Conventional and newly-developed techniques to determine the phosphorus (P) status of Lake Ontario phytoplankton were employed in September 2003, immediately after the passage of the storm system associated with Hurricane Isabel. Surface water (1–5 m) was collected at 29 stations, with selected stations sampled throughout the water column. Chemical estimates of total P concentrations were compared with proxies of P bioavailability: P enrichment bioassays of lake water, alkaline phosphatase activity (APA), and P-dependent bioreporter assays. Average total P (314 nM) and total chlorophyll-α (2.12 μg/L) concentrations measured in pelagic surface waters from throughout Lake Ontario suggest an oligotrophic status prevailed across much of this lake during the sample period. Autotrophic picoplankton (0.2–2 μm) displayed the highest growth rates and were grazed at the highest rate, whereas P-enrichment bioassays favored the production of autotrophic nanoplankton (2–20 μm) and autotrophic microplankton (> 20 μm) biomass. Average concentrations of bacteria (2.61 ×1010 cells/L) were higher than those measured during summer in a similar lake (Erie), whereas the average viral density (1.38 ×1010 virus particles/L) was similar. Pelagic stations exhibited higher APA than coastal stations; cyanobacterial bioreporter responses did not show high correlation with APA suggesting that proxies of P-demand based on residual effects (e.g., enzyme production) were not indicative of shorter-term biological responses related to planktonic growth (bioreporter genetic response). The combination of traditional chemical, biochemical (APA), and cutting-edge biological methods (bioreporter) provided information on nutrient concentrations and primary productivity throughout Lake Ontario, while concurrently allowing real-time assessment of P bioavailability.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 32 • No. 3