1. OVERVIEW AND BUDGETS RESULTS The key objectives of the Land-Ocean Interactions in the Coastal Zone (LOICZ) core project of the International Biosphere-Geosphere Programme (IGBP) are to: · gain a better understanding of the global cycles of the key elemental nutrients carbon (C), nitrogen (N) and phosphorus (P); · understand how the coastal zone affects material fluxes through biogeochemical processes; and · characterise the relationship of these fluxes to environmental change, including human intervention (Pernetta and Milliman 1995). To achieve these objectives, the LOICZ programme of activities has two major thrusts. The first is the development of horizontal and, to a lesser extent, vertical material flux models and their dynamics from continental basins through regional seas to continental oceanic margins, based on our understanding of biogeochemical processes and data for coastal ecosystems and habitats, and the human dimension. The second is the scaling of the material flux models to evaluate coastal changes at spatial scales to global levels and, eventually, across temporal scales. It is recognised that there is a large amount of existing and recorded data and work in progress around the world on coastal habitats at a variety of scales. LOICZ is developing the scientific networks to integrate the expertise and information at these levels in order to deliver science knowledge that addresses our regional and global goals. The United Nations Environment Programme (UNEP) and Global Environment Facility (GEF) have similar interests through the sub-programme: “Sustainable Management and Use of Natural Resources”. LOICZ and UNEP, with GEF funding support, have established a project: “The Role of the Coastal Ocean in the Disturbed and Undisturbed Nutrient and Carbon Cycles” to address these mutual interests; this Workshop is the first of a series of regional activities within the project. The Estuarine Systems of the South China Sea Region: Carbon, Nitrogen, Phosphorus Flux workshop builds on earlier work by LOICZ to assess material flux in the estuaries and coastal seas of global regions (Smith et al. 1997, Smith and Crossland 1999, Smith et al. 1999). The South China Sea is a region of important interaction between extensive watershed areas and the marginal sea, where a large number of riverine systems discharge a globally highly significant volume of materials into coastal waters (Appendix I). The intensity and effects of human activities on these discharges – rates, quality and nature of materials – are obviously undergoing great change; some 5% of the world population live in this maritime region. The South China Sea region is characterised by high population density and rapid continuing population growth and development in the coastal zone. The influence of these changes on natural processes and their impacts on regional socio-economic opportunity and the ramifications of these changes on global “budgets” for material transformation, are leading issues for science, policy and management. The Workshop seeks to provide a basis for initial assessment of coastal ecosystem performance in terms of carbon and nutrient fluxes, fates and, subsequently, to place the results into a global context. The diverse land-use pressures and the array of coastal habitats and system regimes in the South China Sea region provide opportunity to derive a suite of models and budgets representative of tropical systems. Data sets of varying coherence are available for sites throughout the region. The results of this Workshop provide a first step in developing an understanding of the available information, and the LOICZ-UNEP project provides a platform on which regional scientists can continue focussed development and assessment of the relevant scientific information. 1 30°N 20°N 10°N 0°N 10°S 90°E 100°E 110°E 120°E 130°E 140°E 150°E Figure 1.1 Map of budgets sites developed during the South China Sea Region Workshop, July 1999. The Workshop was held in Manila, the Philippines on 19-22 July 1999. The objectives of the Workshop (Appendix VII) and the activities (Appendices IV and VI) are provided in this report. Three resource persons (Prof. Stephen Smith, Ms Vilma Dupra, Dr Chris Crossland) and three regional resource persons (Dr Laura David, Dr Maria Lourdes San Diego-McGlone, Dr Gullaya Wattayakorn) worked with participants from coastal science agencies and universities, representing six countries (China, Indonesia, Malaysia, Philippines, Thailand, Vietnam), to consider, develop and assess biogeochemical budgets for 25 coastal ecosystems in the region. In addition to the resultant budget descriptions, the Workshop provided a vital training forum that is resulting in further system budgets developments. To assist in this extension work, a regional mentor centre has been established at the Marine Science Institute, University of the Philippines (resource persons: Dr Laura David, Dr Maria Lourdes San Diego-McGlone), and is funded by the UNEP/GEF supported project. Mr Nguyen Huan, a workshop participant, took up the South China Sea Workshop Scholarship, which involves additional training in budget analyses at the University of Hawaii for the month of October 1999, before returning to Vietnam and contributing to the resource person activities. Beyond the success of the budgets production and training was the development of additional methodologies (Appendix II and III) that allow detailed assessment of waste load contributions to nutrient budgets and estimation of catchment delivery, in localities where direct data are sparse. Consideration was made of an initial typology (or classification) of regional watersheds (Appendix I); this is being pursued as part of the project and within the broader LOICZ initiatives as a vital approach to regionalise and globalise the budget site information to data-poor locations. The initial session of the Workshop dealt with the LOICZ approach to the global questions of horizontal fluxes of materials, and the previous work and current contributions being made by regional scientists. The Pelorus Sound, New Zealand, estuarine system was presented by Ms Vilma Dupra as a case study, including the stratified and segmented approach to the material flux budgets within the system. The typology approach and a preliminary “snapshot” of watersheds in the region was presented by Dr Liana Talaue-McManus. The LOICZ Budgets Modelling website was described by Prof. Stephen Smith, and the pivotal role of the electronic site and its use by global scientists in 2 making budget contributions to the LOICZ purpose was emphasised. It was noted that contributing scientists are clearly attributed as authors of their contributed budgets, and that there is provision to updated and provide additional assessment of their budgets. The group moved from plenary to further develop the site budgets individually and in small working groups, returning to plenary sessions to discuss the budget developments and to debate points of approach and interpretation. Nineteen budgets were developed during the Workshop, with six additional site completed after the workshop and in time to be included in this report (Figure 1.1). The common element in the budget descriptions is the use of the LOICZ approach to budget development, which allows for global comparisons. The differences in the descriptive presentations reflect the variability in richness of site data, the complexity of the site and its processes, and the extent of detailed process understanding for the site. Support information for the various estuarine locations, describing the physical environmental conditions and related forcing functions including the history and potential anthropogenic pressure, is an important part of the budget information for each site. These budgets, data and their wider availability in electronic form (CD-ROM, LOICZ website) will provide opportunity for further assessment and comparisons, and potential use in consideration of wider scales of patterns in system response and human pressures. The budget information for each site is discussed individually and reported in units that are convenient for that system (either as daily or annual rates). To provide for an overview and ease of comparison, the key data are presented in an “annualised” form and non-conservative fluxes are reported per unit area (Tables 1.1 and 1.2). Key outcomes and findings from the workshop include: i) An initial suite of 25 site budgets reflecting the tapestry of watershed and climate regimes in the tropical South China Sea region. These, and subsequent site budgets, provide a vital opportunity for assessment of trends in patterns of estuarine performance and response to major forcing functions, both natural and anthropogenic. The number of sites and the further development of the site data, provide a basis for in-region evaluation of material flux characteristics and comparison with other tropical regions – from earlier workshops in Australasia and Central America, and planned workshops in Latin America, South Asia and Africa. Trend assessment continues as a vital plank in the LOICZ- UNEP project. ii) Eight site budgets are partially resolved at this stage, reflecting short water residence time parameters and/or limited temporal or spatial data such that initial estimates are based on a part- segment of the site (e.g., upper estuary only) or a part season (e.g., dry season). Three major considerations are exemplified in these systems: a) Ambient data (system concentrations) may be inadequate and