Aria Amirbahman
Steve Norton*
Kaci Fitzgibbon
Firooza Pavri**
Emma Carey
Linda Bacon
Jeff Dennis
Jeremy Deeds
Scott Williams
Colin Holme
Funding from the Senator George J. Mitchell Center for Sustainability Solutions
The background - DEP
• Great Pond Act Classification attainment status
• Status determined by trophic parameters
• Secchi Disk Transparency
• Chlorophyll, Phosphorus,
• Dissolved Oxygen
• Federal Non-point Source Funds (Section 319)
• Non-attainment/Impaired lakes - Restoration
• At-risk lakes - Protection
The background - VLMP
• Founded 1971
• Oldest volunteer lake monitoring
program in nation
• ~1,400 Certified Water Quality Citizen
Scientists who monitor 400+ lake
stations
• Collect 10x as much data as DEP
• Stewardship catalyst
The background – Collaborative History
• 1998 – Stakeholder DEP contacted UM geochemists atypical lakes – anoxia without sediment P release
• Multiple projects revealing critical Al:Fe ratios in sediment in a small
number of lakes and streams (1996-2016)
• 2010 – 2012, DEP collects and characterizes sediments from 106
lakes
• 2015 Current project – Local stakeholder participation
• Physicochemical data collection
• Social surveys
• Analysis of multiple data sets and merger
The resource
• Lakes are ‘gems’ on Maine’s
landscape.
• ~2,800 lakes 10 acres or greater in
size.
• Lakes are home to a diversity of fish
and wildlife.
• Lakes perform various ecosystem
services.
• Activity related to Maine lakes
contributes approximately
$4 billion/year to the state economy.
Threats to Maine lakes
• Atmospheric deposition (acid rain, Hg)
• Invasive species
• Eutrophication
 Land Use
 Internal lake dynamics
• Climate change
 Extreme weather events
 Warming
 Reduced duration of ice cover
 Stronger thermal (density) stratification
 Longer growing season
The urgency
• Climate change threatens Maine lakes.
• Since 1895, average regional temp. has increased by ~3F
• Number of days at >32F has increased by ~14.
• Models predict additional 3-5F increase in temp. & 5-10% increase in
precipitation by 2050 in northeastern U.S.
• More frequent intense storms; ~70% increase in extreme precip. (2” or
more in 24 h) has occurred in last 60 years.
• For example, Lake Auburn exhibited severe dissolved oxygen loss
and its first serious algal blooms in 2011 and 2012. An early iceout year and warm summers resulted in long open-water
seasons. This year (2016) may produce similar responses.
• Excess phosphorus in lake water is the leading cause of water
quality loss.
The objectives
(a) Develop a lake Vulnerability Index to predict which
lakes are more susceptible to deteriorations in water
quality
(b) Use surveys and interviews to identify factors that
encourage successful collaborations among VLMP
monitors and lake associations on lake stewardship
activities
(c) Develop a blueprint of activities - informed by our
physical and social scientific findings - that can
positively influence stewardship behaviors among
the public
Fe-DOC
PO43-
Fe3+
PO43-
Fe(OH)3 -PO43-
The Ferrous Wheel
Fe2+
Lake water/ Hypolimnion
Sediment
PO43- + Fe2+
Concept from Mortimer, 1941; Einsele, 1937
Fe(OH)3-PO4
Courtesy of G. W. G. Ferris, 1882
But, there were problems……
predicted average P flux (mg/m2/day)
For example, data from Amirbahman et al., 2003
16
14
12
10
8
6
4
2
0
0
2
4
6
8
10
12
2
measured average P flux (mg/m /day)
14
16
Lake Auburn, Maine 2015
Dissecting the Core
Lake sediment
0.5 cm
etc.
c..
1.0 cm
etc..
H20 (%), 110oC
LOI (%) = % org., 550oC
Conc. = (ug Hg)/(g dry sed.)
