Team Dynasty

Sunlight controlling Photosynthesis

I. Introduction:

• The purpose of this page is to explain how sunlight controls and effects photosynthesis in the Rappahannock River. Photosynthesis can be measured through oxygen levels, because photosynthesis produces oxygen as a byproduct. Since the amount of oxygen present is determined by how much is produced during photosynthesis, we can calculate the amount of photosynthesis taking place by measuring the amount of oxygen present. Photosynthesis is a process that only occurs if there is sunlight. Sunlight powers or causes photosynthesis to occur thus sunlight controls photosynthesis.

• PowerPoint explaining Video

II. Photosynthesis:

• Photosynthesis is the process used by most plants to make glucose from water, sunlight, and carbon dioxide. Plants take in carbon dioxide, water, and nutrients and through a chemical processes, fueled by light energy, convert them into glucose. During this process oxygen is produced as a byproduct. We can measure the amount of photosynthesis taking place in bodies of water, such as the Rappahannock River, by measuring the amount of oxygen present. To learn more about photosynthesis click here,or watch the video below.

Basic Photosynthesis Equation

In-Depth Explanation of Photosynthesis

III. Photosynthesis Data

In the graph above you have a set of data from the week of October with levels of both oxygen saturation and sunlight, which is measured by the par sensor. Oxygen saturation is the amount of oxygen that has dissolved into the water. While the par sensor shows the amount of sunlight that shone that day. If you look at the graph above you will see that on the sixth day there was little sunlight, this was because it was raining on that particular day. Also if you look above you will see that the oxygen levels went down on the sixth day. This is due to the lack of sunlight causing a slowdown in photosynthesis. The trends of sunlight and oxygen concentration correlate. When sunlight goes up oxygen also goes up. Then at night both the sunlight levels and the oxygen levels drop. This shows how the sunlight controls the photosynthesis because the trends of oxygen and sunlight correlate, and photosynthesis is dependant on sunlight.

IV.Time Lapse Video For Photosynthesis Data

This video shows the days explained in the section above. As you can see, the earlier days are sunny without rain. In the graph the par sensor levels for these days are fairly high. The sixth day is rainy; therefore, on the graph the par sensor levels are low. They return to normal on the seventh day when the sun returns.