Phosphorus Bioavailability in Lake Wapalanne

Cade Weston (Taylor University)

Faculty mentors: Sudipta Rakshit, Kevin Olsen and Dibyendu Sarkar (Montclair State University)

Eutrophication of surface water due to high nutrient load is a common environmental problem.  Eutrophication is caused by algal bloom on high nutrient water and eventual dissolved oxygen depletion by the decomposition of dead algal biomass.  Although eutrophication is mainly caused by N and P, the lake water is typically P limited. Therefore, investigation of dissolved P pool in the lake is important to understand the trophic status of the lake and helps assess the future risks for eutrophication.  Since lake sediment is a major sink for P, change of chemical and biological environments in the lake may release soluble P.  To assess the potential of P to become dissolved or bioavailable, different chemical extraction procedures have been developed.  Here, in this research work, we investigated the bioavailability of P in Lake Wapalanne in Sussex County, NJ.  Several extraction techniques were used e.g. total P (TP), readily desorbable P (RDP), algae- available P (AAP), Mehlic III-P, and Olsen-P and compared to determine the bioavailable pool of P.  Both water and sediment samples were collected across Lake Wapalanne.  Dissolved P in water samples were analyzed colorimetrically by a modified malachite green procedure.  Total-P and bio-available P in sediments were analyzed by ICP-OES.  Dissolved P values confirmed the current oligotrophic status of the lake. However,TP, RDP, AAP, Mehlic-III-P, and olsen-P indicated that if P is released from top 10 cm of the lake sediment, the lake can reach eutrophic status in future.  Our investigation will help lake management practices to make future decisions in lake restoration.