Evans Lake Erie HABs and Hypoxia - Great Lakes … k E i HAB d H iLake Erie HABs and Hypoxia:...

L k E i HAB d H iLake Erie HABs and Hypoxia:

Changing Nutrient Loading andIn-Lake Dynamicsy

Mary Anne EvansUSGS – Great Lakes Science Center

U.S. Department of the InteriorU.S. Geological Survey

The Team

J. David Allan, Kristin K. Arend, Steven Bartell, Dmitry Beletsky, Nate S. Bosch, Stephen B. Brandt, Ruth D. Briland, Irem Daloğlu, Joseph V. DePinto, David M. Dolan, Mary Anne Evans Troy M Farmer Daisuke Goto Haejin Han Tomas O Höök RogerMary Anne Evans, Troy M. Farmer, Daisuke Goto, Haejin Han, Tomas O. Höök, Roger

Knight, Stuart A. Ludsin, Doran Mason, Anna M. Michalak, J.I. Nassauer, R. Peter Richards, James J. Roberts, Daniel K. Rucinski, Edward Rutherford, Donald Scavia,

David J. Schwab, Timothy Sesterhenn, Hongyan Zhang, Yuntao Zhouy gy g

University of Michigan, Purdue University, Grace College, Ohio State University, Heidelberg University, University of Wisconsin-Green Bay, University of Wisconsin-Madison,

LimnoTech, Oregon State University, Korea Environment Institute, Carnegie Institute forLimnoTech, Oregon State University, Korea Environment Institute, Carnegie Institute for Science, Ohio Department of Natural Resources, USGS, NOAA

Physical Scientists, Ecologists and Chemists, Physical and Ecological Modellers, Engineers, Social Scientists, Practitioners

Lake Erie:Southern most, warmest, and most productive Great Lake

Recurrent HABs and Hypoxiaand Hypoxia

“Walleye Capital of the World”

Three goalsThree goals

• Both in lake and external loading changes• Both in lake and external loading changes matter

• Form of phosphorus matters

• Multiple causes and multiple effects must beMultiple causes and multiple effects must be considered to understand the system

Two modelsTwo models

area

??

??

ent Load

Hypo

xic ?

Conservation practicesHAB size

Nutrie

Nutrient Load

ractices

Fish populationConservation practices HAB size

ervatio

n pr

?

Conse

Stumpf et al. 2012


area

?

?

?

?ent Load

Hypo

xic ?


Nutrie

Nutrient Load

ractices


ervatio

n pr

?

Conse

Conservation practices

9

High‐resolution SWAT model the Sandusky WatershedSandusky Watershed

I. Daloglu

Observed DRP Load

6004‐year Moving Average

400

500

300

400

SRP (kg/year)

200

S

0

100

1970 1975 1980 1985 1990 1995 2000 2005 2010 20151970 1975 1980 1985 1990 1995 2000 2005 2010 2015

P. Richards

Calibrated and validated with observed Sandusky DRP loads

500

600

Ob d

Baseline400

500 Observed

ase e300 Baseline

Representative : ‐ Tillage practices‐ Fertilizer inputs

200

‐ Crop choices‐ Fertilizer timing‐ Soil P accumulation

i t il

100

in topsoil01970 1975 1980 1985 1990 1995 2000 2005 2010 2015

4 per. Mov. Avg. (Baseline‐KD8) 4 per. Mov. Avg. (Observed)

How about fertilizer use trends?

300 0

350.0

250.0

300.0

a

150.0

200.0

rtilizer inp

uts k

g/ha

100.0

Fer

0.0

50.0

1974‐1981 1982‐1986 1987‐1991 1992‐1996 1997‐2001 2002‐2006 2007‐2010

Han and Allan 2010

11‐52‐00 11‐52‐00 00‐15‐00

Fertilizer application rate scenario:Little impact on trend600

400

500Constant fertilizer

300

400

Baseline

200

100

01970 1975 1980 1985 1990 1995 2000 2005 2010 2015

4 per. Mov. Avg. (Baseline‐KD8) 4 per. Mov. Avg. (constantfertKD8)

Tillage practices scenario:Increased conservation tillageIncreased conservation tillage

Sandusky County Conservation Tillage

100000

Sandusky County Conservation Tillage

MTWH

40000

60000

80000

Acr

es

MTWH

NTWH

MTSB

NTSB

0

20000

40000A NTSB

MTCN

NTCN

1989 1991 1993 1995 1997 1999 2001 2003 2005

Tillage practices scenario:Appears to ha e some impactAppears to have some impact

600

400

500

100% notill

300Baseline

200

0

100

100% conventional

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

4 per. Mov. Avg. (Baseline‐KD8) 4 per. Mov. Avg. (convKD8)

4 per. Mov. Avg. (notillKD8)

Is this because of the P l ti t t il?

500

600 accumulation at topsoil?

400

Observed

300

200

Baseline

100

01970 1975 1980 1985 1990 1995 2000 2005 2010 2015


Is this because of the P accumulation at topsoil?accumulation at topsoil?

