A resource-based model of competition correctly predicted the ecluilibriulil orltc,omtJ ,tn(l approximated the population and nutrient dynamics of many nutri~l~t-lilnitt,~~ compr~tition experiments with two algal species at temperatures from 8" to 24°C. Silicate growth kinetics of temperature-acclimated Asterionella formosu and Sync~dra ulncl predicted that AstrJrionella should competitively displace Synedra below 20°C and Synudru should displace Astcrionella above 2O"C, as was observed. Although the growth kinetics showed no significant tlifference in silicate requirements

No abstract

Abstract. During a three year study (1985)(1986)(1987) we used a mass balance approach to study the oxidation and reduction reactions related to decomposition of organic carbon in Mirror Lake, New Hampshire. The stoichiometry of the reactions allows us to calculate an electron transfer budget for the summer stratification period in the lake. as well as in benthic chambers and sealed jars.The average decomposition rate measured as dissolved inorganic carbon (DIC) production was 5.33 mm01 m-2 d-l. The proportions of decomposition accounted for by the various electron acceptors varied both during the summer, as well as from year to year. On average, oxygen accounted for 43% of DIC production, while the processes involving sulfate, nitrate, iron and methane formation together accounted for 20%. Despite conservative assumptions we could not account for 37% of the DIC production. The general pattern, including excess DIC production, was also observed in chamber studies conducted over shallow-water sediments and in sealed-jar experiments.Data on burial rates of reduced iron minerals indicate that such minerals are not sufficient to account for the discrepancy in the electron budget. Our analysis suggests that another electron acceptor such as organic carbon reduction, either via fermentation or selective oxidation, is the most likely explanation of excess DIC production.