In broad terms, Ecology is the scientific study of how organisms interact with each other and with their environment (Hatfield 2008). Aquatic Ecology includes the study of these relationships in all aquatic environments, including oceans, estuaries, lakes, ponds, wetlands, rivers, and streams.
An ecosystem is a community of living organisms and their physical and chemical environment, linked by flows of energy and nutrients. Ecosystems function as a discrete ecological unit, and can be defined at a variety of scales. For example, the Kunene River basin can be considered an ecosystem, as can a small pond, a log, or the entire planet. The boundaries of an aquatic ecosystem are somewhat arbitrary, but generally enclose a region for which inflows and outflows can be estimated. Ecosystem ecologists study how nutrients, energy, and water flow through an ecosystem.
Boomslang (Dispholidus typus), Namibia.
Source: Khayat 2008
( click to enlarge )
The physical characteristics of aquatic habitats affect both the type and variety of organisms (Biodiversity) found. Organisms in a particular environment are directly affected by its characteristics, such as nutrient concentrations, temperature, water flow, and shelter. Only those best adapted to these conditions, and best able to use the available resources, will thrive. Interactions between organisms also matter, as predation and competition for resources (e.g. food or habitat) affect species abundance and diversity. In turn, the organisms in an environment can influence some aspects of that environment.
Understanding aquatic ecosystems and the interaction between organisms and their environment can help manage human effects better. Key topics that will be discussed in this section include:
Chapter Summary
This chapter covers the following concepts and material:
