LOICZ Biogeochemical Budgeting Procedures and Examples V Dupra and SV Smith Department of...
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Transcript of LOICZ Biogeochemical Budgeting Procedures and Examples V Dupra and SV Smith Department of...
LOICZ Biogeochemical Budgeting Procedures and Examples
V Dupra and SV SmithDepartment of OceanographyUniversity of HawaiiHonolulu, Hawaii [email protected]@soest.hawaii.edu
INTRODUCTIONINTRODUCTION
Material budget
System
outputs inputs
Net Sourcesor Sinks
[sources – sinks] = outputs - inputs
LOICZ budgeting assumes that materials are conserved. The difference ([sources – sinks]) of imported (inputs) and exported (outputs) materials may be explained by the processes within the system.
Note: Details of the LOICZ biogeochemical budgeting are discussed at http://www.nioz.nl/loicz and in Gordon et al., 1996.
Three parts of the LOICZ budget approach
1) Estimate conservative material fluxes (i.e. water and salt);
2) Calculate non-conservative nutrient fluxes; and
3) Infer apparent net system biogeochemical performance from non-conservative nutrient fluxes.
Outline of the procedure
I. Define the physical boundaries of the system of interest;
II. Calculate water and salt balance;
III. Estimate nutrient balance; and
IV. Derive the apparent net biogeochemical processes.
PROCEDURES AND EXAMPLES
Locate system of interest
Philippine CoastlinesResolution (1:250,000) http://crusty.er.usgs.gov//coast/
PhilippinesSouth China Sea
Luzon
Subic Bay
0 400 Kilometers
N
Define boundary of the budget
Subic Bay, PhilippinesSubic Bay, Philippines Map from Microsoft EncartaMap from Microsoft Encarta
Variables required
• System area and volume;• River runoff, precipitation, evaporation;• Salinity gradient;• Nutrient loads;• Dissolved inorganic phosphorus (DIP); • Dissolved inorganic nitrogen (DIN);• DOP, DON (if available); and• DIC (if available).
SIMPLE SINGLE BOX(well-mixed system)
Calculate water balance
dVsyst/dt = VQ+VP+VE+VG+VO+VR
VR = -(VQ+VP+VE+VG+VO)
at steady state:
Water balance illustration
VP = 1,160VE = 680
Vsyst = 6 x 109 m3
Asyst = 324 x 106 m2
VQ = 870
VG = 10
VR = -1,360
VR = -(VQ+VP+VE+VG+VO)
VR = -(870+1,160-680+10+0)
VR = -1,360 x 106 m3 yr-1
VO = 0 (assumed)
Fluxes in 10Fluxes in 1066 m m33 yr yr-1-1
VX = (-VRSR - VGSG )/(SOcn – SSyst)
Calculate salt balance
Eliminate terms that are equal to or near 0.Eliminate terms that are equal to or near 0.
Salt balance to calculate VX and
Vsyst = 6 x 109 m3
Ssyst = 27.0 psu
SQ = 0 psuVQSQ = 0
VR = -1,360VRSR = -41,480
VX = (-VRSR -VGSG)/(SOcn – SSyst)
SOcn = 34.0 psu SR = (SOcn+ SSyst)/2 SR = 30.5 psu
VX(SOcn- SSyst) = -VRSR -VGSG = 41,420
VX = (41,480 - 60 )/(34.0 – 27.0)
VX = 5,917 x 106 m3 yr-1
= VSyst/(VX + |VR|)
= 6,000/(5,917 + 1,360)
= 0.8 yr 300 days
VX = 5,917
= 300 daysSG = 6.0 psuVGSG = 60
Fluxes in 10Fluxes in 1066 psu-m psu-m33 yr yr-1-1
Calculate non-conservative nutrient fluxes
d(VY)/dt = VQYQ + VGYG +VOYO +VPYP + VEYE + VRYR + VX(Yocn - Ysyst) + Y
System,YSyst
(Y)
River discharge(VQYQ)
Residual flux(VRYR); YR = (YSyst+YOcn)/2
Mixing flux(VXYX); YX = (YOcn-YSyst)
Ocean, YOcn
Other sources (VOYO)
d(VY)/dt = VQYQ + VGYG + VOYO +VPYP + VEYE + VRYR + VX(Yocn - Ysyst) + Y
0 = VQYQ + VGYG + VOYO + VRYR + VX(Yocn - Ysyst) + Y
Y = -VQYQ - VGYG - VOYO - VRYR - VX(Yocn - Ysyst)
Schematic for a single-box estuary
Eliminate terms that are equal to or near 0.
