Zooplankton Community and Species Responses to a Natural Turbidity Gradient in Lake Temiskaming, Ontario–Quebec

1986 ◽  
Vol 43 (3) ◽  
pp. 665-673 ◽  
Author(s):  
Erik R. Zettler ◽  
John C. H. Carter
Keyword(s):  
Zooplankton Community ◽  
Daphnia Galeata ◽  
Mysis Relicta ◽  
Leptodora Kindtii ◽  
Turbid Waters ◽  
Fish Predators ◽  
Vertical Distributions ◽  
Crustacean Plankton ◽  
Daphnia Galeata Mendotae ◽  
Plankton Community Structure

Lake Temiskaming, a long, narrow lake between Ontario and Quebec, contains a permanent turbidity gradient, although seasonal turbidity values continually change throughout. Polar ordination indicated that the crustacean plankton community structure was closely related to the first (turbidity) axis. Mean body size was also positively related to turbidity, suggesting that reduced transparency in turbid waters might protect large zooplankters from visually seeking fish predators. Mysis relicta and Leptodora kindtii, the two largest species, were most abundant at the lake's turbid (northern) end with declining numbers toward the clear (southern) end. Many smaller copepods and cladocerans showed reduced numbers at the northern stations during the turbidity maximum in early June, possibly because of impaired feeding ability, after which they progressively increased through the season relative to numbers in the south. Daphnia galeata mendotae failed to show this seasonal increase at the turbid end, possibly because of selective cropping by Mysis and Leptodora. Many species displayed somewhat higher midday vertical distributions in turbid than in clear waters.

Freshwater Zooplankton Community Structure: Introduction of Large Invertebrate Predators and Large Herbivores to a Small Species Community

1988 ◽  
Vol 45 (10) ◽  
pp. 1758-1770 ◽  
Author(s):  
Michael J. Vanni
Keyword(s):  
Introduced Species ◽  
Zooplankton Community ◽  
Zooplankton Species ◽  
Small Species ◽  
Daphnia Galeata ◽  
Resident Species ◽  
Large Herbivores ◽  
Fishless Lakes ◽  
Invertebrate Predators ◽  
Daphnia Galeata Mendotae

Two hypotheses have been proposed to explain the scarcity of small zooplankton species in fishless lakes, in which large zooplankton species dominate: (1) selective predation on small species by large invertebrate predators and (2) competitive suppression of small species by large herbivores. These hypotheses were tested at the Experimental Lakes Area (ELA) by introducing a large invertebrate predator, Chaoborus americanus, and a large herbivore, Daphnia catawba, both common in fishless ELA lakes, into a zooplankton community typical of ELA lakes with fish (small zooplankton species present). Chaoborus had much more of an impact than D. catawba on resident zooplankton, although both introduced species significantly reduced the abundance of some resident species. Daphnia galeata mendotae, the dominant species in the absence of introduced species, was reduced to virtual extinction by Chaoborus. The cladocerans Bosmina and Diaphanosoma, the copepods Diaptomus spp., and the rotifer Conochilus also were reduced in abundance by Chaoborus. Daphnia galeata mendotae and Bosmina were the only resident species consistently reduced in abundance by D. catawba. These results support current conceptual models that depict invertebrate predation as an important factor responsible for the relative scarcity of small zooplankton species in fishless lakes.

Mysis relicta in Lake Michigan: Abundances and Relationships with their Potential Prey, Daphnia

1990 ◽  
Vol 47 (5) ◽  
pp. 977-983 ◽  
Author(s):  
John T. Lehman ◽  
James A. Bowers ◽  
Robert W. Gensemer ◽  
Glenn J. Warren ◽  
Donn K. Branstrator
Keyword(s):  
Lake Michigan ◽  
Puget Sound ◽  
Mortality Rates ◽  
Reference Station ◽  
Potential Prey ◽  
Mysis Relicta ◽  
The North ◽  
Important Predator ◽  
Vertical Distributions

