An ecosphere is a sealed, self-sustaining miniature ecosystem typically housed within a clear glass sphere. These enclosed environments contain filtered seawater, tiny shrimp, algae, microorganisms, and gravel, designed to mimic Earth’s intricate ecosystem on a small scale. Ecospheres demonstrate how life can be sustained in a materially closed system, with light and temperature as the only external inputs. Sunlight is absolutely necessary for the survival of the shrimp within this self-contained world.
Photosynthesis: The Engine of Life
Photosynthesis, carried out by algae within the sealed sphere, is the fundamental process powering an ecosphere. Algae, as primary producers, capture light energy using chlorophyll, converting it into chemical energy (sugars) for their food source. During this conversion, algae take in carbon dioxide from the water and release oxygen as a byproduct. This photosynthetic activity is the sole source of new energy input into the ecosphere, providing both food and oxygen for other organisms to respire.
The Ecosphere’s Food and Oxygen Cycle
Within the ecosphere, a delicate and interdependent cycle exists between the algae and the shrimp. The shrimp, such as Halocaridina rubra, consume algae or bacterial and algal scum as their primary food source. The oxygen produced by the algae through photosynthesis is utilized by the shrimp for their respiration. As the shrimp respire, they release carbon dioxide, which is then absorbed by the algae for their photosynthetic needs. Additionally, the shrimp’s waste products are broken down by beneficial bacteria in the gravel and water, releasing nutrients that the algae absorb to fuel their growth, creating a continuous loop of nutrient cycling.
The Impact of Light Deprivation
Without an adequate supply of light, the intricate balance within an ecosphere collapses, leading to the demise of the shrimp. The most significant consequence is the cessation of photosynthesis by the algae; they cannot produce necessary sugars, causing their population to decline and cutting off the shrimp’s primary food source. Simultaneously, oxygen production, a crucial byproduct of photosynthesis, halts. While algae stop producing oxygen, shrimp and other microorganisms continue to consume the existing supply, quickly depleting this finite oxygen reserve and leading to an anoxic (oxygen-depleted) environment. The combined effect of starvation and suffocation inevitably leads to the death of the shrimp, underscoring their absolute reliance on light as the ultimate energy source for the entire miniature ecosystem.