institute food agricultural sciences (ifas ......6/22/2008 wbl 9 [50%] 1996 florida 2003 north...
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1
Biogeochemistry of WetlandsS i d A li tiS i d A li ti
Institute of Food and Agricultural Sciences (IFAS)
Science and ApplicationsScience and Applications
Wetland Biogeochemistry LaboratorySoil and Water Science Department
Phosphorus Cycling Processes Phosphorus Cycling Processes
6/22/2008 WBL 16/22/2008 16/22/2008 WBL 1
InstructorK. Ramesh [email protected]
Soil and Water Science DepartmentUniversity of Florida
Phosphorus Cycling ProcessesInstitute of Food and Agricultural Sciences (IFAS)
PPPP
PPPPDRPDRP
DRPDRP
Water columnWater column
6/22/2008 WBL 26/22/2008 WBL 2
PPPPDRPDRPSoilSoil
2
Topic Outline
Phosphorus Cycling Processes
Water Column
IntroductionForms of phosphorusInorganic Phosphorus retention mechanismsOrganic phosphorus dynamicsPhosphorus exchange between soil and overlying water columnRegulators of phosphorus reactivity and
Soil
6/22/2008 WBL 36/22/2008 3
Regulators of phosphorus reactivity and mobilityPhosphorus memory in wetlands
Learning Objectives
Id tif d i i d i f f
Phosphorus Cycling Processes
Identify sources, and inorganic and organic forms of phosphorusInorganic phosphorus retention mechanisms in soilDescibe the influence of soil type on inorganic phosphorus retentionRole of enzymes and microorganisms in organic phosphorus mineralizationBiotic regulation phosphorus retentionPh h h b t il d l i t
6/22/2008 WBL 46/22/2008 4
Phosphorus exchange between soil and overlying water columnDraw the phosphorus cycle and indentify, storages, abiotic and biotic processes, and fluxes in soil and water column
3
TerminologyTerminologyTotal Phosphorus (TP) Dissolved total P (DTP)
Total P in solutions filtered through 0.45 um membrane filterTotal P in solutions filtered through 0.45 um membrane filter
Dissolved reactive P (DRP) or Soluble Reactive P (SRP) Water samples filtered through 0.45 um membrane filter and analyzed for ortho-P.
Dissolved Organic P (DOP) DTP – DRP = DOP
Particulate inorganic P (PIP)
6/22/2008 WBL 56/22/2008 5
Particulate inorganic P (PIP)Particulate matter or soil extracted with acid
Particulate organic P (POP)TP-PIP = POP
Plant biomass PRunoff,
Phosphorus Cycle
AEROBIC
Peataccretion
[Fe, Al or Ca-bound P]
Litterfall
DOP DIP PIPPOP
DIP
DIP
Runoff, Atmospheric Deposition
Outflow
Periphyton P
6/22/2008 WBL 6
ANAEROBIC
accretionPIP
Ca-bound P]Adsorbed
IP
DIP
POP DOPDOP
DIP
4
Fertilizers, Animal wastesBiosolids, Wastewaters
Phosphorus Transfer
Wetlands & Streams
[sink/source]
Uplands[sink/source]
6/22/2008 WBL 7
LakeOkeechobee
Lake [sink]
Phosphorus Imports from Various Sources: Florida
69%8%
8%10% 0%
Fertilizers
AtmosphericDepositionAnimal
Manures
Wastewater
Composts (?)Natural weathering of minerals (?)
6/22/2008 WBL 8
5%Biosolids
1996Total = 61,300 mt P per year
5
Fertilizer Phosphorus Inputs
[8%]
Florida Florida 42,660 42,660
metric ton yearmetric ton year--11
[ ]
[5%]
[17%]
[20%]
North AmericaNorth America1.85 x 101.85 x 1066
6/22/2008 WBL 9
[50%]
1996 Florida2003 North America2003 World
metric tons yearmetric tons year--11
WorldWorld14 x 1014 x 1066
metric tons yearmetric tons year--11
[Mullins et al., 2005]
[Mullins et al., 2005]
Phosphorus Loads from UplandsUplands have been a steady source of P to wetlands and aquatic systems, where
b t ti l t f P h l t d isubstantial amounts of P has accumulated in soils and sedimentsBest management practices and other remedial measures can significantly reduce P loads from uplands to wetlands and aquatic systemsHow will wetlands and aquatic systems respond to P load reduction?
6/22/2008 WBL 10
to P load reduction?How long P memory lasts in wetlands and aquatic systems before they reach stable condition?
