Effect of metalimnetic gradient on phytoplankton and zooplankton (Rotifera, Crustacea) communities in different trophic conditions

Abstract

Theory predicts and recent study revealed that depth of the thermocline can strongly influence the nutrient availability and composition of plankton communities. We are focused on the effect of metalimnetic gradients on water chemistry and plankton communities in three stratified lakes with different trophic conditions. Vertical changes in water chemistry revealed significant increase of macroelement concentrations in the metalimnion of all studied lakes. However, there was no significant increase of nutrient concentrations in the thermocline of lakes with smoother metalimnetic gradient, whereas sharp and deep thermocline zone caused higher concentration of orthophosphates and dissolved inorganic nitrogen in the metalimnion. The maximum concentrations of phytoplankton were observed just below the thermocline and were caused mostly by the abundance of diatoms and cryptophytes. Vertical distribution of the crustacean zooplankton was similar to the distribution of phytoplankton. Especially, Daphnia cucullata was strongly related with the phytoplankton distribution and reached maximum densities in deep layers with high chlorophyll concentrations, and, conversely, smaller crustacean species and rotifers were not affected by the vertical distribution of phytoplankton.

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

“…The abundance of zooplankton in the metalimnion could be argued from several points of view. The peculiar environmental conditions in this transitional layer have also been observed in other studies (Cantin et al, 2011;Karpowicz and Ejsmont-Karabin, 2017). For instance, the non-significant difference in vertical distribution of the nutrients was in compliance with the orthograde regime in oligotrophic lakes.…”

Evaluation of FluoroProbe® performance for the phytoplankton-based assessment of the ecological status of Mediterranean coastal lagoons

“…Phytoplankton taxonomy-based tools are already available, but they require important laboratory efforts and a solid expertise, particularly for the correct identification of organisms. Alternative approaches that exploit the fluorescence properties of algae, such as the spectrofluorometer Fluoroprobe®, are now routinely used in freshwater ecosystems Švanys et al 2014;Patidar et al 2015;Maloufi et al 2016;Morgan-Kiss et al 2016;Poxleitner et al 2016;Silva et al 2016;Wang et al 2016;Blottière et al 2017;Cyr 2017;Karpowicz and Ejsmont-Karabin 2017;Giling et al 2017;Teufel et al 2017). However, the performances of this instrument have never been formally assessed in Mediterranean coastal ecosystems, where both environmental conditions and the composition of phytoplankton assemblages are hugely variable and different from those of freshwater systems.…”

“…FluoroProbe® contains five light-emitting diodes (450, 525, 570, 590, and 610 nm) for excitation of the accessory pigments associated with the photosystem-II antenna system of phytoplankton and one 370 nm diode for excitation and subsequent subtraction of the fluorescence from chromophoric dissolved organic matter (CDOM). This technology is now widely applied in very different environments by scientists and freshwater resource managers for lab and in situ studies of phytoplankton communities (Rolland et al 2010;Catherine et al 2012Catherine et al , 2016Švanys et al 2014;Patidar et al 2015;Maloufi et al 2016;Morgan-Kiss et al 2016;Poxleitner et al 2016;Silva et al 2016;Wang et al 2016;Blottière et al 2017;Cyr 2017;Karpowicz and Ejsmont-Karabin 2017;Giling et al 2017;Teufel et al 2017). FluoroProbe® main advantage is the immediacy of the performed measurements, although it does not give the same level of taxonomic precision as microscopybased methods, and may significantly underestimate the biomass when phytoplankton communities are very dense (i.e., chlorophyll a > 250 μg L −1 , Wang et al 2016), or in samples with very low biomasses (Bradie et al 2018).…”

Изучение Вертикального Распределения Зоопланктона Запорожского Водохранилища Для Расчёта Зарыбления Пёстрым Толстолобиком

“…1). Эффект второго дна также отмечается в литературе [3,4,11,23], в данном слое происходит концентрация взрослых особей. Так, в 1960-е гг.…”

“…В днепровских водохранилищах вертикальное распределение зоопланктона профундали исследовалось В. А. Яковенко [14], а литорального зоопланктона -В. М. Трохимцом с соавторами [12]. В то же время имеются многочисленные работы по вертикальному распределению зоопланктона водоёмов России [4,11,29] и других стран [15,17,21,23,24].…”