Wyniki wyszukiwania - Biblioteka Nauki

1

Growth rates of common pelagic ciliates in a highly eutrophic lake measured with a modified dilution method

100%

Rychert K.

|

2016

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tom Vol. 45, No. 2

216--229

PL

The growth rates of ciliates estimated under natural conditions with the widely used size fractionation method are much lower than those observed in cultures. However, recent studies performed with a modified dilution method demonstrated that the size fractionation method underestimates the ciliate growth, because it does not remove predators of the same size as the organisms studied. Thus, it is still unresolved whether ciliates are food-limited in different systems and whether their growth rates are indeed lower than those in cultures. This study was conducted in highly eutrophic Lake Gardno using a modified dilution method. Each time, two dilution experiments were performed (around noon and around midnight). Four small, common ciliates from the genera Rimostrombidium, Tintinnidium, Cyclidium, and Urotricha were studied. The first three ciliates demonstrated very high mean diel growth rates exceeding 0.1 h-1, which corresponded well to the highest values reported in the literature for the ciliate growth in cultures at similar temperatures. Tintinnidium sp. demonstrated a diel growth rhythm. Urotricha sp. was sensitive to the experimental procedure, and measurements of its growth were unsuccessful. Concentrations of food particles were analyzed to check whether organisms studied were food satiated.

2

Nanoflagellates in the Gdańsk Basin: coexistence between forms belonging to different trophic types

100%

Rychert K.

Oceanologia

|

2006

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tom No. 48 (2)

323-330

EN

Nanoflagellates are important bacterivores, but their role is often underestimated because forms capable of phagotrophy and containing chlorophyll (mixotrophs) are excluded from analyses. Research conducted in the coastal zone of the Gdańsk Basin (Baltic Sea) revealed seasonal changes in the relationship between the biomasses of small (1-8 žm) nanoflagellates with (NFChl+) and without chlorophyll (NFChl-). Three distinct patterns were distinguished: (i) spring, when the biomass of NFChl+ was lower than that of NFChl-, (ii) summer and autumn, when NFChl+ were dominant (about 90%), and (iii) late autumn and winter, when the prevalence of NFChl+ was lower (71-79\%). Additional studies showed the existence of spatial differences in the composition of the nanoflagellate community. These spatial differences were not shaped by freshwater input. The possible importance of mixotrophic forms in the Gdańsk Basin is discussed.

3

Communities of heterotrophic protists (protozoa) in the near-bottom zone of the Gdansk Basin

100%

Rychert K.

|

tom 40

|

nr 3

4

The size structure of the Mesodinium rubrum population in the Gdańsk Basin

100%

Rychert K.

Oceanologia

|

2004

|

tom No. 46 (3)

439-444

EN

The ciliate Mesodinium rubrum Lohmann 1908 (=Myrionecta rubra Jankowski 1976) is an important phototrophic organism in the Gdańsk Basin. In June 2002 the vertical distribution and size structure of the M. rubrum population were studied. Its presence was generally observed in the whole water column (one exception was the anoxic near-bottom zone in the Gdańsk Deep) at all stations studied. Maximum abundance (18300 cells dm-3) was recorded at 26 m depth at the station located in the inner Gulf of Gdańsk. Analysis of the size structure of the counted organisms demonstrated the co-existence of small and large cells of M. rubrum in the upper layer of the water column and a gradual increase with depth of the prevalence of large specimens. This shows that at least two forms of M. rubrum exist in the region studied. Deep migrations are probably undertaken only by relatively large organisms.

5

Planktonic ciliates in the coastal medium-size river: diversity and productivity

100%

Rychert K.

|

2009

|

tom 57

|

nr 3

503-512

EN

Annual changes in abundance, biomass, and taxonomic composition of potamoplanktonic ciliates were assessed in the 139 km long, coastal (Baltic coast) river (the Słupia River, Northern Poland) having mean annual flow – 18 m³ s⁻¹and flowing through several natu ral lakes and reservoirs. The samples were taken from one site, once a week from December 2005 to December 2006, then concentrated by sedimentation and counted and measured under an inverted microscope. Ciliate production was assessed with relevant published formulas. Mean annual abundance and biomass amounted to 6448 cells l⁻¹ and 6.60 μg C l⁻¹, respectively. During the year two distinct peaks of biomass were observed: a spring peak in April and May, and a winter one in December. Spring peak was formed by prostomatids and oligotrichs, whereas winter one by peritrichs. Three aforementioned orders contributed altogether to 64% of abundance and 82% of ciliate biomass. Prevalence of prostomatids seemed to be characteristic for the studied river. Most of ciliates were surprisingly small, fraction below 20 μm contributed 77% of the mean annual abundance. Domination of small ciliates indicated high mean annual potential growth rates ranging from 0.6 d⁻¹ to 0.7d⁻¹. The river is characterised by a narrow variability of the water level and numerous through-flow lakes. As a result ciliate community in the river resembled communities encountered in lakes – free-swimming organisms dominated and sessile forms and those detached from sediments contributed not more than one fifth of ciliate biomass.

6

Dependence between temperature and clearance rate of Balanion comatum Wulff

100%

Rychert K.

|

nr 2

EN

The dependence between temperature and clearance rate of the ciliate Balanion comatum Wulff 1919 was assessed in the coastal zone of the southern Baltic Sea. Five in situ experiments were carried out with the use of wheat starch as a surrogate of food particles. The clearance rate rose from 1.4 to 7.0 μl cell−1 h−1 with a temperature rise from 8 to 19◦C. B. comatum preferred particles of size 1.9–4.4 μm, and the clearance rates calculated for the preferred particles were consistently higher than those measured for the whole range of particles ingested (Wilcoxon’s signed rank test, p = 0.04). The exponential dependence between temperature and clearance rates for preferred particles was statistically significant (R2 = 0.86, p = 0.02) and enabled the Q10 coefficient to be calculated. This amounted to 2.9 and lay within the range of typical values. The linear dependence (also drawn for preferred particles) demonstrated a higher significance (R2 = 0.91, p = 0.02), indicating the linear dynamics of the process.

