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C N P Fluxes in the Coastal Zone The LOICZ Approach to Budgeting and Global Extrapolation S. V. Smith U. Hawaii March 2000.

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Presentation on theme: "C N P Fluxes in the Coastal Zone The LOICZ Approach to Budgeting and Global Extrapolation S. V. Smith U. Hawaii March 2000."— Presentation transcript:


2 C N P Fluxes in the Coastal Zone The LOICZ Approach to Budgeting and Global Extrapolation S. V. Smith U. Hawaii March 2000

3 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.

4 General Background

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

6 Coastal Zone (+200 to –200 m) This domain is nominally m to -200 meters, or about 18% of global area.

7 Coastal Ocean (0 to –200 m) The coastal ocean, being budgeted by LOICZ, is about 5% of global area.

8 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.

9 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

10 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.

11 Alphabet Soup of the IGBP JGOFSJoint Global Ocean Flux Studies IGACInternational Global Atmospheric Chemistry GCTEGlobal Change and Terrestrial Ecosystems BAHCBiospheric Aspects of the Hydrological Cycle PAGESPast Global Change LOICZLand-Ocean Interactions in the Coastal Zone LUCCLand Use and Cover Change GLOBEC Global Ocean Ecosystem Dynamics __________________________________________________ GAIMGlobal Analysis, Integration and Modelling STARTSystem for Analysis, Research, and Training DIS Data and Information System

12 LOICZ Budgeting Background

13 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.

14 LOICZ Budgeting Procedure Conservation of mass is one of the most fundamental concepts of ecology and geochemistry.

15 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).

16 Water and Salt Budgets Salt budget –Net flows known. –Mixing (V X ) conserves salt content. Water budget –Freshwater flows known. –System residual flow (V R ) conserves volume.

17 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) =  DIN obs - 16 x  DIP Nutrient (Y) budgets –Internal dissolved nutrient net source or sink (  Y) to conserve Y.

18 LOICZ Strategy Develop a global inventory of these budgets. –Guidelines, a tutorial, and individual site budgets at –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 at (B. Maxwell)

19 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.

20 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)

21 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)

22 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.

23 LOICZ-UNEP/GEF Tentative Workshop Schedule July 1999Budget--South China Sea; November 1999Budget--South America; February 2000Budget--South Asia; June 2000Budget--East Asia; September 2000Budget—Africa. November 2000Regional—Asia; March 2001Regional—Americas; May 2001Regional—Africa/Europe. November 2001Global Synthesis. ++++One more, as needed.

24 LOICZ Biogeochemical Modelling Web Page



27 Preliminary Budgeting Results

28 LOICZ Budget Sites to Date >100 sites so far; > 200 sites desired.

29 Latitude, Longitude of Budget Sites Present site distribution Poor cover at high latitudes (N & S). Poor cover from 10  N to 15  S. Poor cover in Africa. S. Asia sites not yet posted.

30 Nutrient Load v Latitude Load variation most obvious with DIP. High loads near 15  N are in SE Asia. High loads near 30  S are in Australia

31 Internal Nutrient Flux v Latitude  DIP response to load may differ in the N and S hemispheres.  DIN response to load seems weaker than  DIP.

32  DIP,  DIN v DIP Load  DIP and  DIN both increase (+ or -) at high DIP loads. Responses more prominent for DIP than for DIN.

33  DIP,  DIN v DIN Load No clear effect of DIN load on  DIP.  DIN appears to become negative at high DIN load.

34 Net Ecosystem Metabolism (production – respiration) Remember: Rates are apparent, based on stoichiometric assumptions. No clear overall trend; most values cluster near 0. Extreme values (beyond  10) are questionable.

35 (Nitrogen Fixation – Denitrification) Although values cluster near 0, clear dominance of apparent denitrification. Apparent N fixation >5 seems too high.

36 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.

37 Introduction to Typology Typology: The study of types, as in systematic classification. DEFINITION

38 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.

39 Natural and Anthropogenic Controls on Fluxes to the Ocean 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

40 Statistical Clustering of “Types” in the Global Coastal Zone

41 Example of newly developed statistical clustering techniques Australasia—10 Clusters Distinguish separate clustersEmphasize similar clusters OR

42 Expert typologySimilar clusters Budget Sites We tune thewith and compare with How do budget characteristics conform with clusters? What is the link between typology and the budgets?

43 Conclusions and Comments about 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.

44 Need help or advice about biogeochemical budgeting or setting up a budgeting workshop? Stephen Smith Fred Wulff Vilma Dupra Dennis Swaney Victor Camacho Malou McGlone Laura David LOICZ International Project Office Biogeochemical Modeling Web Page

45 Thank you!


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