6
Capacity for storing phosphorus in
Phosphorus Memory in a Watershed
Water ColumnCapacity for storing phosphorus in various ecosystem components (uplands, wetlands, and aquatic systems)
Transient poolsStable pools
Capacity for showing effects as the result of past practices
Detritus
PP
PP
6/22/2008 WBL 11
result of past practices Length of time over which phosphorus release extends before returning to a stable condition
Soil
Phosphorus Transfer [Lake Okeechobee Basin]
Uplands (82%)
[4157]
Phosphorus BudgetUplands (82%)
[754]
[415] (10%)
[tons/year]
6/22/2008 WBL 126/22/2008 WBL 12
Wetlands& Streams
(8%) LakeOkeechobee
[415] (10%)
7
Phosphorus Gradient in Wetlands
PhosphorusOutflow
PhosphorusLoading
Gradient in nutrient enrichment insoil and water column
6/22/2008 WBL 136/22/2008 WBL 13
[ Distance from inflow]
soil and water column
150
Water column TP - WCA-2A transect
Tota
l P (µ
g/L)
50
100
6/22/2008 WBL 146/22/2008 WBL 14
0 2 4 6 8 10 12 14 160
Distance from Inflow (km)
8
Phosphorus accretion rates inEverglades WCA-2A
y-1 )
1.2AC
CU
MU
LATI
ON
(g m
-2y
0.4
0.6
0.8
1.0
6/22/2008 WBL 156/22/2008 WBL 15
P A
DISTANCE FROM INFLOW (km)0 2 4 6 8 10 12 14 16
0.2
0
Total P concentration in WCA-2A soil (0-10 cm)
1990 1998
6/22/2008 WBL 166/22/2008 WBL 16
9
Everglades – Soil phosphorus
6/22/2008 WBL 176/22/2008 WBL 17
0-40-44-8
Soil Phosphorus Blue Cypress Marsh-1992
Dep
th (c
m) 8-12
16-20
24-28
32 36
4 88-12
12-1616-2020-2424-28 Impacted
6/22/2008 WBL 186/22/2008 WBL 18
D 32-36
36-40
0 1,000 2,000
24-2832-3640-44
0 1,000 2,000Total P (mg /kg)
Unimpactedp
10
External LoadReduction
horu
s
Phosphorus Memory
Internal Memory
BackgroundLevel
r Col
umn
Pho
sph
6/22/2008 WBL 19
Lag time for Recovery
Wat
er
Time - Years
Ecological Significance –Phosphorus Loading
WATERWATER
PLANTS
Labile DETRITUSDETRITUS
N C PN C
6/22/2008 WBL 206/22/2008 WBL 20SOILP N
Microbial Biomass
N
Microbial Biomass
P
P
11
Plant biomass PRunoff,
Phosphorus Cycle
AEROBIC
Peataccretion
[Fe, Al or Ca-bound P]
Litterfall
DOP DIP PIPPOP
DIP
DIP
Runoff, Atmospheric Deposition
Outflow
Periphyton P
6/22/2008 WBL 21
ANAEROBIC
accretionPIP
Ca-bound P]Adsorbed
IP
DIP
POP DOPDOP
DIP
Phosphorus in Wetlands Organic
phosphorusPhosphorus Uptake by
Soil porewaterphosphorus[dissolved]
p ploading algae and
plants
Metal o ides
6/22/2008 WBL 226/22/2008 WBL 22
Metal oxidesand clay mineral
surfaces
Discretephosphate
minerals
12
Soil Phosphorus FormsInorganic PKCl Pi Bioavailable P— KCl-Pi - Bioavailable P
— NaOH-Pi - Fe-/Al- P [slowly available]
— HCl-Pi - Ca-/Mg- P [slowly available]
Organic PMicrobial Biomass P Bioavailable P
6/22/2008 WBL 236/22/2008 WBL 23
— Microbial Biomass P - Bioavailable P — NaOH-Po - Fulvic Acid -P [slowly available] — NaOH-Po - Humic Acid -P [very slowly available]— Residual P -Highly resistant [unavailable]
Phosphate ions and pHPhosphate ions and pHH3PO4 = H+ + H2PO4
- pK = 2.15H2PO4
- = H+ + HPO42- pK = 7.20
HPO42- = H+ + PO4
3- pK = 12.35
H3PO4 PO43-
Oxidation number for P
[+5] [+5]
6/22/2008 WBL 246/22/2008 WBL 24
3 4H2PO4
-
HPO42-
4
PH3
[ 5][+5][+5]
[ ][-3]
13
1 000
3,000
kg-1
) Y = 0.01X1.54
R2 =0 897; n=390
Inorganic Phosphorus-Organic Soils - WCA-2A
10
30
100
300
1,000no
rgan
ic P
(mg
k
WCA1
WCA2
WCA3
R 0.897; n 390
6/22/2008 WBL 256/22/2008 WBL 25
50 100 200 500 1,000 2,000 5,0001
3
Total Phosphorus (mg kg-1 )
Tota
l In WCA3
HWMAEAA
KCl-Pi (available)
Stream Sediments –Okeechobee Drainage Basin
2% 29%
6%
50%
13%
1%7%
10%
Fe- and Al-bound P
Alkali extractable organic P
Ca- and Mg-bound P
Residual P
DL-StreamT l P 8 P/k
6/22/2008 WBL 266/22/2008 WBL 26
71%11%
7%Total P = 877 mg P/kg
Rucks-StreamTotal P + 93 mg P/kg
14
KCl-Pi (available)<0 1%
1%
Organic Wetland Soils –Drainage Effects
1% 7%
Fe- and Al-bound P
Alkali extractable organic P
Ca- and Mg-bound P
Residual P
<0.1%4%
72%
23%
Peat Depth < 10 cmT t l P 836 P/k
6/22/2008 WBL 276/22/2008 WBL 27
24%
21%
47%
Total P = 836 mg P/kg
Peat Depth > 30 cmTotal P = 411 mg P/kg
Inorganic Phosphorus
yPore ater P
Bio
avai
labi
lity High
Low
Pore water P ExchangeableFe-/Al- bound PCa-/Mg-bound PR id l P
6/22/2008 WBL 286/22/2008 WBL 28
Residual P
15
Inorganic PhosphorusAcid soils
AlPO4 . 2H2O [Variscite]AlPO4 . 2H2O [Variscite]FePO4 . 2H2O [Strengite]
Alkaline soilsCa (H2PO4)2 [Monocalcium phosphate]Ca HPO4. 2H2O [Dicalcium phosphate]Ca8 (H2 PO4)6 . H2O [Octacalcium phosphate]
6/22/2008 WBL 296/22/2008 WBL 29
8 ( 2 4)6 2 [ p p ]Ca3 (PO4)2 [Tricalcium phosphate]Ca5 (PO4)3 OH [Hydroxyapatite]Ca5 (PO4)3 F [Fluorapatite]
Phosphate Minerals
5 m
m
1 m
m
6/22/2008 WBL 306/22/2008 WBL 30
VivianiteVivianiteApatiteApatite
W. G. Harris, 2002
16
Phosphate AvailabilityReadily available phosphates
Soil porewaterSoil porewater.
