Sedimentary rocks include: red siltstone; fine- to medium-grained sandstone; dark grey to green mudstone, siltstone and sandstone some with calcareous content; minor red polymictic
conglomerate; and volcaniclastics.
The aims of this study were (1) to review the spring zooplankton versus autumn zooplankton of a shallow polymictic
lake; (2) to assess how much the zooplankton of the transition seasons, i.e.
In general, the ecosystems presented polymictic
regimes with warm, alkaline, well-oxygenated and eutrophic waters during the entire study period.
The most characteristic feature of the Cisna Beds is the occurrence of grey (grey-brown on weathered surfaces), thick-bedded (even more than 3m), fine-to coarse-grained, polymictic
sandstones with calcareous-siliceous cement (so-called Cisna-type sandstones).
This influence might occur especially in Lake Chapala, which is a shallow, polymictic
, and turbid lake where suspended montmorillonite clays may enhance conditions for the bacteria by providing a surface for the adsorption, photodegradation, and desorption of dissolved organic carbon (Tietjen et al., 2005).
The water column is frequently mixed and the lakes are therefore referred to as polymictic
. Some shallow lakes appear turbid due to inorganic matter stirred up from the sediment.
It belongs to the group of shallow, polymictic
lakes, with no fully developed vertical stratification.
The Fuenteobejuna section is 140 m thick, mostly composed of limestones, shales and polymictic
breccias in the upper part.
The lake belongs to the polymictic
type of lakes, where complete mixture of the water body takes place several times a year.