Lake Erie re-Eutrophication Don Scavia Graham Sustainability - - PowerPoint PPT Presentation

▶
lake erie re eutrophication
SMART_READER_LITE
LIVE PREVIEW

Lake Erie re-Eutrophication Don Scavia Graham Sustainability - - PowerPoint PPT Presentation

Nov 25, 2023 185 likes •706 views

Lake Erie re-Eutrophication Don Scavia Graham Sustainability Institute University of Michigan Lake Erie Eutrophication Serious Toxic and Noxious Algal Blooms Annual Hypoxia History: Increased with increasing TP load Decreased with

slide-1
SLIDE 1

Lake Erie “re-Eutrophication”

Don Scavia

Graham Sustainability Institute University of Michigan

slide-2
SLIDE 2

Lake Erie Eutrophication

Annual Hypoxia Serious Toxic and Noxious Algal Blooms

slide-3
SLIDE 3

History: Increased with increasing TP load Decreased with decreasing load

  • Central Basin Anoxia
slide-4
SLIDE 4
  • Central Basin Hypoxia
  • Y. Zhou

Central Basin Anoxia

?

slide-5
SLIDE 5

Water Column Oxygen Depletion Rate

Rucinski, et al 2010

slide-6
SLIDE 6

Similar Trends in Algal Biomass

Conroy & Culver 2005

  • plus return of cyanobacteria
slide-7
SLIDE 7

Microcystis in Lake Erie

  • The Microcystis-Anabaena bloom of 2009 was the

largest in recent years in our sampling region

2011

  • …until 2011
  • T. Bridgeman
slide-8
SLIDE 8

Extent of 2011 Bloom

WLE Bloom driven by concentration Note apparent diluting effect of Detroit River

slide-9
SLIDE 9

Thickness of Central Basin Bottom Layer

Air temperature, winds, length of season

Organic Matter Flux to the Bottom

Algal production and settling

– P supply – Length of season

What Matters to Hypoxia?

slide-10
SLIDE 10

Air temperature, winds, length of season Algal production

– P supply – Length of season

What Matters to Algal Blooms?

slide-11
SLIDE 11

So What’s Been Going On?

slide-12
SLIDE 12

Mussel Impact on Hypoxia Not Obvious

p=0.72 Pre-ZM: 1969-1989 Post-ZM: 1990-2002

  • Pre-ZM: 1969-1989

Post-ZM: 1990-2002

slide-13
SLIDE 13

Thickness of Central Basin Bottom Layer

Air temperature, winds, length of season

Organic Matter Flux to the Bottom

Algal production and settling

– P supply – Length of season

What Matters to Hypoxia?

slide-14
SLIDE 14

Thinner Bottom Layer?

=> Less O2 Available

slide-15
SLIDE 15

y = 0.0264x - 71.129 R² = 0.1223 y = -0.0109x + 16.977 R² = 0.0363

  • 22
  • 17
  • 12
  • 7
  • 2

3

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thermocline Depth and Stratification Strength

  • D. Beletsky et al

No clear evidence yet

Rucinski et al. 2010

slide-16
SLIDE 16

Thickness of Central Basin Bottom Layer

Air temperature, winds, length of season

Organic Matter Flux to the Bottom

Algal production and settling

– P supply – Length of season

What Matters to HAB and Hypoxia?

slide-17
SLIDE 17

What accounts for the large interannual variation in Microcystis blooms?

  • What is the effect of Maumee River P loading?

The best predictor of Microcystis annual crop is the cumulative TP load from the Maumee River from January to August.

slide-18
SLIDE 18

Rucinski et al 2010 SRP Load O2 depletion rate

slide-19
SLIDE 19

Rucinski et al 2010

WHY?

slide-20
SLIDE 20
  • D. Baker
slide-21
SLIDE 21
slide-22
SLIDE 22

Phosphorus Loads to Western Basin - 2005

5,697 Metric Tonnes/year Data compiled by Dave Dolan, UW-Green Bay Maumee data from Heidelberg University

slide-23
SLIDE 23

The Trends Particulate Phosphorus

!

  • "#$#!%

&'(

  • "#$#!%
  • P. Richards, Heidelberg

Maumee River Sandusky River

slide-24
SLIDE 24

The Trends in Dissolved Reactive P

SRP

!

  • "#$#!%

&'(

  • "#$#!%

Maumee River Sandusky River

  • P. Richards, Heidelberg
slide-25
SLIDE 25

Ashtabula-Chagrin

! ! !

Maumee Grand Thames Sandusky Raisin Big Creek

  • St. Clair

Huron Sydenham Clinton Detroit Grand Cuyahoga Black-Rocky Cedar- Portage Cedar Creek Huron- Vermilion Cattaraugus Chautauqua-Conneaut Buffalo-Eighteenmile Ottawa-Stony Rondeau Watersheds Lake

  • St. Clair

Rondeau Ashtabula- Chagrin Ottawa-Stony

)*

slide-26
SLIDE 26

Relative importance of individual P sources

slide-27
SLIDE 27

Calibrated Soil & Water Assessment Tool (SWAT) models for Major Watersheds

  • I. Daloglu

Higher resolution exploration in the Sandusky

slide-28
SLIDE 28

Simulated DRP Load

SWAT model calibrated to

  • bserved Sandusky loads.

Model Observation (4 year moving average)

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Observed (4 yr average) 4 per. Mov. Avg. (Baseline)

slide-29
SLIDE 29

Simulated DRP Load

Constant High Fertilizer Actual Fertilizer Trend Constant Low Fertilizer Something else is happening – perhaps tillage practices?