Slowly available phosphatesFe, Al, and Mn phosphates (acid soils) and Ca and Mg
phosphates (alkaline soils) that have been freshly precipitated or are held mostly on the surface of fine particles in the soil. Labile organic compounds.
V l l il bl h h t
6/22/2008 WBL 316/22/2008 WBL 31
Very slowly available phosphatesPrecipitates of Fe, Al, Mn, Ca, and Mg phosphates that
have aged and are well crystallized. Phosphates that were held on particle surfaces have penetrated the particles, little remaining on the surface. Stable organic compounds
PhosphorusIs P one of the redox elements ?Is P one of the redox elements ?
HPO42- + 10H+ + 8e- = PH3 + 4H2O
Is P solubility affected by changes in redox potential?
FePO4 + H+ + e- = Fe2+ + HPO42-
6/22/2008 WBL 326/22/2008 WBL 32
17
Phosphorus RetentionPhosphorus Retentionby Soilsby Soils
Adsorption DesorptionAdsorption –DesorptionPrecipitation – DissolutionImmobilization - mineralization
Retention = Adsorption + Precipitation
6/22/2008 WBL 336/22/2008 WBL 33
Retention = Adsorption + Precipitation+ Immobilization
Sorption of PhosphateIntensity factorIntensity factor : Concentration of h h t i il tphosphate in soil porewater.
Capacity factorCapacity factor : Ability of solid phases to replenish phosphate as it is depleted from solution.
6/22/2008 WBL 346/22/2008 WBL 34
PsolutionPadsorbed
Solidphase
18
Inorganic Phosphate Reactions
Precipitation by Al, Fe, Mn, Ca, and Mg ionsAl3+ + H2PO4
- + 2H2O = 2H+ + Al (OH)2 H2PO4 (insoluble) (Variscite)
Anion exchange
Reaction with hydrous oxidesAl OH2
+ OH + H2PO4- = Al OH2
+ H2PO4 + OH-
OHOH
+ H PO - = AlOHOH + OH-Al
6/22/2008 WBL 356/22/2008 WBL 35
Fixation by silicate claysAl2 SiO5 (OH)4 + 2H2PO4
- = 2Al (OH)2 H2PO4 + Si2O52-
OHOH
+ H2PO4 = AlH2PO4
OH + OHAl
pH- Dependent Charge on Solid Phase
0
[+]
[-]
Cha
rge
Negative charge[loss of H+]
Positive chargeZPC
[ i t h ]
6/22/2008 WBL 366/22/2008 WBL 36
[ ]
3 4 5 6 7 8 9 10pH
Positive charge[gains H+]
[zero point charge]
19
No chargeSolid phase
SoilSolution
Negative chargeSolid phase
Variable Charge on Solid Phase
Al – OH + OH- = Al–O- + H2O
COOH + OH- = COO- + H2O
AlOH + H+ = AlOH2+
6/22/2008 WBL 376/22/2008 WBL 37
AlO- + H+ AlOH + H+ AlOH2+
Negative charge[high pH]
No charge[Intermediate pH]
Positive charge[low pH]
Inorganic Phosphate ReactionsInorganic Phosphate Reactions
Alkaline pH conditions:Alkaline pH conditions:Ca2+ + 2H2PO4
- = Ca (H2PO4)2
Ca (H2PO4)2 + Ca2+ + 2OH- = 2CaHPO4 + 2H2O2CaHPO4 + Ca2+ + 2OH- = 2Ca3 (PO4)2 + 2H2O
6/22/2008 WBL 386/22/2008 WBL 38
20
I: Initial equilibriumcondition
Solid phase Solution phaseI
Sorption of Phosphate
condition
II: Increase in solutionP concentration ---Rapid adsorption tosolid surface
= Phosphate ions
II
6/22/2008 WBL 396/22/2008 WBL 39
III: Diffusion intosolid phase
[Time = seconds to minutes]
[Time = hours to days]
III
ptio
n Smax
Phosphorus Sorption Isotherm
EPCo
Ads
orp
orpt
ion
slope = KDPw
PsPad Pret
Soil
Water
6/22/2008 WBL 406/22/2008 WBL 40
Phosphorus in Soil Porewater
P desorption underambient conditionsD
eso
SoSoil
21
Phosphorus Sorption Isotherm
tion
Low P Load
EPCo
Ads
orpt
orpt
ion
EPCoHigh P Load
P Retention
6/22/2008 WBL 416/22/2008 WBL 41
Phosphorus in Soil Porewater
Des
o P Release
Influence of Phosphorus Loading on EPC0
[Nair et al. 1997][Nair et al. 1997]
Land use Total P (mg/kg) EPCo (mg/L)
Intensive 2,330 5.0HoldingPasture 31
181 1.40.1
6/22/2008 WBL 426/22/2008 WBL 42
Beef 31Forage 23 0.2Native
0.1
0.118
22
2
Anaerobic 0-10 cm
