Changes To Global Freshwater Networks

Although most of our water-drinking necessities rest on the water beneath our feet, lakes, streams, and freshwater systems maintain ecosystems and the necessary biodiversity within them. They are used to not only relay the current strain of climate hazards but also contain keystone species on which scientists and entire ecosystems rely. Therefore, leaving many to worry about these networks’ current state as time progresses and greenhouse gasses continue to grow in quantity.

Changing Weather Phenomena’s

As global weather patterns are continuously altered by an increase in air temperature, lakes, rivers, and streams experience the implications. Precipitation and evaporation rates have begun impacting freshwater areas in various ways. Shallow, stagnant water being more susceptible to a change, are escalating to warmer temperatures thus completely altering the chemical composition of said body. The Environmental Institute at Indiana University exclaimed, “Increasing temperatures, causing earlier snowmelt, combined with higher precipitation amounts and more severe weather and flooding will impact the reproduction abilities of aquatic species. Changes in the timing of high and low stream flow creates stress on aquatic plants and animals, decreasing survival rates.” Evaporation naturally increases through the addition of heat to bodies of water. This suggests that the water is closer to changing forms into a gaseous state. So, these frequent and rapid changes in aquatic levels induce a stressful environment for biotic inhabitants.

One of the most heavily researched lakes, The Caspian Sea, provides a focal point for environmental scientists. It is said to display the clear effects of weather and atmospheric alterations instigated by the climate crisis. The American Association for the Advancement of Science (AAAS) stated in a recent article that “‘The Caspian Sea can be viewed as representative of many other lakes in the world. Many people are not even aware that an inland lake is dramatically shrinking due to climate change, as our models indicate,’ says Matthias Prange. The report of the Intergovernmental Panel on Climate Change (IPCC) also failed to mention lakes, and disregarded the social, political and economic consequences of global warming on the affected regions.”

Local Environmental Changes Can Instigate Vast Modifications to Surrounding Bodies of Water

Deforestation and agriculture are often environmental issues that are discussed individually without mention of the effects they might have on alternate aquatic environments. Nonetheless, these ecosystems are in constant relation to one another and interferences with one affects the integrity of the next. Deforestation, to start, is the removal of trees which frequently includes their roots. These roots are responsible for holding soil in the ground ensuring decreased erosion. However, when removed from the equation, erosion is increased and soil commonly ends up in local freshwater systems. In addition to the already warmed body of water, this creates an ideal environment for blooming activity. Soil includes nutrients which then fuels algae growth inherently allowing for a flourishing effect.

Agricultural runoff virtually has the same result. Rather than the plain soil eroding from farms and ranches, most commercialized crops require fertilizer which incorporates into the dirt. Thus, increasing the nutrient levels present in the sediments. This often finds its way into neighboring streams and lakes influencing similar but even heightened events. With the absence of surrounding trees, these bodies have no protection from erosion. Indiana University continues to explain that “Warmer water temperatures in deep lakes slows down processes that add oxygen to the water, creating dead zones, or areas with less oxygen that are unable to support life. These dead zones can produce large-scale fish mortality and toxic algal blooms.” Dead-zones are becoming more and more apparent as Climate Change progresses.

Changes in Speciation

Species’ presence is also altered as a result of changing freshwater environments. Specialist species that reside in specific environments shaped to their needs, require an ecosystem that will suffice to their minuscule range of tolerance. However, as mentioned, chemical compositions of lakes and streams are more frequently undergoing a complete refashioning of chemical and physical traits: temperature, oxygenation, water level, TSS (total suspended sediment), and other various alterations. Not to mention, after soil erosion infiltrates into these aquatic environments, the sediment within the water often creates a scene in which gilled fish cannot survive. Sediments will adhere to the tight space and slowly kill the organism limiting necessary oxygenation. Alternatively, Generalist species-often known as invasive- easily adapt and thrive in various environments due to their natural adaptability. Not only will they out-compete the native Specialist species present, but will thrive in the new condition modifying the entire ecosystem.

Invasive Cyanobacteria

“Warmer air and water temperatures,” the Environmental Resilience Institute at Indiana State exclaims, “may also expand the ranges of current invasive species, or allow new ones to establish. Invasive species can pose challenges to the success of ecosystem protection efforts ranging from large ecosystem management, such as the Great Lakes, to the restoration of coastal estuaries.” Every day there is an increase in species added to the list of endangered species. Some may seem as insignificant as an aquatic plant, but all have a place in an ecosystem that may suffer in its absence.


“Lakes, Rivers, and Streams.” Environmental Resilience Institute Part of the Prepared for Environmental Change Grand Challenge, 

marum_de. “Climate Crisis Is Causing Lakes to Shrink.” EurekAlert!, 

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