Summer Phosphorus

Phosphorus is an essential nutrient that fuels aquatic food webs by supporting algae and aquatic plant growth. However, too much phosphorus caused by human activities on the shoreline and in the watershed can create undesirable lake conditions such as frequent algal blooms and deep water oxygen.

Summer total phosphorus helps us understand how much phosphorus is entering the lake from its watershed (external loading) and is used to calculate a lake's trophic status - oligotrophic, mesotrophic, or eutrophic. Check out our phosphorus fact sheet to learn more.

Summer phosphorus measurements are taken over the deepest location in a lake in late August or September. Volunteers will need a canoe, kayak, paddleboat, or motor boat.

Details

• Cost to enroll: $30/ year

• Enrollment deadline: May 10, 2025

• Equipment requirements: Sample collection bottles are included with the enrollment fee and will be mailed to the Lead Volunteer.

• Time commitment: Volunteers measure Summer Phosphorus once per year in late summer. Sampling dates depend on county - See Summer Phosphorus Schedule for details.

• Training requirement: Training for this parameter is optional, but recommended. See training events here and watch the recorded phosphorus training videos below.

How do I measure Summer Phosphorus?

• Phosphorus Procedure Checklist

• 2025 Summer Phosphorus Sampling Schedule

• 2025 Summer Phosphorus Data Form

• Phosphorus Recorded Training Presentation (2024)

• Visit the Training Page for in-person and virtual training events.

Additional Information

• Phosphorus Fact Sheet

• Sampling Reminders

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