C N P Fluxes in the Coastal Zone

The LOICZ Approach to Budgeting and Global Extrapolation

What is the role of the coastal ocean in global CNP cycles?

• Easier to quantify globally than locally:– Via global loading budgets;– Little understanding of distribution or controls.

• Function of biota and inorganic reactions;• Function of environmental conditions:

– F(land inputs, oceanic exchanges);– F(human pressures);– F(regional, global environmental change).

• An environmentally important question that can be approached via geochemical reasoning.

General Background

Global Elevation

Only a small portion lies in the “LOICZ domain.”

Coastal Zone (+200 to –200 m)

This domain is nominally + 200 m to -200 meters, orabout 18% of global area.

Coastal Ocean (0 to –200 m)

The coastal ocean, being budgeted by LOICZ, is about 5% of global area.

The Global Coastal Ocean: A Narrow, Uneven, Chemically Reactive “Ribbon”

Most net biogeochemical reaction is thought to occur in the landward, estuarine, portion of the ribbon.

Most materials entering the ocean from land pass through this ribbon.

LAND

OCEAN

This ribbon is ~ 500,000 km long and averages about 50 km in width.

The Global Coastal Ocean: A Narrow, Uneven, Chemically Reactive “Ribbon”

LAND

OCEAN

LOICZ covers only ~5% of the global ocean, but:18-33% of the global PP ~83% of POM mineralisationPreservation of ~87% of ocean POMTransit for major part of the elements controling Ocean PP (N, P, Si, Fe, etc)

LOICZ and IGBP

• IGBP is the “International Geosphere-Biosphere Programme.”– Part of ICSU, the International Council of

Scientific Unions

• LOICZ is “Land-Ocean Interactions in the Coastal Zone.”– A key project element of IGBP

IGBP:International Geosphere-Biosphere

Programme

IGBP aim --To describe and understand the interactive physical, chemical and biological processes that regulate the Earth System, the environment provided for life, the changes occurring in the system, and the influences of human actions.

LOICZ aim -- About the same as IGBP aim —for the coastal zone.

Alphabet Soup of the IGBP• JGOFS Joint Global Ocean Flux Studies• IGAC International Global Atmospheric Chemistry• GCTE Global Change and Terrestrial Ecosystems• BAHC Biospheric Aspects of the Hydrological Cycle• PAGES Past Global Change• LOICZ Land-Ocean Interactions in the Coastal Zone• LUCC Land Use and Cover Change• GLOBEC Global Ocean Ecosystem Dynamics

__________________________________________________• GAIM Global Analysis, Integration and Modelling• START System for Analysis, Research, and Training• DIS Data and Information System

• Stephen Smith svsmith@soest.hawaii.edu • Fred Wulff fred@system.ecology.su.se• Vilma Dupra vdupra@soest.hawaii.edu• Dennis Swaney dennis@system.ecology.su.se• Victor Camacho vcamacho@bahia.ens.uabc.mx•  Malou McGlone mcglonem@msi01.cs.upd.edu.ph•  Laura David ldavid@msi01.cs.upd.edu.ph• LOICZ International Project Office loicz@nioz.nl•  Biogeochemical Modeling

Web Page http://data.ecology.su.se/MNODE/

LOICZBudgeting Background

Develop a “Globally Applicable” Method of Flux Estimation

• Ability to work with secondary data;

• Minimal data requirements;

• Widely applicable, uniform methodology;

• Robust;

• Informative about processes of CNP flux.

LOICZ Budgeting Procedure

• Conservation of mass is one of the most fundamental concepts of ecology and geochemistry.

(inputs) (outputs)

(in terna l sources, sinks)

systemstorage

M ATERIAL B UDG ET

Water, Salt, and “Stoichiometrically Linked” Nutrient Budgets

• Water and salt budgets are used to estimate water exchange in coastal systems.

• Departure of nutrient budgets from conservative behavior measures “system biogeochemical fluxes.”

• Nonconservative DIP flux is assumed proportional to (primary production – respiration).