Influence of Phosphorus Loading on EPC0
[Everglades – WCA-2a]
0.5
1
1.5
EPC
o (m
g P/
L)
Anaerobic 0-10 cm
Aerobic 0-10 cm
6/22/2008 WBL 436/22/2008 WBL 43
0 2 4 6 8 10 120
Distance from inflow (km)
3000
2400g
Swamp forestMineral/peat soil
[Richardson, 1985]Phosphorus Sorption
2400
1800
1200
P so
rbed
, mg/
kg
Houghton fenPeat soil
Pocosin bogMineral/peat soil
6/22/2008 WBL 446/22/2008 WBL 44
600
00 30 90 150 210
P in solution, mg/L
Pocosin bogPeat soil
23
P Sorption by WCA-2A soils
1,000
1,500
2,000
/kg) DesorptionSite 1
[Anaerobic]
Ambient PW-P
0.01 0.1 1 10 1000
500
Site 8
1 000
1,500
rbed
P (m
g P
Sorption
[Anaerobic]
[Anaerobic]Ambient PW-P
6/22/2008 WBL 456/22/2008 WBL 45
0.001 0.01 0.1 1 10 1000
500
1,000
Solution P concentration (mg P/L)
Sor
SorptionDesorption
Phosphorus Sorption IsothermLinear Equation
S K CS = KL Cwhere: S = mass of P sorbed per mass of solid phase;
C = P concentration in solution; KL = adsorption coefficient related to binding strength
Freundlich EquationS = KF CN [log S = N log C + log KF]where: S = mass of P sorbed per mass of solid phase;
6/22/2008 WBL 466/22/2008 WBL 46
where: S = mass of P sorbed per mass of solid phase; C = P concentration in solution; KF = adsorption coefficient related to binding strength; N = empirical constant
24
Phosphorus Sorption Isotherm
Langmuir Equation Slope = 1/SLangmuir EquationS = [k C Smax]/1 + k CC/S = [1/Smax] C + 1/k Smaxwhere: S = mass of P sorbed per mass
of solid phase; C = P concentration in solution; k = constant related to
(C/S
)
C
1/kSmax
Slope = 1/Smax
6/22/2008 WBL 476/22/2008 WBL 47
binding strength; Smax = maximum amount of P sorbed per mass of solid phase
C
ion Adsorption
Phosphorus Sorption Isotherm
EPCo
Ads
orpt
ptio
n
Smax
slope = KD
Precipitation
6/22/2008 WBL 486/22/2008 WBL 48
Phosphorus in Soil Porewater
P desorption underambient conditionsD
esor
So
25
Saturation Index (SI)Ca Ab = aC + bA
[C]a [A]b
[Ca Ab]K =
Ion Activity Product (IAP) =Ion Activity Product (IAP) = [C][C]a a [A][A]bb
Sat ration Inde (SI) IAP/KSat ration Inde (SI) IAP/K
6/22/2008 WBL 496/22/2008 WBL 49
Saturation Index (SI) = IAP/KSaturation Index (SI) = IAP/KSI < 1 = Solution is “undersaturated”SI > 1 = Solution is “supersaturated”SI = 1 = Solution saturated (near equilibrium)
P in solution; t = 0r
Precipitation of Phosphate
1
AB
P in solution; t 0
Supersaturation withrespect to B
Supersaturation withrespect to Cen
sity
Fac
tor 1
2
3
6/22/2008 WBL 506/22/2008 WBL 50
C
Capacity Factor
Inte
26
Co-precipitation of Phosphorus
Coating of hydrated ferric oxide(Fe2O3 nH2O) co-precipitatedwith ferric phosphate, aluminum phosphate, and calcium phosphate
6/22/2008 WBL 516/22/2008 WBL 51
Silt or Clay Particle
Pmaxon
Phosphorus Retention Isotherm
Overlying Water
EPCw
P release under
Pmax
slope = AP re
tent
ioea
se
Overlying Water
Rel
ease
Retention
6/22/2008 WBL 526/22/2008 WBL 52
P release underambient conditions
Phosphorus in Water Column
P re
leSediment/Soil
27
High0
Phosphorus Retention Isotherm
P added to water column – range of concentrations
EPCw
6/22/2008 WBL 536/22/2008 WBL 53
Phosphorus Retention byWetlands Soils and Stream
Sediments[Okeechobee Basin Florida]
WetlandsPr = 118 [SRP] - 54.2 r2 = 0.71 n = 11EPCw = 0.47 mg P/L
Stream sediments
[Okeechobee Basin, Florida]
6/22/2008 WBL 546/22/2008 WBL 54
Stream sedimentsPr = 128 [SRP] - 12.4 r2 = 0.95 n = 175EPCw = 0.1 mg P/L
28
20
40ea
se
EPCw=33 ug/L
Phosphorus Retention byMud Sediments – Lake Okeechobee
-80
