Phosphorus and Plankton By: Salish Sea Expeditions Students

Background Knowledge This subject is solely related to the Puget Sound, because the Puget Sound is our watershed (watershed meaning a body of water affected by nature and/or human impact).

Introduction We are from Anacortes Middle School, located on Fidalgo Island, in the San Juan Islands. With a group of 28 students we traveled around these Islands on the Carlyn, April 25 - 27, 2018 We chose to compare phosphates and plankton because we learned that phosphates are an important nutrient that can help life thrive (in this case plankton), but in large amounts, it can also kill off life.

Question Does the amount of Phosphorus affect the amount of Plankton?

Prediction If there are more phosphates in the water, then there will be more plankton because phosphorus is a nutrient that plankton use to thrive. If there are more nutrients, then the plankton thrive.

Materials Carabiner Rope Weight Niskin Bottle Funnel Graduated Cylinder Plankton net

Variables For this project the manipulated variable was the amount of phosphates. The responding variable to the phosphate is the amount of plankton that there are in the water. The controlled variable is the materials we used to collect the samples.

Methods The first station was at N48 - 122. The nets were 2 meters under the surface of the water, and the nets were held there for 1 minute. The weather was Force 1 on the Beaufort Scale (no cloud clouds or rain) The second station was at N40 - 122. Again, it was held 2 meters under the surface of the water for 1 minute (with the same Force on the Beaufort scale) The third station was at N48-122. The nets were 2 meters under the surface of the water, held there for 3 minutes with 75% cloud cover without rain (2 on the Beafort scale). The first station that we took samples from was at; N48-122: 2 meters down for 1 minute, with no cloud cover or rain, and force 1 on the Beaufort Scale. The second station was at N40-122: 2 meters down for 1 minute with no clouds or rain, it was very warm. N48-126: 2 meters down for 3 minutes with no precipitation or cloud cover. The Beaufort Scale was a 3 and the tide was an ebb. The third station was at N48-122: 2 meters down for 3 minutes with no cloud cover or rain. N48-122: 2 meters down for 3 minutes with 75% cloud cover and no rain. The beaufort scale was a 2 with the tide stage being at a flood.

Data Analysis Phosphates (PPM) Plankton (ML) Sample 1 0.15 1.5 0.59 1.25 Sample 3 0.67 3.75 Sample 4 1.24 2.75 Sample 5 0.32 25

Evaluation Q: What would you do differently in this study? A: We would put our plankton nets in the water for the same time for each trial. We had different amounts of time we put the nets in the water each day. Some variables we should include the next time we do this experiment are currents, tide level, wind speed, weather, etc.

Conclusion The data shows that the plankton population didn't change much depending on phosphates as much as location does. For example, in Sample 1, there is a lot of plankton but a low amount of phosphates. In Sample 2, there were less plankton than Sample 1, but there were more phosphates. There isn’t a huge difference though. Sample 3 proves that there are more plankton with more phosphates, but Sample 4 trumps that theory, with less plankton and more phosphorus than Sample 3. We think this may be because after the bloom in plankton population, the plankton run out of phosphorus and compete for the supplies they need to live, then die off, leaving low phosphorus and plankton. After we collected our data, it appeared that our hypothesis was only partially correct. The data shows that the plankton population doesn't change much depending on phosphates as much as location does. For example, in sample 1, there is a lot of plankton but a low amount of phosphates. In sample 2, there are less plankton then sample 2, but more phosphates. There isn’t a huge difference though. Sample 3 proves that there are more plankton with more phosphates, but sample 4 trumps that theory, with less plankton and more phosphorus than sample 3. We think this may be because after the bloom in plankton population, the plankton run out of phosphorus and compete for the supplies they need to live, then die off, leaving low phosphorus and plankton.

Ideas for the Future Since phosphorous doesn’t appear to have much effect on plankton, it would be interesting to test for variables that do affect plankton. Some variables that can affect plankton that we can test for are oxygen, PH, nitrate, and nutrient levels.