• Mismatch from “Redfield expectations” for DIP and DIN flux is assumed proportional to (nitrogen fixation – denitrification).

Water and Salt Budgets

• Salt budget– Net flows known.

– Mixing (VX) conserves salt content.

• Water budget– Freshwater flows

known.

– System residual flow (VR) conserves volume.

oceanSocean

system

Vsystem, Ssystem

VR =VE - (VP+VQ+VG+VO)

VPVE

VQ, VG, VO

WATER BUDGET

VPSE

= 0VESE

= 0

VQSQ, VGSG, VOSO = 0ocean

Socean

systemVsystem, Ssystem

SR = (Socean + Ssystem)/2

VRSR

VX = VRSR/(Socean-Ssystem)SALT BUDGET

Nutrient Budgets

• Calculations based on simple system stoichiometry– Assume Redfield C:N:P ratio (106:16:1)

• (production - respiration) = -106 x DIP

• (Nitrogen fixation - denitrification) = DINobs - 16 x DIP

• Nutrient (Y) budgets– Internal dissolved

nutrient net source or sink (Y) to conserve Y.

ocean system

NUTRIENTS

Y = outputs - inputs

sediments

LOICZ Strategy

• Develop a global inventory of these budgets.– Guidelines, a tutorial, and individual site

budgets at http://nest.su.se/mnode/• Use “typology” (classification) techniques to

extrapolate from budgeted sites to global coastal zone.

LOICZ Budgeting Research

• New, or “primary,” data collection is not a primary aim of LOICZ budgeting research.

• There is heavy reliance on available secondary data to insure widespread (“global”) coverage.

• Workshops and information sharing via the World Wide Web are the major tools for adding information to the LOICZ budgeting data base.

• Funding for workshops has come from UNEP/GEF, LOICZ, WOTRO, local sponsorship.

• Develop analytical tools to assist in budgeting.

LOICZ Budget Sites to Date

# ### #### # # #### ######

#######

######

# ##

## ### ## ## ## ## #### ### ## #### ##### ####### ## ######### ## ###

##### ## ##

### # ## # ## ###

# #

#

#####

##

#

# ### #### # # #### ######

#######

######

# ##

## ### ## ## ## ## #### ### ## #### ##### ####### ## ######### ## ###

##### ## ##

### # ## # ## ###

# #

#

#####

##

#

>100 sites so far; > 200 sites desired.

Latitude, Longitude of Budget Sites

# ### #### # # #### #############

######

# ## ## ##### ## ## ## #### ### ## #### ############ ## ######### ## ### ##### ## ##

### # ## ### ###

# ##

#####

###

# ### #### # # #### #############

######

# ## ## ##### ## ## ## #### ### ## #### ############ ## ######### ## ### ##### ## ##

### # ## ### ###

# ##

#####

###

no. sites

0 5 10 15 20

Latit

ude

-90

-60

-30

0

30

60

90

Longitude

-180 -120 -60 0 60 120 180

no.

site

s

0

5

10

15

Present site distribution

•Poor cover at high latitudes (N & S).

•Poor cover from 10N to 15S.

•Poor cover in Africa.

•S. Asia sites not yet posted.

Nutrient Load v Latitude

DIP load

(mmol m-2 yr-1)

100 101 102 103

Latit

ude

-90

-60

-30

0

30

60

90

DIN load

(mmol m-2 yr-1)

100 101 102 103 104-90

-60

-30

0

30

60

90

•Load variation most obvious with DIP.

•High loads near 15N are in SE Asia.

•High loads near 30S are in Australia

Internal Nutrient Flux v Latitude

DIP(mmol m-2 yr-1)

-300 0 300

Latit

ude

-90

-60

-30

0

30

60

90

DINmmol m-2 yr-1)

-6000 0 6000

DIP response to load may differ in the N and S hemispheres.

DIN response to load seems weaker than DIP.

