First fecundity observations on female copepods from three northern Patagonian lakes (Pellaifa, Calafquén, Panguipulli; Chile)

Crustaceana ◽  
2019 ◽  
Vol 92 (8) ◽  
pp. 897-905
Author(s):  
Patricio De los Ríos ◽  
Jorge Farias-Avendaño ◽  
Maria J. Suazo

Abstract The crustacean zooplankton in Chilean Patagonian lakes is characterized by a marked dominance of calanoid copepods when under an oligotrophic status. The aim of the present study was to analyse the number of eggs and the relation of that feature with the total length of females of calanoid and cyclopoid copepods reported in three northern Chilean Patagonian lakes. The calanoid copepods found were Boeckella gracilipes in Lake Pellaifa and Tumeodiaptomus diabolicus in the lakes Panguipulli and Calafquén, whereas the cyclopoid Mesocyclops araucanus was found in the lakes Pellaifa and Calafquén. For calanoid copepods, high egg numbers were found and thus also a high value for the ratio of egg number per female length in Lake Panguipulli, whereas for M. araucanus a high value was found in Lake Pellaifa. These differences would presumably be associated with community structure, specifically predator-prey relationships and possibly other interactions, as, e.g., potential interspecific competition.

Diversity ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 21 ◽  
Author(s):  
Julie E. Keister ◽  
Amanda K. Winans ◽  
BethElLee Herrmann

Several hypotheses of how zooplankton communities respond to coastal hypoxia have been put forward in the literature over the past few decades. We explored three of those that are focused on how zooplankton composition or biomass is affected by seasonal hypoxia using data collected over two summers in Hood Canal, a seasonally-hypoxic sub-basin of Puget Sound, Washington. We conducted hydrographic profiles and zooplankton net tows at four stations, from a region in the south that annually experiences moderate hypoxia to a region in the north where oxygen remains above hypoxic levels. The specific hypotheses tested were that low oxygen leads to: (1) increased dominance of gelatinous relative to crustacean zooplankton, (2) increased dominance of cyclopoid copepods relative to calanoid copepods, and (3) overall decreased zooplankton abundance and biomass at hypoxic sites compared to where oxygen levels are high. Additionally, we examined whether the temporal stability of community structure was decreased by hypoxia. We found evidence of a shift toward more gelatinous zooplankton and lower total zooplankton abundance and biomass at hypoxic sites, but no clear increase in the dominance of cyclopoid relative to calanoid copepods. We also found the lowest variance in community structure at the most hypoxic site, in contrast to our prediction. Hypoxia can fundamentally alter marine ecosystems, but the impacts differ among systems.


Crustaceana ◽  
2011 ◽  
Vol 84 (9) ◽  
pp. 1061-1068 ◽  
Author(s):  
Patricio De Los Ríos-Escalante ◽  
Stefan Woelfl

AbstractThe zooplankton assemblages in deep, mostly oligotrophic northern Patagonian lakes are characterized by a low species number and a marked dominance of calanoid copepods, as well as often by the presence of large mixotrophic ciliates (Stentor). In the present study, data collected in field work on four northern Patagonian lakes were analysed using co-occurrence of null models, with the aim to determine potential regulating factors for the observed crustacean and mixotrophic ciliate assemblages, using a presence-absence matrix. The null model uses species co-occurrence, and the basis of this model is that the species associations observed are random. The results revealed the absence of regulating factors and indicate that the sites are relatively homogeneous, with low species numbers, and similar plankton assemblages at all study sites. This finding coincides with similar descriptions for zooplankton assemblages in other Chilean Patagonian lakes.


Crustaceana ◽  
2017 ◽  
Vol 90 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Patricio De los Ríos-Escalante ◽  
Stefan Woelfl

Zooplankton assemblages in Northern Patagonian lakes are characterized by a low species richness and a marked dominance of calanoid copepods. The aim of the present study was to do a null model analysis to explain the composition of the zooplankton assemblages in two North Patagonian lakes. The first aspect to which null model analysis was applied was species co-occurrence, and there the model indicates that the species associations found are not random. The second aspect was niche sharing, and that analysis denotes that the species do not share niches. The third aspect tested was size overlap, and the model there denotes that the species have no size overlap. The results obtained indicate that the sites are relatively homogeneous, which would explain the random effect in species co-ocurrence, whereas the absence of niche sharing is due to the presence of different energetic resources at both sites investigated, which would separate the niche of each species from those of other faunistic elements. Finally, the third application of the null model analysis demonstrates that there is no competition among the species reported upon herein.


