Zooplankton in Ancient and Oligotrophic Lake Ohrid (Europe) in Association with Environmental Variables

Abstract

Zooplankton is studied in the ancient, tectonic, oligomictic and oligotrophic Lake Ohrid (Macedonia, South Eastern Europe). The main aim of this study was to assess the seasonal and spatial patterns of the zooplankton functional feeding guilds in relation to the environmental conditions. Metalimnion of the lake was detected as the most productive environment, where biomass of the phytoplankton and abundance of the zooplankton reached their maxima. Pelagial zooplankton of low abundance (25 ± 22 ind. L -1 ) consisted of 16 species including two endemic copepods, Arctodiaptomus steindachneri (Richard, 1897) and Cyclops ochridanus (Kiefer, 1932). Copepods obtained remarkable share (60%) in the zooplankton assemblage. Microphagous zooplankton was mainly comprised of the most abundant rotifer Kellicottia longispina (Kellicott, 1879) in summer, and copepod nauplii during the spring Eudiaptomus gracilis (Sars, 1862) and C.ochridanus, and autumn C.ochridanus. Due to their requirements for the bacterio-detritus suspension, this microphagous zooplankton occupied aphotic hypolimnion during the entire study period. Raptorials were typically represented by copepodites and adult copepods in the metalimnion, and were significantly and positively affected by temperature (r = 0.417, p = 0.001), dissolved oxygen (r = 0.463, p = 0.0001) and, particularly, phytoplankton biomass (r = 0.708, p < 0.00001). This is the first study in which the link between the lower and higher trophic levels is investigated in Lake Ohrid.

Zooplankton communities in three adjacent softwater lobelia lakes of slightly differentiated morphology and trophic state

“…5. Principal component analysis (PCA) with abundance of zooplankton dominating species (Apri -Asplanchna priodonta; Cuni -Conochilus unicornis; Gsty -Gastropus stylifer; Klon -Kellicottia longispina; Kcoc -Keratella cochlearis; Kqua -Keratella quadrata; Kser -Keratella serrulata; Prem -Polyarthra remata; Pvul -Polyarthra vulgaris; Tins -Trichocerca insignis; Anan -Alonella nana; Blon -Bosmina longispina; Cqua -Ceriodaphnia quadrangula; Cpul -Ceriodaphnia pulchella; Egra -Eudiaptomus gracilis) and environmental factors (Chl a -chlorophyll-a concentration, TN -total nitrogen, TRP -total reactive phosphorus, Cond -conductivity, pH) and lakes Tasevska et al 2017). Rotifers dominated over crustaceans, which suggests the presence of fish in all the water bodies (Helenius et al 2015).The highest share of rotifers was found in Pomysko Lake;,rising contents of total nitrogen as well as chlorophyll a had a positive impact on the densities of some rotifer species (Polyarthra remata, Polyarthra vulgaris, Trichocerca insignis) in this lake.…”

The Use of Zooplankton Metrics to Determine the Trophic Status and Ecological Potential: An Approach in a Large Mediterranean Watershed

“…Worldwide, in waterbodies with different environmental conditions, several studies have used the whole zooplankton community as an indicator [7,[18][19][20][21] or used only specific zooplankton groups, such as rotifers or microcrustaceans [22][23][24][25]. Recently, within the Iberian Peninsula, the use of zooplankton species as indicators of trophic status in reservoirs has been evaluated in different basins such as Ebro [26,27], Cavado [28], and Jucar [29].…”

Small Standing-Water Ecosystems in the Transitional Temperate Climate of the Western Balkans

“…Zooplankton organisms, with main groups: Rotifera, Cladocera and Copepoda (Fig. 2.3), contribute significantly to the aquatic ecosystem diversity, play a pivotal role between primary producers and higher trophic levels, and are also known as very sensitive indicators of the environmental alterations [31][32][33][34][35][36][37]. Zooplankton indicator value arises from rapid growth, numerous populations and quick response to deteriorated environmental conditions, and application of zooplankton traits as a tool in the ecological assessment should be developed for small-shallow ecosystems [6,38].…”

“…In zooplankton diversity rotifer share 80% (120 species), while distinctly lower contributed Cladocera and Copepoda, 16% and 6%, 25 and 16 species, respectively (Table 2.2). Many species recorded in this survey as limited to specific region, are previously recorded across the studied region, but probably in different seasons and/or different localities [7,35,[43][44][45][46][47][48].…”