DIP, DIN v DIP Load

DIP load (mmol m-2 yr-1)

100 101 102 103

DIP

(m

mol

m-2

yr-1

)

-400

-200

0

200

400

100 101 102 103

DIN

(m

mol

m-2

yr-1

)

-8000

-4000

0

4000

8000

DIP and DIN both increase (+ or -) at high DIP loads.

•Responses more prominent for DIP than for DIN.

DIP, DIN v DIN Load

DIN load (mmol m-2 yr-1)

100 101 102 103 104

DIP

(m

mol

m-2

yr-1

)

-400

-200

0

200

400

100 101 102 103 104 D

IN (

mm

ol m

-2 y

r-1)

-8000

-4000

0

4000

8000

•No clear effect of DIN load on DIP.

DIN appears to become negative at high DIN load.

Net Ecosystem Metabolism(production – respiration)

0

5

10

15

20

25

30

< -2

0

-15

to -1

0

-9 to

-8

-7 to

-6

-5 to

-4

-3 to

-2

-1 to

01

to 2

3 to

45

to 6

7 to

8

9 to

10

15 to

20

(p-r ) mol m-2 yr-1

nu

mb

er o

f si

tes apparent

heterotrophy at 51 sitesapparent

autotrophy at 55 sites

•Remember: Rates are apparent, based on stoichiometric assumptions.

•No clear overall trend; most values cluster near 0.

•Extreme values (beyond 10) are questionable.

(Nitrogen Fixation – Denitrification)

0

10

20

30

40

50

60

-8 to

-7

-7 to

-6

-6 to

-5

-5 to

-4

-4 to

-3

-3 to

-2

-2 to

-1

-1 to

00

to 1

1 to

22

to 3

3 to

44

to 5

5 to

66

to 7

7 to

8

(nfix - denit ) mol m-2 yr-1

nu

mb

er o

f si

tes

apparent denitrification64 sites

apparent N fixation42 sites

•Although values cluster near 0, clear dominance of apparent denitrification.

•Apparent N fixation >5 seems too high.

Some Cautionary Notes

• Individual budgets may suffer from data quality or other analytical problems.

• Stoichiometry is “apparent,” and not always reliable.• Simple averaging of budgets is not a legitimate estimate of

global average performance; the coastal zone is too heterogeneous and sampling is too biased for such averaging.

• Also, system size, or relative geographic importance, not accounted for in simple averaging.

• “Upscaling” must take these factors into account.

LOICZ Biogeochemical Budgeting Procedures and Examples

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 sum of the uptake or release of the for the sum 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 variables

The 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

Gracias

LOICZ-CABARET

Computer Assisted Budget Analysis for Research, Education,

and TrainingL.T. David 1, S.V. Smith 2, J. de Leon 1, C. Villanoy 1,V.C. Dupra 1,2 , and F. Wulff 3

1Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101, Philippines2School of Ocean and Earth Science and Technology, Honolulu, Hawaii, USA3Department of Systems Ecology, Stockholm University, Stockholm, Sweden

• Statement of Purpose

The Computer Assisted Budget Analysis for Research, Education, and Training or LOICZ-CABARET was designed to simplify the process of calculations in applying the LOICZ approach to biogeochemical budget calculations.

This current version can assist in the calculation of the water, salt, and nutrient budget of any single-box or multi-box single-layer or multi-layer system by seasons or monthly. It can also assist in the calculation of the area and volume of a system in its entirely or treated as sub-systems through its on-screen digitization. Finally, to circumvent observed complications of previous users in unit conversions, the LOICZ-CABARET automatically transforms units into m3/yr for easier comparison between systems. Results are displayed in the familiar LOICZ box-diagram format.

For questions and suggestion, contact LOICZ@usa.net

Additional improvements are periodically posted at the LOICZ webpage www.nioz.nl/loicz

The program can be downloaded from the LOICZ webpage as an executable ZIP file. It is best if the downloaded file is placed and unzipped inside a blank folder. All future working files must reside in this folder for the program to work.

To unzip, just double click the executable zip. Run program by double-clicking on cabaret.exe

The program should work in windows 95/97/2000 and NT.