Crustaceana ◽  
2017 ◽  
Vol 90 (14) ◽  
pp. 1793-1802
Author(s):  
Patricio R. De los Ríos Escalante ◽  
Fatima Kies

The Patagonian lakes (38-55°S) are characterized by their marked oligotrophy, low number of species of crustacean zooplankton, and a marked predominance of calanoid copepods. Within this context, we considered that a review about the ecology of the zooplankton in central and southern Chilean lakes would be useful, aiming to understand the ecological importance of this group. Data obtained from the literature for freshwater bodies in central and southern Chilean lakes were analysed. In addition, data from various bays with widely differing trophic status in Llanquihue Lake were examined. The results revealed the existence of originally pristine and oligotrophic sites, all with a low number of species and marked calanoid dominance. However, in northern Patagonia there are many lakes in which human intervention has caused an increase in phytoplankton activity, with a consequent replacement of calanoid copepods by daphniid cladocerans. Other important factors that could affect the zooplankton community would be fish predation, which is due to generate a decrease in large-bodied groups of zooplankton; and stress due to exposure to natural ultraviolet radiation. Ecological, biogeographical, and evolutionary topics are discussed within the framework described.


Crustaceana ◽  
2019 ◽  
Vol 92 (6) ◽  
pp. 665-673
Author(s):  
Patricio De los Ríos ◽  
Jorge Farias-Avendaño ◽  
Maria J. Suazo

Abstract The northern Patagonian lakes (38-41°S), are characterized by their location in catchment basins that have been markedly altered through human intervention. In those basins, the original native, perennial forest has been replaced by towns, villages and agricultural zones. The present study was done in two interconnected north Patagonian lakes (the lakes Calafquén and Pellaifa), where the species composition of the crustacean zooplankton community was compared, using a biodiversity index and size-structure null models. The results denoted the presence of marked differences between both sites, Calafquén lake being inhabited by less species and in general showing lower abundances of individuals in comparison to Pellaifa lake. The results of size-structure null models revealed the absence of interspecific competition for both sites. The obtained results would agree with similar observations for other northern Patagonian lakes in Argentina and Chile.


Hydrobiologia ◽  
2009 ◽  
Vol 632 (1) ◽  
pp. 225-233 ◽  
Author(s):  
S. Matthew Drenner ◽  
Stanley I. Dodson ◽  
Ray W. Drenner ◽  
John E. Pinder III

2014 ◽  
Vol 396 ◽  
pp. 108-113 ◽  
Author(s):  
Qiuhui Pan ◽  
Haoying Wang ◽  
Luyi Chen ◽  
Zhong Huang ◽  
Mingfeng He

1987 ◽  
Vol 44 (S1) ◽  
pp. s163-s172 ◽  
Author(s):  
S. G. Lawrence ◽  
M. H. Holoka

The toxic effects of cadmium to total community and individual species of zooplankton generally decreased as pH of the lake was experimentally lowered over a number of years by additions of acids. The biomass of crustacean zooplankton held in small impoundment systems suspended in the lake for fourteen days was reduced by 60–70% when pH was 6.7–6.8 and concentrations of Cd were maintained at 1 μg∙L−1, and by 70–80% when Cd was at 3 μg∙L−1. At a pH of 5.9, however, biomass was reduced only 20–30% in concentrations of Cd of 1 μg∙L−1, and at pH 5.6, biomass decreased by only 20% when subjected to 3 μg∙L−1 Cd. The cladocerans Bosmina longirostris and Holopedium gibberum were the most sensitive to cadmium. Cladocerans were more sensitive to cadmium than calanoid copepods, and both these groups were more sensitive then cyclopoid copepods. The decrease in toxicity of cadmium with increasing H+ may be analogous to the inhibition of uptake of cadmium by calcium.


2014 ◽  
Vol 281 (1797) ◽  
pp. 20142103 ◽  
Author(s):  
Marlee A. Tucker ◽  
Tracey L. Rogers

Predator–prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator–prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator–prey ratio across terrestrial ( n = 51) and marine ( n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator–prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.


2012 ◽  
Vol 69 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Carolyn Faithfull ◽  
Magnus Huss ◽  
Tobias Vrede ◽  
Jan Karlsson ◽  
Ann-Kristin Bergström

Additions of labile organic carbon (C) enhanced bacterial production (BP) and were associated with increases in crustacean zooplankton and planktivorous fish biomasses. This was shown in a mesocosm experiment where we traced the contribution of BP to zooplankton and fish using stable isotopes and labile glucose-C as a biomarker. BP increased with glucose-C addition, and all zooplankton and fish incorporated some glucose-C. However, the effect of labile-C addition on zooplankton was taxa-dependant, as although cladocerans incorporated the most labile-C, increased BP did not affect cladoceran biomass. Instead, calanoid copepod biomass increased with glucose addition. This suggests that the ability to selectively graze on high quality food, such as bacterial grazing protists capable of trophic upgrading, had a stronger positive effect on calanoid copepods biomass than unselective grazing on bacteria and protists had on cladoceran biomass. Higher BP was associated with increased survival and population growth of young-of-the-year perch ( Perca fluviatilis ) when stocked at high densities, which suggested that BP had a density-dependant positive effect on fish growth.


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