-60
-40
-20
00 20 40 60 80 100 120 140
P re
tent
ion/
rele
(mg/
m2
Year
)
P re
leas
e y
sedi
men
ts
P retention by sediments
6/22/2008 WBL 556/22/2008 WBL 55
-120
-100
DR
P
Water Column DRP ug/L
by
1,2002
Phosphorus Adsorption Coefficient[Organic Soils]
K [
L/kg
]
400
600
800
1,000 r2 = 0.89n = 36
6/22/2008 WBL 566/22/2008 WBL 56
0 20 40 60 800
200
Ash content (%)
29
50kg
)
Phosphorus Retention CapacityPhosphorus Retention CapacityMineral Wetland Soils Mineral Wetland Soils -- Okeechobee
Basin
10
20
30
40
ax (m
mol
es P
/k Smax = 1.74 + 0.172 [Fe + Al]r2 = 0.78 n = 285
0.1 0.3 1 3 10 30 100 3000Sm
a
Oxalate Extractable [Fe + Al] (mmol/kg)
200
160 Y = 1 21+0 015(x)
Phosphorus Retention Phosphorus Retention ––Peat/Mineral Wetland Soils Peat/Mineral Wetland Soils
160
120
80
sorb
ed [m
g/kg
]/og
of P
in s
olut
ion Y = 1.21+0.015(x)
R2 = 0.87
6/22/2008 WBL 586/22/2008 WBL 58
40
0 0 2 4 6 8 10
P lo
Oxalate extractable Al, g/kg
Richardson, 1985
30
Phosphorus solubility as a function of pH and Eh
6/22/2008 WBL 596/22/2008 WBL 59
Iron solubility as a function of pH and Eh
6/22/2008 WBL 606/22/2008 WBL 60
31
P)
Dissolved P in Sediments
Dis
solv
ed P
(uM
6/22/2008 WBL 616/22/2008 WBL 61
Phosphorus Solubility under Anaerobic Soil Conditions
SO42- H2S + FePO4
Fe2+ + PO43- FePO4FeS
Fe(OH)2-PO4
[Strengite]
6/22/2008 WBL 626/22/2008 WBL 62
Fe3(PO4)2[Vivianite]
[Strengite]
32
6000
7000l) OxidizedOxidized
Lake Okeechobee
2000
3000
4000
5000
6000ac
tivity
(cpm
/ml
ReducedReduced
6/22/2008 WBL 636/22/2008 WBL 63
Littoral Peat Mud Mud Mud Mud0
1000
2000
32P
a
Mechanisms of Phosphorus Release in Wetlands
Reduction of insoluble ferric phosphate to more p psoluble ferrous phosphateRelease occluded phosphate by reduction of hydrated ferric oxide coatingHigher solubility of ferric and aluminum phosphates due to increased soil pHDisplacement of phosphate from ferric and aluminum phosphate by organic anions
6/22/2008 WBL 646/22/2008 WBL 64
p p y gIncreased phosphate availability during sulfate reductionIncreased solubility of calcium phosphate in alkaline soils as result of pH decrease under flooded conditions
33
Regulators of Inorganic Phosphorus Retention
pH and EhpH and EhPhosphate concentrationClay contentIron and aluminum oxidesOrganic matter content
6/22/2008 WBL 656/22/2008 WBL 65
Calcium carbonate contentTime of reaction/agingTemperature
Plant biomass PRunoff,
Phosphorus Cycle
AEROBIC
Peataccretion
[Fe, Al or Ca-bound P]
Litterfall
DOP DIP PIPPOP
DIP
DIP
Runoff, Atmospheric Deposition
Outflow
Periphyton P
6/22/2008 WBL 666/22/2008 WBL 66
ANAEROBIC
accretionPIP
Ca-bound P]Adsorbe
d IP
DIP
POP DOPDOP
DIP
34
Plant LitterAttached POP DOP Epiphytic
i h tEALeaching
Organic Phosphorus
Attached to plant
Detritusdeposited
on soil surface
Decomposeddetritus from pervious years
POP periphyton
POP DOP DIP Benthic periphyton
Microbialbiomass
POP DOP DIPInorganicsolids
Microbial
EA EA
EA EA
6/22/2008 WBL 676/22/2008 WBL 67
Well decomposeddetritus accreted
into soil
Microbialbiomass
POP DOP DIPInorganicsolids
EA EA
Detrital Matter
Organic Phosphorus
PhytinPhospholipidsNucleic acids
Sugar phosphatesPlantsAnimalsMicrobes
Humus
6/22/2008 WBL 686/22/2008 WBL 68
Inorganic Phosphate
Microbes
35
Organic P fractions (% of total organic P) in growing organisms and soils*
>5025102220Monoesters
523302015Phospholipids
252605865Nucleic Acids
SoilsNicotianaSpirodellaFungiE. coli
6/22/2008 WBL 696/22/2008 WBL 69
*From Magid, et al., (1996) after numerous sources.
