EVERYDAY SCIENCE

Detailed explanation-1: -Typically, oligotrophic lakes are deep, with the hypolimnion much more extensive than the epilimnion. The low nutrient content means that plankton blooms are rare and littoral plants are scarce. The low organic content means that dissolved oxygen levels are high.

Detailed explanation-2: -In oligotrophic lakes, oxygen is found at high levels throughout the water column. Cold water can hold more dissolved oxygen than warm water, and the deep region of oligotrophic lakes stays very cold. In addition, low algal concentration allows deeper light penetration and less decomposition.

Detailed explanation-3: -"Oligotrophic lakes are generally clear, deep and free of weeds or large algae blooms. Though beautiful, they are low in nutrients and do not support large fish populations, However, oligotrophic lakes often develop a good food chain capable of sustaining a very desirable fishery of large game fish.

Detailed explanation-4: -Oligotrophic lakes are those that are unproductive: net primary production is only between 50 and 100 milligrams of carbon per square metre per day, nutrients are in poor supply, and secondary production is depressed.

Detailed explanation-5: -A eutrophic lake where dissolved-oxygen concentrations are low. Algal blooms can occur under such conditions. Rapidly moving water, such as in a mountain stream or large river, tends to contain a lot of dissolved oxygen, whereas stagnant water contains less.