1.2 PRACTICAL LIMNOLOGY
Limnology is often described as inland or freshwater oceanography. The term `limnology' is
derived from the Greek word limnos, which refers to pools, lakes, and swamps. Limnology is a field
that fits the ecosystem perspective well because in order to understand or explain aquatic life and their
interactions, a thorough knowledge of their physical and chemical environments is necessary. And the
collective system of interactions between aquatic organisms and the chemical and physical processes of
their environment is the aquatic ecosystem.
In limnology, as in other fields, physical processes are comparatively well understood and
predictable compared with chemical and biological processes. Biological processes are the least
predictable and where chemical processes interact with biological processes, predictions of chemical
characteristics are also difficult. It follows, then, that while specific accurate predictions can be made
using complex models of lake physical processes, only the most general informed guesses can often be
made about the biota.
Environmental systems or ecological systems are more difficult to predict than social or
economic systems. We have so much less direct knowledge of these ecological systems that
consequences of our decisions about ecosystems are much less likely to be predicted accurately than
decisions about our personal lives. This is due to two reasons, a lack of knowledge of many of the
processes which influence ecosystems and a lack of empirical data about real systems. This workshop
is designed to aid field personnel with the collection of useful data about real systems.
1.2.2 WHAT IS A SYSTEM AND WHAT GOOD IS IT?
For this discussion, any reference to a system will imply an environmental or ecological
system. And these two terms will be used interchangeably. Furthermore, an ecological system will
be considered synonymous with ecosystem. And an ecosystem will be considered in the sense of its
original definition by Tansley in 1935 which is any system composed of interacting physical, chemical,
and biological components, regardless of size.
A moment of consideration of that definition will show it to be vague and, short of applying the
concept, it is trivial. However, Tansley had good reasons for formalizing the concept, although other
scientists had implied the concept long before. Today, the ecosystem concept or perspective has
achieved widespread acceptance as the only realistic approach to understanding ecological interactions.
Sadly, it is rarely applied to practical problems in resource management.