Nutrient Profile Surface Water Test

Overview

This panel measures nitrate, total phosphorus, and total Kjeldahl nitrogen: the combination limnologists use to assess a lake's nutrient status and its risk of excessive algae and plant growth. Nitrogen and phosphorus are the two nutrients that control how much a lake can grow, and measuring them together is what makes the results interpretable. Methods EPA 300.0, EPA 365.1, and EPA 351.2, reported in parts per million.

What problem does this solve for our lake?

Eutrophication — the progressive nutrient enrichment that turns a clear lake into a productive, algae-dominated one — is the central problem in lake management. It is driven by two nutrients, and the ratio between them matters as much as their absolute levels. • Nitrate as N (EPA 300.0; MDL 0.01 ppm, RL 0.1 ppm) — the mobile, immediately plant-available form of nitrogen, and the best indicator of active watershed loading from fertilizer, agriculture, or septic systems. • Total Phosphorus (EPA 365.1; MDL 0.008 ppm, RL 0.01 ppm) — every form of phosphorus in the sample, dissolved and particulate. In most freshwater lakes phosphorus is the limiting nutrient, which means it sets the ceiling on algal growth. As a rough guide: below about 0.010 ppm is a clear, low-productivity lake; roughly 0.010 to 0.025 ppm is moderately productive; above about 0.025 ppm blooms become likely. • Total Kjeldahl Nitrogen (EPA 351.2; MDL 0.249 ppm, RL 0.5 ppm) — organic nitrogen plus ammonia. Added to nitrate it gives total nitrogen. The ratio is where the interpretation happens. When total nitrogen divided by total phosphorus is above roughly 20 to 1, phosphorus is limiting and phosphorus is what you manage. Below about 10 to 1, nitrogen is limiting — an uncommon but important case, because it is the condition under which nitrogen-fixing cyanobacteria gain a competitive advantage. Between those values, both matter. This is the panel that tells a board whether the watershed work they are contemplating will actually change anything.

What's included?

• A complete nitrate, total phosphorus, and TKN test kit shipped directly to you
• All materials required for clean, contamination-free sample collection
• Step-by-step collection and preservation instructions
• Prepaid 2-day return shipping to our certified partner laboratory
• Analysis by EPA-approved methods at an accredited partner laboratory, with full chain of custody
• Results loaded automatically into your lake's account

What's not included

• Sample collection. You collect the sample; we supply everything you need to do it correctly.
• Boat, dock, or shoreline access to your sampling site
• Depth-profile sampling. This is a single grab sample unless you order multiple kits.
• Ice or a cooler for shipping, which you supply
• Treatment, remediation, or applicator services
• A written management plan. The Boathouse can help you interpret results and decide next steps.
• Ammonia. If you need to distinguish external loading from internal sediment release, order the Nitrogen Sequence Surface Water Test.
• Dissolved or orthophosphate fractions
• Sediment phosphorus, which is what drives internal loading in many older lakes

Requirements

• A sample collected from open water at a consistent depth, away from inflows and shoreline disturbance
• Same-day shipment after collection, kept cold
• Consistent site and season if you intend to track a trend
• A Plus, Lake Admin, or PRO subscription to have results loaded into your Lake Pulse account
• Questions about site selection, timing, or which test fits your lake? Contact the Lake Pulse Boathouse before you order.