Index Catalog // ScholarsArchive@OSU

Creator:: Wheeler, Patricia A. and Kirchman, David L.
Abstract:: The relative contribution of various inorganic and organic forms of nitrogen to the nitrogen requirements of picoplankton was examined with 15N tracers. Size fractionation was used to measure uptake by <1-μM size microorganisms, and inhibitors of protein synthesis were used to separate procaryotic from eucaryotic nitrogen uptake, Picoplankton utilized mainly...
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Full Text:: WHEELER, PATRICIA A., AND DAVID L. KIRCHMAN. Utilization of

Creator:: Fujita, Rodney M., Wheeler, Patricia A., and Edwards, Robert L.
Abstract:: The relationship between nitrogen (N) availability and the growth of macroalgae in a seasonal upwelling region (Yaquina Head, Oregon, USA) was investigated. Water column nutrient concentrations were relatively high and stable during the winter, decreased in early spring, and were highly variable in the summer and early fall. Periods of...
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Full Text:: region Rodney M. Fujita*, Patricia A. Wheeler**, Robert L. Edwards College of Oceanography, Oregon

Creator:: Kirchman, David L., Keil, Richard G., and Wheeler, Patricia A.
Abstract:: The purpose of this study was to test the hypothesis that NH4+ uptake by heterotrophic bacteria in the subarctic Pacific is C limited. Addition of glucose (0.5–1.0 μM) stimulated NH4+ uptake in unfractionated water but had no effect on bacterial abundance. Glucose stimulation of NH4+ uptake was even greater in...
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Full Text:: KIRCHMAN, DAVID L., RICHARD G. KEIL, AND PATRICIA A. WHEELER

Creator:: Kokkinakis, Steven A. and Wheeler, Patricia A.
Abstract:: The stable isotope 15N was used to measure nitrogen uptake in the coastal upwelling region off Oregon and Washington, USA, where nitrate concentrations in the surface water ranged from 0.7 to 49.1 μM. Nanoplankton biomass (1 to 10 pm) was relatively more abundant at low-nitrate stations, while netplankton biomass (10...
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Full Text:: growth rates of 1 to 2 d-l. Inclusion of ammonium as a nitrogen source and assumption that all ammonium

Creator:: Wheeler, Patricia A., Glibert, Patricia M., and McCarthy, James J.
Abstract:: Using 15N-labeled NH4+, we assessed the time-course of NH4+ uptake, the parameters of saturation kinetics, and the rates of incorporation of NH4+ into trichloroacetic acid-insoluble material by Chesapeake Bay phytoplankton. The amount of NH4+ taken up by the phytoplankton increased linearly with time for 2 h for all samples growing...
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Full Text:: or near detection levels it is difficult to enrich at a true “trace” level (Glibert and Goldman

Creator:: Wheeler, Patricia A. and McCarthy, James J.
Abstract:: The uptake of methylammonium (MA) by Chesapeake Bay phytoplankton was measured in short term experiments by using the 14C radioisotope. This uptake was inversely related to ambient NH4+ concentrations, and the specificity for uptake of both substrates was demonstrated by competitive inhibition. At stations with low ambient NH4+, MA uptake...
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Full Text:: ammonium analogue for field uptake measurements L Patricia A. Wheeler2 und James J. McCurthy Museum of

Creator:: Wetz, Michael S. and Wheeler, Patricia A.
Abstract:: Until recently, studies of the fate of primary production in coastal upwelling systems have focused mainly on export through sinking of particulate organic matter (POM). In week-long deck incubations conducted during the upwelling season off Oregon, a large accumulation of carbonrich (C:N ≥ 16) dissolved organic matter (DOM) occurred following...
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Full Text:: results in the devel- opment of large (>10 µg chlorophyll a l–1) phytoplankton blooms and accumulation of

Creator:: Dickson, Mary-Lynn and Wheeler, Patricia A.
Abstract:: Ammonium uptake and regeneration rates were measured in time course experiments with 15N as a tracer. Both ammonium uptake and regeneration rates measured over 12 to 18 h remained essentially constant. However, as the length of the incubations increased the amount of usable data decreased dramatically due to substrate depletion...
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Full Text:: be a more serious problem at 0 and 8 m (47 :L) than at 25 m (22 %). As a result, ammonium uptake

Creator:: Kristiansen, Svein, Farbrot, Tove, and Wheeler, Patricia A.
Abstract:: The uptake rates of nitrate, ammonium, and urea were measured with a ¹⁵N technique during seven cruises in the marginal ice zone (MIZ) in the Barents Sea in 1984–1988. The results from all the cruises were pooled to obtain means for the prebloom, bloom, transition, and postbloom periods. New production—nitrate...
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Full Text:: . Plankton was size-fractionated after a 12-l 6-h incubation by gravity filtration through 142- mm 0.8pm

Creator:: Miller, Charles B., Frost, Bruce W., Wheeler, Patricia A., Landry, Michael R., Welschmeyer, Nicholas, and Powell, Thomas M.
Abstract:: It has been suggested that production in offshore waters of the subarctic Pacific is limited by availability of dissolved Fe. Although that is not yet adequately established, the functional consequences of the limitation (if it exists) can be characterized from the results of the Subarctic Pacific Ecosystem Research (SUPER) program....
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Full Text:: of Alaska, a major part of the subarctic Pacific (Fig. l), was the observational basis for

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