The effect of zooplankton on phytoplankton productivity in the epilimnion of a subalpine lake

Redfield, Garth W.

doi:10.1007/bf00016763

Cited by 27 publications

(26 citation statements)

References 14 publications

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“…All species were relatively small ( Table 2, GALD < 11 pm), well within the size range susceptible to ingestion by Daphnia of the size used in this experiment. In meso-oligotrophic Castle Lake, grazers had appreciable direct and indirect effects on nutrient availability, algal growth rates, and algal biomass and productivity, as has been observed previously by other researchers in this lake (Redfield and Goldman 1978;Janik 1988;Elser and Goldman in press). Both ambient and Daphnia experiments yielded similar results, reflecting the fact that the ambient zooplankton community at Castle Lake is dominated by a Daphnia species (0. rosea).…”

Section: Discussionsupporting

confidence: 75%

Zooplankton effects on phytoplankton in lakes of contrasting trophic status

Elser

Goldman

1991

Limnology & Oceanography

198

118

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Studies were carried out in three lakes of strongly contrasting trophic state to evaluate how the effects of zooplankton on phytoplankton vary as a function of lake productivity. Chlorophyll and total P concentrations differed by 2-3 orders of magnitude among ultra-oligotrophic Lake Tahoe, meso-oligotrophic Castle Lake, and strongly eutrophic Clear Lake. Three experimental designs involving short-term (4 d) manipulations of nutrients, ambient zooplankton, and the common crustacean grazer Duphnia were performed in each lake. Algal responses were assessed at both the "aggregate," community (Chl, primary productivity, nutrient status) and species levels.Experiments in Lake Tahoe revealed a high degree of nutrient sensitivity but negligible grazing impacts by the very low densities of ambient zooplankton. Daphnia grazing had substantial impacts on Tahoe phytoplankton, however, indicating high susceptibility to grazing in this assemblage of relatively small-sized algal species. Castle Lake experiments revealed strong direct and indirect impacts of both ambient zooplankton and Duphnia on the nutrient-limited algal assemblage. The cyanobacteria-dominated algal community of Clear Lake was resistant to grazing impacts, responding relatively weakly only to the highest densities of Duphnin. Good correspondence between estimates of algal biomass made from chlorophyll measurements and microscopic examination were obtained, and, in Castle Lake, concordance between estimated community productivity tumover times made from species-specific growth determinations and community productivity measurements was observed. The contrasting responses to experimental zooplankton manipulations in the three lakes provide support for the view that the coupling between zooplankton and phytoplankton is strongest in lakes of intermediate productivity and imply that food-web alterations at the top of the food web are most likely to propagate to the level of the phytoplankton (and therefore lake water quality) in lakes of moderate trophic status.The relationship between nutrient loading and lake trophic state or productivity (Vollenweider 1976) is one of the most wellfounded empirical properties of lakes. Having established this relationship and used it in lake management with success, limnologists increasingly have focused their attention on the considerable amount of unexplained variance which remains in these empirical relationships.One explanation proposes that the chain of predatory interactions within the pelagic food web can strongly alter phytoplankton abundance by ' Present address:

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Section: Discussionsupporting

confidence: 75%

Zooplankton effects on phytoplankton in lakes of contrasting trophic status

Elser

Goldman

1991

Limnology & Oceanography

198

118

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“…However, for the epilimnion of Castle Lake, the latter is insignificant (Redfield 1979) and therefore, the mineralization rates reported here are largely the result of microbial processes. Mineralization is functionally defined as the ammonium release in control bottles without zooplankton after correction for phytoplankton uptake.…”

Section: Regeneration Methodsmentioning

confidence: 66%

“…The water was then prefiltered through 80-p..m Nitex netting to remove zooplankton and added to 1-L bottles for 15 N uptake determinations and to 21-L bottles for regeneration determinations. vertical migration in Castle Lake (Redfield andGoldman 1978, Redfield 1979) were used to estimate nocturnal densities in the epilimnion. Replicate samples were preserved in formalin for subsequent enumeration.…”

Section: Samplingmentioning

confidence: 99%

The Importance of Regenerated Nitrogen to Phytoplankton Productivity to Phytoplankton Productivity in a Subalpine Lake

Axler¹,

Redfield²,

Goldman³

1981

Ecology

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Experiments utilizing epilimnetic water were conducted to determine the rate of ammonium regeneration, due to zooplankton excretion and microbial mineralization processes, in relation to the rate of inorganic nitrogen assimilation by phytoplankton. The euphotic zone of dimictic, meso-oligotrophic Castle Lake is characterized by a rapid depletion of both nitrate and ammonium soon after spring thaw. External inputs of nitrogen are minimal during this period and levels of inorganic nitrogen remain low until fall overturn. The rate of ammonium assimilation was high relative to nitrate assimilation, and was significantly correlated with the rate of ammonium regeneration. The importance of this rapid turnover of nitrogen to phytoplankton growth is consistent with the results of previous Castle Lake studies, and with the current conceptual model of primary production in the mixed layer of nitrogen-deficient marine ecosystems.

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“…Moreover, the coincidence of certain factors can lead to the de-veloping of algal blooms (Porter, 1977). It can change seasonally or more frequently depending on the composition of phyto-and zooplankton (Redfield, 1980). It can change seasonally or more frequently depending on the composition of phyto-and zooplankton (Redfield, 1980).…”

mentioning

confidence: 99%

Composition, density and feeding of crustacean zooplankton community in a shallow, temperate lake (Lake Balaton, Hungary)

Zánkai

Ponyi

1986

Hydrobiologia

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Composition density and filtering rates of crustacean zooplankton were studied in the open water and among the macrophytes of the oligo-mesotrophic part of Lake Balaton from 1981 to 1983. From the individual filtering rates of the different populations and the densities community grazing rates were derived.Copepoda made up 79-90% of crustacean plankton community in the open lake and 95-97% of it in littoral zone. Among them the nauplii dominated. At the end of summer 1982, when Anabaenopsis was in bloom, the filter-feeding species (Eudiaptomus, Daphnia) practically disappeared, being replaced by cyclopoids.Daphnia had the highest filtering rates followed by those of Eudiaptomus and Diaphanosoma. Among copepods, the filtering rates in decreasing order were: ovigerous Q > all adults > copepodites > nauplii. Q > 0 . The filtering rates of the different species varied both seasonally as well as from year to year. In 1983, when the concentration of organic seston decreased, filtering rate increased compared with those in the earlier years. During the water bloom in 1982, the rates decreased by 70% on the average. The community grazing rate was very low (3% per day) in the open lake and among macrophytes, both in 1981 and 1982; also the share of crustacean zooplankton in grazing was very low. In 1983, together with the improving of water quality, the community grazing rate increased 4-fold. In 1981 and 1983 the rates were influenced by water temperature but in 1982 by seston concentration. In March end 1982, although the crustacean standing crops was low because of the intensive in-J M A N J J A S C ice acean zooplankton in 1981-1983. A, B, D = open lake; C = in the

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The effect of zooplankton on phytoplankton productivity in the epilimnion of a subalpine lake

Cited by 27 publications

References 14 publications

Zooplankton effects on phytoplankton in lakes of contrasting trophic status

Zooplankton effects on phytoplankton in lakes of contrasting trophic status

The Importance of Regenerated Nitrogen to Phytoplankton Productivity to Phytoplankton Productivity in a Subalpine Lake

Composition, density and feeding of crustacean zooplankton community in a shallow, temperate lake (Lake Balaton, Hungary)

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