Functional Interaction of Phytoplankton and Zooplankton along the Trophic Gradient in Green Bay, Lake Michigan

1991 ◽  
Vol 48 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Paul E. Sager ◽  
Sumner Richman
Keyword(s):  
Growth Rates ◽  
Lake Michigan ◽  
Algal Species ◽  
Phytoplankton Growth ◽  
Calanoid Copepods ◽  
Trophic Gradient ◽  
Functional Interaction ◽  
Trophic Conditions ◽  
Green Bay

The functional interaction of phytoplankton and zooplankton, expressed in terms of the numerical difference between phytoplankton growth rates per day (in situ,14C method) and zooplankton grazing rates per day (in situ feeding experiments), was studied along the trophic gradient in Green Bay, Lake Michigan. Growth–grazing differences increased with trophic conditions, averaging 0.08 for the water column in the meso-oligotrophic northern bay and 0.56 in the eutrophic southern bay for the summers of 1986, 1987, and 1988. Eutrophic conditions produced dominance of growth by large-size cyanobacteria and low grazing rates by microcrustaceans Small and occasionally negative growth–grazing differences in the meso-oligotrophic region were associated with dominance of larger cladocerans and calanoid copepods and small algal species Phytoplankton growth rates in the northern bay averaged about 28% those of the eutrophic region. A unimodal phytoplankton growth response to increased grazing was observed in the northern bay, suggesting variation in positive (growth stimulating) and negative (grazing losses) effects of zooplankton on the phytoplankton.

Zooplankton standing stock, species composition and size distribution along a trophic gradient in Green Bay, Lake Michigan

1984 ◽  
Vol 22 (1) ◽  
pp. 475-487 ◽  
Author(s):  
Sumner Richman ◽  
Megan D. Bailiff ◽  
Lawrence J. Mackey ◽  
David W. Bolgrien
Keyword(s):  
Species Composition ◽  
Size Distribution ◽  
Lake Michigan ◽  
Standing Stock ◽  
Trophic Gradient ◽  
Green Bay

The importance of nannoplankton along the trophic gradient in Green Bay, Lake Michigan

1988 ◽  
Vol 23 (1) ◽  
pp. 376-379
Author(s):  
Paul E. Sager ◽  
Barbara Rubio ◽  
Jeff Kirk
Keyword(s):  
Lake Michigan ◽  
Trophic Gradient ◽  
Green Bay

Food-web manipulations influence grazer control of phytoplankton growth rates in Lake Michigan

1987 ◽  
Vol 9 (5) ◽  
pp. 891-899 ◽  
Author(s):  
Robert M. Dorazio ◽  
James A. Bowers ◽  
John T. Lehman
Keyword(s):  
Food Web ◽  
Growth Rates ◽  
Lake Michigan ◽  
Phytoplankton Growth

scholarly journals Disparities between <i>Phaeocystis</i> in situ and optically-derived carbon biomass and growth rates: potential effect on remote-sensing primary production estimates

2014 ◽  
Vol 11 (4) ◽  
pp. 6119-6149
Author(s):  
L. Peperzak ◽  
H. J. van der Woerd ◽  
K. R. Timmermans
Keyword(s):  
Growth Rate ◽  
Quantum Efficiency ◽  
Growth Rates ◽  
Standing Stock ◽  
Phytoplankton Growth ◽  
Ex Situ ◽  
Fluorescent Light ◽  
Limited Growth ◽  
Global Carbon

