lakes and rivers

[...]... public awareness of the importance and fragility of freshwater ecosystems plays a vital role in their sustainable management As I hope this book makes clear, what happens in the air, on land, and in the sea, affects lakes and rivers What happens in lakes and rivers affects us all XIII CHAPTER 1 FRESHWATER, LAKES, AND RIVERS Rivers run through channels in the landscape Lakes fill hollows They do so in... systems were created, how lakes come to lie in landscapes and how rivers move through them, and how both shape the land surface Chapter 3 offers portraits of eight of the world’s rivers and three of its lakes These are chosen to reflect the diversity of XI XII LAKES AND RIVERS major freshwater ecosystems Each example reveals how the interplay of physical geography, climate, and human activity influences... that lakes and rivers provide are costed, acre for acre they are considerably more valuable than the land that borders them Exploiting lakes and rivers, as chapter 8 shows, has its environmental costs People alter the rate at which water is cycled through lakes and rivers They add harmful substances to freshwater, they harvest some of its creatures at an unsustainable rate, and they move animals and. .. but the very coldest, hottest, and driest places on land Together, lakes and rivers contain less than 1 percent of all the freshwater on Earth’s surface However, this tiny fraction is disproportionately important Lakes and rivers are vital stores of freshwater that people utilize in many different ways Rivers shape the land Seen from the air, the winding course of rivers and streams is one of the most... abundance This is partly because the water in rivers and freshwater lakes drains away and evaporates and is replaced by water flowing in This makes the amount of water passing through lakes and rivers substantial Likewise, water is cycled through lakes and rivers much more rapidly, in proportion to their volume, than it is through the larger water stores such as oceans and glaciers Scientists express the average... several miles a day in search of water holes and drying riverbeds For people, lakes and rivers form transport corridors, supply freshwater for drinking and for irrigating crops, and provide fish for food The control of access to such resources shapes human history As streams and rivers carve into hills and mountains, they transport the eroded material downstream and deposit it as sediment (deposited particulate... than 3.5 percent of the land surface, they have an impact on other biomes that is out of all proportion to their size Chapter 1 clarifies some key differences between lakes and rivers and explains the nature of the water that is contained within them Rivers are unique in connecting all the landbased biomes with the oceans Chapter 2 describes the physical geography of lakes and rivers It considers how... Earth’s surface and the residence times in each Compartment Percentage of total Typical residence time Oceans Ice caps and glaciers Groundwater (in rock) 97.4 1.9 >0.6 Thousands of years Thousands of years Days to thousands of years Weeks Years Years to thousands of years 1–2 weeks 2 weeks 1 week Soil moisture Freshwater lakes Saline (salty) lakes 0.01 0.008 0.006 Atmosphere Rivers Plants and animals 0.001... FRESHWATER, LAKES, AND RIVERS is the time it takes for all the water in that compartment to be replaced Streams and rivers have residence times of the order of days to weeks, freshwater lakes of the order of years, but oceans and glaciers take thousands of years before all their water is recycled The size of a system, and the pace at which water is recycled through it, affects the dilution of pollutants and. .. except Antarctica By comparison, most lakes are very young Lake Baikal in Siberia, probably the world’s oldest lake, is contained in a basin with parts more than 25 million years old Most lakes are only a few hundred or thousand years old, and on geological timescales, smaller ones are like puddles in the landscape that will soon shrink and disappear 1 2 LAKES AND RIVERS A stream cascading through a . life, and the hydrologic cycle 25 CHAPTER 2 PHYSICAL GEOGRAPHY OF LAKES AND RIVERS 26 The creation of lakes 26 The properties of lakes 28 Saline lakes 29 Lakes through time 31 The creation of rivers. geography of lakes and rivers. It considers how these freshwater systems were creat- ed, how lakes come to lie in landscapes and how rivers move through them, and how both shape the land surface. Chapter. 142 Coevolution 144 Wetlands 146 CHAPTER 6 RIVERS AND LAKES IN HISTORY 151 Rivers, lakes, and human health 152 The arrival of two water-related diseases in the Americas 154 Dam-building and disease 156 The