Groundwater (VGYG)
DIP balance illustration
Y = - VRYR - VX(Yocn - Ysyst) – VQYQ – VGYG - VOYO
DIP = - VRDIPR - VX(DIPocn - DIPsyst) – VQDIPQ - VGDIPG - VODIPO
DIP = 544 - 2,367 – 261 –1 - 30 = -2,115 x 103 mole yr-1
DIPsyst = 0.2 M
DIPQ = 0.3VQDIPQ = 261
VRDIPR = -544
DIPOcn = 0.6 MDIPR = 0.4 M
VX(DIPOcn- DIPSyst) = 2,367
DIP = -2,115 DIPG = 0.1VGDIPG = 1
VODIPO = 30(other sources,e.g., waste, aquaculture)
DIN = +15,780 x 103 mole yr-1 (calculated the same as DIP)
Fluxes in 10Fluxes in 1033 mole yr mole yr-1-1
STOCHIOMETIC CALCULATIONS
Stoichiometric linkage of the non-conservative (Y’s)
106CO2 + 16H+ + 16NO3- + H3PO4 + 122H2O
(CH2O)106(NH3)16H3PO4 + 138O2
Redfield Equation(p-r) or net ecosystem metabolism, NEM = -DIPx106(C:P)
(nfix-denit) = DINobs - DINexp
= DINobs - DIPx16(N:P)
Where: (C:P) ratio is 106:1 and (N:P) ratio is 16:1 (Redfield ratio)
Note: Redfield C:N:P is a good approximation where local C:N:P is absent.
Stoichiometric calculations
(p-r)= -DIPx106(C:P)
= -(-2,115) x 106
= +224,190 x 103 mole yr-1
= +2 mmol m-2 day-1
(nfix-denit) = DINobs - DINexp
= DINobs - DIPx16(N:P)
= 15,780 – (-2,115 x 16)
= +49,620 x 103 mole yr-1
= +0.4 mmol m-2 day-1
Note:Note: Derived net processes are apparent net performance Derived net processes are apparent net performance of the system. Other non-biological processes may be responsible of the system. Other non-biological processes may be responsible for the some of the uptake or release of the for the some of the uptake or release of the Y’s. Y’s.
TWO-LAYER BOX(STRATIFIED SYSTEM)
Stratified system (two-layer box model)
Two-layer water and salt budget model
Upper LayerSSyst-s
Lower LayerSSyst-d
VQ (Runoff)
VQSQ
VZ (Volume Mixing)
VZ(SSyst-d-SSyst-s)VDeep’ (Entrainment)
VDeep’SSyst-d
VSurf (Surface Flow)
VSurfSSyst-s
VDeep (Deep Water Flow)
VDeepSOcn-d
SOcn-d
VQ +VP + VE + VSurf + VDeep' = 0
VQSQ + VSurfSSyst-s + VDeep‘SSyst-d + VZ(SSyst-d - SSyst-s) = 0
VE VP
Two-layer budget equations
VQ + VSurf + VDeep = 0
VDeep = VR'(SSyst-s)/(SSyst-s-SOcn-d )
VR’ = -VQ -VP -VE
VZ = VDeep(SOcn-d -SSyst-d)/(SSyst-d-SSyst-s)
= VSyst/(|VSurf|)
Note: Visit LOICZ website <http://data.ecology.su.se/MNODE/Methods/TWOLAYER.HTM> for detailed derivation of the above equations.