210
Pb = Bq/(g dry sed.)
t1/2 = 22 y
137
Cs (1963/4 maximum)
241
Am (1963/4 maximum)
2.0 cm
Sediment-water interface at 35 m
water depth
Speciation of the elements of interest,
including Al, Fe, and P
Sequential Extraction of sediment slices
Sediment
1 M NH4Cl @ pH 7
Residue
0.1 M Na2S2O4/NaHCO3
Modifications of Psenner
technique
Residue
0.1 M NaOH 25°C
Residue
0.5 M HCl
Labile
Fe-P
Ca-P
Digestion
NaOH TP -
NaOH rP
NaOH-Al
Residue
=
NaOH-nrP
Org./Bact.-P
1 M NaOH 85°C
Residue
Refractory-P
Modified after Psenner
Highland Lake, ME - Accumulation Rates for P
210Pb
age
0.0
0.5
umoles/cm2/y
1.0
1.5
2003
2000
1996
1990
1983
1977
1971
1964
1955
1942
1926
2.0
2.5
NH4Cl
BD
NaOH-25
HCl
NaOH-85
Pennesseewassee Lake, ME – Accumulation
Rates for 2P
210Pb
age
0.0
2003
2000
1996
1992
1986
1979
1968
1952
1927
1912
1888
0.5
umoles/cm /y
1.0
1.5
2.0
2.5
NH4Cl
BD
NaOH-25
HCl
NaOH-85
from Coolidge, K. 2004
Kopáček et al., 2005
Magical Numbers
If Al(OH)3,(BD+NaOH)/Fe(OH)3,(BD+NaOH) ≥ 3,
and if Al(OH)3,(NaOH) > 25P(BD+NaOH+EX)
there will be no release of P during anoxia.
concept from Kopáček et al., 2005
The study lakes
high
trophic state
Thompson (4400*)
Emden (1568)
Hopkins (442)
Long (2700)
Great (8240)
Messalonski (3500)
North (2900)
Salmon (666)/McGrath (486)
East (1823)
Pleasant in Casco (1312)
Clearwater (750)
Pleasant in Caratunk (1120)
Damariscotta (4400)
Mousam (900)/Square (840)
Taylor (650)
Meddybemps (6765)
Sabbatus (1960)
Unity (2500)
Webber (1200)
Tunk (2010)
Auburn (2260)
China (3844)
low
citizen
involvement
high
low
* Numbers are lake surface area in acres
Working with the VLMP volunteers
Transparency
Dissolved Oxygen &
Temp
Water Samples
Chorophyll a
Total Phosphorus
Anions, Cations
DOC, pH, ANC
Sediment Samples
Al, Fe, P speciation
Sediment (0 to 2 cm) and
epilimnetic data
August of 2012-2015 (n = 140
lakes)
Physical and epilimnetic data (n = 100 lakes)
August, 2011-2012
70
Chlorophyll a (ppb)
60
50
40
30
20
10
0
0
500
1000
Schmidt stability (J/m2)
1500
2000
2500
3000
Conclusions
Lake vulnerability to eutrophication is a combination of external and
internal characteristics. External factors, not considered here, include
bedrock and surficial geology, precipitation water quality, soil types,
land use, watershed/lake areal ratio, lake orientation, and
weather/climate. Precipitation water quality, land use, and
weather/climate are variables influenced by human behavior.
Internal factors include sediment quality and lake morphometry
(maximum depth, thermal profiles, and water volume distribution with
depth). Sediment quality has a major influence on potential
eutrophication because sediment quality determines the amount of
internal recycling of phosphorus. Speciation of Al, Fe, and P is critical.
Climate warming alters the thermal structure of lakes, encouraging the
development of anoxic waters, thereby fueling release of P from the
sediment, which may lead to eutrophication and nuisance algae.
Lake vulnerability to eutrophication is a combination of external and internal characteristics.
External factors, not considered here, include bedrock and surficial geology, precipitation
water quality, soil types, land use, watershed/lake areal ratio, lake orientation, and
weather/climate. Precipitation water quality, land use, and weather/climate are variables
influenced by human behavior.
Internal factors include sediment quality and lake morphometry (maximum depth, thermal
profiles, and water volume distribution with depth). Sediment quality has a major influence
on potential eutrophication because sediment quality determines the amount of internal
recycling of phosphorus. Speciation of Al, Fe, and P is critical.
Climate warming alters the thermal structure of lakes, encouraging the development of anoxic
waters, thereby fueling release of P from the sediment, which may lead to eutrophication and
nuisance algae.
Photo by S. Nort