Chrysophycean stomatocysts associated with the carnivorous plants (genus Utricularia) from Jeleniak-Mikuliny Nature Reserve

An account is given of chrysophycean stomatocysts and algae occurring together with the carnivorous plants known as bladderworts, Utricularia intermedia, U. minor and U. australis, in the peat bog of Jeleniak-Mikuliny Nature Reserve. Eleven chrysophycean stomatocyst morphotypes were found, all reported for the first time from this nature reserve. Among them, two are new records for Europe (stomatocysts 330 and 208) and another two are new for Poland (stomatocysts 112 and 387). Descriptions are provided together with SEM illustrations. General data about cyanobacteria and eukaryotic algae occurring with these stomatocysts are enumerated

Development of

This paper reports data on a community of Trachelomonas species (Euglenophyta) occurring during Planktothrix agardhii bloom formation in a shallow, highly eutrophic dam reservoir. The results come from a long-term study of Siemianówka Dam Reservoir, located on the upper Narew River (NE Poland). From April to October 2007, 132 alga taxa were identified, including 32 Trachelomonas taxa, 23 of which are new for the reservoir; of those, three are first records for Poland: T. armata (Ehrenberg) Stein var. heterospina Swirenko, T. atomaria Skvortzov var. minor Hortobagi and T. minima Dreżepolski. One variety, T. curta var. pappilata Wołowski, is described as new for science. The ultrastructural details of Trachelomonas species are illustrated. The highest number of Trachelomonas taxa was recorded in August in the shore zone of the reservoir. At the end of summer 2007, the conspicuous development of P. agardhii (Gomont) Anagnostidis et Komarek, caused a rapid decrease of Trachelomonas biomass due to lower water transparency and the oxygen concentration. In addition, a decline in the Trachelomonas taxa and biomass was associated with a decrease of water temperature. The negative impact of extracellular microcystin on the Trachelomonas development requires further study.This study reveals for the first time an interaction between toxic strains of Planktothrix agardhii and communities of Trachelomonas taxa (Euglenophyta) in an eutrophic shallow reservoir during bloom formation by toxic P. agardhii. We summarize taxonomical and ecological data for 23 Trachelomonas taxa including 3 new taxa for Poland, and 1 variety new to science

Algae commensal community in Genlisea traps

The community of algae occurring in Genlisea traps and on the external traps surface in laboratory conditions were studied. A total of 29 taxa were found inside the traps, with abundant diatoms, green algae (Chlamydophyceae) and four morphotypes of chrysophytes stomatocysts. One morphotype is described as new for science. There are two ways of algae getting into Genlisea traps. The majority of those recorded inside the traps, are mobile; swimming freely by flagella or moving exuding mucilage like diatoms being ablate to colonize the traps themselves. Another possibility is transport of algae by invertebrates such as mites and crustaceans. In any case algae in the Genlisea traps come from the surrounding environment. Two dominant groups of algae (Chladymonas div. and diatoms) in the trap environment, show ability to hydrolyze phosphomonoseters. We suggest that algae in carnivorous plant traps can compete with plant (host) for organic phosphate (phosphomonoseters). From the spectrum and ecological requirements of algal species found in the traps, environment inside the traps seems to be acidic. However, further studies are needed to test the relations between algae and carnivorous plants both in laboratory conditions and in the natural environment. All the reported taxa are described briefly and documented with 74 LM and SEM micrographs

Diversity of algae in a thallium and other heavy metals-polluted environment

Thallium (Tl) compounds are extremely toxic to living organisms, including algae, but there is a dearth of basic information regarding the mechanisms of action of Tl in the environment and its effects on algae in natural conditions. This study examined algal diversity in an environment highly polluted by Tl. Graniczna Woda stream is contaminated by Tl and other heavy metal compounds (Cd, Pb and Zn). There we found 66 algae taxa representing five phyla, among which euglenophytes prevailed. We found that euglenophytes, including Phacus species, can survive and can show high species diversity in the presence of high Tl concentrations. The fact that these small organisms covered only by a pellicle are able to thrive in such inhospitable habitat, shows a great plasticity of these organisms. It is unclear whether the algae of Graniczna Woda stream have a broad tolerance to harmful conditions or rather represent new varieties/clones that evolved in metal-contaminated waters and are adapted to this environment

Aging of Utricularia traps and variability of microorganisms associated with that microhabitat

Various authors have described algae in aquatic Utricularia traps as commensals, as stress factors or as prey. This study examined the diversity and abundance of organisms (prey, algae, protozoa and bacteria) in the traps of aquatic Utricularia reflexa in relation to prey occurrence and trap age. The number of organisms increased with the trap age. In both young and old traps, phytoplankton dominated of all organisms found. In young traps, Scenedesmus spp. and Characiopsis sp. were the most abundant algae, while Scenedesmus spp. and the palmelloidal form of Euglena spp. dominated in the old traps. Most of the algal species found stayed alive in the trap environment. The number of living algae and ciliates inside the traps increased with the increasing trap age, too. As the number of Paramecium bursaria inside traps consistently increased with the trap age and number of bacteria, which serve as a food for them, ciliates can be regarded as commensals, but not as prey for the plant. The predominant organisms in the traps were those that can be considered either commensals or intruders, exceeding captured macroscopic prey

Asynchronous multitrophic level regime shifts show resilience to lake browning

Lake browning is widespread due to increased supply of dissolved organic carbon under climate warming and nitrogen deposition. However, multitrophic level responses to lake browning are poorly understood. Our study aims to explore such responses across multitrophic levels based on sedimentary records of diatoms, chrysophyte stomatocysts and chironomids in a remote headwater lake in the Three Gorges Reservoir region, central China. Although all biotic proxies were analysed in the same core, the timing of shifts in chironomids (1886 ± 18 CE) preceded that in chrysophyte stomatocysts (∼1914 ± 10 CE) and diatoms (∼1941 ± 6 CE). Shifts in biotic communities were closely linked to rising temperature, δ15N depletion (a proxy for nitrogen deposition), δ13C enrichment (a proxy for littoral moss expansion), as well as biotic interactions, whereas the relative importance of the driving forces varied among the three biotic groups. Our results suggest that the zoobenthos grazing effect might be more important than bottom-up pathways in humic environments. Additionally, the coexistence of benthic, littoral and pelagic algae after the 1950s suggested that mixotrophic chrysophytes could reduce lake browning through heterotrophic processes and sustain the ecological equilibrium between littoral, pelagic and benthic productivity. Therefore, lake browning ecosystem regime shifts require analyses of multiple trophic levels. Our results suggest that heterotrophy may become more important in lake ecosystem carbon cycling with water brownification in Mulong Lake, as well as similar montane lakes