Agnieszka Pociecha

Alien cyanobacteria: an unsolved part of the “expansion and evolution” jigsaw puzzle?

Abstract Some algal species have extended their native range. Problems in settling on a proper definition of ‘alien’ for microorganisms have made it difficult to unequivocally assess whether their spread was natural or resulted from human intervention. As direct evidence seems to be virtually non-existent, the only option is to rely on circumstantial evidence. In this paper, we discuss the expansion routes of three cyanobacteria species: Cylindrospermopsis raciborskii, Raphidiopsis mediterranea and Cuspidothrix issatschenkoi. We analyse the information available for these species, which are commonly regarded as alien, in order to establish the context in which the migration and evolution of these microorganisms should be understood, so that a proper assessment of their geographic expansion can be made. A more complete picture of the expansion and evolution of microorganisms must combine many types of information, including the history of local expansions, ecological ranges, and data from studies in morphology, ecology, genetics and paleolimnology.

Comments on the diet of Asplanchna priodonta [Gosse, 1850] in the Dobczycki dam reservoir on the basis of field sample observations

Comments on the diet of Asplanchna priodonta (Gosse, 1850) in the Dobczycki dam reservoir on the basis of field sample observations During a monitoring programme the diet composition of Asplanchna priodonta was studied. Samples were collected every month from the deepest part of the Dobczycki dam reservoir (Southern Poland). The diet of A. priodonta, which included colonial cyanobacteria, diatoms, dinoflagelates and protozoa, indicated that it is both a grazer and a predator. These results support the hypothesis that A. priodonta is an opportunistic feeder. Additionally these results include the first observations of the protozoan Tintinnopsis sp. as a food source of Asplanchna.

Phyto- and zooplankton in fishponds contaminated with heavy metal runoff from a lead-zinc mine

This investigation focused on plankton inhabiting fishponds, which previously received mine waters from the lead-zinc mine ‘Matylda’, located in southern Poland (Upper Silesia). The purpose of the investigation was to study the effects of chronic and persistent contamination of fishpond bottom sediments with heavy metals originated from the lead and zinc mine. The phyto-and zooplankton in the four fishponds were dominated by diatoms, green algae and rotifers. Plankton composition of the reference non-contaminated pond was different, since Chrysophytes dominated, and Copepoda were the most numerous among zooplankton. In the contaminated fishponds, we observed teratological forms, both for phyto-and zooplankton species, but only as individuals. Our results showed that planktonic communities had adapted to chronic and persistent heavy metal contamination.

A preliminary study on the plankton assemblages of Lough Derg (Ireland) during a winter-spring season

A preliminary study on the plankton assemblages of Lough Derg (Ireland) during a winter-spring season During a winter-spring season, physicochemical variables and plankton dynamics were studied in Lough Derg (Ireland). Samples were collected monthly from three water layers (surface, middle and bottom) at a deep central sampling point on the lake. As expected, phyto- and zooplankton densities and chlorophyll a concentrations were low during the study period, probably reflecting low temperatures and wind-driven turbulence typical of the winter-spring period. Diatoms and rotifers were the most abundant phyto- and zooplankton groups, respectively.

Biodiversity of rotifers in urban water reservoirs of Southern Poland

Abstract Rotifer diversity was studied in three different types of artificial water bodies situated in one of the largest cities in Poland. The bodies of water were as follows: a fountain in a city park, the Nowa Huta dam reservoir, and the Bagry gravelpit. The lowest number of rotifer species (23) was noted in the urban fountain, and the highest (36) in the Bagry gravel-pit lake. Rotifers’ communities in the investigated water reservoirs showed different levels of diversity and density. The most numerous species in the dam reservoir was Trichocerca similis (2511 ind. l-1) and in the Bagry gravel-pit lake was Polyarthra dolichoptera (2634 ind. l-1). However, the most abundant species in the fountain was Brachionus urceolaris (863 ind. l-1). The highest values of Shannon and evenness diversity indices were found in the Bagry gravel-pit lake (H’ = 2.521, J’ = 0.783), while the lowest in the urban fountain (H’ = 0.568, J’ = 0.258). The DCA analysis (Detrended Correspondence Analysis) showed that the diversity of rotifers communities in the studied reservoirs was related to the concentration of magnesium and calcium, and to water conductivity.

Spatial distribution of zooplankton in a cascade system of Pomeranian dam reservoirs (Hajka, Rosnowo), northern Poland

Spatial distribution of zooplankton in a cascade system of Pomeranian dam reservoirs (Hajka, Rosnowo), northern Poland The structure of the zooplankton community and its spatial distribution were examined in two stratified rheolimnic Pomeranian reservoirs, Rosnowski (7 sampling sites) and Hajka (4 sampling sites), in July 1999. These reservoirs are part of the cascade system situated on the Radew River in northern Poland. In the Rosnowski reservoir 34 species of zooplankton were identified and in Hajka, 32. The two dominant species of rotifers in both reservoirs were Keratella cochlearis f. tecta and Polyarthra vulgaris. The dominant copepod and cladoceran species in both reservoirs were Mesocyclops leuckarti and Daphnia cucullata, respectively. Along the longitudinal axis of both reservoirs, rotifers were the dominant group at all sampling sites, except for the hypolimnion layer in both reservoirs and the metalimnion layer in Hajka reservoir at site H1. This initial study was undertaken in order to determine the spatial distribution of rotifer, copepod and cladoceran communities in riverine reservoirs built in the cascade system.

Is zooplankton an indicator of the water trophic level in dam reservoirs

Abstract The trophic state of ten dam reservoirs was assessed using a zooplankton community. In order to determine the trophic state of dam reservoirs, we used indices calculated on the basis of density and species structure of Rotifera and Crustacea communities. Samples were collected once during summer 2012 in ten dam reservoirs. The largest numbers of zooplankton taxa were found in a lowland high meso-eutrophic dam reservoir (Koronowski) and the lowest ones in a submontane low eutrophic dam reservoir (Lubachowski). The trophic state was determined for the investigated dam reservoirs. In the case of the Rotifera community, the percentage of the tecta form in the Keratella cochlearis population and the proportion of high-trophic species in the total species density were the best indices to describe the water trophic status. In the case of the crustacean community, the best indices were the density of Crustacea and the biomass of Cyclopoida. The high value of all indices calculated on the basis of density and species structure of Rotifera and Crustacea was determined for Zygmunt August Lake, whose trophic status was defined as highly eutrophic to polytrophic. Our study has shown that zooplankton could be a good ecosystem indicator of the water trophic level in dam reservoirs.

Has zooplankton 24 hour vertical distribution pattern in Lough Derg (Ireland) been changed over the period of ∼90 years?

The vertical distribution of zooplankton was examined in Lough Derg, Ireland. Zooplankton was collected at one location every 2 m from the surface to the bottom during 24 hours at four-hour intervals. Zooplankton was identified to the species level and its density was calculated for each taxon, depth and hour. We recorded 9 rotifer, 3 copepod, and 4 cladoceran species. The highest total zooplankton density (rotifers, copepods, cladocerans, mysids and zebra mussel larvae) was recorded at 3 a.m. Rotifers preferred mainly a depth from 0 to 8 m, while copepods and cladocerans were observed within the whole water column during a 24 hour observation. It was a different pattern of diurnal migration than that Southern and Gardiner (1932) received, though they didn’t study rotifers. Probably food concentration and/or predators, or other environmental factors could influence the diel vertical migration of zooplankton from Loug Derg.