Sequentially fill in the necessary data. To help guide users through the program, a flow chart can be accessed at any time by clicking on the menu choice named FLOWCHART.

Close the flowchart window by clicking DONE.

• FLOW CHART

• ALPHA/PERSONAL

In order to be duly recognized as a contributor, make sure to fill in the Contact Person Information Window.

Note that the two buttons at the bottom allows the user to go back to the previous window (B) or forward to the next sequential window (N)

• ALPHA/DESCRIPTION

Site description goes inside this window. It is necessary to enter the following fields:

•ESTUARY NAME

•COUNTRY

•THE NORTH, SOUTH, EAST, WEST BORDERS OF THE SYSTEM

•NO. OF SEASONS & THE START AND END MONTHS OF EACH SEASON

• CALIBRATE Choose the type of system

The No. of boxes

The No. of layers

The area per box

If the area is unknown, LOICZ-CABARET also allows for the estimation of the area using the on-screen digitization.

To use this feature you must have a bmp image of your system.

Type in the length of your calibration bar found in most maps or use the latitude lines and then click on the MAP button.

• BMP OF MAP

A small window asking for the bmp file name opens when you click on MAP.

The map image then opens.

Click the ends of the calibration bar then click DONE.

• ESTIMATING BOX AREA

To estimate the area per box, double-click on the corresponding box area.

This will once again open the bmp image of your system.

Digitize the box area on-screen. The box area polygon is designed to automatically close upon clicking of DONE.

• ALPHA/MATERIALS

The water, salt and nutrient data are typed in this window.

The minimum fields to be filled are the following:

•Layer depth

•At least one freshwater flow

•At least the salt and nutrient concentration of the outer box and the system box

This should be done per box and per layer.

Afterwards, click BUILDHTML

• RESULT - WATER AND SALT BALANCE

Results can be viewed using any web-browser.

Make sure to re-load the page after every edit.

• RESULT - PHOSPHATE & NITRATE BALANCE

• VISION

It is hoped that LOICZ-CABARET will not only encourage the users to contribute to the LOICZ endeavor but also experiment with the forcing functions and response sensitivity of their systems. Finally, LOICZ-CABARET is also envisioned to be used as a teaching tool in estuaries and coastal lagoon studies.

Estimation of Waste Load

Marine Science InstituteUniversity of the Philippines

Coastal Water Body

Precipitation Evaporation

Residual flux

Mixing flux

Runoff

Groundwater

Sewage/Waste

Sources of Waste (human activity)

household activities

livestock

agriculture

urban runoff

aquaculture

manufacturing

Steps in the Calculation of Waste Load

1. Identify relevant human activities

households - solid waste, domestic sewage, detergent

livestock - piggery, poultry, cattle

agriculture - soil erosion, fertilizer runoff

urban runoff - unsewered areas

aquaculture - prawns, fish

manufacturing - food, textiles, chemicals

2. Determine the level of each human activity

from government statistics, preferably at local level

household - size of the population

livestock - no of pig, chicken, cow

aquaculture - tons of prawn, fish

urban runoff - urban area

agriculture - tons of soil eroded

3. Approximate TN and TP (in effluent discharge)

TN = activity level x discharge coefficient

TP = activity level x discharge coefficient

T

The discharge coefficients for various human activities

are given in the following spreadsheet.

This spreadsheet calculates TN and TP load in waste generated by various human activities. Knowledge of the activities relevant to the coastal area is necessary and the only input needed in the spreadsheet would be the level of the waste generating activity (fill in white cells).

