Eutrophication Continues To Increase in Blue Lakes Due to Climate Change

According to a recent study that gives a global inventory of lake hue, blue lakes throughout the world are at risk of becoming green-brown if global warming continues.

Changes in the hue of lake water can signal a decline in ecological health. While algae and sediments can influence lake color, the new study discovered that air temperature, precipitation, lake depth, and elevation all play vital roles in defining a lake's most prevalent water hue.

Climate change is making lakes turn green-brown

(Photo : Ales Krivec/Unsplash)

Blue lakes are deeper and located in chilly, high-latitude locations with substantial precipitation and winter ice cover, accounting for fewer than one-third of the world's lakes, as per ScienceDaily.

Green-brown lakes, which account for 69% of all lakes, are more common and may be found in drier regions, continental interiors, and along coasts, according to the research.

The new study was published in Geophysical Research Letters, a journal of the American Geophysical Union that publishes high-impact, short-format findings having direct significance in the Earth and space disciplines.

From 2013 to 2020, the researchers examined 5.14 million satellite pictures of 85,360 lakes and reservoirs throughout the world to find the most frequent water hue.

No one has previously investigated the hue of lakes on a worldwide scale, according to Xiao Yang, the study's author, and a remote sensing hydrologist at Southern Methodist University.

There have been previous studies of perhaps 200 lakes throughout the world, but the scale we're aiming for here is much, much higher in terms of both the number of lakes and the coverage of tiny lakes.

Even while we are not investigating every lake on the planet, we are attempting to cover a substantial and representative sample of the lakes that exist.

Because the color of a lake might fluctuate seasonally owing to variations in algal development, the scientists described lake color by analyzing the most frequent lake color across a seven-year period.

In addition, the new study looked at how varying degrees of heat would influence water color as climate change continues. According to the study, climate change may reduce the percentage of blue lakes, which are common in the Rocky Mountains, northeastern Canada, northern Europe, and New Zealand.

Warmer water, which causes more algal blooms, causes lakes to become green, according to Catherine O'Reilly, an aquatic biologist at Illinois State University the and lead author of the new study. There are several cases of individuals observing this phenomenon while studying a single lake.

General effects of eutrophication

Algae differ from microscopic animal life in our bodies of water in their mode of respiration: they release more oxygen than they use during the day and absorb more carbon dioxide than they release, whereas animals and other non-photosynthetic organisms release carbon dioxide and absorb oxygen from their surroundings, as per Lenntech.

During the night, algae normally react in a reverse way, acting as dead organic matter, boosting BOD load. It is critical to carefully analyze any activity that removes algae from a body of water: the oxygen produced by algae during photosynthesis is useful to most types of life in streams, thus removal would often be detrimental rather than beneficial.

Because of the large population of species in a eutrophic environment, competition for resources and predator pressure are common.

The battle for life in eutrophic environments is exacerbated by the high level of competition and, at times, considerable chemical or physical stress.

As a result, the variety of species in eutrophic environments is smaller than in oligotrophic ones.