tailieunhanh - STREAM ECOLOGY & SELF PURIFICATION: An Introduction - Chapter 3

Trái ngược với giả định không chính xác năm, năng lượng Không chu kỳ thông qua hệ sinh thái năm làm hóa chất. Các chất dinh dưỡng vô cơ thông qua chu kỳ hơn các sinh vật, tuy nhiên, họ cũng nhập vào các đại dương, khí quyển, và sự kiện nhạc rock. Cả hai luận án Bởi vì các hóa chất chu kỳ, thông qua các thế giới sinh học và địa chất, chúng ta gọi là chu trình sinh địa hoá quần overalls chu kỳ. S. | CHAPTER 3 Biogeochemical Cycles Water is Earth s proud setter up and puller down of kings. 28 NUTRIENT CYCLES STREAMS and rivers are complex ecosystems that take part in the physical and chemical cycles biogeochemical cycles that shape our planet and allow life to A biogeochemical cycle is composed of bioelements chemical elements that cycle through living organisms and it occurs when there is interaction between the biological and physical exchanges of bioelements. Note Contrary to an incorrect assumption energy does not cycle through an ecosystem chemicals do. The inorganic nutrients cycle through more than the organisms however they also enter the oceans atmosphere and even rocks. Because these chemicals cycle through both the biological and the geological worlds we call the overall cycles biogeochemical cycles. Each chemical has a unique cycle but all cycles have some things in common. Reservoirs are those parts of the cycle where the chemical is held in large quantities for long periods of times . the oceans for water and rocks for phosphorous . In exchange pools on the other hand the chemical is held for only a short time . the atmosphere a cloud . The length of time a chemical is held in an exchange pool or a reservoir is termed its residence time. The biotic community includes all living organisms. This community may serve as an exchange pool although for some chemicals like carbon that can be bound in certain tree species for a thousand years it may seem more like a reservoir and it 28Shakespeare s description of Richard the Kingmaker during the Wars of the Roses. 29Cave c. Stream Ecology http cristi p. 1 1998. 25 Copyright 2001 by Technomic Publishing Company Inc. 26 BIOGEOCHEMICAL CYCLES also may serve to move chemicals bioelements from one stage of the cycle to another. For instance the trees of the tropical rain forest bring water up from the forest floor to be transpired into the atmosphere. Likewise coral organisms