Effects of different light/dark regimes and algal food on growth, fecundity, ephippial induction and molting of freshwater cladoceran, Ceriodaphnia quadrangula

Fishless Andean high mountain lakes may be vulnerable to fish invasion because they tend to be small, oligotrophic and contain low zooplankton diversity. During the first decades of the twentieth century, rainbow trout, Oncorhynchus mikiss, was introduced in South America, and stocking of juvenile stages (fry) in lakes continues today. However, their effect on plankton in these lakes has been little studied. We performed a mesocosms experiment to assess effects of trout of different ontogenetic stages on zooplankton and phytoplankton in a tropical-Andean high mountain lake. The presence of trout fry resulted in declines in several large zooplankton taxa, increases in chlorophyll a and dissolved inorganic nitrogen (DIN). Our results showed that small fry consume large copepods (Colombodiaptomus brandorffi) at a faster rate than larger fry, and also consumed medium sized copepods (Tropocyclops prasinus) that are not affected by the larger trout fry. Fish of both sizes consumed Ceriodaphnia quadrangula, a midsize cladoceran. Fish predation had weak effect on the phytoplankton biomass, but we found a correlation between zooplankton biomass and phytoplankton richness, and significantly larger cell of the alga Peridinium in the presence of fish. Our results indicate that trout introduction produces cascading ecological and phenotypic effects on the plankton communities of tropical mountain lakes, similar to those observed in temperate latitudes.

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The pigments of Artemia

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1960.0028 ◽

1960 ◽

Vol 152 (946) ◽

pp. 118-136 ◽

Cited By ~ 30

Keyword(s):

Brine Shrimp ◽

Phaeodactylum Tricornutum ◽

Artemia Salina ◽

Dunaliella Tertiolecta ◽

Carotenoid Pigment ◽

Algal Food ◽

Feeding Experiments ◽

Unicellular Algae ◽

Bright Orange ◽

Egg Shells

The eggs of the brine shrimp, Artemia salina , vary in colour from pale cream to dark brown. This variation is due to different amounts of haematin in the egg shells. Nauplii of Artemia are bright orange in colour owing to a carotenoid pigment, esterified astaxanthin. The same carotenoid is present in the eggs. Adult Artemia which has been reared on bakers’ yeast, in which we found no carotenoids, contains only a small amount of astaxanthin ester, presumably derived from that present in the egg. The carotenoids of the unicellular algae Dunaliella tertiolecta and Phaeodactylum tricornutum have been examined as a preliminary to feeding experiments with Artemia . The carotenoids identified from Dunaliella were β -carotene, γ -carotene, a carotene oxide, lutein, violaxanthin, and neoxanthin; those from Phaeodactylum were β -carotene, diadinoxanthin, fucoxanthin and neofucoxanthin. Adult Artemia reared on Dunaliella retains varying amounts of all the algal carotenoids, and in addition changes some of them to astaxanthin which becomes esterified and is quantitatively the most abundant carotenoid in the animal. A keto-carotenoid has been found in Artemia examined soon after being fed on Dunaliella . Artemia fed on Phaeodactylum retains all the algal xanthophylls to some extent. No β -carotene was found in the animals; a large amount of a keto-carotenoid was found, as well as astaxanthin. There is evidence that β -carotene in the algal food is the precursor of astaxanthin found in the adult Artemia and that the transformation proceeds through the keto-carotenoids.

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Effect of habitat complexity on the distribution of Ceriodaphnia quadrangula (O. F. Müller, 1785) (Crustacea: Cladocera) in a deep lake

Biological Letters ◽

10.2478/v10120-009-0019-8 ◽

2010 ◽

Vol 47 (2) ◽

pp. 51-58 ◽

Cited By ~ 1

Author(s):

Małgorzata Adamczuk

Keyword(s):

Surface Layer ◽

Brood Size ◽

Habitat Complexity ◽

Littoral Zone ◽

Open Water ◽

The Other ◽

Pelagic Zone ◽

Submerged Vegetation ◽

Deep Lake ◽

Ceriodaphnia Quadrangula

Effect of habitat complexity on the distribution of Ceriodaphnia quadrangula (O. F. Müller, 1785) (Crustacea: Cladocera) in a deep lake The aim of the study was to compare the density, body size, and reproduction of the cladoceran, Ceriodaphnia quadrangula (O. F. Müller, 1785), in various habitats of Lake Piaseczno (38.8 m deep) in eastern Poland. Samples were taken in the littoral zone (from emergent and submerged vegetation, as well as from open water and the surface layer of water above submerged vegetation) and in the pelagic zone (from the epilimnion, metalimnion, and hypolimnion). The results show that C. quadrangula prefers the littoral zone, as it achieves there much higher values of the analysed variables than in the pelagic zone. The number and size of adults (including ovigerous females), as well as brood size achieved equally high values in emergent and submerged vegetation, and much lower values in the other habitats (including pelagic ones). Juveniles also preferred to stay in the littoral zone but displayed clear preferences to none of the habitats.

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