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Phosphorus forms in the sediment of seagrass meadows affected mainly by fungi rather than bacteria : a preliminary study based on 31P-NMR and high-throughput sequencing

Zhao Muqiu, Wang Hui, Wang Shuai, Han Qiuying, Shi Yunfeng

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 4

408--420

EN

Microorganisms play an important role in the circulation of phosphorus (P) in the sediment of coastal wetland ecosystems. In this study, solution 31P nuclear magnetic resonance (NMR) was used to determine different forms of P in the sediments of four different seagrass meadows and a bare tidal flat, while high-throughput 16S and ITS rRNA gene sequencing was used to determine the microbial community composition. The solution 31P-NMR spectra revealed six forms of the P compounds detected by the NaOH-EDTA extraction of sediments, where Ortho-P was the most dominant P compound, followed by Mono-P. The Po compounds were more varied in the seagrass meadow sediments and more abundant compared to the bare tidal flat. Bacterial communities in the sediments collected from E. acoroides and fungal communities in the bare tidal flat were relatively different from those at the other sites. The relative abundance of P-cycling-related fungi belonging to the phylum Ascomycota was 26.20% and was much higher than that of bacteria (only 0.29%) belonging to the class Bacilli. Mono-P was the major factor determining the distribution of P-cycling-related fungi and negatively correlated with the relative abundance of Aspergillus and Trichoderma. We believe that fungi can affect P forms in the sediment of seagrass meadows more than bacteria.

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Effect of selenium application on some oxidoreductive enzymes in loamy sand contaminated with diesel oil

Stręk M., Telesiński A.

Environment Protection Engineering

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2017

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Vol. 43, nr 1

151--160

EN

The aim of the study was to assess the impact of diesel oil on the activity of oxidoreductases in loamy sand, and to evaluate effect of selenium addition in the restoration of homeostasis of soil contaminated with diesel oil. The experiment was carried out under laboratory conditions with loamy sand. 0.05 mmol/kg of selenium (Se(IV) or Se(VI)), and diesel oil in the doses of 2, 10 and 50 g/kg were added to the soil samples. In soil treated with selenium and diesel oil activities of dehydrogenases, catalase, o-diphenol oxidase and nitrate reductase were measured on 1, 7, 14, 28, 56 and 112 day of the experiment. Contamination with diesel oil did not cause significant changes only in the activity of o-diphenol oxidase. The highest increase was observed in activity of dehydrogenases. Selenium limited hydrocarbons impact on activity of soil oxidoreductases, especially in loamy sand with diesel oil in the dose of 10 g/kg. Obtained results showed that this effect was reduced after treatment with selenium in both oxidation states but for nitrate reductase and catalase this reduction was reported after application of Se(VI) and Se(IV), respectively.

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Microbial transformations of fossil organic matter of kupferschiefer black shale – elements mobilization from metalloorganic compounds and metalloporphyrins by a community of indigenous microorganisms

Matlakowska R., Ruszkowski D., Sklodowska A.

Physicochemical Problems of Mineral Processing

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2013

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Vol. 49, iss. 1

223--231

EN

The presented article describes the role of community of indigenous microorganisms occurring in the Kupferschiefer black shale in elements mobilization from fossil organic matter of the deposit. The short description of metalloorganic compounds and metalloporphyrins extracted from black shale was presented as well as the characterization of indigenous microorganisms. The processes of fossil organic matter colonization, biofilm development and elements mobilization accompanying bacterial growth was summarized.

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Daphnia: model herbivore, predator and prey

Lampert Winfried

Polish Journal of Ecology

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2006

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Vol. 54, nr 4

607-620

EN

In the past 30 years, Daphnia has become a model organism in aquatic ecology. I review the changing concepts and paradigms in plankton ecology as reflected in the work on Daphnia. The availability of radiotracers favoured a new physiological approach that resulted in better energetic models and more reliable estimates of filtering rates. This led to deeper insights into the role of herbivore grazing on phytoplankton and microbial communities, and nutrient recycling. It provided a conceptual basis for general hypotheses on predictable seasonal successions (e.g. the PEG model). On the other hand, increasing knowledge about selective predation on zooplankton triggered population dynamic models and gave explanations for changing community structures. The Size-Efficiency-Hypothesis generated a framework for studies on trade-offs between competitive ability and susceptibility to predation. Daphnia was now in the centre of interaction-based concepts, being predator and prey at the same time. It was the backbone of practical applications of the theory in food-web manipulations. When ultimate factors came into the focus, Daphnia played an important role in explaining striking phenomena like diel vertical migration and cyclomorphosis. Its central position in food-webs, the unique propagation mode, easy cultivation and accessibility by molecular genetic methods made it a favourite object for studies in evolutionary ecology, concerning local adaptation, evolution of defences and life histories, induced phenotypic change, and genetic diversity. The large advantage of Daphnia over other biological model organisms is that its importance in pelagic freshwater systems is undoubtedly known. Hence there is a direct way of applying the results to ecological systems.

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Surface microlayer in lakes of different trophic status : dissolved organic matter and microbial community

Kostrzewska-Szlakowska I.

Polish Journal of Ecology

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2005

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Vol. 53, nr 3

341-351

EN

The aim of this paper was to recognize the abundance and frequency of occurrence of neustonic organisms (i.e. bacteria and algae) and accumulation of organic matter in the surface microlayer of three lakes of various trophic status. Water samples of surface microlayer (0.5-0.6 mm) were taken (with Larsson plate) as well as from respective epilimnion layer (0.5 m deep). The samples were collected from shallow, humic (Sphagnum bog) lake (L. Flosek), shallow, eutrophic (L. Zełwążek) and deeper, mesotrophic lake (L. Kuc) in the period May-October during several years. The ratio of the organisms' density in the surface microlayer to that in deeper (0.5 m) layer was considered as the enrichment factor (Ef). Heterotrophic bacteria accumulation in the surface microlayer was more frequent in the humic lake (75% of samples), than in meso- and eutrophic lakes (64%). Mean Ef values for bacteria ranged from 1.3 to 1.4. Frequent, but not strong accumulation of dissolved organic matter measured as the absorbance A254 was noted in the surface microlayer. Dissolved organic carbon (DOC) measured in automatic analyzer showed much stronger accumulation in microlayer, particularly in humic lake. Concentration of chlorophyll a in the surface microlayer was found as the most fluctuating and the highest mean Ef value was found in the mesotrophic lake (Ef = 6.3). An attempt was undertaken to explain these differences between the lakes in terms of variable ratio between allochthonous and autochthonous production in humic, mesotrophic and eutrophic lakes.