the health of lake erie: past, present, and future · lake erie total phosphorus loading, 1967-2008...
TRANSCRIPT
The Health of Lake Erie: Past, Present, and Future
R. Peter Richards National Center for Water Quality Research
Heidelberg University Tiffin, Ohio
Lakeside, Ohio Chautauqua Lecture Series July 10, 2013
Outline • Lake Erie : The Lake that “Died”
• Lake Erie ecology 1900-1995
• Lake Erie ecology 1995-present
• Phosphorus inputs to Lake Erie and what to
do about them
• Predicting the severity of algal blooms
• What about the future?
• Conclusions
1. Lake Erie’s Pollution Woes
June 22, 1969
“I heard Lake Erie is the place fish go to die.”
- Johnny Carson, 1976
Gail Hesse, OLEPF
Even Dr. Seuss had something to say about Lake Erie…!
Gail Hesse, OLEPF
“They’ll walk on their fins and get woefully weary in search of some water that isn’t so smeary. I hear things are just as bad up in Lake Erie.”
http://en.wikipedia.org/wiki/File:The_Lorax.jpg Gail Hesse, OLEPF
What was wrong with Lake Erie?
Contaminated Harbors
•Oil and grease
•Phenols
•Iron and other metals
•PAHs
•PCBs
Contaminated Open Lake and Fish
• Mercury
• PCBs
• DDT, DDE
Lampreys
Alewives
Cladophora
Overfishing
•Blue Pike
•Walleye No more mayflies...
Hypoxia HABs
Causes of hypoxia
Toledo Buffalo epilimnion
hypolimnion
• A Central Basin problem
• Excess nutrient loading
• Thin hypolimnion
Some basic things about HABs
• Excessive algae reflect excess nutrients
• When an essential nutrient (N, P) gets used up, algal growth stops
• HABs can be reduced or eliminated by controlling phosphorus (P) [but nitrogen (N) is problematic]
• In the 1970s, most of the P came from sewage treatment plants
• At present, most of the P entering the Western Basin comes from the landscape - non-point source origin
• Most of the P entering the Central Basin comes from the Western Basin
Forms of P
(Total) Dissolved P • 90% of it is Dissolved
Reactive P (DRP)
• “Reactive” because…
Particulate P (PP)
Total Phosphorus (TP)
2. Eco-History to ca. 1995
Hypoxia increasing rapidly!
Modified from EPA-GLNPO
Pre-settlement hypoxia?!
Central Basin anoxia over time
0
10
20
30
40
50
60
70
80
1925 1935 1945 1955 1965 1975
% A
noxia
Western Basin Algae Problems
Microcystis
Western Basin Algae Problems
Cladophora
Remediation • Make phosphorus the limiting nutrient
• Set target load for P of 11,000 mta
• Reduce phosphorus inputs o Detergent phosphorus ban
o Sewage Treatment Plant upgrades
o Nonpoint source management • Fertilizer and manure management
• Erosion prevention – Conservation tillage
– Buffer strips
Looking for Signs of Success
Dai
ly d
isch
arge,
Mau
mee
Riv
er
Compared to short-term fluctuations, trends are quite subtle things!
Tributaries improved…
Maumee R.
Sandusky R.
0
25
50
75
100Suspended Solids
1975 1980 1985 1990 1995
0
0.1
0.2
0.3
0.4Total Phosphorus
1975 1980 1985 1990 1995
Maumee R.
Sandusky R.
0
0.025
0.050
0.075
0.100
0.125 Dissolved Reactive Phosphorus
1975 1980 1985 1990 1995
Maumee R.
Sandusky R.
…as did point source inputs.
0
5,000
10,000
15,000
20,000
25,000
30,0001967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
An
nu
al
load
, m
etr
ic t
on
s
Direct Point Sources Atmospheric Deposition Lake Huron Input
Indirect Point Sources Tributary Monitored NPS only Adjustment for Unmonitored AreaLoad, all sources
Data from Dave Dolan, UWGB
Lake Erie Total Phosphorus Loading, 1967-2008
TP target load 11,000 metric tons
y = -0.0015x + 58.122
R2 = 0.0798
p=0.0003
0
5
10
15
20
25
30
35
40
1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009
To
tal
Ph
osp
ho
ru
s C
on
cen
trati
on
µg
/L
Central Basin Spring TP
Data from EPA-GLNPO
Central Basin Oxygen Depletion Rate
Using tentative alternate method, Rucinski et al. (in prep)
y = -0.283x + 564.87
R2 = 0.729
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006
Wate
r C
olu
mn
Oxyg
en
Dem
an
d
mg
/L/
mo
nth
Dan Rucinski, LimnoTech
Central Basin anoxia over time
0
10
20
30
40
50
60
70
80
1955 1960 1965 1970 1975 1980 1985
% A
noxia
Anoxia decreasing again…
EPA-GLNPO
Success • By 1981, P target load (11,000 tonnes)
was met
• By mid 1990s: • Algal blooms greatly reduced
• Hypoxia greatly reduced
• Victory declared!
