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Estuarine Ecology

  • Erscheinungsdatum: 19.09.2012
  • Verlag: Wiley-Blackwell
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Estuarine Ecology

Estuaries are among the most biologically productive ecosystems on the planet--critical to the life cycles of fish, other aquatic animals, and the creatures which feed on them. Estuarine Ecology, Second Edition , covers the physical and chemical aspects of estuaries, the biology and ecology of key organisms, the flow of organic matter through estuaries, and human interactions, such as the environmental impact of fisheries on estuaries and the effects of global climate change on these important ecosystems. Authored by a team of world experts from the estuarine science community, this long-awaited, full-color edition includes new chapters covering phytoplankton, seagrasses, coastal marshes, mangroves, benthic algae, Integrated Coastal Zone Management techniques, and the effects of global climate change. It also features an entriely new section on estuarine ecosystem processes, trophic webs, ecosystem metabolism, and the interactions between estuaries and other ecosystems such as wetlands and marshes John W. Day, Jr. is a Distinguished Professor in the Dept. of Oceanography and Coastal Sciences and the Coastal Ecology Institute at Louisiana State University, Baton Rouge. Byron C. Crump is an Assistant Professor at the University of Maryland Center for Environmental Science, Horn Point Laboratory, Cambridge, Maryland W. Michael Kemp is a Professor at Horn Point Laboratory, University of Maryland Center for Environmental Science, Baltimore Alejandro Yáñ;ez-Arancibia is a Research Scientist and Full Professor as well as Head of the Program of Coastal Resources at the Instituto de Ecología, A.C. (INECOL), Mexico


    Format: ePUB
    Kopierschutz: AdobeDRM
    Seitenzahl: 568
    Erscheinungsdatum: 19.09.2012
    Sprache: Englisch
    ISBN: 9781118391914
    Verlag: Wiley-Blackwell
    Größe: 47108 kBytes
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Estuarine Ecology

Chapter One

Introduction to Estuarine Ecology

John W. Day Jr., Alejandro Yáñ;ez-Arancibia, W. Michael Kemp,

and Byron C. Crump
1.1 Background, Theory, And Issues

We begin this description of estuaries and their functions by defining estuaries very broadly as that portion of the earth's coastal zone where there is interaction of ocean water, fresh water, land, and atmosphere. Large estuarine zones are most common in low relief coastal regions such as the broad coastal plains of Europe and the east coast of North America. They are much less common in uplifted coastlines such as the Pacific edge of North and South America. We begin our assessment as broadly as possible to include all portions of the earth that interact at the edge of the sea because these regions influence the smaller scale ecosystems sometimes more narrowly defined as estuaries proper.

From the vantage point of an orbiting satellite, several of the most basic attributes of estuaries are observable. Plumes of sediment-laden water float seaward on the ocean surface from the largest rivers, such as the Amazon, the Ganges, and the Mississippi. Color differences among various water masses, representing waters of different histories and different biotic richness, are often apparent. Coastal waters in areas with significant riverine input and broad shelf areas generally appear more greenish brown than the deep blue waters adjacent to many other coastlines. There are also atmospheric features of importance to estuaries obvious from space. Clouds commonly form directly over the edges of continents as one manifestation of the atmospheric "thermal engine" that maintains the freshwater cycle on which estuaries depend. At the altitude of a satellite, the dense human populations that proliferate in coastal zones are outlined at night by their lights.

The two most recent geological epochs, collectively named the Holocene, could be called the age of the estuary , for estuaries are abundant today, even though they are geologically tenuous. All present day estuaries are less than about 5000 years old, representing the time since sea level reached near its present level following the last ice age. Human populations flourished during this same period, in no small measure owing to exploitation of the rich estuarine resources of the coastal margin. Most "cradles of civilization" arose in deltaic and lower floodplain areas where natural biota was abundant and where flooding cycles produced the rich bottomland soils and readily available freshwater supplies on which agriculture flourished (Kennett and Kennett, 2006; Day et al., 2007). Early centers of civilization that developed in estuarine or deltaic environments include those of the Tabascan lowlands of Mexico; the valley of the Nile; Tigris-Euphrates, Yellow, and Indus Rivers; and along the Andean coast of western South America where upwelling systems bordered estuarine systems.

Let us now continue our aerial survey of estuaries, but this time at a much lower altitude, about 1000 m, in a light airplane following the course of a coastal plain river in the temperate zone from its headwaters to the ocean. The headwater river is narrow with rapids and falls, but changes near the coast to a larger meandering form with broad marshy areas where the actual edge of the river is not always clearly evident. The color of the water changes from clear blue to yellowish brown as the river picks up silt. As the river water nears the coast tidal currents become apparent and, moving seaward, the influence of tidal currents becomes greater.

Along the banks of the estuary, fresh and brackish water marsh plants grow at the edges of embayments. These marshes are often flanked by rows of houses and yards and spanned by narrow piers to provide access to deeper water. Among these marshes, a variety of wading birds may be observed stalkin

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