Soil Phosphorus
TPo = -49 + 0.89 TP1,000
Blue Cypress Marsh
600
800
TPo
(mg
kg-1
)
NENW
6/22/2008 WBL 706/22/2008 WBL 70
400
T
400 600 800 1000TP (mg kg-1)
NWSW
36
Organic PhosphorusOrganic Phosphorus
Microbial biomass P y Hi hMicrobial biomass PLabile organic PFulvic acid - PHumic acid - PResidual organic P
Bio
avai
labi
lity High
Low
6/22/2008 WBL 716/22/2008 WBL 71
Residual organic P
Soil phosphorus compositionSoil phosphorus composition
O th h h t tO th h h t t
Solution 31P NMR spectrum of an alkaline extract of a Swedish tundra soil
Solution 31P NMR spectrum of an alkaline extract of a Swedish tundra soil
PhosphonatesPhosphonates
Inorganic orthophosphate
Inorganic orthophosphate
PhospholipidsPhospholipids
Orthophosphate monoestersOrthophosphate monoesters
Polyphosphate end-groupsPolyphosphate end-groups
Mid-chain l h h
Mid-chain l h h
DNADNA
P h hP h h
6/22/2008 WBL 726/22/2008 WBL 72
pppolyphosphatespolyphosphatesPyrophosphatePyrophosphate
Chemical shift (ppm)Chemical shift (ppm)-20-20-10-100010102020
37
OxygenReduction
ExtracellularEnzymaticActivity
Organic Matter Decomposition and Nutrient Release
Simple
Compounds
ComplexOrganic
OrganicMatter
Hydrolysis
OrganicCompounds
Acid Fermentation
ManganeseReduction
Iron Reduction
NitrateReduction
Sulfate
BioavailableNutrients
Activity
CO2
6/22/2008 WBL 736/22/2008 WBL 73
Short-chainFatty Acids CO
Reduction
SulfateReduction
2
BioavailableNutrients
CH4Hydrogen
Periphyton/Macrophytes
Phosphorus Availability
Detrital MatterPh i
Organic P + P+Organic
PhytinPhospholipidsNucleic acids
Sugar phosphates
6/22/2008 WBL 746/22/2008 WBL 74
EnzymesPhosphatases
38
S +S + EE EE SS EE PP
Enzyme – Catalyzed Reaction
S + S + EE E E SS EE + P+ P
S = Substrate E = Enzyme P = Product
R - O-PO32- + H2O R-OH + HO-PO32-
6/22/2008 WBL 756/22/2008 WBL 75
R O PO3 H2O R OH HO PO3
Alkaline phosphataseEsterlinkage
Phosphatase ActivityPeriphyton APA along the WCA 2a
Nutrient GradientJuly 1996 [Newman, S]
200
300
400
500
6/22/2008 WBL 766/22/2008 WBL 76Source: Newman, unpubl’d data
0
100
0 2 4 6 8 10 12 14 16Distance from the S10s (km)
39
Periphyton
6/22/2008 WBL 776/22/2008 WBL 77
Phosphatase-Cyanobacterial Cells
PPB
C
6/22/2008 WBL 786/22/2008 WBL 78
40
20
25May 1996l )
Alkaline Phosphatase ActivityEverglades- WCA-2A
5
10
15
20
p-ni
troph
enol
(mg
g-1hr
-1) Litter
0-10 cm10-30 cm
6/22/2008 WBL 796/22/2008 WBL 79
00 1 2 3 4 5 6 7 8 9 10 11
Distance from inflow (km)
our
Soil Phosphatase Activity
400 NE
Blue Cypress Marsh
PA, m
g M
UF/
g h
o
100
200
300NW [R]
SW
6/22/2008 WBL 806/22/2008 WBL 80
Mar June July Sept Dec Jan
2001 2002
AP
0
41
Phosphatase Activity[Sunnyhill Farm Wetland]
gg--1 1 hh--11 400
Acid Phosphatase
pp--ni
trop
heno
l g
nitr
ophe
nol
g
100
200
300Acid PhosphataseAlkaline PhosphataseTotal Phosphatase
6/22/2008 WBL 816/22/2008 WBL 81
μμg g pp
Oxygen Nitrate Sulfate BicarbonateEh (mV) 616 228 -162 -217pH 4.7 7.5 7.7 6.6
0
y = 0.36x - 0.32R2 = 0.72100
120140
izat
ion
h-1
Sunnyhill Farm Wetland
020406080
100
anic
P M
iner
alm
g P
g-1 dw
6/22/2008 WBL 826/22/2008 WBL 82
00 100 200 300
Total Phosphatase Activitymg p-nitrophenol g-1 h-1
Org
42
30
Microbial Biomass P[Sunnyhill Farm Wetland][Sunnyhill Farm Wetland]
10
20
Mic
robi
al P
,M
icro
bial
P,
(% o
f tot
al P
)(%
of t
otal
P)
6/22/2008 WBL 836/22/2008 WBL 83
0Oxygen Nitrate Sulfate icarbonate
Eh (mV) 616 228 -162 -217pH 4.7 7.5 7.7 6.6
25Feb'96 Aug.'96 Mar. '97
P
Microbial Biomass Phosphorus[Water Conservation Area[Water Conservation Area--2A]2A]
510
15
20 0-10 cm Soil Depth
robi
al b
iom
ass
(as %
tot
al P
)
05
0 2 4 6 8 10Distance from inflow (km)
Mic (
43
6070
m-2
1.5
Lake Apopka Marsh
1020304050
uble
reac
tive
P, m
g m
0.5
1SO4 -S
NO3 -N
O
g m
-2
6/22/2008 WBL 856/22/2008 WBL 85
4 60
10
Time, daysSo
lu0
02 4 6
Time, days
O2
0 2
Soluble P, mg L-1
1 2Dissolved Fe, mg L-1
3
Lake Apopka Marsh
Water
epth
, cm
0102030
2 4 6 8 1 20 0 3
