Eutrophication of lakes

The eutrophication of lakes on golf courses occurs when their waters become enriched in nutrients. In this situation there is an exacerbated growth of plants and other organisms, which, when they die, rot and fill the water with bad odours, diminishing its quality and giving it a nauseating appearance.

The process of putrefaction consumes much of the dissolved oxygen and the waters become unsuitable for most living things. The end result is a nearly destroyed ecosystem.

On the other hand, if the lake is nutrient-poor (oligotrophic), the water is clear, light penetrates well, algal growth is small and it supports few living things. As the lake becomes nutrient-loaded, it becomes eutrophic. Algae grow in large numbers, making the water cloudy. When algae and other organisms die, they are decomposed by bacterial activity, consuming oxygen and killing fish. Anaerobic putrefaction occurs with foul odours. The water is turbid with a sediment-filled bottom and decreasing depth.

The nutrients that most influence this process are phosphates and nitrogen.

Nitrogen is more mobile than phosphorus and can be washed through the soil or pass into the air by evaporation of ammonia or denitrification. Phosphorus is more strongly adsorbed by soil particles and moved by erosion or leached by surface water. Under natural conditions, about 1 kg of phosphate per hectare per year normally reaches all water bodies, but under conditions of intensive cultivation such as those on golf courses these quantities multiply enormously.

To determine the level of eutrophication of lake water, the chlorophyll content of a water column is measured and combined with measurements of nitrogen, phosphorus and light penetration capacity.