Chlorophyll budgets: Zooplankton grazing and phytoplankton growth in a temperate fjord and the Central Pacific Gyres1

The processes controlling the daily production and fate of phytoplankton pigments were evaluated in a moderately productive fjord (Dabob Bay, Washington) and the oligotrophic open ocean (North and South Central Pacific Gyres). The processes included phytoplankton growth, macrozooplankton grazing, microzooplankton grazing, the downward vertical flux of pheopigments, photodegradation, dark degradation, cell sinking, cell senescence, and physical mixing. A model was constructed describing the dynamic budget of chlorophyll and pheopigments within the euphotic zone. The model provides estimates of phytoplankton growth, macrozooplankton grazing, and microzooplankton grazing based on field measurements of the vertical distribution of pigments, the vertical flux of pigments out of the euphotic zone, and the flux of solar radiation through the water column. The pigment-specific rates (d−1) provided by the model are derived in situ without manipulation of either the phytoplankton or zooplankton, and the experiments are largely container-free. Growth rates, averaged over the whole euphotic zone, varied seasonally in Dabob Bay (0.05–0.9 d−1) and ca. 67% of the total daily grazing rate was due to macrozooplankton herbivores. Phytoplankton growth rates, averaged over the whole euphotic zone, were ca. 0.2 d−1 in the oceanic gyres, regardless of season or location, and ca. 95% of daily grazing was due to microzooplankton herbivores. The model suggests that grazing and growth are in balance.

[1]  F. D. King,et al.  Estimates of vertical eddy diffusion through the thermocline from phytoplankton nitrate uptake rates in the mixed layer of the eastern tropical Pacific1 , 1979 .

[2]  M. Perry,et al.  Phytoplankton rate processes in the oligotrophic waters of the central North Pacific Ocean , 1980 .

[3]  F. Whitney,et al.  Biochemical Changes of Sedimented Matter in Sediment Trap in Shallow Coastal Waters , 1980 .

[4]  H. Postma,et al.  Dissolved and particulate organic carbon in the North Equatorial current of the Atlantic Ocean , 1979 .

[5]  P. Bienfang.  Phytoplankton sinking rates in oligotrophic waters off Hawaii, USA , 1980 .

[6]  R. Eppley,et al.  Estimating Phytoplankton Growth Rates in the Central Oligotrophic Oceans , 1980 .

[7]  R. P. Hassett,et al.  Estimating the grazing impact of marine micro-zooplankton , 1982 .

[8]  F. S. Russell,et al.  Plankton Production and its Control , 1935, Journal of the Marine Biological Association of the United Kingdom.

[9]  W. Broecker.  Radioisotopes and the rate of mixing across the main thermoclines of the ocean , 1966 .

[10]  S. Gelder,et al.  Identification of phaeopigments in the digestive gland of Mytilus edulis L. by microspectrofluorimetry , 1980 .

[11]  A. Copping,et al.  Sinking rates of organic particles1 , 1983 .

[12]  J. Ryther.  Photosynthesis and fish production in the sea. , 1969, Science.

[13]  John H. Steele,et al.  The Structure of Plankton Communities , 1977 .

[14]  N. Welschmeyer,et al.  The in situ sinking rates of herbivore fecal pellets , 1983 .

[15]  E. Venrick,et al.  Possible consequences of containing microplankton for physiological rate measurements , 1977 .

[16]  S. Tijssen.  Diurnal oxygen rhythm and primary production in the mixed layer of the Atlantic Ocean at 20°N , 1979 .

[17]  M. Perry,et al.  Phosphate uptake by phytoplankton in the central North Pacific Ocean , 1981 .

[18]  Earl D. Rainville,et al.  Elementary Differential Equations , 1970 .

[19]  N. Welschmeyer,et al.  Carbon‐14 labeling of phytoplankton carbon and chlorophyll a carbon: Determination of specific growth rates1 , 1984 .

[20]  A. Copping,et al.  Particulate organic carbon flux in the subarctic Pacific , 1983 .

[21]  C. Yentsch.  Distribution of chlorophyll and phaeophytin in the open ocean , 1965 .

[22]  T. Parsons,et al.  A practical handbook of seawater analysis , 1968 .

[23]  C. Yentsch,et al.  The role of chlorophyllase and light in the decomposition of chlorophyll from marine phytoplankton , 1970 .

[24]  Kenneth W. Bruland,et al.  Fluxes of particulate carbon, nitrogen, and phosphorus in the upper water column of the northeast Pacific , 1979 .

[25]  W. Moore.  Radium-228: Application to thermocline mixing studies , 1972 .

[26]  Richard H. Fleming,et al.  The Control of Diatom Populations by Grazing , 1939 .

[27]  I. N. McCave.  Vertical flux of particles in the ocean , 1975 .

[28]  C. Lorenzen,et al.  Fluorometric Determination of Chlorophyll , 1965 .

[29]  W. J. Jenkins,et al.  Oxygen utilization rates in North Atlantic subtropical gyre and primary production in oligotrophic systems , 1982, Nature.

[30]  R. Margalef.  Life-forms of phytoplankton as survival alternatives in an unstable environment , 1978 .

[31]  S. W. Jeffrey.  Profiles of photosynthetic pigments in the ocean using thin-layer chromatography , 1974 .

[32]  T. G. Owens,et al.  Diel periodicity in cellular chlorophyll content in marine diatoms , 1980 .

[33]  C. Greenblatt,et al.  Environmental Factors Affecting Growth and Chlorophyll Synthesis in Euglena. I. Physical and Chemical. II. The Effectiveness of the Spectrum for Chlorophyll Synthesis. , 1955 .

[34]  J. Heinbokel.  Studies on the functional role of tintinnids in the Southern California Bight. II. Grazing rates of field populations , 1978 .

[35]  T. G. Owens,et al.  Enzymatic degradation of chlorophyll a by marine phytoplankton in vitro , 1982 .

[36]  R. Eppley,et al.  The residence time of particulate organic carbon in the surface layer of the ocean , 1983 .

[37]  Erwin Suess,et al.  Particulate organic carbon flux in the oceans—surface productivity and oxygen utilization , 1980, Nature.

[38]  C. Lorenzen,et al.  Quantitative degradation of chlorophyll by a marine herbivore1 , 1975 .

[39]  D. F. Winter,et al.  A theoretical study of phytoplankton growth and nutrient distribution in the Pacific Ocean off the northwestern U.S. coast , 1977 .

[40]  T. Smayda.  The suspension and sinking of phytoplankton in the sea , 1970 .

[41]  T. Platt,et al.  Autotrophic Picoplankton in the Tropical Ocean , 1983, Science.

[42]  F. Rosa,et al.  In situ measurement of the settling velocity of organic carbon particles and 10 species of phytoplankton , 1980 .

[43]  T. Parsons,et al.  DISTRIBUTION OF CHLOROPHYLL a AND DEGRADATION PRODUCTS IN VARIOUS MARINE MATERIALS , 1963 .