Water and salt budget for stratified system (illustration)
Water flux in 106 m3 day-1
and salt flux in106 psu-m3 day-1.
Lower LayerVSyst-d = 55.0x109 m3
SSyst-d = 31.2 psu = 466 days
SQ = 0.1 psuVQ = 10VQSQ = 1
VZ = 37VZ(SSyst-d-SSyst-s) = 122
VDeep’ = 81VDeep’SSyst-d = 2,527
VSurf = 95VSurfSSyst-s= 2,650
VDeep = 81VDeepSOcn-d = 2,649
SOcn-d = 32.7 psu
VE= 0 VP = 4
Aysen SoundUpper Layer
Vsyst-s = 11.8x109 m3
SSyst-s= 27.9 psu = 89 days
Syst = 703 days
Two-layer nutrient budget model
Upper LayerYSyst-s
YSyst-s
Lower LayerYsyst-d
YSyst-d
River discharge(VQYQ)
Mixing flux(VZ(YSyst-d-Ysyst-s))
Entrainment flux(VDeep’YSyst-d)
Upper layer residual flux(VSurfYSyst-s)
Lower layer residual flux(VDeepYOcn-d)
Ocean lower Layer, Yocn-d
YSyst = (YSyst-s+YSyst-d)
DIP balance for stratified system(illustration)
Fluxes in103 mole day-1.
Lower LayerDIPSyst-d = 1.7 M
DIP = +32
DIPQ = 0.1MVQ = 10VQDIPQ = 1
VZ = 37VZ(DIPSyst-d-DIPSyst-s)=7
VDeep’ = 81VDeep’DIPSyst-d = 138
VSurf = 95VSurfDIPSyst-s= 143
VDeep = 81VDeepDIPOcn-d = 113
DIPOcn-d = 1.4 M
Aysen SoundUpper Layer
DIPSyst-s= 1.5 MDIP = -3
DIPSyst = +29
COMPLEX SYSTEMS IN SERIES
Pelorus Sound, New Zealand
Red dashed lines show segmentation of the system.
NN
UpperUpperPelorusPelorus
LowerLower
PelorusPelorus TawhitinuiTawhitinuiReachReach
HavelockHavelockArmArm
KenepuruKenepuruArmArm
Schematic of systems in series
Segmentation for Pelorus Sound Budget.
Ocean
N
Lower Pelorus
Upper Pelorus
Havelock Arm
KenepuruArm
TawhitinuiReach
Beatrix, Clove Craig Bays
Water balance for stratified systems in series
Complex system likePelorus Sound can be budgeted as a combinationof single-layer and two-layer segments.
Pelorus Sound Steady-State Water Budget
0.2 0.7
0.6 1.4 0.8
0.7
266
2.4 2.1
2.6
76
116
1.4
3.4
2.4 10.5 3.6
480
15.1
12.9
590
470
19.3 19.3
893
20.0
19.3 48.0
47.3 31.5 47.3
944
2230
562.8 108.1
187.6
192.0
770 400
TEMPORAL AND SPATIALVARIATION
Implication of temporal and spatial variation
Products of the averages
= 5.5(39)
= 215
Averages of the products
= (15 + 30 + 50 +0)/4
= 24
X = 15, 6, 1, 0Y = 1, 5, 50, 100
Systems should be segmented spatially or temporally if there is Systems should be segmented spatially or temporally if there is significant spatial and temporal variation. The algebraic reasonsignificant spatial and temporal variation. The algebraic reasonis that in general the product of averages does not equal the average is that in general the product of averages does not equal the average of the products. Visit the web site <of the products. Visit the web site <http://data.ecology.su.se/MNODE/http://data.ecology.su.se/MNODE/Methods/spattemp.htmMethods/spattemp.htm> for a more detailed explanation of this point.> for a more detailed explanation of this point.
Temporal patterns of the variablesThe average of the nutrient flux does not equal to the product of the annual average flow and concentration. The budget based on the annual average data is simply not as accurate as the budget on the average fluxes.
Temporal gradients of variables will give clue to seasonal division of the data
End