Abstract. The oceans play a pivotal role in the global carbon cycle. Unfortunately, the daily production of organic carbon, the product of phytoplankton standing stock and growth rate cannot be measured globally by discrete oceanographic methods. Instead, optical proxies from Earth-orbiting satellites must be used. To test the accuracy of optically-derived proxies of phytoplankton physiology and growth rate, standard ex situ data from the wax and wane of a Phaeocystis bloom in laboratory mesocosms were compared with hyperspectral reflectance data. Chlorophyll biomass could be estimated accurately from reflectance using specific chlorophyll absorption algorithms. However, the conversion of chlorophyll (Chl) to carbon (C) was obscured by the observed increase in C : Chl under nutrient-limited growth. C : Chl was inversely correlated (r2 = 0.88) with Photosystem II quantum efficiency (Fv/Fm), the in situ fluorometric oceanographic proxy for growth rate. In addition, the optical proxy for growth rate, the quantum efficiency of fluorescence &amp;varphi; was linearly correlated to Fv/Fm (r2 = 0.84), but not – as by definition – by using total phytoplankton absorption, because during nutrient-limited growth the concentrations of non-fluorescent light-absorbing pigments increased. As a consequence, none of the three proxies (C : Chl, Fv/Fm, φ) was correlated to carbon or cellular phytoplankton growth rates. Therefore, it is concluded that although satellite derived estimates of chlorophyll biomass may be accurate, physiologically-induced non-linear shifts in growth rate proxies may obscure accurate phytoplankton growth rates and hence global carbon production estimates.

Phytoplankton standing stock, size distribution, species composition and productivity along a trophic gradient in Green Bay, Lake Michigan

1984 ◽  
Vol 22 (1) ◽  
pp. 460-469 ◽  
Author(s):  
Sumner Richman ◽  
Paul E. Sager ◽  
Gary Banta ◽  
T. Rodman Harvey ◽  
Bart T. Destasio
Keyword(s):  
Species Composition ◽  
Size Distribution ◽  
Lake Michigan ◽  
Standing Stock ◽  
Trophic Gradient ◽  
Green Bay ◽  
Stock Size

In situ, high-resolution time series of dissolved phosphate in Green Bay, Lake Michigan

2018 ◽  
Vol 44 (5) ◽  
pp. 875-882
Author(s):  
Michael E. Zorn ◽  
James T. Waples ◽  
Tracy J. Valenta ◽  
John Kennedy ◽  
J. Val Klump
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Lake Michigan ◽  
Resolution Time ◽  
Green Bay

scholarly journals Herbivorous protist growth and grazing rates at in situ and artificially elevated temperatures during an Arctic phytoplankton spring bloom

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5264 ◽  
Author(s):  
Susanne Menden-Deuer ◽  
Caitlyn Lawrence ◽  
Gayantonia Franzè
Keyword(s):  
Primary Production ◽  
Growth Rates ◽  
Elevated Temperatures ◽  
Size Fraction ◽  
Temperature Shift ◽  
Phytoplankton Growth ◽  
Grazing Impact ◽  
Large Variability ◽  
Species Specific

To assess protistan grazing impact and temperature sensitivity on plankton population dynamics, we measured bulk and species-specific phytoplankton growth and herbivorous protist grazing rates in Disko Bay, West Greenland in April-May 2011. Rate estimates were made at three different temperatures in situ (0 °C), +3 °C and +6 °C over ambient. In situ Chlorophyll a (Chl a) doubled during the observation period to ∼12  µg Chl a L−1, with 60–97% of Chl a in the >20 µm size-fraction dominated by the diatom genus Chaetoceros. Herbivorous dinoflagellates comprised 60–80% of microplankton grazer biomass. At in situ temperatures, phytoplankton growth or grazing by herbivorous predators <200 µm was not measurable until 11 days after observations commenced. Thereafter, phytoplankton growth was on average 0.25 d−1. Phytoplankton mortality due to herbivorous grazing was only measured on three occasions but the magnitude was substantial, up to 0.58 d−1. Grazing of this magnitude removed ∼100% of primary production. In short-term temperature-shift incubation experiments, phytoplankton growth rate increased significantly (20%) at elevated temperatures. In contrast, herbivorous protist grazing and species-specific growth rates decreased significantly (50%) at +6 °C. This differential response in phytoplankton and herbivores to temperature increases resulted in a decrease of primary production removed with increasing temperature. Phaeocystis spp. abundance was negatively correlated with bulk grazing rate. Growth and grazing rates were variable but showed no evidence of an inherent, low temperature limitation. Herbivorous protist growth rates in this study and in a literature review were comparable to rates from temperate waters. Thus, an inherent physiological inhibition of protistan growth or grazing rates in polar waters is not supported by the data. The large variability between lack of grazing and high rates of primary production removal observed here and confirmed in the literature for polar waters implies larger amplitude fluctuations in phytoplankton biomass than slower, steady grazing losses of primary production.

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