Richard W. Eppley

University of California, San Diego

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Edward H. Renger

Scripps Institution of Oceanography

James J. McCarthy

Medical College of Wisconsin

E. Stewart

UK Centre for Ecology & Hydrology

W. G. Harrison

Bedford Institute of Oceanography

Jane N. Rogers

University of California, San Diego

Wolfgang Koeve

GEOMAR Helmholtz Centre for Ocean Research Kiel

Freda M.H. Reid

Scripps Institution of Oceanography

Mark R. Abbott

University of Pittsburgh

Sigrid Podewski

Kiel University

John Strickland

Eastern Virginia Medical School

Cooperative Institutions

University of California, San Diego

Scripps Institution of Oceanography

Woods Hole Oceanographic Institution

University of Washington

Virginia Tech

Bigelow Laboratory for Ocean Sciences

University of California, Los Angeles

Kiel University

University of Southern California

Oregon State University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

INORGANIC NITROGEN ASSIMILATION OF DITYLUM BRIGHTWELLII, A MARINE PLANKTON DIATOM^1,²

Journal of Phycology (1970)

Richard W. Eppley Jane N. Rogers

SUMMARY Apparent K m values for nitrite reductase, glutamic dehydrogenase, and nitrate reductase are of the order 10 −4 molar for nitrite, ammonia, and nitrate, respectively while half‐saturation constants for the corresponding uptake mechanisms approximate 10 −6 molar. Ammonium and nitrate are accumulated in the vacuolated cells of the diatom (about 10 and 40 mmoles/liter cell volume, respectively) and these intracellular pools serve as substrate for the assimilatory enzymes. Nitrite is either not accumulated or is concentrated, in a very small cellular compartment. Ammonium and nitrate in the external medium exert modifying effects on uptake and assimilatory mechanisms which can be distinguished from effects of the ions accumulated within the cells. Several of these effects are described and fitted into a general scheme of nitrogen assimilation by D. brightwellii .

Nitrogen Assimilation

Assimilation (phonology)

10.1111/j.1529-8817.1970.tb02405.x

Cite

Citations (119)

Development ofEDTAMedia for the Rapid Growth ofChlamydomonas mundana

The Journal of Protozoology (1963)

Frank M. MaciasR Richard W. Eppley

SYNOPSIS. An empirical method is used to determine mixtures of the chelating agent, EDTA (ethylenediamine tetraacetate), and trace metals which allow maximum growth rates of Chlamydomonas mundana under optimum environmental conditions. In this method which resembles an immunological titration one trace metal (Ca, Fe, Mn or Zn), in increasing concentrations, is used to “saturate” a standard amount of EDTA. Other required trace metals are added in a range of minimum concentrations. Extent of growth with each mixture is evaluated after 24 hours of incubation. Mixtures allowing greatest growth are then used to evaluate growth rate. Media with manganese as the EDTA‐saturating trace metal allow most rapid growth rates equivalent to 11.0 doublings per day. Magnesium as the EDTA‐saturating metal does not allow growth, suggesting that Mg does not displace other required trace metals from EDTA‐complex. Since the mixtures allowing maximum growth rate are “underchelated” it appears that the free metals rather than the metal‐chelate complexes are utilized by the alga in rapid growth.

Trace metal

Chlamydomonas

Recovery rate

10.1111/j.1550-7408.1963.tb01670.x

Cite

Citations (20)

PROCEEDINGS OF THE AMERICAN SOCIETY OF LIMNOLOGY AND OCEANOGRAPHY, INC.

Limnology and Oceanography (1973)

H B Baker Bruce H. Corliss Joan Hel- Lerman Carl Obrecht William C. Starrett

The Business Meeting was called to order at 1114; 146 members were present.President G

Limnology

10.4319/lo.1973.18.1.0184

Cite

Citations (0)

Vertical motion of the thermocline, nitracline and chlorophyll maximum layers in relation to currents on the Southern California Shelf

Journal of Marine Research (1983)

John J. Cullen E. Stewart Edward H. Renger Richard W. Eppley Clinton D. Winant

10.1357/002224083788520171

Cite

Citations (71)

LIGHT/DARK PERIODICITY IN NITROGEN ASSIMILATION OF THE MARINE PHYTOPLANKTERS SKELETONEMA COSTATUM AND COCCOLITHUS HUXLEYI IN N‐LIMITED CHEMOSTAT CULTURE¹,²

Journal of Phycology (1971)

Richard W. Eppley Jane N. Rogers James J. McCarthy Alain Sournia

SUMMARY Skeletonema costatum and Coccolithus huxleyi were grown in nitrogen‐limited chemostat cultures with illumination provided in light/dark cycles. S. costatum assimilated nitrate and ammonium primarily during the day and less so at night. Conversely, the concentration of nitrate and ammonium in the culture medium varied periodically, increasing at night and decreasing in the light. C. huxleyi assimilated both N sources at a rate sufficient to keep them at very low levels both day and night. However, the activity of N‐assimilating enzymes, measured in cell‐free extracts, were higher in the light than in the dark periods, implying light/dark differences in the capacity to assimilate nitrogen. Such periodicity in the rate of uptake and enzymatic activity appears to complicate the mathematical expression of nutrient‐limited growth of phytoplankton exposed to natural light/dark cycles. Three aspects of dial periodicity in N assimilation have been observed in natural phytoplankton communities in the sea: (1) in assimilation rate, (2) in activity of enzymes of N‐assimilation, and (3) in the ammonium concentration of the seawater. The cultures also showed periodicity in these parameters and appear to be useful model systems for study.

Chemostat

Emiliania huxleyi

Assimilation (phonology)

Nitrogen Assimilation

Darkness

10.1111/j.1529-8817.1971.tb01494.x

Cite

Citations (144)

List of References

Springer eBooks (2013)

Richard W. Eppley

10.1002/9781118669235.refs

Cite

Citations (0)

Estimating Phytoplankton Growth Rates in the Central Oligotrophic Oceans

Springer eBooks (1980)

Richard W. Eppley

Maxima

10.1007/978-1-4684-3890-1_13

Cite

Citations (125)

The residence time of particulate organic carbon in the surface layer of the ocean

Deep Sea Research Part A Oceanographic Research Papers (1983)

Richard W. Eppley Edward H. Renger Peter R. Betzer

Particulate organic carbon

Sediment trap

Carbon fibers

New production

Surface layer

Mixed layer

10.1016/0198-0149(83)90013-4

Cite

Citations (117)

The PRPOOS program: A study of plankton rate processes in oligotrophic oceans

Eos (1982)

Richard W. Eppley

Measuring the rates of biological processes in the open sea remains a challenging problem to experimentalists. The problems are especially acute in the central gyres of the subtropical oceans where the concentrations of plankton and nutrients take minimum values (i.e., in oligotrophic waters). Historically, this led to the use of radioisotopic tracers to measure fundamental rate processes of the plankton such as photosynthetic carbon assimilation. Such technology requires incubating samples of seawater in bottles. This has long been worrisome since enclosing the plankton for several hours may well lead to artifacts. There ought to be better ways of making the measurements; finding some is one of the PRPOOS tasks.

Assimilation (phonology)

Bacterioplankton

10.1029/eo063i022p00522-01

Cite

Citations (34)

Hydrolysis of Polyphospliates by Porphyra and Other Seaweeds

Physiologia Plantarum (1962)

Richard W. Eppley

10.1111/j.1399-3054.1962.tb08025.x

Cite

Citations (18)