Natural resource system challenge IV: oceans and aquatic ecosystems

Abstract

Water is vital for all life on earth. It is also vital for humanity's food security and health. At present at least one billion people lack access to an adequate supply of safe water, and 1.7 billion people do not adequate sanitation. Freshwater is vital, not only for drinking but also for food security; agriculture is responsible for 93 percent of total water consumed by all economic sectors. Many countries have increasing problems in providing clean water to sustain human activities. The oceans are used extensively to provide fish for human consumption, and there are already indications that this extraction of seafood is unsustainable, yet human populations are growing by 90 million per year and the demand for seafood is growing. The food security requirements of an increasing human population will exacerbate current problems with water availability and quality. Human health and economic development are threatened, or restricted, by water quality issues that limit human welfare and water uses. These include salinization of rivers and lakes, microbiological and organic pollution, and pollution by wastes from human activities (for example, heavy metals, toxic organic compounds, nutrients, and eroded soils). Human activities also exacerbate water-related diseases, especially in the tropical world where economic development is still greatly limited by illnesses such as river blindness (onchocerciasis), malaria, bacterial diarrhea, and bitharziasis (schistosomiasis). These problems may become worse in the future. The aim of this essay is to guide the reader through the various pathways followed by surface water on earth. It will describe the dominant processes that govern how organisms interact with water and with each other, and how they in turn can modify water properties. This knowledge is important for humanity. Indeed, only by understanding our actions' impacts upon water, and the animals and plants living in it, can we learn to exploit water, marine and freshwater habitats and the living organisms, without destroying the resources on which our livelihood and very survival depend.