ater makes life possible
No other natural element is so universally required by living things. Our bodies are comprised largely of water, and all life on Earth depends on it, either for drinking, nurturing eggs and young, or providing living space. Even ocean creatures rely on fresh water; all water is inexorably linked. This essential connection between fresh water and seawater underpins the great array of life in the sea.
Freshwater ecosystems are diverse and valuable in their own right. The number of species supported by freshwater systems far exceeds that which would be expected given the small amount of space they occupy on the planet. For instance, inland wetlands occupy less than 1% of the Earth’s surface, yet support 40% of known fish species. In fact, it has been estimated that a quarter or more of all vertebrate species live in or near inland waters. Endemism—that is, existence of species that exist nowhere else in the world—is generally high in rivers, streams, and lakes, since physical barriers set the stage for speciation.
Rivers and streams deliver fresh water and other nutrients to estuaries, and to all coastal seas. But the link between rivers and oceans also has a cost—whatever degradation is occurring in freshwater ecosystems inevitably impacts marine life as well. As pressures on aquatic systems mount around the world in response to growing needs for drinking water, irrigation, and energy needs, less and less water is able to reach the world’s coasts—changing the very nature of marine ecosystems, making estuaries more saline, and diminishing the extent of ecologically important brackish waters. And as poor land use practices lead to pollution and erosion, runoff and other non-point discharges create a toxic brew of coastal seas downstream. Disappearing coastal wetlands only exacerbate the problem, as the ecosystem service of water filtration that these critical habitats provide is being lost.
Thus fresh water has become an issue more and more evident in the press and international awareness. As the impact of degradation becomes apparent—as supplies dwindle, the water table subsides, and rivers run empty into the sea — the public has become more and more directly concerned and affected, leading to many initiatives and policy developments focused on freshwater issues. Indeed, some international conflicts have been reinterpreted as battles for freshwater supplies adequate to protect national interests from upstream degradation and consumption.
What is astonishing, however, is the disconnect between freshwater and ocean issues in the global discussion. For example, the World Water Forum, the major international body for research, the definition of policy, and implementation of freshwater management structures, draws the line of their concern at the salt line. At its international conference in Mexico City in 2006, attended by 10,000 researchers and decision-makers in this field, with hundreds of papers on every aspect of freshwater policy, the ocean was scarcely even mentioned. In reality, the focus of this important body excludes the basic scientific fact of the hydrological cycle, the system of freshwater/saltwater land/sea circulation that is taught to every student in introductory science. To base policy on such flawed science can only lead to flawed policy. And to compound it internationally further denies the incontrovertible impact of bad policy on the coast and beyond—dams, for example, altering the ecosystems of bays and estuaries, or persistent toxic pollutants, circulating worldwide by ocean currents and damaging species and habitats far away.
Some change is in the air. Some hope lies in the multi-stakeholder and international efforts to better manage watersheds, as is occurring in many of the world's great river systems, and to better understand the downstream coastal and deep ocean consequences of freshwater actions. So, too, does hope lie in the greater awakening of the public to the crucial role that healthy freshwater systems play in supporting the world ocean, and vice versa.
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