Mysis relicta were sampled at a 100-m reference staton in southeastern Lake Michigan (43°N 86°40′W) from 1985 to 1989, to quantify nighttime water column abundances and to compare vertical distributions with those of Daphnia. Diel vertical migration produced maximum concentrations in the thermocline at night of 1 to 10 mysids∙m−3. Variation among replicates averaged 28% with a 3-net Tucker trawl and 19% with Puget Sound vertical closing nets. Mean areal abundances over 5 yr averaged 110 mysids∙m−2 (SE = 20; n = 30; range = 25 to 645) based on nighttime vertical and oblique net tows at 1–3-wk intervals during summers at the reference station. Synoptic cruises from 43°N to 45°N during August indicated that densities were considerably greater offshore than inshore, and greater in the north than in the south. Hypothesized long-term changes in mysid abundances were not detected. Although Mysis is potentially an important predator on Daphnia, differences in nighttime vertical distributions reduce encounters between Mysis and Daphnia during summer in Lake Michigan, such that Mysis exert mortality rates on Daphnia of < 1.5% per day; the latter are in general less than 10% of the birth rates of Daphnia populations, estimated from fecundities.

Dieldrin reduces male production and sex ratio in Daphnia galeata mendotae

1999 ◽  
Vol 15 (1-2) ◽  
pp. 193-200 ◽  
Author(s):  
Christine M. Merritt ◽  
Laura Torrentera ◽  
Katherine M. Winter ◽  
Christopher K. Tornehl ◽  
Kristin Girvin ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Male Production ◽  
Daphnia Galeata ◽  
Daphnia Galeata Mendotae

Periodicity of Egg Laying and Egg Age Distributions in Planktonic Cladocera

1984 ◽  
Vol 41 (3) ◽  
pp. 409-413 ◽  
Author(s):  
Alan J. Tessier
Keyword(s):  
Negative Correlation ◽  
Natural Populations ◽  
Egg Laying ◽  
Daphnia Galeata ◽  
Molt Cycle ◽  
Egg Development ◽  
Daphnia Species ◽  
Diel Cycles ◽  
Development Times ◽  
Daphnia Galeata Mendotae

In natural populations of planktonic Cladocera, I observed significant diel, molt cycle, and cohort periodicity of egg laying. Diel cycles of egg laying were pronounced in one population of Daphnia galeata mendotae; most females laid eggs only at dawn. There was a strongly negative correlation between diel egg laying cycles of coexisting Daphnia species. Egg laying in two Daphnia populations cycled with a period approximating the egg development times, suggesting a synchronization of individual molt cycles. Noncontiguous reproduction was characteristic of a population of Holopedium gibberum. Adults reproduced synchronously and then died; there was little overlap of generations.

scholarly journals Role of jellyfish in the plankton ecosystem revealed using a global ocean biogeochemical model

2021 ◽  
Vol 18 (4) ◽  
pp. 1291-1320
Author(s):  
Rebecca M. Wright ◽  
Corinne Le Quéré ◽  
Erik Buitenhuis ◽  
Sophie Pitois ◽  
Mark J. Gibbons
Keyword(s):  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Zooplankton Community ◽  
Ocean Model ◽  
Plankton Community ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Ocean Biogeochemical Model ◽  
Spatio Temporal ◽  
Plankton Community Structure

Abstract. Jellyfish are increasingly recognised as important components of the marine ecosystem, yet their specific role is poorly defined compared to that of other zooplankton groups. This paper presents the first global ocean biogeochemical model that includes an explicit representation of jellyfish and uses the model to gain insight into the influence of jellyfish on the plankton community. The Plankton Type Ocean Model (PlankTOM11) model groups organisms into plankton functional types (PFTs). The jellyfish PFT is parameterised here based on our synthesis of observations on jellyfish growth, grazing, respiration and mortality rates as functions of temperature and jellyfish biomass. The distribution of jellyfish is unique compared to that of other PFTs in the model. The jellyfish global biomass of 0.13 PgC is within the observational range and comparable to the biomass of other zooplankton and phytoplankton PFTs. The introduction of jellyfish in the model has a large direct influence on the crustacean macrozooplankton PFT and influences indirectly the rest of the plankton ecosystem through trophic cascades. The zooplankton community in PlankTOM11 is highly sensitive to the jellyfish mortality rate, with jellyfish increasingly dominating the zooplankton community as its mortality diminishes. Overall, the results suggest that jellyfish play an important role in regulating global marine plankton ecosystems across plankton community structure, spatio-temporal dynamics and biomass, which is a role that has been generally neglected so far.

