How Temperature affects the Respiration Rate in Goldfish

The Effect of Temperature of the Respiration Rate of Fish

By,

Udaikaran Singh and Goerge Ajit

Abstract

The purpose of this experiment is to explore the affects water temperature has on the respiration rate of a goldfish. The key findings we found were that as the temperature grew colder, the respiration rate slowed down and the goldfish would try to stay as still as possible, however when the temperature got warmer, the respiration rate increased and the goldfish began to move around more. From this we conclude that higher water temperature causes goldfish to have a higher respiration rate. The information we have going into the experiment is that goldfish are exothermic, meaning that their environment directly affects their circulatory system.

Introduction

This test was conducted to test the effect of temperature on goldfish's respiratory rate. The background information we took into account is the knowledge of exothermic circulatory system and the 2 chamber heart within fish. The method to test this is to test the respiration for each temperature range by adding ice or cold water. We predict that as the temperature decreases, the respiration rate will also decrease. We hypothesize this, because we know goldfish are exothermic, so their blood circulation will be directly affected by the temperature. As circulation decreases, so will the need for oxygen and therefore, there will be a decrease of respiration. 

Methods and Materials

For this testing, the supplies we used are a cylinder, tap water, ice, heated water, and a thermometer. First, we took the goldfish, putting it into the cylinder and filling it with water. From there, we took the thermometer and adjusted the temperature of the water till it was between 15-20º C. From there we counted how many times the gills opened and closed on the fish for 5 minutes. From there, we dumped a portion of the water out and added ice into the cylinder and waited until the water adjusted to 10-14º C. Again we counted the opening and closing of the gills for 5 minutes. We then added a few more pieces of ice and allowed the water to reduce to 5-9º C. Again we counted the gills opening and closing for 5 minutes. We then dumped out a majority of the water, and began to add heated water into the cylinder. We did this until the temperature reached 21-25º C. When it did, we again counted the gills opening and closing for 5 minutes. Lastly, we increased the temperature by adding more hot water until it reached 26-30º C. When it did, we counted the gills opening and closing for another 5 minutes.

Below is the setup we used to conduct this experiment. In the last picture shown, we used an electronic thermometer, however a standard mercury thermometer will work the same way.

Results

On top, we have a chart comparing the respiration of our goldfish to Kyle's, Bryon's and Arya's goldfish. Below that, there is a chart showing how our goldfish compares to the average of the 3 groups. As shown in the chart, we had a lower respiration rate in all the temperature ranges except for the 15-20º C. Also, there was a similar drop of respiration between the 15-20º C to the 10-14º C, however the drop for our goldfish was greater than the average. A noticeable difference is that in Kyle and Bryon's results, there was a considerable drop from the 10-14º C to 5-10º C range, however we did not see as big of a change.

Discussion and Conclusion 

The final conclusion we found through this experiment is that a change in temperature of the water the fish is in will have a direct influence on the respiration rate of the goldfish. One of the irregularities in our results in comparison to the compared goldfish is the large drop of respiration rate between the 15-20º C to the 10-14º C. We may equate this to us putting too much ice at once when trying to decrease the temperature. This abrupt change of temperature may have shocked the heart and caused the irregular heart rate. Also, we saw that during the colder temperature ranges, our goldfish was almost completely still for the whole time we recorded the respirations. This may also be the cause, because this means the goldfish needs less oxygen and therefore would not have to breathe as fast to get oxygen to its cells. 

In our testing, we found that temperature had a direct influence of respiration rate. As the temperature dropped, so did the respiration rate. Likewise, as it increased, so did the respiration rate increase. Also, we saw a connection between respiration rate and activity. When it was cold, the fish would try to stay in one place, but when it was hot, it would constantly move around. This may be because the higher circulation causes more oxygen to the muscles, allowing it to expend more oxygen by moving around. 

The other factors that may have affected the respiration rate are the pressure put on the fish, such as how many times time was the beaker dumped out and refilled with water, the amount of stirring of the water, and lastly the amount the beaker was moved during the tests.

Our fish was similar to the average in the warm water testing and room temperature testing, but very different in the cold water testing. The average is probably more accurate, because just using one test leaves a lot of room for error. 

If I were to make a secondary experiment that tested the effect of light, I would have a beaker with a goldfish under a lamp. I would make sure the water within the beaker is consistent throughout the experiment. Then, I would take plastic with different opacity levels and cover the lamp with them separately and test the respiration rate for 5 minute periods. The opacity would drop by 10% each plastic covering. 

Our prediction before this lab started was correct. We feel the fish reacted this way because they are exothermic, meaning their environment affects them. With the lower temperature, the circulation goes down, therefore the respiration goes down. Likewise, when the temperature goes up, the respiration goes up. This is consistent within humans, as when we exercise, our heart rate increases, therefore our respiration increases. We are, however, not directly affected by our environment, because we can control our internal temperature.