Eutrophication

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Eutrophication

• Definition
• Importance of lake fertility

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Causes of Eutrophication

• Natural nutrients
• Anthropogenic
• N vs. P

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Problems cause by eutrophication

• Anoxia
• Taste and odor problems for drinking water
• Harmful algal blooms
• Aesthetics

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1000
Clear Water Western Civilization likes it
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Lake Tahoe
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Chlorophyll a (µg / Liter)
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0.1
0.1 1 10
100 Secchi Disk Transparency (meters)
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Defining Eutrophication

• Arbitrary scales

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Defining Eutrophication
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Modelling Eutrophication

• Vollenweider loading model

Sedimentation rate, rs 10 / mean depth
(unitless) Hydraulic flushing rf
outflow volume / inflow volume
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Eutrophication in the Great Lakes
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Agriculture and nutrient loading
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Approaches for Managing Nutrient Loading

• 3 overall techniques
• Reduction in nutrient inflow

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Approaches for Managing Nutrient Loading

• 3 overall techniques
• Reduction in nutrient inflow
• Disruption of internal nutrient cycles

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Approaches for Managing Nutrient Loading

• 3 overall techniques
• Reduction in nutrient inflow
• Disruption of internal nutrient cycles
• Acceleration of nutrient outflow

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Eutrophication issues in Farmington Bay

and the Great Salt Lake

Great Salt Lake Technical Team, Feb. 21, 2007

Wayne Wurtsbaugh, Utah State Univ.
wurts_at_cc.usu.edu

Beneficial Use Designation


Farmington Bay




Aquatic Wildlife

Brine shrimp

Brine flies

Birds


Contact Recreation


Swimming

Hunting


Public health

Odors






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Nutrient loading of one million people from WWTP
to the shallow bay is extremely high, with
predictions of hypereutrophic conditions

• - Causeway shallowness of bay (ca. 3 ft)
  exacerbates problem
• Loading estimates vary considerably, depending
  on assumptions.
• - A detailed study of loading is needed

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Eutrophication High nutrient loading produces
excessive algal growths
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Although it is not on the Utahs 303d list of
impaired waters, Farmington Bay is the most
eutrophic water body in the State of Utah.
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Human Health
Cyanobacteria Densities Farmington Bay - 2005
Density (cell / mL)

• The surface blooms of cyanobacteria like those
  shown on previous page result in a High
  Probability of health-effects- rating by the
  World Health Organization.

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World Health Organization Moderate Health
Effects (20 ug/L) Mild Health Effects (2-4 ug/L)
Cyanotoxins from the abundant Nodularia in
Farmington Bay are hepatotoxins and tumor
promoters. Cyanotoxins accumulate in ducks and
advisories for eating ducks have been suggested
for countries boarding the Baltic Sea (Sipia et
al. 2006) Farmington Bay is not safe for
swimming!
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Farmington Bay and the Bridger Bay Swimming
Beaches Are Not Safe
Health effects of contact during recreation (no
ingestion) Effects of skin irritation, skin
rash, as well as vomiting, diarrhea, cold/flu
symptoms, mouth ulcers and fever at above 5,000
cyanobacterial cells per ml (World Health
Organization 2003). Cyanobacterial cells in
Farmington Bay have exceeded this level gt100-fold.
Waters from Farmington Bay impact Bridger Bay
swimming beach. A rash (somewhat less intense
than photo) was viewed on a child playing in
water near Bridger Bay that had overflow waters
from Farmington Bay (May 2005). These rashes,
although severe, are not life-threatening and
affect 10-20 of population (Pilotto et al.
2004).
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Wildlife Domestic Animal Health
Bioaccumulation
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Zooplankton High seasonal variations, Extreme
Water Quality
Very high densities in Farmington Bay in spring
early summer, but very low in the fall. Why so
low?
May Jun Jul Aug Sep Oct
Nov
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Odor Issues
In a 2002 National Geographic article the Great
Salt Lake was derided by residents as a
putrid, fly-infested sump, a dead thing. (LaRoe
2002). A preliminary survey of people working
and living around the lake indicated that most
noxious odors were associated with Farmington Bay
(Table 1). 505 Responses obtained.
The odor problem is not new Coburn and Eckhoff
warned in 1967 that Farmington Bay was in danger
of becoming a tremendously large mismanaged
waste lagoon, upwind from metropolitan Salt Lake
City.
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Conclusions

• Farmington Bay is
• highly eutrophic

• Beneficial uses for swimming are impacted.
• Odor is an issue. Wildlife impacts unclear.

Algal Plume

• Eutrophication of FB
• influences ( -)
• Gilbert Bay as well

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Lake Washington
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Tommy Edmondson,Lake Washington
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Lake Washington
Secchi Transparency (m)
Loading (gallons/d)
Loading (103 kg / yr)
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Announcements

• Exam Monday
• Seminar on Sawtooth Limnology
• Monday 400, Engineering 101

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Eutrophication in Streams

• Periphyton
• Phytoplankton

Potomac River, Maryland
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Stream Eutrophication
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0.06 1 10
40 630 4000
mg / m2
Log Mean
Chlorophyll Levels