C N P Fluxes in the Coastal Zone

The LOICZ Approach to Budgeting and Global Extrapolation

S. V. Smith

U. Hawaii

March 2000

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.

LOICZ and IGBP

• IGBP is the “International Geosphere-Biosphere Programme.”– http://www.igbp.kva.se/

– Part of ICSU, the International Council of Scientific Unions

• LOICZ is “Land-Ocean Interactions in the Coastal Zone.”– http://kellia.nioz.nl/loicz

– A key project element of IGBP

IGBP:International Geosphere-

Biosphere ProgrammeIGBP 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

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://data.ecology.su.se/MNODE/

– Under direction of S. V. Smith, F. Wulff

– Major emphasis of this presentation.

• Use “typology” (classification) techniques to extrapolate from budgeted sites to global coastal zone.

– Under direction of R. W. Buddemeier

– Tools and examples available athttp://www.palantir.swarthmore.edu/~maxwell/loicz/(B. Maxwell)

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 workshops to date

• September 1995—Guidelines Development – (Halifax, Canada)

• December 1995—Introduce guidelines to SWOL– (Penang, Malaysia)

• October 1996—LOICZ/JGOFS Continental Margins– (Lagos, Nigeria)

• June 1997—Mexico lagoons – (Ensenada, Mexico)

• October 1997—LOICZ/JGOFS Continental Margins– (Texel, The Netherlands)

LOICZ budget workshops, cont.

• October 1998—Australasia estuaries– (Canberra, Australia)

• January 1999—Mexico, C. America lagoons II– (Merida, Mexico)

• July 1999—South China Sea estuaries– (Manila, Philippines)

• November 1999—South America estuaries– (Bahia Blanca, Argentina)

• February 2000—South Asia estuaries– (Goa, India)

The Global Environment Facility (GEF) of the United Nations Environment Programme

(UNEP) has funded LOICZ to conduct a series of local budget, regional typology and

global synthesis workshops.

LOICZ-UNEP/GEF Tentative Workshop Schedule

• July 1999 Budget--South China Sea;November 1999 Budget--South America;February 2000 Budget--South Asia;June 2000 Budget--East Asia;September 2000 Budget—Africa.

• November 2000 Regional—Asia;March 2001 Regional—Americas;May 2001 Regional—Africa/Europe.

• November 2001 Global Synthesis.

• ++++ One more, as needed.

Table of Contents (abbreviated)

LOICZ home page

LOICZ Biogeochemical Modelling Node home page

Methodological Guidelines Introduction and background

Overview of the budgeting procedure

Scaling and how to set boundaries of a system

Water and salt budgets (with various subsections and links toexamples)

- Estimating precipitation and evaporation (with various subsections)

-An estimator of runoff

- Estimating flows from groundwater (with various subsections)

LOICZ Biogeochemical Modelling Web Page

Table of Contents (continued)

Nutrient budgets

- Estimating nutrient inputs from agriculture and other humanactivities

-Inputs from point sources (sewage and other waste loads)

-Effluent discharge coefficients

- Estimating nutrient inputs from the atmosphere

Stoichiometric Calculations

Downloadable budget templates (excel spreadsheets)and guidelines for reports

References

Contributors

Budgets of Coastal Ecosystems Africa

Australia and New Zealand

Central and South America

Europe

Japan, the Philippines and Southeast Asia

Mexico

North America and the Pacific

Back to [Node Introduction] [LOICZ]

Last Updated 15 Jan 2000 by DPS

Table of Contents (concluded)

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

Preliminary Budgeting Results

LOICZ Budget Sites to Date

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######

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

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#

#####

##

#

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######

# ##

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

### ## ######

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

# #

#

#####

##

#

>100 sites so far; > 200 sites desired.

Latitude, Longitude of Budget Sites

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

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

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######

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########

###

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.

Introduction to Typology

Typology:

The study of types, as in systematic classification.

DEFINITION

e. g., N. American Budget Sites and River Flow

There are many considerations in developing a “coastal zone typology.”

•It is important to relate sites to characteristics of freshwater inflow.

•Most of coastline characterized by small coastal watersheds.

Natural and Anthropogenic Controls on Fluxes to the Ocean

# ### ##

### #

# ### ### ###

##

##

#

##

###

##

#

#

#

Modified U Md landuse

forestwoodlandshrublandgrasslandcroplandbare groundurbanNo Data

Other Factors

•Population density;

•Economic drivers;

•Fertilizer use;

•Atmospheric deposition;

•Et cetera.

What is carried in river inflow, and why?

Land use, vegetation type,

and budget sites

Statistical Clustering of “Types” in the Global Coastal Zone

Example of newly developed statistical clustering techniques

Australasia—10 Clusters

Distinguish separate clusters Emphasize similar clustersOR

Expert typology Similar clusters

Budget Sites

We tune the with

and compare with

How do budget characteristics conform with clusters?

What is the link between typology and the budgets?

Conclusions and Commentsabout Budgeting and Typology

• We are accumulating coverage of global CNP fluxes in much of the coastal zone.

• Some trends are beginning to emerge.• Extrapolating from individual budget sites to

the “global coastal zone” remains a challenge.• This extrapolation is being approached via a

“global typology.”• Natural influences and human dimension must

be addressed by both budgets and typology.

Need help or advice about biogeochemical budgeting or setting up a budgeting workshop?

• 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/

Thank you!