TY - JOUR AU - Austin, Bradley J. AU - Eagle, Violet AU - Evans-White, Michelle A. AU - Scott, J. Thad AU - Haggard, Brian E. PY - 2020/04/03 Y2 - 2024/03/29 TI - Sediment phosphorus release sustains nuisance periphyton growth when nitrogen is not limiting: Sediment phosphorus sustains nuisance periphyton JF - Journal of Limnology JA - J Limnol VL - 79 IS - 3 SE - Original Articles DO - 10.4081/jlimnol.2020.1913 UR - https://www.jlimnol.it/jlimnol/article/view/jlimnol.2020.1913 SP - AB - <p>Nuisance periphyton growth influences the aesthetics, recreation, and aquatic life of waterbodies. Partners Lake is a shallow spring-fed lake in the headwaters of the Illinois River Watershed in Cave Springs, Arkansas, that experiences nuisance growth of periphyton (i.e., <em>Spirogyra spp.</em>) each year. The ratio of dissolved nitrogen (N ~5.0 mg L<sup>-1</sup>) and phosphorus (P ~0.030 mg L<sup>-1</sup>) in the lake water (N:P≥288), as well as nutrient limitation assays, suggests that periphyton growth should be P-limited. While the water column lacks sufficient P to promote growth, the sediments have the ability to release P to the overlying water; P-flux ranged from 1.63 mg m<sup>-2</sup> d<sup>-1</sup> to over 10 mg m<sup>-2</sup> d<sup>-1</sup>, reaching final concentrations of 0.08 to 0.34 mg L<sup>-1</sup>. However, soluble reactive phosphorus concentrations were consistently at or below 0.030 mg L<sup>-1</sup>, in the lake, suggesting that the periphyton were likely immobilizing P as quickly as it was released from the sediments. In the lab, maximal periphyton growth (~30 to 35 mg m<sup>-2</sup>) occurred in the 0.10 to 0.25 mg L<sup>-1</sup> P treatments, over a 6 day incubation period. Similar levels of growth occurred when lake sediments were the P source, suggesting P released from the sediments is sufficient to support nuisance algal growth. We need to begin managing the legacy P stored in the sediments, in addition to external P loads, because internal P can sustain nuisance periphyton biomass when N is not limiting.</p> ER -