Seasonal vertical distribution and diel migration of zooplankton in a temperate stratified lake

Abstract

The investigation of the vertical distribution of the zooplankton community in the temperate Lake Trichonis during four seasons in 2005, showed the existence of vertical segregation among species, ontogenetic stages and sexes within and between the major groups. In each season, the two or three more abundant rotifer species distributed at separate depth layers, while this feature was maintained during the entire 24 h period, since no diel vertical migrations (DVM) were performed. In contrast, the crustacean community, comprised mainly by the calanoid copepod Eudiaptomus drieschi and the cladoceran Diaphanosoma orghidani, showed various patterns of DVM, being more pronounced in spring and summer. Females of E. drieschi distributed deeper than males, while the copepod nauplii were found mainly in the surface layer in all four seasons. Temperature was the most important abiotic factor affecting directly and indirectly the vertical distribution and migration of various species. During stratification, the metalimnion was the most productive layer in Lake Trichonis, having maximum values of dissolved oxygen and low transparency due to high concentration of organic matter and phytoplankton. The DVM patterns of the crustaceans indicate that the metalimnion acts probably as a daylight refuge against predation by Atherina boyeri, which is the dominant planktivorous fish in the lake.

Zooplankton dynamics in a gypsum karst lake and interrelation with the abiotic environment

“…This resembled the pattern described for Lake Trichonis by Doulka & Kehayias (2008, 2011 and, considering that most of the species were common between the two lakes, is pointing the influence of certain elements in the adaptation of this spatial distribution. In accordance with the present results, Doulka & Kehayias (2008) reported that the main factor affecting the group of copepods in Lake Trichonis was the concentration of dissolved oxygen, especially for the calanoid E. drieschi and nauplii.…”

“…In addition, some crustacean species can survive in hypoxic and even anoxic conditions for a small period of time using hypoxic zones not accessible to fish as a potential refuge against fish predation during the daylight, while migrate towards shallower depths in the night (Vanderploeg et al 2009). Doulka & Kehayias (2011) showed that most of the crustacean species found in the lake along with D. polymorpha larvae, present various types of diel vertical migration (DVM) with the general trend to be the ascent in shallower depth during the night. Although there is no information for the existence of DVM in Lake Amvrakia, as sampling was conducted only in morning hours, this ethological adaptation could explain the presence of zooplankton organisms in such unfavorable conditions during the day.…”

Zooplankton and environmental factors of a recovering eutrophic lake (Lysimachia Lake, Western Greece)

“…The seasonal variation of total phosphorus is similar to that described in the nearby lakes Trichonis (Doulka 2010;Doulka & Kehayias 2011) and Amvrakia (Chalkia et al 2012a) where elevated concentrations were recorded during warmer months, near to the bottom. High chl-a values were recorded in autumn as also reported by Overbeck et al (1982) and the maximum concentrations were found to be similar.…”

Vertical variability of pelagic zooplankton fauna in deep Latvian lakes, with some notes on changes in ecological conditions

“…Many reviews and investigations emphasize this (e.g. Stich & Lampert, 1981;Primicerio & Klemetsen, 1999;Primicerio, 2000;Kehayias et al, 2004;Kessler & Lampert, 2004;Pinel-Alloul et al, 2004;Ka et al, 2006;Trifonova & Makartseva, 2006;Adamczuk, 2009;Doulka & Kehayias, 2011).…”