Steady-state growth of the marine diatom Thalassiosira pseudonana

Journal Article · Mon Sep 01 00:00:00 EDT 1980 · Plant Physiol.; (United States)

OSTI ID:7080535

Olson, R J ^[1]; SooHoo, J B; Kiefer, D A

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1. Scripps Inst. of Oceanography, La Jolla, CA

Seasonal studies of the vertical distribution of nitrate, nitrite, and phytoplankton in the oceans and studies using /sup 15/N as a tracer of nitrate metabolism indicate that the reduction of nitrate by phytoplankton is a source of nitrite in the upper waters of the ocean. To better understand this process, the relationship between nitrate uptake and nitrite production has been examined with continuous cultures of the small marine diatom Thalassiosira pseudonana. In a turbidostat culture, the rates of nitrite production by T. Pseudonana increase with light intensity. This process is only loosely coupled to rates of nitrate assimilation since the ratio of net nitrite production to total nitrate assimilation increases with increased rates of growth. In continuous cultures where steady-state concentrations of nitrate and nitrite were varied, T. pseudonana produced nitrite at rates which increased with increasing concentrations of nitrate. Again, the rates of nitrite production were uncoupled from rates of nitrate assimilation. The study was used to derive a mathematical description of nitrate and nitrite metabolism by T. pseudonana. The validity of this model was supported by the results of a study in which /sup 15/N-labeled nitrite was introduced into the continuous culture, and the model was used to examine patterns in distribution of nitrite in the Antarctic Ocean and the Sargasso Sea.

• OSTI ID: 7080535
• Journal Information: Plant Physiol.; (United States), Vol. 66:3
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
DIATOMS
METABOLISM
NITRATES
UPTAKE
AMMONIA
AQUATIC ECOSYSTEMS
BIOCHEMICAL REACTION KINETICS
BIOMASS
BOTANY
DENITRIFICATION
LABELLED COMPOUNDS
MATHEMATICS
NITROGEN 15
NITROGEN CYCLE
PHYTOPLANKTON
PLANT GROWTH
QUALITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
SEAS
SEASONAL VARIATIONS
TRACER TECHNIQUES
TURBIDITY
VISIBLE RADIATION
ALGAE
AQUATIC ORGANISMS
BIOLOGY
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
ECOSYSTEMS
ELECTROMAGNETIC RADIATION
ENERGY SOURCES
GROWTH
HYDRIDES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PLANKTON
PLANTS
RADIATIONS
REACTION KINETICS
RENEWABLE ENERGY SOURCES
STABLE ISOTOPES
SURFACE WATERS
VARIATIONS
520101* - Environment
Aquatic- Basic Studies- Radiometric Techniques- (-1989)
550500 - Metabolism