
Latitude
Longitude
Measured Value
(March 1984)
Measured Value
(Sep. 1984)
SOD #1
26º 55' 00"
82º 06' 18"
1.49
1.03
SOD #2
26º 48' 18"
82º 06' 30"
N/A
1.39
SOD #1
SOD (g O2 /m2/d)
2
1.5
BOD
1
Ks
SOD
0.5
0
100
150
200
250
300
CBOD
Kd2
SOD #2
2
NBOD
1.5
1
0.5
0
Water
Sediments
50
Julian Day
SOD (g O2 /m2/d)
DOwater
50
100
150
200
Julian Day
250
300
KN2
DOsed
Volume of Bottom Hypoxic Water is Related to River
Discharge, Ri, and Tide
w a te r a n d
r iv e r d is c h a r g e
J ul il iaa n
n
J u
DD a ay
2 2 0
y
3
0
2 4 0
0
2E+08
4E+06
4E+08
8E+06
6E+08
1.2E+07
3
V o lu m e o f b o t t o m w a t e r f o r D O ( b e lo w 2 m g / l) a n d R i # ( o v e r 0 . 5 5 )
1
. 4
E
+
0
7
1
. 2
E
+
0
7
1
E
+
0
7
8
E
+
0
6
6
E
+
0
6
4
E
+
0
6
2
E
+
0
6
0
180
200
220
J u lia n D a y
240
0
1
8
0
2
0
0
J u
l i a
n
D
a
y
2
2
0
2
4
0
- 5
0
- 1
0
0
Water surface elevation (cm NAVD88)
2 0 0
3
1 8 0
Volume of bottom water for RI # (m )
0
1 0
River discharge (m /sec)
1.2E+07
8E+06
2 0
4E+06
3 0
Volume of bottom water for DO (m )
3
Volume of bottom water (m )
o f b o tto m
4 0
Volume of bottom water (m )
3
V o lu m e
Can we control Hypoxia?
• Sediment Oxygen Demand (SOD) is due to the
oxidation of organic matter in bottom sediments.
• The main sources of organic matter in bottom
sediments are from river loading, waste
discharge, and dead algae following major bloom.
• SOD can be a large fraction of oxygen
consumption in surface water bodies.
DO and SOD with reduced nutrient/CBOD loading
C H 0 0 5
(B o tto m )
B a s e lin e
5 0 % R e d u c t io n
1 0 0 % R e d u c t io n
DO (mg/l)
5
4
3
2 6 0
DO (mg/l)
7
2 6 5
C H 0 0 9
2 7 0
J u lia n
D a y
2 7 5
(B o tto m )
B a s e lin e
5 0 % R e d u c tio n
1 0 0 % R e d u c t io n
6 .5
6
5 .5
52 6 0
2 6 5
2 7 0
J u lia n
D a y
2 7 5
2
SOD (g O2/m /d)
1 .5
1
0 .5
02 6 0
2
2
2 8 0
CH005
2
SOD (g O2/m /d)
2 8 0
1 .5
B a s e lin e
5 0 % R e d u c t io n
1 0 0 % R e d u c tio n
265
270
J u l ia n D a y
275
280
CH009
B a s e li n e
5 0 % R e d u c tio n
1 0 0 % R e d u c t io n
1
0 .5
02 6 0
265
270
J u l ia n D a y
275
280
SOD in the Upper Charlotte Harbor
(Increased air temperature of 3°)
CH005
SOD (g O2/m2/d)
2
1.5
1
0.5
0260
SOD (g O2/m2/d)
2
Baseline
Increased air temperature (3 'C)
265
270
Julian Day
275
280
CH009
Baseline
Increased air temperature (3 'C)
1.5
1
0.5
0260
265
270
Julian Day
275
280
DO in the Upper Charlotte Harbor
(Increased air temperature of 3°)
6
CH005 (Bottom)
Baseline
Increased air temperature
DO (mg/l)
5
4
3
2
1260
DO (mg/l)
7
265
270
Julian D ay
CH009 (Bottom)
275
280
Baseline
Increased air temperature
6
5
4260
265
270
Julian D ay
275
280
Phytoplankton (ug/l)
Phytoplankton in the Upper Charlotte Harbor
(Increased air temperature of 3°)
CH005 (Baseline)
Diatom
Dinoflagellates
Cynobacteria
10
5
Phytoplankton (ug/l)
50
100
150
200
Julian Day
250
300
250
300
CH005 (Increase air temperature)
Diatom
Dinoflagellates
Cynobacteria
10
5
50
100
150
200
Julian Day
Conclusion
• Hypoxia exists in Gulf of Mexico, Chesapeake Bay, and
Florida.
• Hypoxia in Charlotte Harbor is governed by river flow
induced stratification and Sediment Oxygen Demand.
• Bottom hypoxic water decreases when
– stratification decreases (low river flow, high wind, high tide)
– external loading (nutrients/CBOD) decreases
• Peak hypoxic water volume is reduced by 5-10% with
50-100% load reduction
• Climate change will lead to increase in SOD and
decrease in DO, and changes in phytoplankton species