ESTIMATION OF WASTE LOADEconomic Activity Discharge coef Source Activity level Total N Total P DIN DIP

(unit) (no) (unit) (kg/yr) (kg/yr) (mol/yr) (mol/yr)Householda. solid waste 1.86 kgN/prn/yr a person 0 0 0 0

0.37 kgP/prn/yr bb. domestic sewage 4 kgN/prn/yr c person 0 0 0 0

1 kgP/prn/yr cc. detergent 1 kgP/prn/yr c person 0 0

Urban runoff 1.9 mgN/liter d avg rain(m/yr) 0 0 0 0 (unsewered areas) 0.4 mgP/liter d x urban area(m2)

Livestocka. cattle 43.8 kgN/cow/yre cow 0 0 0 0

11.3 kgP/cow/yreb. horses 95.3 kgN/hor/yr e horse 0 0 0 0

16.4 kgP/hor/yr ec. sheep 4 kgN/shp/yre sheep 0 0 0 0

21.5 kgP/shp/yrea. piggery 7.3 kgN/pig/yr e pig 0 0 0 0

2.3 kgP/pig/yr eb. poultry 0.3 kgN/bird/yrf bird 0 0 0 0

0.7 kgP/bird/yrf

Aquaculturea. prawn 5.2 kgN/ton/yr g ton prawn 0 0 0 0

4.7 kgP/ton/yr gb. milkfish 2.9 kgN/ton/yr b ton fish 0 0 0 0

2.6 kgP/ton/yr b

Non-point agricultural runoffa. cropland erosion 1.68 kgN/ton b ton soil 0 0 0 0

0.04 kgP/ton b eroded/yr

SUM 0 0

References:a Sogreah. 1974. Laguna de Bay Water Resources Development Study.

Laguna Lake Development Authority, Pasig City, Philippines.b Padilla, J., L. Castro, A. Morales, C. Naz. 1997. Evaluation of economy-environment

interactions in the Lingayen Gulf Basin: A partial area-based environmental accounting approach. DENR and USAID, Philippines.

c World Bank. 1993. Environmental Sector Study. Towards Improved Management of Environmental Impacts. Washington, D.C., USA.

d Gianessi, L. and H. Peskin. 1984. An overview of the RFF Environmental Data InventoryMethods, Sources and Preliminary Results. Vol 1. N.W., Washington, D.C.:Renewable Resources Division, Resources for the Future.

e World Health Organization (WHO). 1993. Rapid Assessment of Sources of Air, Water, and Land Pollution. Geneva, Switzerland

f Valiela, I., G. Collins, J. Kremer, K. Lajitna, M.Geist, B. Seely, J.Brawley, and C.H. Sham. 1997. Nitrogen loading from coastal watersheds to receiving estuaries: New methods and application. Ecological Applications. 7(2):358-380.

g Gonzales, J.A., H,J. Gonzales, R.C. Sanares, and E.T. Tabernal. 1996. River pollution:an investigation of the influence of aquaculture and other agro-industrial effluentson communal waterways. Institute of Aquaculture, College of Fisheries, Universityof the Philippines in the Visayas. 89pp.

h Howarth, R.W., G. Billen, D. Swaney, A. Townsend, N. Jaworski, K/ Lajitha, J.A. Downing,R. Elmgren, N. Caraco, T. Jordan, F. Berendse, J. Freney, V. Kudeyarov, P. Murdoch,and Z. Zhao-Liang. 1996. Regional nitrogen budgets and riverine N and P fluxes for drainages to the North Atlantic Ocean; Natural human influences. Biogeochemistry. 35:75-139.

Sources of Discharge Coefficients

TN and TP (in the spreadsheet) are approximated using the following calculations.

TN = activity level x discharge coefficient

Ex. for Domestic Sewage

activity level = 2000 persons

discharge coefficient = 4 kgN/person/yr

TN = 4 kgN/person/yr x 2000 persons

TN = 8000 kgN/yr

TP = activity level x discharge coefficient

discharge coefficient = 1 kgP/person/yr

TP = 1 kgP/person/yr x 2000 persons

TP = 2000 kgP/yr

*from San Diego-McGlone, M.L. ,S.V. Smith, and V. Nicolas. 1999.Stoichiometric interpretation of C:N:P ratios in organic wastematerials by (Accepted in Marine Pollution Bulletin).

