The process of altering the amount of photosynthesis a plant carries out can be altered using an external light source or stimulus. In this essay, the effect of the intensity of external light on the rate of photosynthesis is carried out and investigated through a series of experiments. Firstly, the Pygmy Chain Sword plant was placed in normal sunshine, with a light intensity of 2. 62 lux, and the rate of photosynthesis was monitored (measured by the amount of dissolved oxygen in the water) for one day to see how much dissolved oxygen was produced in normal conditions of light intensities.
Then, the plant was exposed to 24 hours of constant light at a normal intensity of 2. 62 lux to see the concentrations of dissolved oxygen in the water throughout the 24 hour time period while monitoring the light intensity with a lux meter to see if the amount of the dissolved oxygen had been increased or decreased due to the light exposure. The experiment was then repeated three times at each light intensity, and the results were averaged to gain a better range of data.
The experiment was then repeated using different light intensities to see the affect of light intensity on the amount of dissolved oxygen produced by the aquatic plant. The results of the experiment showed that despite some inaccuracies or fluctuations in the dissolved oxygen concentrations or the light intensity readings, the amount of dissolved oxygen produced by the Pygmy Chain Sword decreased with decreasing light intensity. This is because the process of photosynthesis needs light to convert carbon dioxide into organic compounds such as sugar and starch and oxygen is reduced as a waste product.
With less light, less organic compounds are formed, and less oxygen is produced and released as a waste gas. Introduction: As my research question is about the effect of decreasing light intensity on the photosynthesis rate of Echinodorus tenellus within a twenty four hour time period, it is important to look into what the process of photosynthesis is and the factors which control it, and the relevance of this process into all different aspects of our lives. Photosynthesis occurs in all plants in the world, whether they are on dry land or aquatic, whether they are broad-leafed or narrow-leafed.
This process involves converting carbon dioxide into organic compounds such as starch and sugar using the energy gained from the sun while at the same time releasing oxygen as a waste product. Occurring in algae, plants and some bacteria, this process is essential for life on Earth as it maintains the oxygen levels in our atmosphere by taking in carbon dioxide and releasing oxygen as a waste product, but essentially it plays a major role in all food chains as organisms either rely on it for energy, or feed off other organisms which photosynthesize.
“It is the basis for most terrestrial food chains, is the ultimate source of the fuel energy in oil and coal, and is responsible for the origin and maintenance of oxygen in the atmosphere. ” (Charles F. Delwiche) Without photosynthesis, life as we know it would be impossible, as a major link of the food chain would be missing. At the bottom of every food chain, regardless of what environment it may be in, be it the African Sahara or in the Arctic Circle, plants are the primary producers.
Plants, being photoautotrophs, which can use light energy to convert inorganic substances into food substances such as starch or glucose and at the same time, release oxygen as a waste gas, are the foundations of every food supply. Apart from photosynthesizing plants, all other organisms have to either feed off other organisms or feed on plants themselves to gain energy, as they themselves are unable to convert the solar energy from the sun into energy stores that they can use.
For example, in a food chain containing grass, rabbits and foxes, the grass would photosynthesize using light energy to produce starch and release oxygen at the same time. Rabbits, only able to gain energy through feeding, would then feed on the grass, while the fox in turn would feed on the rabbit. If we suddenly take out photosynthesizing plants from the bottom of the food chain, life would be impossible, and all the other organisms would die off from starvation or suffocation, as organisms would have nothing to feed on and no way of gaining energy to sustain the energy requirements which their bodies have.
Photosynthesis is “the synthesis by organisms of organic chemical compounds, esp. carbohydrates, from carbon dioxide using energy obtained from light rather than the oxidation of chemical compounds” (Smith. A. L. ) , in which plants take in carbon dioxide from the air and build them up into sugars, also help to maintain the levels of carbon dioxide throughout the world and simultaneously help to replenish the amount of oxygen we have in our atmosphere. All living things respire, where they take in oxygen and exhale carbon dioxide.
Plants respire as well, however the production of oxygen through photosynthesis cancels out the amount of carbon dioxide they produce and gives a total net output of oxygen instead of carbon dioxide. With the increasing human population where humans live longer lives than before due to medical care, increasing the amount of livestock such as cows and pigs being raised to feed the human population, all of which respire by inhaling oxygen and exhaling carbon dioxide, photosynthesis is crucial in balancing the levels of carbon dioxide and oxygen in our atmosphere.
By taking in carbon dioxide and giving off oxygen as a waste gas, plants which photosynthesize help to replenish the oxygen levels providing organisms around the world with the oxygen that they need to live. Many factors affect the rate of photosynthesis in plants, such as light, pH, and temperature, with the factor of light being divided into light intensity, length of exposure, and the wavelength of the light that the plant is exposed to.
These factors influence the rate of photosynthesis and in turn the amount of carbon dioxide which is taken in from the atmosphere and the amount of oxygen that is released as a waste gas. Therefore it is vital that we understand this complex process as without the process of photosynthesis to convert carbon dioxide into oxygen, oxygen levels in our atmosphere would plummet while carbon dioxide levels would skyrocket as oxygen is inhaled and used in respiration by all organisms, followed by the organisms slowly dying off from suffocation due to lack of oxygen in the air around them, which is essential for life.