• …and we stopped looking. Bad idea!
3. Eco-History since 1995
And then it happened… The return of
It’s back?
EPA-GLNPO
Central Basin anoxia over time
0
10
20
30
40
50
60
70
80
90
100
1959 1969 1979 1989 1999 2009
% A
noxia
Chan
ge o
f bas
is f
or c
alcu
lati
on
Tributary P trends 1975-2007
Sandusky River data
y = -0.0015x + 58.122
R2 = 0.0798
p=0.0003
y = 0.0009x - 17.622
R2 = 0.0745
p<0.0001
0
5
10
15
20
25
30
35
40
1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009
To
tal P
ho
sp
ho
ru
s C
on
cen
trati
on
µg
/L
Central Basin Spring TP
Data from EPA-GLNPO
y = -0.283x + 564.87
R2 = 0.729
y = 0.0777x - 154.94
R2 = 0.689
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006
Wate
r C
olu
mn
Oxyg
en
Dem
an
d
mg
/L/
mo
nth
Central Basin Oxygen Depletion Rate
Using tentative alternate method, Rucinski et al. (in prep)
?
Dan Rucinski, LimnoTech
Western Basin Algae Problems
Microcystis
Western Basin Algae Problems
Lingbya
Cladophora
Microcystis in Lake Erie The Microcystis-Anabaena bloom of 2009 was the
largest in recent years in our sampling region
2011
…until 2011
Western Basin Algae Problems
Tom Bridgeman, U. Toledo
Cladophora and noxious
“blue-green algae” are back
with a vengeance!
City of Toledo - $3000/day to
treat drinking water for
microcystin.
Microcystin 1000 ppb in
Western Basin, 2000 ppb in
Grand Lake St. Marys. WHO
recommendations 1 ppb for
drinking water (20 ppb for
swimming)
Where are the nutrients that
drive this coming from?
Increased Anoxia
Shift in lake response
y = -0.0015x + 58.122
R2 = 0.0798
p=0.0003
y = 0.0009x - 17.622
R2 = 0.0745
p<0.0001
0
5
10
15
20
25
30
35
40
1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009
To
tal
Ph
osp
ho
ru
s C
on
cen
trati
on
µg
/L
In-lake TP
y = -0.283x + 564.87
R2 = 0.729
y = 0.0777x - 154.94
R2 = 0.689
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006
Wate
r C
olu
mn
Oxyg
en
Dem
an
d
mg
/L/
mo
nth
Water Column O2 Demand
WHY?
4. P Inputs to Lake Erie
0
5,000
10,000
15,000
20,000
25,000
30,0001967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
An
nu
al
load
, m
etr
ic t
on
s
Direct Point Sources Atmospheric Deposition Lake Huron Input
Indirect Point Sources Tributary Monitored NPS only Adjustment for Unmonitored AreaLoad, all sources
Data from Dave Dolan, UWGB
Lake Erie Total Phosphorus Loading, 1967-2008
TP target load 11,000 metric tons
Western Basin Total Phosphorus Loading
Importance of DRP
(Total) Dissolved P • 90% of it is Dissolved
Reactive P (DRP)
• DRP is 100% bioavailable
Particulate P (PP) •~30% bioavailable
• Tends to settle to bottom
Tributary P trends 1975-2007
Sandusky River data
Importance of DRP
Dissolved P
• 90% DRP
• DRP is 100% bioavailable for algal growth
Particulate P
• ~30% bioavailable
• Tends to settle to bottom
But why has this happened?
Why has this happened?
• We know that sewage treatment plants are meeting their effluent limits and more
• => the problem is non-point source
• 80% of the drainage basin of Western Lake Erie is row-crop agriculture
• We can infer that the problem is related to crop farming
• … but how?!!!
Corn & soybeans Wheat
Soil Test Level
BuildupRange
MaintenanceRange
DrawdownRange
CriticalLevel
MaintenanceLevel
Fert
iliz
er
Ra
te 18%
50%
48%
33%
34%
17%
83%
P concentration in soil
P stratification in soil
Standard soil core - ideally 8” deep, Homogenized and measured for P content. Supposed to represent the “plow layer”
Split soil core - 0-2” and 2-8”, standard analysis of each part. What diference in P content is there with depth?