Dieldrin reduces male production and sex ratio in Daphnia galeata mendotae

1999 ◽  
Vol 15 (1) ◽  
pp. 192-199 ◽  
Author(s):  
S.I. Dodson ◽  
C.M. Merritt ◽  
L. Torrentera ◽  
K.M. Winter ◽  
C.K. Tornehl ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Male Production ◽  
Daphnia Galeata ◽  
Daphnia Galeata Mendotae

Vertical Migration in Daphnia galeata mendotae (Brooks): Demographic Responses to Changes in Planktivore Abundance

1990 ◽  
Vol 47 (2) ◽  
pp. 395-400 ◽  
Author(s):  
D. G. Stirling ◽  
D. J. McQueen ◽  
M. R. S. Johannes
Keyword(s):  
Residence Time ◽  
Vertical Migration ◽  
Daphnia Galeata ◽  
Population Densities ◽  
Data Set ◽  
Migration Patterns ◽  
Order Of Magnitude ◽  
Daphnia Galeata Mendotae ◽  
Demographic Responses

We tested the hypothesis that changes in vertical migration patterns in Daphnia galeata mendotae were correlated with changes in planktivore numbers. A 4-yr data set from Lake St. George showed that during 1982, when planktivores numbered approximately 2500∙ha−1, adult D. galeata mendotae were found in the epilimnion at both midday and midnight. During 1984 and 1985, when planktivores were almost an order of magnitude more abundant, adult D. galeata mendotae were detected in the epilimnion only at night, and the amplitude of migration increased by a factor of two. Changes in diel population densities were associated with these interannual differences in vertical migration patterns. These results suggest that between-year differences in vertical migration patterns were strongly associated with changes in planktivore density which may have influenced the selective value of increased hypolimnetic residence time.

Inferred effects of lake acidification on Daphnia galeata mendotae

1990 ◽  
Vol 24 (8) ◽  
pp. 1259-1261 ◽  
Author(s):  
Wendel Keller ◽  
Norman D. Yan ◽  
Keith E. Holtze ◽  
J. Roger Pitblado
Keyword(s):  
Lake Acidification ◽  
Daphnia Galeata ◽  
Daphnia Galeata Mendotae

Population Dynamics of Daphnia galeata mendotae as Modified by Chronic Cadmium Stress

1978 ◽  
Vol 35 (4) ◽  
pp. 461-469 ◽  
Author(s):  
J. S. Marshall
Keyword(s):  
Population Dynamics ◽  
Carrying Capacity ◽  
Brood Size ◽  
Lake Michigan ◽  
Cadmium Stress ◽  
Whole Body ◽  
Average Weight ◽  
Daphnia Galeata ◽  
Female Ratio ◽  
Daphnia Galeata Mendotae

Forty populations of Daphnia galeata mendotae were maintained for 22 wk (or until they became extinct) in a medium consisting of filtered Lake Michigan water to which Chlamydomonas reinhardi and different concentrations of a mixture of labelled (109Cd) plus stable CdCl2 were added 24 h before use. The medium was changed daily Monday through Fridays. Weekly determinations were made of total numbers, average individual dry weight, mean brood size, egg–female ratio, aborted eggs and embryos, and average whole-body 109Cd content. Chronic cadmium stress reduced the populations' average numbers and biomass, while it increased the populations' turnover rates, temporal variability, probability of extinction, and proportion of ovigerous females. For individuals there was increased prenatal mortality, reduced life expectancy, increased average weight, and increased brood size. Due to compensatory increases in the proportion of ovigerous females and mean brood size, the cadmium sensitivity of population attributes was considerably less than that of the most sensitive individual attribute, prenatal mortality. A linear relationship between population carrying capacity (relative mean numbers) and added cadmium concentration indicated that the effective concentration for a 50% reduction of carrying capacity (EC50) is 7.7 μg Cd/L and that for a 1% reduction (EC1) is 0.15 μg Cd/L. An increase of 0.15 μg Cd/L in Lake Michigan itself, barring synergistic interaction with other factors in the lake, would probably not have a detectable effect on the population dynamics of D. galeata mendotae. Key words: zooplankton dynamics, stress ecology, Daphnia galeata mendotae, cadmium, heavy metals, toxic substances, Laurentian Great Lakes

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