Appendix B. Tables and a figure showing (1) summary statistics for the partial redundancy analysis, (2) results from the ANOSIM test, and (3) regression results.

Tables and a figure showing (1) summary statistics for the partial redundancy analysis, (2) results from the ANOSIM test, and (3) regression results

Appendix A. Tables showing supplemental data including (1) watershed characteristics, (2) temperature and hydrology treatments, (3) plant species, and (4) chemical and physical properties of the study sites.

Tables showing supplemental data including (1) watershed characteristics, (2) temperature and hydrology treatments, (3) plant species, and (4) chemical and physical properties of the study sites

Stress Responses of Aquatic Plants to Silver Nanoparticles

Silver nanoparticles (AgNPs) are increasingly used in consumer products, biotechnology, and medicine, and are released into aquatic ecosystems through wastewater discharge. This study investigated the phytotoxicity of AgNPs to aquatic plants, <i>Egeria densa</i> and <i>Juncus effusus</i> by measuring physiologic and enzymatic responses to AgNP exposure under three release scenarios: two chronic (8.7 mg, weekly) exposures to either zerovalent AgNPs or sulfidized silver nanoparticles; and a pulsed (450 mg, one-time) exposure to zerovalent AgNPs. Plant enzymatic and biochemical stress responses were assessed using superoxide dismutase (SOD) and peroxidase (POD) activity, malondialdehyde (MDA) concentrations and chlorophyll content as markers of defense and phytotoxicity, respectively. The high initial pulse treatment resulted in rapid changes in physiological characteristics and silver concentration in plant tissue at the beginning of each AgNPs exposure (6 h, 36 h, and 9 days), while continuous AgNP and sulfidized AgNP chronic treatments gave delayed responses. Both <i>E. densa</i> and <i>J. effusus</i> enhanced their tolerance to AgNPs toxicity by increasing POD and SOD activities to scavenge free radicals but at different growth phases. Chlorophyll did not change. After AgNPs exposure, MDA, an index of membrane damage, was higher in submerged <i>E. densa</i> than emergent <i>J. effusus</i>, which suggested that engineered nanoparticles exerted more stress to submerged macrophytes