Kyle McCanney Adam Baumann NY Lake Comparison Kyle McCanney Adam Baumann

Phosphorus Many forms of phosphorus We are concerned with SRP Different techniques for each type We are concerned with SRP Soluble Reactive Phosphorus Biologically available phosphorus Nutrient uptake

Why Phosphorus? ATP and ADP Limiting Nutrient Energy currency of the cell Limiting Nutrient Redfield ratio Most limiting nutrient Far less is available than what is needed Indicator of trophic state of lake

SRP Measurement React the lake samples with a combined reagent Form a phospho-antimony-molybdate complex (in acidic medium) Further reduced by ascorbic acid to form a blue colored complex Absorbs light around 880nm

Quantification of SRP Make known standard solutions of phosphate Cover range of phosphate concentrations expected Measure absorbance's at 880nm Treated same as samples will be Plot absorbance vs. concentration To be used to quantify unknown samples

MAGIC MAGnesium Induced Coprecipitation Addition of NaOH to samples Precipitates Brucite [Mg(OH)2], pulling soluble P with it Samples are centrifuged and precipitate is acidified Allows for lower detection limit Freshwater samples?

Arbutus and Rich Diel Vertical Migration of Zooplankton Proximate cause = light Ultimate cause = avoid predation We sampled during the day Most zooplankton found below irradiance level corresponds to lower nutrient levels at these depths

Green Green lakes phosphorus data looks unique However, most zooplankton found at concentration consistent with Rich and Arbutus Also below level of irradiance

Measurements and Errors Nitrogen levels Compare nutrient information Error Too many people sampling too many different parameters First time technique users