Cells & Homeostasis: PBL Research – Day 4

For our final day with the Chromebooks, students were asked to research how algae fit into the Puget Sound food web.   After a student mentioned that algae obtain energy through photosynthesis, students were introduced to the formal scientific concept of limiting factors.  We used the example of phosphate, a chemical students measured while on the field trip which is also a critical component of ATP.  Photosynthesis is the process of storing the energy from sunlight within a molecule of glucose, and that energy is transferred to ATP during the process of cellular respiration.  ATP, or adenosine triphosphate, consists of an adenine group with three phosphate molecules attached.  When there is an excess of phosphate in the environment, the organisms that live there are not limited in their ability to multiply.  Therefore, phosphate availability is a limiting factor for algal blooms.  Michigan State University has a more in-depth scientific explanation of limiting factors in aquatic environments.

As student projects take shape, students were reminded that they need to dig deeply into the science to explore why their proposed solution will reduce the frequency of harmful algae blooms.  Next week, they will have some additional computer time coupled with time to work on their posters and presentations.  The posters and presentations will be the action piece of the project – students will present their work to their stakeholders and seek feedback about their proposed solutions.