Arsenic transformation by algae: The role of phosphorus luxury uptake

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Arsenic transformation by algaeThe role of
phosphorus luxury uptake

• Ferdi Hellweger(1)(2), Kevin Farley(2)(3),
• Manu Lall(1) and Dom Di Toro(2)(4)
• presented at
• 226th National Meeting
• American Chemical Society (ACS)
• New York City, NY
• September 7, 2003

(1)
(2)
(3)
(4)
2
Pacific Ocean (off Southern California)
Andreae, Deep-Sea Res. 25 (1978)
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Step 1 As(V) uptake
Yummy! P
Step 2 Reduction methylation
Step 3 Excretion
Yak! As
As(III)
DMA
As(V) ? As(III) ? MMA ? DMA
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Laboratory Batch Culture
BLOOM
Hasegawa et al., Chemosphere 43 (2001)
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Lake Biwa, Japan
BLOOM
BLOOM
Sohrin et al., Environ. Sci. Technol. 31 (1997)
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Proposed Mechanism (Hypothesis)
P-LIMITED
NON P-LIMITED
DMA
DMA
DMA
DMA
PO4
P
PO4
P
MMA
As(V)
As(V)
As(V)
MMA
As(V)
As(III)
As(III)
As(III)
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Luxury Uptake
Hasegawa et al., Chemosphere 43 (2001)
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Testing the hypothesis Build a numerical model
and apply it to (1) Laboratory batch
experiment (2) Lake Biwa, Japan
Data sources (1) Hasegawa et al., Chemosphere 43
(2001) (2) Sohrin et al., Environ. Sci. Technol.
31 (1997), Hori et al., Jpn. J. Limnol. 57
(1996), Ueda et al. Data of regular limnological
survey of Lake Biwa 1998. Center for Ecological
Research, Kyoto University.
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(No Transcript)
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a
WATER COLUMN
(SO4)
ox
DO
Phyto- plankton
Herbivorous Zooplankton
Carnivorous Zooplankton
H2S
POM
DOM
POC
PC
DOC
HZC
CZC
(CO2)
h
zg
ox
p/r
zp
d
PON
NH4
NO3
DON
PN
HZN
CZN
ox
u
h
m
zg
zp
d
u/e
POP
PO4
DOP
PP
HZP
CZP
zp
d
h
m
zg
u/e
SiO2
PSi
BSi
u
d
d/z
DO
H2S
(CO2)
SEDIMENT BED
ox
d1
POM

• Spatial segmentation
• Settling vertical mixing
• Multiple phytoplankton species
• Multiple POM DOM reactivity classes
• Temperature, light concentration dependent
  rate expressions

POC
(CO2)
d2
PON
NH4
NO3
(SO4)
ox
d
PO4
POP
d
dn
(N2)
SiO2
BSi
d
Ecological Model, OldLace, Version 1.0 beta
(9/5/03)
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PRELIMINARY RESULTS
Lake Biwa Chlorophyll a
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PRELIMINARY RESULTS
Lake Biwa Phosphate
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PRELIMINARY RESULTS
Lake Biwa Disolved Inorganic Nitrogen
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PRELIMINARY RESULTS
Lake Biwa Dissolved Oxygen
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PRELIMINARY RESULTS
Lake Biwa Arsenic
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Thank You for your attention! Questions?
Lake Biwa Photo S. Endoh (2000)
More info Hellweger et al., Limnol Oceanogr, in
press Hellweger et al., Environ Sci Technol, in
preparation www.columbia.edu/flh23 (these slides
more)