If only BOD and COD data are available, TN and TP can be approximated using the following ratios*

TN/BOD = 0.5

TP/BOD = 0.042

COD/BOD = 2.6

Ex if available data is BOD at 5 mg/L

TN = 5 mg/L x 0.5 = 2.5 mg/L

Ex if available data is COD at 5 mg/L

TN = 5 mg/L x 1/26 (BOD/COD) x 0.5

= 1 mg/L

The previous spreadsheet also approximates DIN and DIP. The following calculations illustrate how this is done.

4. Calculate DIN and DIP in the effluent dischargeAssumption: 25% of waste enter the bayUse stoichiometric ratio*

DIN/TN = 0.38DIP/TP =0.5

DIN = TN÷atomic wt N x DIN/TN x 25%

DIN = 8000 kgN/yr ÷14 g/mole x 0.38 x 0.25

DIN = 54,000 moles/yr

DIP = TP÷atomic wt P x DIP/TP x 25%

DIP = 2000 kgP/yr÷31 g/mole x 0.5 x 0.25

DIP = 8,000moles/yr

*from San Diego-McGlone, M.L. ,S.V. Smith, and V. Nicolas. 1999.Stoichiometric interpretation of C:N:P ratios in organic wastematerials by (Accepted in Marine Pollution Bulletin).

The following N and P budgets of a Philippine bay (LINGAYEN GULF) are given to illustrate how waste is quantified and show that this is an important input to the system.

NITROGEN AND PHOSPHORUS BUDGETS FOR LINGAYEN GULF

114.00 118.00 122.00 126.004.00

8.00

12.00

16.00

20.00

Lingayen Gulf

Manila BaySo

uth

Chi

na S

ea

Lingayen Gulf divided into three boxes

119.90 120.00 120.10 120.20 120.30 120.40

16.00

16.10

16.20

16.30

16.40

16.50

16.60

Upper Gulf1764 km2, 81 km3

Bolinao126 km2, 0.3 km3

Nearshore

210 km2 , 3.2 km3

LINGAYEN GULFWater Budget (fluxes in 109m3/yr)

Upper Gulf1764 km2, 81 km3

Nearshore210 km2, 3.2 km3

Bolinao126 km2, 0.3 km3

Ocean

VR = 1

VR = 8

VR = 11

VQ = 0.2

VG = 0.7

VP = 0.3

VP =4

VQ = 2

VG = 0.4

VQ = 8

VG = 0.2

VP = 0.5

VE = 0.3

VE = 0.4

VE = 4

S2 = 34.0

S1N = 31

S1B = 33.5

LINGAYEN GULFSalt Budget (salt fluxes in 109 psu-m3/yr)

Upper Gulf1764 km2, 81 km3

Nearshore210 km2, 3.2 km3

Bolinao126 km2, 0.3 km3

Ocean

VX = 68

VRSR = 34

S3 = 34.4

VRSR = 376 VX = 940

VRSR = 260 VX = 87

= 2 days = 27 days

= 12 days

Table 1. Effluents produced by economic activities in Lingayen Gulf (in 106 mole yr-1).

ECONOMIC ACTIVITY NITROGEN PHOSPHORUS

Household activities 1,754 202 - domestic sewage 1,595 91 - solid waste 159 11 - detergents - 100Urban Runoff 126 5Agricultural Runoff 3,465 174 - crop fertilization 1,820 157 - cropland erosion 1,645 17Livestock 29 2 - commercial piggery 25 2 - poultry 4 -Aquaculture 22 2Total 5,396 385

ECONOMIC ACTIVITY NITROGEN PHOSPHORUS

Household activities 1,754 202 - domestic sewage 1,595 91 - solid waste 159 11 - detergents - 100Urban Runoff 126 5Agricultural Runoff 3,465 174 - crop fertilization 1,820 157 - cropland erosion 1,645 17Livestock 29 2 - commercial piggery 25 2 - poultry 4 -Aquaculture 22 2Total 5,396 385

VODIPO = 35

VODIPO = 35

VODIPO = 46

Nearshore

LINGAYEN GULFDIP Budget (fluxes in 106 moles/yr)

