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Eutrophication

Hotel Lake is one of 110 million lakes on our planet and Canada has more lakes than any other country on the planet. Only about 55% of these lakes are considered fresh water lakes.

 

In 1986 the International Lake Environment Committee ILEC Foundation was established to seek international knowledge exchange and research promotion to develop sustainable management of the world lakes and reservoirs.

 

Lakes, which contain about ninety percent of freshwater on the earth, are a vital global water resource, providing rich and essential components for wildlife and humans as well as providing a variety of secondary benefits for human recreation. In spite of their global importance, many lakes and other inland waters around the world are in or are approaching critical condition and will be severely affected by global warming because of their lentic (static) nature as water systems. In coping with these situations, ILEC has been promoting the sustainable management of lakes and their basins in collaboration with our worldwide counterparts from the academic, administrative and private sectors engaged in the conservation of lakes and other inland waters.

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The Life Cycle of Lakes

 from a National Geographic article

 

Once formed, lakes do not stay the same. Like people, they go through different life stages—youth, maturity, old age, and death. All lakes, even the largest, slowly disappear as their basins fill with sediment and plant material. The natural aging of a lake happens very slowly, over the course of hundreds and even thousands of years. But with human influence, it can take only decades. 

 

A lake’s plants and algae slowly die. The warm, shallow water of the upper layer of the lake causes plants and algae to decompose, and eventually they sink to the basin. Dust and mineral deposits on the bottom of the lake combine with the plants to form sediment. Rain washes soil and pebbles into the basin. The remains of fish and other animals pile up on the lake’s bottom. The lake becomes smaller, starting at the edges and working toward the middle. Eventually, the lake becomes a marsh, bog, or swamp. At this point, the drying-up process slows down dramatically; limnologists, people who study lakes and ponds, aren’t sure why. Eventually, the lake becomes dry land.

 

Dry lake beds are a perfect place to find and study fossils. Archaeologists often excavate ancient lake beds, such as Fossil Butte in the U.S. state of Wyoming. The remains of organisms, from single-celled bacteria to dinosaurs, were preserved over time as sediment on the lake bed built up around and on top of them. In fact, some scientists believe the first living organisms on Earth developed in lakes.

 

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Each lake is unique.  Each lake, along with its catchment basin and wildlife interact to create a unique balance. Over long periods of time, if left undisturbed, most lakes will undergo natural changes that we refer to as eutrophication.

 

Eutrophication is a natural process whereby a lake’s concentration of plant and animal induced nutrient builds up slowly over centuries.  Cultural or artificial eutrophication occurs more rapidly when human activity introduces artificial amounts of nutrients (mainly phosphates), which speeds up plant growth that may eventually choke the lake of all animal life.  Human introduction of toxins can also have detrimental effects and cause damage to the ecosystem and result in a so-called “dead lakes”.

 

The threats to all lakes on the planet vary depending on the local environment. Simply put, excessive nutrients and pollution of various types will threaten the health and water quality of a lake. 

Eutrophication, a closer look:

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Eutrophication, the gradual increase in the concentration of phosphorusnitrogen, and other plant nutrients in an aging aquatic ecosystem such as a lake. The productivity or fertility of such an ecosystem naturally increases as the amount of organic material that can be broken down into nutrients increases. This material enters the ecosystem primarily by runoff from land that carries debris and products of the reproduction and death of terrestrial organisms. Water blooms, or great concentrations of algae and microscopic organisms, often develop on the surface, preventing the light penetration and oxygen absorption necessary for underwater life. Eutrophic waters are often murky and may support fewer large animals, such as fish and birds, than non-eutrophic waters.

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Cultural or artificial eutrophication occurs when human activity and water pollution speeds up the aging process by introducing sewage, detergentsfertilizers, and other nutrient sources into the ecosystem. Cultural eutrophication can produce dramatic consequences on freshwater resources, fisheries, and recreational bodies in a relatively short period of time.

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Morning scum on Hotel Lake? A closer look reveals what appear to be natural droppings from the overhanging forest.  With help from our readers perhaps we will find out what these are.  The wind will blow these clusters against the shoreline and they will eventually sink below the surface and begin to decompose; natural eutrophication? 

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Morning scum on Hotel Lake? A closer look reveals what appear to be soap or detergent bubbles.  If these are indeed caused by human introduction of soap, this constitutes an unnatural introduction of phosphates into the lake which contributes to cultural or artificial eutrophication. 

You might already see how pervasive the cultural or artificial eutrophication problem might be. There is a growing number of case studies and examples of lakes that have suffered and how difficult it is to reverse the damage.

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There is growing awareness that we need to come together as friends and neighbours and work together in this direction and

 

To be able to slow down cultural or artificial eutrophication will take a lot of common understanding of the issues that drive it.  Better practices in the riparian areas, greater attention and sensitivity about keeping garbage and discarded items from being thrown away into the natural environment, are some of the first steps in the right directions to protect Hotel Lake.

 

 

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