6/22/2008 WBL 866/22/2008 WBL 86
De 0
-20-10 Soil
44
BP = Benthic PeriphytonFP = Floating PeriphytonEP = Epiphytic Periphyton
Periphyton-Phosphorus-Interactions
Soluble PEPFP
BP
Ca Ca -P
EP Epiphytic Periphyton
Water
6/22/2008 WBL 876/22/2008 WBL 87
BP
Soluble PSoil
Calcareous Periphyton Mats
6/22/2008 WBL 886/22/2008 WBL 88
45
Calcareous Periphyton Mats
6/22/2008 WBL 896/22/2008 WBL 89
With CaCOWith CaCO33 Without CaCOWithout CaCO33
6/22/2008 WBL 90
46
6/22/2008 WBL 91
Distribution of 32P between Water and Benthic Periphyton
1010 2211
WaterWater
Abi tiAbi ti
Light = 10 W mLight = 10 W m--22
22%22%
5%5%
10%10%
2%2%
Water DRP = 5 ug LWater DRP = 5 ug L--11
PeriphytonPeriphyton
6/22/2008 WBL 926/22/2008 WBL 92
AbioticAbiotic
BioticBiotic
1 hour1 hour 12 hour12 hour
74%74%22%22%
88%88%
47
P
Periphyton-Phosphorus-CaCO3 Interactions
P
P
P
PPeriphyton
6/22/2008 WBL 936/22/2008 WBL 93
PSolution P CaCO3
3000
) Live-above ground
Plant Tissue PhosphorusPlant Tissue Phosphorus--WCAWCA--2A2A
500
1000
1500
2000
2500
Tota
l P (m
g kg
-1 Detritus-above groundBelow ground
6/22/2008 WBL 946/22/2008 WBL 94
0
500
F-1 Typha
F-3 Typha
F-3 Cladium
F-5 Cladium
T
Impacted Transition Unimpacted
48
1
1.2
tion
Everglades-WCA 2AR2 = 0.969
0.2
0.4
0.6
0.81
phor
us A
ccum
ulat
(g/m
2ye
ar)
6/22/2008 WBL 956/22/2008 WBL 95
0 5 10 15 20 25 30 350
0.2
Calcium Accumulation (g/m 2 year)
Phos
p
DIP DOP
Soil/Sediment-Water Interactions
DIP DOP PIP POP
SedimentationResuspensionDiffusionWater
Soil/Sediment
DIP DOPPorewater
PIP POP
49
Total Phosphorus in WCA-2A soils (0-10 cm)
1990 1998
6/22/2008 WBL 976/22/2008 WBL 97DeBusk et al. 2001
External LoadReduction
horu
s
Phosphorus Memory
Internal Memory
BackgroundLevel
r Col
umn
Pho
sph
6/22/2008 WBL 986/22/2008 WBL 98
Lag time for Recovery
Wat
er
Time - Years
50
Water Column
Internal Phosphorus Load
Soil
6/22/2008 WBL 996/22/2008 WBL 99
ExternalNutrient Periphyton
Nutrient Impacts in Wetlands
Load
InternalNutrient
Load
Vegetation
Detritus
Water
6/22/2008 WBL 1006/22/2008 WBL 100
Microbial/ChemicalProcesses
Load0-10 cm
10-30 cm
51
Soluble Phosphorus Flux from Sediments
6/22/2008 WBL 1016/22/2008 WBL 101
Lower St. Johns River- SRP ProfilesBeauclair
BluffDoctors
LakeColleeCove
RacyPoint
-20
-15
-20
-15
-20
-15
-20-15
-20
-15
-20
-15
-20
-15
[Malecki et al. 2003]
Dep
th (c
m)
-10
5
10
15
20
25
30
15
-10
-5
5
10
15
20
25
-15
-10
-5
05
10
15
20
25
15-10-50
-15
-10
-5
051015202530
5
10
15
20
25
15
-10
-5
5
10
15
20
25
-15
-10
-5
0
5
10
15
20
25
6/22/2008 WBL 1026/22/2008 WBL 102
2.64 ± 0.85 mg m-2 d-1
7.38 ± 1.71 mg m-2 d-1
1.26 ± 0.29 mg m-2 d-1
4.09 ± 0.03 mg m-2 d-1
SRP conc. (mg L-1)
35
4045
SRP concentration (mg L -1)
25
30
35
SRP concentration (mg L -1) SRP concentration (mg L -1)
30
350 4 8 12
SRP conc. (mg L-1) SRP conc. (mg L-1) SRP conc. (mg L-1)0 4 8 12 0 4 8 12 0 4 8 12
35 25
30
35
25
30
35
25
30
35
52
Internal vs. External Loads
44%32%
TN Lower St. Johns River Estuary
24%
Total Non-pointTotal Point SourceTotal Internal Load
42%25%TP
Total = 7,969 mt year-1
6/22/2008 WBL 103
33%
Total Non-point Total Point SourceTotal Internal Load
[J. R. white 2004]Total = 1,600 mt year-1
Phosphorus Flux from Soil to Water ColumnStation Porewater Benthic IncubatedStation Porewater
equilibratorsBenthicchambers
IncubatedSoil cores
[km]
1.4 0.3 10.0 6.5
[mg P/m2 day]
6/22/2008 WBL 1046/22/2008 WBL 104
3.3 0.8 9.1 1.5
10.1 -0.001 ND ND
53
Flooded Agricultural Land Lake Griffin Flow-way, Florida
Station P – Flux EPCw
mg P m-2 day-1
DRP TP
w
mg L-1
1D 0.40 0.74 0.11
2E 0.94 1.54 0.25
6/22/2008 WBL 105
3D 1.62 2.38 0.43
5C 0.25 0.34 0.07
P memory = 30 – 140 yearsReddy et al., 1997
Internal Phosphorus Load Everglades -WCA-2A
6
y)
12345
P flu
x (m
g P
/m2
day
6/22/2008 WBL 1066/22/2008 WBL 106
00 2 4 6 8 10 12
Distance from inflow (km)
(
54
6
Phosphorus Flux from FloodedAgricultural Land
y = 5.31 e-0.051x
R2 = 0.95
12345
P flu
x m
g P
