scholarly journals Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Sergei Maslov ◽  
Kim Sneppen
Keyword(s):  
Species Diversity ◽  
Population Cycles ◽  
Microbial Ecosystems

scholarly journals Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems

2016 ◽  
Author(s):  
Sergei Maslov ◽  
Kim Sneppen
Keyword(s):  
Species Diversity ◽  
Bacterial Population ◽  
Population Cycles ◽  
Volterra Equations ◽  
Bacterial Populations ◽  
Microbial Ecosystems ◽  
Dynamic Scenario ◽  
Cyclic Dynamics ◽  
Ecosystem Diversity ◽  
Static Equilibrium State

AbstractDeterminants of species diversity in microbial ecosystems remain poorly understood. Bacteriophages are believed to increase the diversity by the virtue of Kill-the-Winner infection bias preventing the fastest growing organism from taking over the community. Phage-bacterial ecosystems are traditionally described in terms of the static equilibrium state of Lotka-Volterra equations in which bacterial growth is exactly balanced by losses due to phage predation. Here we consider a more dynamic scenario in which phage infections give rise to abrupt and severe collapses of bacterial populations whenever they become sufficiently large. As a consequence, each bacterial population in our model follows cyclic dynamics of exponential growth interrupted by sudden declines. The total population of all species fluctuates around the carrying capacity of the environment, making these cycles cryptic. While a subset of the slowest growing species in our model is always driven towards extinction, in general the overall ecosystem diversity remains high. The number of surviving species is inversely proportional to the variation in their growth rates but increases with the frequency and severity of phage-induced collapses. Thus counter-intuitively we predict that microbial communities exposed to more violent perturbations should have higher diversity.

Diatoms in the Early Valdai (Weichselian) sediments in Lake Ladoga basin

2019 ◽  
pp. 225-228
Author(s):  
Anna V. Ludikova
Keyword(s):  
Species Diversity ◽  
High Energy ◽  
Lake Ladoga ◽  
Diatom Assemblages ◽  
Marine Diatoms ◽  
Selective Preservation

The pioneer diatom study of the Early Weichselian (Valdai) sediments in Lake Ladoga basin was performed. The specifics of the diatom assemblages (co-occurrence of ecologically incompatible taxa, poor species diversity, low diatom concentration and selective preservation) suggest that during the Early Weichselian time intense erosion of previously deposited marine Eemian (Mikulino) sediments prevailed, which resulted in re-deposition of marine diatoms. The sedimentation took place in high-energy environments unfavorable for diatom accumulation and preservation.

Algae of the Sefunim Cave (Israel): species diversity affected by light, humidity and rock stresses

2009 ◽  
Vol 11 (2) ◽  
pp. 99-116 ◽  
Author(s):  
O. N. Vinogradova ◽  
Eviatar Nevo ◽  
Solomon P. Wasser
Keyword(s):  
Species Diversity
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