Aquatic Ecosystem Topics

Introduction to Aquatic Ecosystems

As with all ecosystems, aquatic ecosystems are complex, natural self-sustaining systems made u of physical and living elements. The interconnected web they create fluidly spans time and space, with each component connected in some way to every other component. The connections within an ecosystem are so profound that any occurrence within that ecosystem will affect every member in some way, at some time. The aquatic ecosystems of the Columbia Basin have been altered by changes to their physical structure, additions to and deletions from their biological components, and introduction of toxic compounds.

Water is the most prominent physical component of an aquatic ecosystem, interacting with the biota, geography and climate of an area to produce a specific kind of environment. 99.99% of the Earth’s water is in the oceans, the remaining 0.01% may take the form of lakes and ponds or rivers and streams. Geography and climate affect the behaviour of the water, whether it will stand still or flow, freeze or evaporate, stagnate or circulate. The water’s interaction with its environment determines its physical and chemical properties which in turn affects the productivity, biodiversity and complexity of the aquatic community formed therein. Because they are all connected, the life forms which will flourish depend on the combined characteristics of the aquatic ecosystem.

Columbia Basin

In the Columbia Basin there are lakes and rivers of various sizes. Streams collect fresh water from extensive watersheds where the forests harbour the annual rain and snowfall and funnel it downward through pristine valleys into large rivers and lakes in the valley bottoms. Glacial melt from the high alpine flows into small alpine lakes or joins the downhill flow. The water collected in the lakes and rivers holds the nutrients which will support the first tier of the aquatic food chain: phytoplankton. Phytoplankton creates food using the sun’s energy and the water’s nutrients. Tiny microscopic animals will eat the phytoplankton, and then small fish and other animals eat the zooplankton. Larger fish will eat the small fish, and mammals of all sorts, including humans, will feed on the fish. Decomposition will occur at all stages of the chain and serve to replenish the lake’s nutrient.

The following map shows the major river and lake networks in the Columbia River Basin.

Macleans magazine recognized the damming of the Columbia River, a result of the Columbia River Treaty negotiated between Canada and the USA in 1964, as one of the 25 major nation-shaping events of the twentieth century, ranking it as equally significant to giving women the vote, incorporating Newfoundland and Nunavut into Canada, creating medicare and the CBC, and the Free Trade Agreement. In the Columbia Basin, alterations to the physical structure by hydroelectric dams, and the resulting challenges to biodiversity have affected kokanee and trout populations, with consequent effects on the social, cultural and economic viability of the region. The following sections outline the biological, structural and managerial elements of the aquatic systems in the region.