Surface application of P fertilizer and manureFertilizer application exceeding crop needsFertilizer application exceeding crop needs

Adoption of conservation tillageSoil stratification

Modified topsoil SRP: runoff concentration ratio in the SWAT model

600

the SWAT model

400

500

l

200

300

duce No‐Til

0

100

1970 1975 1980 1985 1990 1995 2000 2005 2010

Introd

Higher values allow phosphorus to accumulate at topsoill ll ff/ l b lLower values allow more P runoff/vulnerability

Simulated SRP Loadb f f

500

600Appears to be a significant factor

400

500

300

Constant PHOSKD

But …

100

200

Baseline

01970 1975 1980 1985 1990 1995 2000 2005 2010 2015

4 M A (B li KD8) 4 M A (b li )

Baseline

4 per. Mov. Avg. (Baseline‐KD8) 4 per. Mov. Avg. (baseline)

Lake Erie Extreme Precipitation

12

Sandusky Watershed

10

8

orm events

4

6

Num

ber o

f sto

2

N

0

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Random weather scenario

450

500

A t l W th

350

400Actual Weather

250

300 Random Weather

100

150

200

0

50

100

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Reversed weather scenario600 Weather matters, but interacts

with land‐based conditions

400

500

Actual Weather

R dW th

300

400 Reversed Weather

200

100

01970 1975 1980 1985 1990 1995 2000 2005 2010 2015

4 per. Mov. Avg. (Reversed weather) 4 per. Mov. Avg. (Baseline‐KD8)

Simulated SRP Load W t h dWatershed appears more vulnerable to weather impacts in

600

recent years.

Soil P accumulation

500 Observed

and tillage and fertilizing practices appear to underlie the 300

400

weather driver.

Change in overall 200

Baseline

fertilizer rates shift load but do not seem to drive the pattern.

100

01970 1975 1980 1985 1990 1995 2000 2005 2010 2015



area

??

??

ent Load

Hypo

xic ?


Nutrie

Nutrient Load

ractices


ervatio

n pr

?

Conse

Thermocline Depth and Stratification Strength

‐2

3

D. Beletsky et al

y = 0 0109x + 16 977

‐7

y = 0.0264x ‐ 71.129²

y = ‐0.0109x + 16.977R² = 0.0363

‐12

R² = 0.1223‐17

‐22

1970 1975 1980 1985 1990 1995 2000 2005 2010

N l id h h 2005No clear evidence through 2005

Rucinski et al. 2010

Water Column Oxygen Depletion Rate

Rucinski, et al 2010

Water Column Oxygen Depletion Rate

DRP LoadDRP Load

O2 depletion rate

Rucinski et al 2010

Build Mixing Model2005

Diffusion

WCOD

2005

Epilimnion

SOD Model

Epilimnion

Hypolimnion

Data


Eutrophication Model


Model Calibration

Observations

Model


Model‐derived Response Curve Envelop encompasses interannual weather variabilityEnvelop encompasses interannual weather variability

46% reduction

Scavia et al. 2014

Model‐derived Response Curve Based on Dissolved Reactive Phosphorus (DRP)Based on Dissolved Reactive Phosphorus (DRP)

78% reduction

Scavia et al. 2014


area

??

??

ent Load

Hypo

xic ?


Nutrie

Nutrient Load

ractices


ervatio

n pr

?

Conse

ance

n)

3.0

3.5

1987-2005S lt C i l Fi h i

elat

ive

abun

dabe

r / tr

awl m

i

1.5

2.0

2.5 R2 = 0.46 Smelt: Commercial Fisheries Hypoxia: Water Quality Model

Sm

elt r

e(n

umb

0.0

0.5

1.0

Hypoxia duration (days)40 50 60 70 80 90 100

t

10000

erci

al h

arve

stto

nnes

)6000

8000 1987-2005R2 = 0.64

Sm

elt c

omm

e(m

etic

t

2000

4000

Ludsin, Pangle et al. Hypoxia duration (days)40 50 60 70 80 90 100

S

0

Vertical Distributions under Strong Hypoxia

0Rainbow Smelt Yellow Perch

0

Daily Max.

DensityHypoxia OFF

10

5

75%

50%

OFF15

20

25%

0%

Depth (m) Multi‐species, 1‐D individual‐based modelHöök et al

Oxy‐thermal Squeeze0

Daily Max.

Rainbow Smelt, Strong Hypoxia, Baseline

5

yDensity

Temperature10

75%

Depth

15

50%(m)

Oxygen20

25%

0%Jun Jul Aug Sep Oct Nov

Multi‐species, 1‐D individual‐based modelHöök et al


area

??

??

ent Load

Hypo

xic ?


Nutrie

Nutrient Load

ractices


ervatio

n pr

?

Conse

Three goalsThree goals

• Both in lake and external loading changes• Both in lake and external loading changes matter

• Form of phosphorus matters

• Multiple causes and multiple effects must beMultiple causes and multiple effects must be considered to understand the system

Evans Lake Erie HABs and Hypoxia - Great Lakes … k E i HAB d H iLake Erie HABs and Hypoxia:...

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