The World’s Largest Lake is at Stake

Why is the world’s largest body of freshwater (by volume), Lake Baikal, currently in danger and why does it matter so much? It is known for its unmatched biodiversity and happens to hold 20% of the world’s freshwater. This impressive combination certainly makes it worthy of global attention. To better understand what’s at stake, let’s take a look at the past, present, and future of Lake Baikal.

A Lake Like No Other

Located in snowy southeast-Siberia in the Russian Federation near the border of Mongolia, Lake Baikal tops all other lakes in volume, number of species, and antiquity. This one-of-a-kind lake ecosystem is home to well over 2,000 species that have continuously evolved to environmental conditions since the lake’s formation 25 million years ago.

Cold Water, Hotspot for Biodiversity

Despite frigid and nutrient-limited waters, Lake Baikal hosts a rich biodiversity. Seventy-five percent of species are considered endemic, meaning they are only found within a particular geographic area and are therefore more vulnerable to extinction. Oxygen and nutrients are brought up from the depths of the lake by hydrothermal vents when the lake is mixed by seasonal winds.

The primary producers, such as diatoms and other photosynthesizing organisms, make up the base this complex food web depend on these processes. Because Lake Baikal is usually nutrient poor, or oligotrophic, for a large portion of the year, high nutrient loads can be detrimental to certain primary producers, as we will see in a moment.  

The Lake Baikal

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A nerpa pup, just one of Lake Baikal’s many endemic species

Ecosystems often experience dramatic changes in organisms we don’t always see or predict. These organisms are often lowest on the food web and often microscopic, such as algae. Diatoms, a group of algae, serve as an important food source that support Lake Baikal’s unique food web. The endemic Baikal seal, locally known as the nerpa, rely on these algae in an indirect way. If the dominant primary producers decline due to competition from other algae, a phenomenon called a trophic cascade occurs from the bottom of the food web to the top.

A trophic cascade is like a domino effect from the “bottom up” or “top down” that disrupts food web structure by altering competition and predation, and ultimately food source availability and survival. Many factors influence algae abundance in Lake Baikal, especially warming waters and nutrient enrichment. For instance, they are affected by the length of “ice on” season, because during this critical time frame when the ice is transparent, diatoms attach themselves to the bottom of the ice and photosynthesize.

Algal growth is also limited by nutrient concentrations dissolved in the water.  Local nutrient loading from sewage and fertilizers in rivers as well as surface runoff from melting permafrost create an excess of nutrients that triggers rapid algal growth called a bloom. Oftentimes, algal blooms are harmful to people and lake organisms, especially Lake Baikal’s endemic sponges.

“Sacred Sea” In Danger

Known as the “Sacred Sea,” Lake Baikal is treasured by locals, but algae and adorable seals are not all they are concerned about. Climate change is a gradually increasing concern, predicted to affect the wind patterns, nutrient loading, water temperature, and the “ice on” season. Since 1946, Lake Baikal’s surface waters have warmed by 2.1 degrees Fahrenheit and ice thickness has decreased by an average of one foot. Rising temperatures also contribute to algal growth, resulting in a 300% increase in algal blooms since 1979.

Water quality is far from pristine and for the past fifty years, Lake Baikal has also been under pressure from toxic pollutants released from the Baikalsk Paper and Pulp Mill (BPPM). The mill discharged pollutants that slowly accumulated in organisms and lake sediments, while also putting people at risk of cancer. Because the unregulated pollution violated Lake Baikal’s UNESCO status and Russian law and lots of protesting, the mill eventually closed in 2008. Despite public opposition, it was re-opened in 2010, but failed to generate sufficient profits. Thankfully, BPPM has been closed for good since 2013.

Not Another Dam Problem…

In the 1950s, Russia built a hydroelectric dam on the only outflow of Lake Baikal, causing a rise of more than 1 m in water level and displacement of 15,000 people. Despite potential risks, Mongolia has recently devised a plan to construct three hydroelectric dams within the watershed surrounding Lake Baikal. Watersheds are regions where all water in an area drains and Lake Baikal drains all of the rivers where the dams would be located. Currently, 92.7% of Mongolia’s power is derived from coal-fired thermal power plants, and building the dams would significantly reduce emissions. However, this would come with ecological costs.

What are the costs? The States Parties of the Russian Federation as well as Mongolia cannot approve the construction plans until an environmental impact assessment (EIA) has been conducted and approved by the World Heritage Centre and IUCN, or International Union for Conservation of Nature. Biodiversity assays are required to discern migration routes and key habitats of concern, especially with regards to migratory fish and birds important to the lake ecosystem.

A Lake That Transcends Boundaries

The dam construction as it relates to Lake Baikal is an example a cross-national and global issue concerning ecological integrity and surpassing geographical boundaries. As Lewis Pugh, an endurance swimmer and passionate defender of Lake Baikal who swam the frigid waters to bring awareness to the plight of Lake Baikal said, “Environmental threats know no geographical boundaries.”

Lake Baikal’s history is proof that humans can be the cause and the solution to the degradation of our water resources, but that doesn’t mean that we can completely reverse the damage we have done. Further environmental impact assessments, ecological research, government policies, and local stewardship are necessary to perpetuate active awareness and dialogue about Lake Baikal’s future.

image04Suzie Henderson is an undergraduate student in the Odum School of Ecology at the University of Georgia. She is an amateur naturalist, experimental gardener, sporadic artist, and has a passion for our green planet and the crazy people who are a part of it. If this article sparked your interest or a question, connect with her on Facebook or suzieuga@uga.edu. More from Suzie Henderson.