Upper Gulf Bolinao

Ocean

DIP1B = 0.4 DIP2 = 0.1µM

DIP1N = 0.4µM

VXDIPX = 20

VR DIPR= 2

VRDIPR = 0

VXDIPX = 26

DIP3 = 0.0µMVRDIPR = 1 VXDIPX = 94

VQDIPQ = 1

VQDIPQ = 88

VQDIPQ = 1

VGDIPG = 1

VGDIPG = 2

VGDIPG = 0DIP=-27

DIP = +10

DIP = -97

VODINO = 262

VODINO = 262

VODINO = 350

DIN1N = 1.7µM

VQDINQ = 4VQDINQ = 8

VQDINQ =128

Ocean

LINGAYEN GULFDIN Budget (fluxes in 106 moles/yr)

Upper Gulf

Nearshore

Bolinao

DIN1B = 3.9µM DIN2 = 0.8µMVXDINX = 211

VR DINR= 10

VRDINR = 2

VXDINX = 78

DIN3 = 0.5µMVRDINR = 7 VXDINX = 282

VGDING = 28

VGDING =11

VGDING = 39DIN = -180

DIN = -310

DIN = -313

Stoichiometric Links

Net ecosystem metabolism (p-r) or photosynthesis minus respiration, can be calculated using the formulation

(p-r ) = -DIP (C:P)part

Estimates of (nfix-denit) or N-fixation minus denitrification,can be approximated using the formulation

(nfix-denit) = DIN - DIP (N:P)part

where (C:P)part and (N:P)part are the ratios of organic matter reacting in the system

(Area, Vol.)

% area

Nearshore Box

(210 km2,

3.2 km3)

10%

Bolinao Box

(126 km2,

0.3 km3)

6%

Upper Gulf Box

(1,764 km2,

81 km3)

84%

Whole System

(2,100 km2,

84.5 km3)

100%

mol m-2 yr-1 mol m-2 yr-1 mol m-2 yr-1 mol m-2 yr-1

DIP -0.46 -0.21 +0.006 -0.05DIN -1.5 -1.4 -0.2 -0.4

(p-r) +49 +23 -0.6 +6

(nfix-denit) +1,239 +2.0 -0.5 +0.3

Autotrophic

N fixation

Autotrophic

N fixation

Heterotrophic

Denitrification

Autotrophic

N fixation

Table 2. Summary of nonconservative fluxes in three boxes of Lingayen Gulf.

(Area, Vol.)

% area

Nearshore Box

(210 km2,

3.2 km3)

10%

Bolinao Box

(126 km2,

0.3 km3)

6%

Upper Gulf Box

(1,764 km2,

81 km3)

84%

Whole System

(2,100 km2,

84.5 km3)

100%

mol m-2 yr-1 mol m-2 yr-1 mol m-2 yr-1 mol m-2 yr-1

DIP -0.46 -0.21 +0.006 -0.05DIN -1.5 -1.4 -0.2 -0.4

(p-r) +49 +23 -0.6 +6

(nfix-denit) +2.0 -0.5 +0.3

Autotrophic

N fixation

Autotrophic

N fixation

Heterotrophic

Denitrification

Autotrophic

N fixation

+5.9

Table 3. Effects of changing waste load on (p-r) and (nfix-denit).

Change in waste load (p-r)

in mol m-2 yr-1

(nfix-denit)

in mol m-2 yr-1

0 load -0.5 -0.03

Current load +6 +0.3

0.5 x current load +2.5 +0.2

2 x current load +11 +0.9

IMPLICATIONS

The system is able to breakdown waste inputs and export most of these as N and P out of theGulf with some amount retained, perhaps in the sediments.

Since the average nutrient concentrations of N and P in the upper Gulf have not varied much over the years, this is an indication of the system’s current assimilative capacity. However, buildup of organic matter is critical

for the nearshore and Bolinao boxes and willeventually affect the Gulf’s ability to process these materials.