Diurnal Uptake of N03 and NH4 by a Ceratophyllum‐Periphyton Community1

Abstract

The diurnal assimilation of NH, and NOa quantities of NOs and NH4 in natural waby communities of Ceratophyllum-periphyton ters by removing large quantities of these was studied in situ in a small lake. Plants nutrients from circulation. The work rewere exposed to "N-NH4 and 15N-N03 for 6 consecutive periods of 4-hr duration. The ported here uses uptake values obtained community assimilated NH, both during the during short periods to predict the daily day and at night. The rate of NO, assimila-

Plant community dynamics in a chain of lakes: principal factors in the decline of rooted macrophytes with eutrophication

“…These are responding as do the phytoplankton to inflowing nutrient availability, consistent with observations of Goulder and Boatman (1971). C. demersum is particularly known for its nitrophily (Goulder and Boatman 1971;Toetz 1971;Best 1980). Its ability to grow rapidly in the upper water column enables it to maximize light availability for which it competes with phytoplankton (Chapman et al, 1974;Phillips et al, 1978), thus simultaneously adapting to and contributing to the light attenuation factor in the lake.…”

Zooplankton community composition and some limnological aspects of an oxbow lake of the Paraopeba River, São Francisco River Basin, Minas Gerais, Brazil

“…The values of NH 4 -N found indicated a high degree of decompositional activity. The lower values of NH 4 -N observed at the surface could have been partially due to assimilation by the phytoplankton and macrophyte communities (Toetz, 1971). When compared to the high water period, only the concentration of nitrate was higher during low water, while the concentrations of ammonia and especially nitrite decreased.…”

Nitrogen and phosphorus dynamics in hot desert streams of Southwestern U.S.A.

“…i n continuous culture, however, was related to light only at high dilutions (Malone et al 1975), and uptake by Ulva lactuca was light-independent (Franzisket 1974) . Nitrate assimilation bya macrophyte community, however, was strongly light dependent (Toetz 1971) . Phosphate uptake is apparently not light dependent (Healey 1973) .…”