/m2
day)
6/22/2008 WBL 1076/22/2008 WBL 107
00 10 20 30 40
Time after flooding (months)
(m
Soluble Phosphorus Flux from Wetlands
mg/m2 day
Lake Apopka Marsh 2- 5.50.3 - 1.1Disney World
Orange County 0.02 – 0.16STA-1W 0.3- 1.6
6/22/2008 WBL 1086/22/2008 WBL 108
55
Soluble Phosphorus Flux from Sediments [mg P/m2 day]
Lake Apopka 1 - 5.3Lake OkeechobeeLake Okeechobee
0.1 - 1.9Mud ZonePeat Zone 0.2 - 2.2Sand ZoneLittoral Zone
0.1 - 0.50.6 - 1.5
Lower St Johns River 1 3 7 4
6/22/2008 WBL 1096/22/2008 WBL 109
Lake Barco 0.02 - 0.05
Otter Creek -0.8 - 3.3Indian River Lagoon 0.6 - 1.7
Lower St. Johns River
Tampa Bay 1.9 - 6.3
1.3 - 7.4
Soluble Phosphorus Flux from Sediments
PPPP
PPPPDRPDRP
DRPDRP
Water columnWater column
6/22/2008 WBL 1106/22/2008 WBL 110
SedimentSediment
56
0 1
0.15CaCO3 Ca(OH)2od
wat
er
Lake Apopka Marsh SoilsLake Apopka Marsh Soils[Effect of Chemical Amendments on Phosphorus Release]
0
0.05
0.1
0.1
0.15 Dolomite CaCO3 + Ca(OH)2
le P
rele
ased
into
floo
(mm
ol P
/kg)
4 3 + 3 2 t/h
8.6 t/ha 6.3 t/ha
6/22/2008 WBL 1116/22/2008 WBL 111
0 200 400 600 800 1,000
0
0.05
0 200 400 600 800 1,000
Solu
b
Ca2+ added (mmol/kg)
4.3 + 3.2 t/ha8.2 t/ha
Alum0.1
0.15FeCl3
oodw
ater
(a) (b)
Lake Apopka Marsh SoilsLake Apopka Marsh Soils[Effect of Chemical Amendments on Phosphorus Release]
4 50
0.05
Alum + CaCO3
0.05
0.1
0.15
ble
P re
leas
ed in
to fl
o(m
mol
P/k
g)
(c) (d)FeCl3 + CaCO3
4.0 t/ha1.0 t/ha
2.1 + 4.3 t/ha0.5 + 2.5 t/ha
6/22/2008 WBL 1126/22/2008 WBL 112
0 10 20 30 400 10 20 30 40
0
Fe3+ added (mmol/kg)
Solu
b
Al3+ added (mmol/kg)
57
FePO4 Fe3+ + PO43- Organic P
O2 PO43- Periphyton/Detritus
Water Columnprecipitation
Processes Controlling Phosphorus Processes Controlling Phosphorus
diffusion
4 4 g
Fe2+ PO43-
Fe2+ + PO43-
3 Fe2+ + 2 PO43- Fe3(PO4)2
FePO4 Organic P(amorphous)
(amorphous)
Aerobic
Soi
l/Sed
imen
t
oxidation
burial burial
reduction
diffusion
diffusion
6/22/2008 WBL 1136/22/2008 WBL 113
Fe2+ + CO32- FeCO3
3Ca2+ + 2PO43- B-Ca3(PO4)2
Ca2+ + CO32- CaCO3
(beta tricalcium phosphate))
(calcite))
(siderite)
(vivianite)Anaerobic precipitation
Plant biomass PRunoff,
Phosphorus Cycle
AEROBIC
Peataccretion
[Fe, Al or Ca-bound P]
Litterfall
DOP DIP PIPPOP
DIP
DIP
Runoff, Atmospheric Deposition
Outflow
Periphyton P
6/22/2008 WBL 1146/22/2008 WBL 114
ANAEROBIC
accretionPIP
Ca-bound P]Adsorbe
d IP
DIP
POP DOPDOP
DIP
58
Summary
Phosphorus Cycling Processes
Common inorganic phosphorus pools include: loosely bound; fractions associated with Al, Fe, and Mn oxides and hydroxides; Ca and Mg bound fraction; mineralsPhosphate is not commonly used as an oxidant, but is affected by redox dynamics. Oxidized forms of iron can react with phosphorus and form insoluble compoundsSoil’s capacity to adsorb phosphorus is regulated by the EPCo, at which point adsorption equals desorptionI i h h t ti i l t d b H Eh h h t
6/22/2008 WBL 1156/22/2008 115
Inorganic phosphorus retention is regulated by pH, Eh, phosphate concentration (there is a limited amount of substrate for adsorption), concentrations of Fe, Al, and calcium carbonate, and temperature
Summary
Phosphorus Cycling Processes
Much of the organic phosphorus is present as monoesters and diesters. Monoesters include sugar phosphates, phosphoproteins, mononucleotides, and inositol phosphates. Diestersinclude nucleic acids, phospholipids, and aromatic compounds. Compared to monoesters, diesters are more accessible to microbial attack. Organic phosphorus availability from monoesters requires enzymatic cleavage of the ester linkage. This occurs primarily through several extracellular enzymes such as phosphatases
6/22/2008 WBL 1166/22/2008 116
g y p pthrough hydrolysis of phosphate esters. The “phosphorus memory” can extend the time required for a wetland or an aquatic system to reach an alternate stable condition to meet environmental regulation such as TMDLs (total daily maximum daily load