Lake Tahoe Ecosystem

Introduction

Lake Tahoe is twenty-two miles long and twelve miles wide fresh water lake situated within the border between Nevada City and California in the United States. With sixty-three tributaries draining into it and only one outlet, Lake Tahoe enjoys the novelty of being the largest alpine lake in North America. Apart from being one of the largest freshwater lakes in Sierra Nevada, the lake is also popular for clarity and the beautiful scenery mountains that decorate its surrounding. In order to appreciate this beautiful combination of both living and nonliving creatures, called ecosystem, it is important to understand its components and the interactive processes through which Lake Tahoe has undergone. 

Structural and Functional Dynamics

The stable state of the Lake Tahoe’s ecosystem has been facilitated by the mutual interactions between its autotrophic and heterotrophic components,  terrestrially and in the fresh, aquatic environment. The autotrophic component of this ecosystem is composed of both terrestrial and aquatic plants. As for the heterotrophic component, it consists of inland animals, including human beings and wildlife, and the aquatic animals such as reptiles and fish.

Out of three general trophic status categories of lakes, the UCDAVIS’ report placed Lake Tahoe as oligotrophic lake. This reveals the lake’s condition of having clear water with few nutrients and fewer aquatic plants such as algae and rooted plants. The lake is found to be rich dissolved oxygen. The life-rich aquatic environment in this lake has resulted in diverse and healthy fish species, in addition to other several aquatic animals.    

The structure of the Lake Tahoe ecosystem gets its base from the autotrophic organisms, which is majorly represented by the algae as the main of oxygen for the aquatic life. According the recent research done on the photosynthetic picoplankton dynamics in this lake, Winder (2009) established that some other autotrophic picoplankton, including micro photosynthetic organisms, were also at the base of Lake Tahoe’s food web. Apart from being the fundamental source of energy to this aquatic food web, these microorganisms are also responsible for the purification of air and fixation of carbon within the lake (Winder, 2009). The freshness Lake Tahoe’s water can largely be attributed to these picoplanktons compared to algae because they are known to have higher nutrient absorption and growth rate as compared to algae.

The next levels in the structure of the Lake Tahoe ecosystem are solely composed of heterotrophic animals. The first level of these heterotrophs consists of smaller fish that primarily feed on the planktons and are, therefore, known as the primary consumers in this food web. Bigger species of fish form the next level of primary and secondary carnivores. The man completes this ecosystem structure as the tertiary consumer by feeding on the fish.

However, this structure has tremendously changed through the natural means and man’s intentional activities. The Ultraviolet radiations has resulted in the destruction and reduction of picoplankton in the lake, thereby creating steady increase of both nitrogen and phosphorus nutrients. The result is, therefore, progressive bulk growth of algae. Further change in the structure has been caused by the exotic species that were introduced into the lake, both intentionally and unintentionally.  Species such as Mysis shrimp, Asian clams, Eurasian water milfoils, smallmouth bass, bigmouth bass, carp and bluegill, either were introduced or invaded the lake.   

Human Effect on Biogeochemical Cycles

The general alteration of the lake’s ecosystem can greatly be attributed to the human’s destructive activities that have taken place within this ecosystem. As early as 1860s, surroundings of Lake Tahoe had already started experiencing extensive deforestation for the sake of other human activities such as supporting gold and silver mining in Virginia City. Such anthropogenic disturbances in the environment have resulted in uncountable side effects such as accelerated soil erosions.

As a result, the lake has lost its long cherished clarity due to the tiny soil particles that stay suspended in the lake’s water (Allen, 2012). Besides the heavy deforestation that has been witnessed around the lake, human’s use of fertilizers, driving along the lake banks and car exhausts have been major contributors to this water clarity loss. Consequently, the suspended particles interfere with aquatic photosynthesis by blocking sunlight from reaching the submerged plants. The cultural eutrophication resulting from man’s disturbances of Lake Tahoe’s watershed has led to the overwhelming increase in both phosphorus and nitrogen nutrients into the lake.

Significance of Understanding the Ecosystem’s Structure and Function in Developing Management and Restoration Plans

The management of the Lake Tahoe should be encouraged to understand the basics of ecosystem’s structure and functions for the purpose of effective and informed restoration of the lake. Understanding of the ecosystem’s structure and function would help in knowing the components of the well-balanced ecosystem. Therefore, the management will adequately understand the impact of every level on the ecosystem’s food web. Ultimately, this knowledge is likely to facilitate the development of a management plan that is focused on eliminating process that might alter the ecosystems structure.   

Implication of Species Interactions in Ecosystem Management and Restoration

In the same spirit of understanding the structure of an ecosystem, the knowledge of species interaction is of great importance in managing and restoring a sustainable ecosystem. Species within a given ecosystem should be mutually interacting in order to avoid depletion of species in any level of the food web. Depletion or increase of the organism in a given level of the food web gradually lead to the total eradication of the organism both in the immediate lower and immediate upper levels of the food web. The results would be a complete depletion of the whole ecosystem.    

Conclusion

The historical review of Lake Tahoe ecosystem paints a picture of glorious and attractive state that any ecosystem would be expected to have. Consequently, it is fundamental that the committee responsible for managing this ecosystem should use the researches that have been done about it and implement the recommendations from. This would help in planning and restoring this lake to its former glory.