Liana Talaue-McManus

Humans, Hydrology, and the Distribution of Inorganic Nutrient Loading to the Ocean

Abstract Most modern estimates of dissolved nitrogen and phosphorus delivery to the ocean use Meybecks estimates from approximately 30 large rivers. We have derived an extended database of approximately 165 sites with nutrient loads. For both dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), the logarithmic yields (log [load/area]) can be parameterized as functions of log (population density) and log (runoff/area) (R2 for DIN and DIP approximately 0.6). Landscape production of DIN and DIP is largely assimilated. Even though DIN and DIP follow substantially different biogeochemical cycles, loading for DIN and DIP is tightly coupled (R2 for log DIN versus log DIP approximately 0.8), with a constant loading ratio of about 18:1. Estimates of DIN and DIP fluxes are distributed globally around the world coastlines by using basin population density and runoff at 0.5° increments of latitude and longitude. We estimate that total loads for the 1990s are about three times Meybecks estimates for the 1970s.

Biogeochemistry of Continental Margins in a Global Context

Continental margins while being recognized as an important component in the Earth’s biogeochemical system are relatively poorly understood. In the past attention given to continental margins focused on continental shelves, which constitute a major part of continental margins. In recent years, it has been increasingly appreciated that influences of the land–ocean boundary often extend beyond the shelf edge. Such new ideas have led to recognition of the significance of continental margins in the earth system. The studies have enabled a more quantitative depiction of biogeochemical cycles in continental margins, which is presented in this book.

Biophysical and socio-economic assessments of the coastal zone: the LOICZ approach

Abstract The Land–Ocean Interactions in the Coastal Zone Project of the International Geosphere–Biosphere Programme focused on quantifying the role of the global coastal zone in the cycling of carbon and nutrients. From 1993 to date, it has developed protocols and tools that allow for site-specific and global assessments of coastal processes and their drivers. Indicators used in coastal assessments include the contribution of population and economic activities to waste load generation, and the resulting coastal system states relative to net production and nitrogen cycling.

Abrupt Changes: The Achilles' Heels of the Earth System

Abstract Records from the past show that abrupt global change is the norm, not the exception, in the Earth System. Many recent changes-such as the globalization of the worlds economy and the formation of the ozone hole over Antarctica-appear rapid even from the perspective of a single lifetime. What do we now know about the nature of abrupt changes in the Earth System and the probability that human actions could trigger them?

Carbon–Nitrogen–Phosphorus Fluxes in the Coastal Zone: The LOICZ Approach to Global Assessment

One of the major questions within the Land–Ocean Interaction in the Coastal Zone (LOICZ) Core Project is to evaluate the role of the coastal ocean in global carbon–nitrogen–phosphorus cycles. Carbon is generally considered to be the “major currency” within the International Geosphere-Biosphere Programme (IGBP), and the nitrogen and phosphorus cycles are intimately linked to carbon. Various authors (e.g., Smith and Mackenzie 1987; Smith and Hollibaugh1993; Sarmiento and Sundquist 1992) have argued that the ocean is net heterotrophic, and Smith and Hollibaugh (1993) have made the case that most of this net heterotrophy probably occurs in the coastal ocean. Evidence suggests that human activity can shift (indeed, is shifting) the trophic status of the coastal ocean toward increasing net heterotrophy (e.g., Rabouille et al. 2001). At the same time, other authors (Kemp et al. 1997) have argued that some parts of the coastal zone are presently clearly net autotrophic, arguing that this could represent a shift historically as a result of growing coastal eutrophication. Obviously, addressing this question becomes a major piece in the puzzle of evaluating the role of oceanic biological reactions in the global carbon cycle.

Opportunities and Challenges of Establishing Coastal Observing Systems

Some of the challenges to establishing and sustaining environmental monitoring are potentially overcome under the framework of global observing systems. Observing systems go beyond monitoring by enabling links between user needs and observations and by providing valued information products to user groups at appropriate spatial and temporal scales. The United Nations established three global observing systems; for climate, oceans, and land and freshwater. Initiatives have also begun to address important issues within coastal ecosystems. Recent socio-political awareness and technical advances have imporoved the opportunities for establishing these observing systems and ensuring their sustainability. Awareness and current technology alone are not enough, and ongoing implementation of these systems is still stymied by a variety of factors. We make several recommendations to promote their success now and in the future.

Enhancing the Global Ocean Observing System to meet evidence based needs for the ecosystem‐based management of coastal ecosystem services

Ecosystem-based approaches (EBAs) to managing anthropogenic pressures on ecosystems, adapting to changes in ecosystem states (indicators of ecosystem health), and mitigating the impacts of state changes on ecosystem services are needed for sustainable development. EBAs are informed by integrated ecosystem assessments (IEAs) that must be compiled and updated frequently for EBAs to be effective. Frequently updated IEAs depend on the sustained provision of data and information on pressures, state changes, and impacts of state changes on services. Nowhere is this truer than in the coastal zone, where people and ecosystem services are concentrated and where anthropogenic pressures converge. This study identifies the essential indicator variables required for the sustained provision of frequently updated IEAs, and offers an approach to establishing a global network of coastal observations within the framework of the Global Ocean Observing System. The need for and challenges of capacity-building are highlighted, and examples are given of current programmes that could contribute to the implementation of a coastal ocean observing system of systems on a global scale. This illustrates the need for new approaches to ocean governance that can achieve coordinated integration of existing programmes and technologies as a first step towards this goal.

Examining Human Impacts on Global Biogeochemical Cycling Via the Coastal Zone and Ocean Margins

Biogeochemical cycling, like most earth system functions, is increasingly subject to human perturbation. Nowhere is this more evident than in the coastal zone, the interphase domain between land, ocean, and atmosphere. The coast and its ecosystems, including wetlands, estuaries, marshes, mangroves, seagrasses, and coral reefs, are continuously modified by human activities through changing land and water uses, and increasing waste loading from economic activities. This chapter aims to provide a most recent synoptic and by no means comprehensive overview of human impacts on the biogeochemical transformations that coastal ecosystems, healthy or otherwise, perform for ecosystem integrity and human well-being. How humans have transformed the planet’s behavior through their activities along the catchment–coast continuum is discussed in Sect. 9.2. Large-scale ecosystem impacts resulting from these activities are the focus of Sect. 9.3. Finally, Sect. 9.4 examines approaches and innovations that may enable human institutions to enhance human well-being as well as ecosystem health across the water continuum.