Photosynthesis Lab

Measuring the Rate Oxygen Production using an Oxygen Electrode Chamber in Photosynthesis of Spinacia oleracea with Varying Light Intensities

Have you ever really wondered how different variables can affect how plants go through photosynthesis? Well, in this experiment, the purpose was to see how various environmental conditions can affect the overall photosynthetic capacity of a specific plant. The factors, light, darkness, cold, and heat were applied to see how the different components would affect the photosynthesis on spinach plants. Each group was given a different factor to test. Out group was given the light factor. The hypothesis for this experiment is that when adding light as a factor, the light will affect the overall plant photosynthesis.

To performed the experiment, a volumeter was set up to measure the net oxygen production under white light, then a second step was followed to measure oxygen consumption under dark conditions (oxygen production only happens in the presence of light and oxygen consumption in the presence of dark light) and finally, a third step consisted of recording the measure of the net oxygen production under the presence of green light.

-Measuring the pH of a solution (such as in the lab we had) could also help determine the rate of photosynthesis. You would need a much more specific pH meter, but generally, if pH goes down, the level of CO2 is higher, meaning more cellular respiration. Higher pH means there’s less CO2, so more photosynthesis.

Figure 1: Amount of O2 gas curves to the time at which it was measured according to low, medium, and high pH.

The problem that needed to be solved for this experiment was, “How are organisms able to survive and function with proficiency despite metabolic activities that have the disastrous ability to alter pH from a neutral to an acidic or basic environment?” This question needed to be answered by testing different biological materials, as well as tap water, in order to find out what allows modern day organisms to survive such hazardous conditions. A hypothesis that was formulated before experimenting was, “If type of substance is Tap Water, then the changes in pH will be more drastic because water, considered neutral on the pH scale, doesn’t contain a component that will prevent such a change, unlike the content of a buffer solution.” The independent variable for this experiment was type of substance, evidently because this was the part of the experiment that was constantly being changed from trial to trial. The dependent variable for this experiment was pH of the substance because the pH constantly changed depending on the type of substance was being experimented with. The control of this experiment was the tap water and buffer solutions, as the results of the data from the biological materials were constantly compared to the data from both of these solutions.

Water column phosphorus concentrations have also been shown to increase under anoxic conditions (Webb, K.L. and D'Elia, C.F. 1980). This is because some of the iron oxyhydroxides that

During the summers the oxygen content atop the water normally has a salinity level consistent with “more than 8 milligrams per liter”; but when oxygen content drops down to “less than 2 milligrams per liter” the water is then known to be in hypoxic state (CENR, 2000; USGS, 2006). Hypoxia is the result of oxygen levels decreasing to the point where aquatic organisms can no longer survive in the water column. Organisms such as fish, shrimps, and crabs are capable to evacuate the area but the fauna that cannot move either become stress and/or die. Due to this, many call the hypoxia zone the “dead zone” (Overview, 2008; USGS, 2006).

Projected changes of pH over the next 100 years due to Ocean acidification effects phytoplankton-doubling time.

The hypothesis that an increase in algae concentration when exposed to light would increase the rate of photosynthesis in diluted indicator solution was supported by the results of this investigation. As Table 1. Indicates the pH levels and absorbance (AU) increased in respects to an increase in algae concentration when the algae was exposed to light. However when an equal amount of algae concentration was not exposed to light the absorbance and pH levels of the algae was lower, therefore indicating that light and algae concentration increased the rate of photosynthesis in algae. Figure 1. also demonstrates that the mean absorbance of algae increased with an increase of pH levels and therefore increased the rate of photosynthesis occurring in the algae.

The intention of this experiment is to determine the effects of pH on the rate of photosynthesis in living leaves. Photosynthesis is a process by which plants convert light energy captured from the sun into chemical energy which they use to perform various plant functions. During the photosynthesis process, light, carbon dioxide, and water react to produce products: sugar and oxygen. The equation for photosynthesis is:

Title: Analysis of the effect of changing pressure on oxygen saturation and the effect of pH on

Chlamydomonas reinhardtii are single celled photosynthetic organisms that are highly adaptable, versatile and can thrive in many varying environments around the world. Chlamydomonas reinhardtii are easily manipulated and used in many lab based research experiments as a model system because they are extremely adaptable to numerous environmental conditions placed upon them making them perfect for experimentation and research in a lab based environment (Grossman ect al. 2003)

In this lab, the students will be testing waters to see what difference each compound will make. It is needed to know how certain pH levels have different affects in order to understand other possible affects. Nitrate, phosphate, and oxygen will all have an affect on freshwaters within ecosystems. Also, the environmental effect that a petroleum refinery has around us to show why it causes so much pollution.

This puts a strain on aquatic life such as mollusks, coral, and plankton, which rely on a stable PH level to build their exoskeletons (Simon et al., 2007).