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 4 per. Mov. Avg. (BaselineKD15) 4 per. Mov. Avg. (Low2) 4 per. Mov. Avg. (High2)

slide-30
SLIDE 30

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 Total P (mg/L)

Mean Annual TP in Runoff as a Function

  • f Tillage Management

Conv. No-till

No-till decreases TP in runoff …

Sims and Kleinman. 2006. Phosphorus

Paired treatment begins

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 Dissolved P (mg/L)

Mean Annual DP in Runoff as a Function

  • f Tillage Management

Conv. No-till

…but increases DP in runoff.

Perhaps a “no-till impact”?

slide-31
SLIDE 31

Enriched soil P near surface

  • 7
  • 6
  • 5
  • 4
  • 3
  • 2
  • 1

50 100 Depth Below Soil Surface - Inches lbs/ac Bray P1

Phosphorus Stratification After 20 Years of No-till on a Blount silt loam, Seneca County, OH

South Part Field North Part Field

Bill McKibben, CCA Logan Labs

slide-32
SLIDE 32

Simulated DRP Load

No-till Actual Tillage Trend Conventional tillage

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 4 per. Mov. Avg. (BaselineKD15) 4 per. Mov. Avg. (Conventional) 4 per. Mov. Avg. (Notill)

slide-33
SLIDE 33

20 40 60 80 100 120

1962 1973 1976 1979 1980 1983 1984 1985 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Bary P1 (lbs/acre)

Long-Term Soil P for NW Ohio

From A&L Laboratory, Ohio

slide-34
SLIDE 34

PHOSKD values (Soil P/Runoff P)

Introduce No-Till

50 100 150 200 250 300 350 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 PHOSKD (m3/Mg)

slide-35
SLIDE 35

Simulated DRP Load

Variable PHOSKD Constant PHOSKD

?

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 4 per. Mov. Avg. (BaselineKD15) 4 per. Mov. Avg. (Baseline-KDConstant)

slide-36
SLIDE 36

2 4 6 8 10 12

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Number of storm events

Lake Erie Extreme Precipitation

Sandusky Watershed

  • I. Daloglu
slide-37
SLIDE 37

Simulated DRP Load

Actual Weather

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 4 per. Mov. Avg. (BaselineKD15)

slide-38
SLIDE 38

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 4 per. Mov. Avg. (BaselineKD15) 4 per. Mov. Avg. (1970-2010)

Reversed Weather

Simulated DRP Load

Actual Weather

slide-39
SLIDE 39

100 200 300 400 500 600 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Simulated DRP Load

Model Observation

  • I. Daloglu, UM

Trend appears to be function of:

  • Soil P build up through early 1990s
  • no-Till or other practices making DRP loss more vulnerable after mid 1990s
  • Exacerbated by recent extreme storm intensity

Still testing:

Spring vs. Fall Application

slide-40
SLIDE 40

If weather patterns matter …

… where are we heading?

slide-41
SLIDE 41

Thickness of Central Basin Bottom Layer

Air temperature, winds, length of season

Organic Matter Flux to the Bottom

Algal production and settling

– P supply – Length of season

Why Climate Matters

slide-42
SLIDE 42

Thickness of Central Basin Bottom Layer

Air temperature, winds, length of season

Organic Matter Flux to the Bottom

Algal production and settling

– P supply – Length of season

Why Climate Matters

Processes exacerbated by future climate

slide-43
SLIDE 43

Can We Set New Load Targets?

slide-44
SLIDE 44

Lower Food Web Model

Dissolved Oxygen Available Phosphorus Basin Loading Phytoplankton Detrital Carbon Sediments Atmosphere Unavailable Phosphorus Zooplankton

mineralization settling settling

  • xidation

death death settling uptake photosyn. respiration reaeration grazing

  • D. Rucinski
slide-45
SLIDE 45

Rucinski, et al.

Hypoxic Days TP Load

“early ‘90s” “Today”

Getting Close!

slide-46
SLIDE 46

y = 0.0254x + 10.052 R² = 0.5626 10 20 30 40 50 60 70 80 500 1000 1500 2000 2500

Hypoxic Days SRP Load

  • D. Rucinski
slide-47
SLIDE 47

Microcystis Response Curve

Workin’ on it!

NSF Water Sustainability and Climate Project:

Assessing the effects of climate-change-induced extreme events on water quality and ecology in the Great Lakes

http://miseagrant.umich.edu/nsfclimate

slide-48
SLIDE 48

With new targets, where to do we focus?

slide-49
SLIDE 49

Potential Solutions to Agriculture Contribution:

Apply fertilizer in spring & incorporate Don’t apply before precipitation Apply only to replace crop removal Don’t apply if soil P>2x agronomic need Limit manure to P replacement amounts Precision apply based on yield maps Develop BMPs specifically for DRP

Richards, et al.

slide-50
SLIDE 50

Closing Arguments:

  • Hypoxia/HABs increased since the 1990s
  • It matters to fish
  • Increased hypoxia likely reflects increased SRP load
  • Increased SRP load appears driven by increased

storm intensity and agricultural practices (no-till?)

  • Current suite and use of BMPs may not be sufficient
  • Climate change will make reductions more difficult

We may need a whole new set of BMPs to control dissolved phosphorus runoff under this new climate regime!

slide-51
SLIDE 51

Are we preparing?