Ecology is the study of relationships between organisms and their surroundings. This study is fundamental to an understanding of biology because organisms cannot live as isolated units. The activities which comprise their lives are dependent upon, and closely controlled by, their external circumstances, by the physical and chemical conditions in which they live and the populations of other organisms with which they interact. In addition, the activities of organisms have effects on their surroundings, altering them in various ways. Organisms therefore exist only as parts of a complex entity made up of interacting inorganic and biotic elements, to which we apply the term ecosystem.
All life on earth constitutes a single ecosystem divisible into innumerable parts. This book is concerned with the greatest of these divisions, the marine ecosystem, occupying a larger volume of the biosphere than any other. The marine ecosystem can be further subdivided into many component ecosystems in different parts of the sea.
Living processes involve energy exchanges. Energy for life is drawn primarily from solar radiation, transformed into the chemical energy of organic compounds by the photosynthetic processes of plants; thence transferred through the ecosystem by movements of materials within and between organisms, mainly through the agencies of feeding, growth, reproduction and decomposition. An ecosystem is therefore essentially a working, changing and evolving sequence of operations, powered by solar energy. In the long term, the intake of energy to the system is balanced by energy loss as heat. Most scientists believe that life began within the solar-powered environment of the ocean ecosystem. With the discovery in the 1970s of complex animal communities powered by geothermal energy at deep-sea vents (see Section 6.4.4), some scientists now argue that these vents may have allowed the first primitive organisms, such as bacteria, to evolve.
The aim of marine ecological studies is to understand marine ecosystems as working processes. At present our knowledge is incomplete and only speculative analyses can be made. This book provides general information about how marine organisms are influenced by, and have effects on, their environment, and describes some of the methods of investigation which may eventually provide the necessary information for a better understanding of marine ecosystems. A good starting-
point is to describe briefly some of the major physical features of the oceans. There are several excellent introductory oceanography texts to which the student should refer for more detailed information. These are given in the references at the end of Chapter 1.
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Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.