Zone of rainfall interaction with soil
P stratification in soil
Other factors - fall
application and weather
• Increasing trend to apply fertilizer/manure in fall/winter
• Often not incorporated
• Warmer winters => more rain, less snow and frozen ground => more P loss
• ≥50% of annual DRP load in three winter months
What can be done? • Know fertility levels and don’t over-apply
• Watch the weather and don’t apply when rain is likely
• Consider precision application, linked to yield variation within field
• Fertilize in spring if possible
• Incorporate fertilizer/manure!
• Don’t apply to frozen ground, especially on snow
• Consider winter cover crops
What else can be done?
• Improve sewage treatment, prevent CSOs
• Phosphorus-free lawn fertilizer or no fertilizer at all
• Phosphorus-free dishwasher detergent
• Find alternative to orthophosphorus for corrosion control in drinking water
Lost resources… • Nutrient losses from Maumee River
watershed, 2007: o P: 3,500 tons N: 29,600 tons
• Cost to replace them at 2008 prices: o P: $9,100,000 N: $57,500,000
• Cost per acre receiving fertilizer: o $62/acre
4. Predicting HAB Strength (Western Basin)
Concept • P loading drives algal growth
• HABs occur in late summer
• Perhaps P loads in some seasons are more important than loads in others.
• Relate “cyanobacteria index” (CI) to discharge and P loading
• CI best predicted by March-June discharge
• March-June TP and DRP also predictive
• Initial work done late in 2011 – can we predict 2012?
NOAA work
0.0
1.0
2.0
3.0
4.0
5.0
6.01975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Dis
ch
arg
e (
cu
bic
kil
om
ete
rs)
2011 and 2012 are the extremes - 2012 is 20% of 2011!
Spring Discharge (March-June)
NOAA Ecofore/Maumee Loads.xls
0
500
1000
1500
2000
25001975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
TP
Lo
ad
(m
etr
ic t
on
s)
2011 and 2012 are extreme - 2012 is 17% of 2011!
Spring TP Load
NOAA Ecofore/Maumee Loads.xls
0
50
100
150
200
250
300
350
400
450
5001975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
DR
P L
oad
(m
etr
ic t
on
s)
2011 and 2012 are extreme - 2012 is 15% of 2011!
Spring DRP Load
NOAA Ecofore/Maumee Loads.xls
2012 Forecast (mild bloom) and Observed Bloom
2012
Forecast
Measured
08/30/2012 (DOY=243)
09/03/2011 (DOY=246)
What about 2013? • Spring totals just completed at end
of June
• Predictions given last week at a webinar at Stone Lab
March-June Maumee Discharge
2.77
March-June Maumee Total P
1,099
March-June Maumee DRP
238
2013 Forecast: Significant bloom, similar to 2003, much milder than 2011
2013
2013 prediction for western Lake Erie similar in intensity to 2003,
<1/5 of 2011
low medium high
concentration
2013 may resemble 2003 2011 for comparison
NOAA Lake Erie Harmful Algal Bloom Bulletin, 2013, 5th year
Sign up to receive the weekly bulletin Search for NOAA Lake Erie Bloom Bulletin
5. What Does the Future Hold?
A look to the future • The crystal ball is murky, but…
• Projected increased intensity of storms will lead to increased erosion with associated loss of soil and attached nutrients
• Projected warmer winters may increase winter rain and loss of surface-applied nutrients
A look to the future • Warmer summers mean
• HABs starting earlier and perhaps lasting longer
• perhaps a thinner hyplimnion and longer stratified season, making hypoxia worse
• 2011 might represent a typical condition in the future, not an extreme one
• Things likely to get worse, not better, unless we redouble our efforts to limit nutrient inputs
Whew! Almost Done…
Summary • Excess nutrients are causing major
ecological problems in Lake Erie
• HABs in the Western Basin
• Hypoxia in the Central Basin
• Currently, the major source of excess nutrients is runoff from the land
• We fixed the problem once, but it has returned for changed reasons
• Future climate scenarios are discouraging unless we change our ways!
Useful References • Ohio Lake Erie Phosphorus Task Force
• http://www.epa.ohio.gov/dsw/lakeerie/index.aspx
• Paper on climate change, Lake Erie, and water sustainability • Anna Michalak and many others including me, Proceedings
of the National Academy of Sciences
• http://www.pnas.org/content/110/16/6448
October 7, 2011
Useful References • Ohio Lake Erie Phosphorus Task Force
• http://www.epa.ohio.gov/dsw/lakeerie/index.aspx
• Paper on climate change, Lake Erie, and water sustainability • Anna Michalak and many others including me, Proceedings
of the National Academy of Sciences
• http://www.pnas.org/content/110/16/6448