7

Particle size selectivity of two marine ciliates - Balanion comatum Wulff and Strombidium sp.

100%

Rychert K.

Polish Journal of Ecology

|

2008

|

tom 56

|

nr 2

251-257

EN

Food selectivity of marine ciliates Balanion comatum Wulff and Strombidium sp. (mean size of cell 19 μm) were studied in situ during incubation with wheat starch particles as a surrogate food. Range of particles ingested by Balanion comatum was 1.25–7.50 μm with preference for 3.75 μm particles (statistically significant result). Strombidium sp. engulfed particles ranging from 1.25 μm to 5.00 μm also with preference for 3.75 μm particles. In the Baltic Sea size range of particles preferred by both ciliates is dominated by nanoflagellates.

8

Particle size selectivity of two marine ciliates - Balanion comatum Wulff and Strombidium sp.

100%

Rychert K.

Polish Journal of Ecology

|

2008

|

tom Vol. 56, nr 2

251-257

EN

Food selectivity of marine ciliates Balanion comatum Wulff and Strombidium sp. (mean size of cell 19 [mi]m) were studied in situ during incubation with wheat starch particles as a surrogate food. Range of particles ingested by Balanion comatum was 1.25-7.50 [mi]m with preference for 3.75 [mi]m particles (statistically significant result). Strombidium sp. engulfed particles ranging from 1.25 [mi]m to 5.00 [mi]m also with preference for 3.75 [mi]m particles. In the Baltic Sea size range of particles preferred by both ciliates is dominated by nanoflagellates.

9

Growth rates of common pelagic ciliates in a highly eutrophic lake measured with a modified dilution method

100%

Rychert K.

|

tom 45

|

nr 2

10

Nanoflagellates in the Gdańsk Basin: coexistence between forms belonging to different trophic types

100%

Rychert K.

Oceanologia

|

2006

|

tom 48

|

nr 2

EN

Nanoflagellates are important bacterivores, but their role is often underestimated because forms capable of phagotrophy and containing chlorophyll (mixotrophs) are excluded from analyses. Research conducted in the coastal zone of the Gdańsk Basin (Baltic Sea) revealed seasonal changes in the relationship between the biomasses of small (1–8 μm) nanoflagellates with (NFChl+) and without chlorophyll (NFChl–). Three distinct patterns were distinguished: (i) spring, when the biomass of NFChl+ was lower than that of NFChl–, (ii) summer and autumn, when NFChl+ were dominant (about 90%), and (iii) late autumn and winter, when the prevalence of NFChl+ was lower (71–79%). Additional studies showed the existence of spatial differences in the composition of the nanoflagellate community. These spatial differences were not shaped by freshwater input. The possible importance of mixotrophic forms in the Gdańsk Basin is discussed.

11

Ciliate Mesodinium rubrum in the coastal zone of the southern Baltic Sea (Central Pomerania)

63%

Rychert K. , Pączkowska M.

|

tom 16

EN

The abundance and biomass of Mesodinium rubrum was assessed in the coastal zone of the southern Baltic Sea near the town of Ustka. The two-year study permitted estimating the mean annual biomass of M. rubrum, which was 2.8 3gC l-1 and 3.1 3gC l-1 in 2006 and 2007, respectively. During the year, abundance changed irregularly with the highest values observed during spring (April-June). The standing crops estimated correspond well with the biomass of this ciliate observed in other regions of the Baltic Sea.

PL

Mesodinium rubrum Lohmann 1908 (= Myrionecta rubra Jankowski 1976) to pospolity orzęsek występujący w wodach słonych i słonawych. Zgodnie z aktualnymi ustaleniami jest on miksotrofem odżywiającym się drogą fotosyntezy prowadzonej w przetrzymywanych kryptofitach, jest on jednakże również zdolny do fagocytozy. M. rubrum jest najczęściej obserwowanym orzęskiem w Morzu Bałtyckim, ze względu jednak na to, że jest on funkcjonalnym autotrofem zalicza się go do fitoplanktonu. Prezentowane badania miały na celu uzupełnienie wiedzy na temat sezonowego występowania M. rubrum w południowej części Morza Bałtyckiego na stanowisku badawczym w pobliży miasta Ustka (54º35′N, 16º50′E). Istnienie tego typu danych umożliwia obserwację długofalowych zmian zachodzących w efekcie działania wielkoskalowych procesów, takich jak eutrofizacja oraz globalne ocieplenie. Badania prowadzono od kwietnia 2006 do kwietnia 2008, pobierając łącznie 30 prób podczas wszystkich pór roku. Próby utrwalano kwaśnym płynem Lugola i analizowano pod mikroskopem odwróconym za pomocą metody Utermöhla. Biomasa M. rubrum zmieniała się dość nieregularnie. Najniższą biomasę notowano zimą, natomiast jej szczytowy wzrost obserwowano w okresie kwiecień-czerwiec. Najwyższą wartość (12,7 3gC l-1) zaobserwowano w czerwcu 2006 roku. Średnioroczna biomasa dla okresu pomiędzy kwietniem 2006 a kwietniem 2007 wynosiła 2,8 3gC l-1. Podobną wartość (3.1 3gC l-1) określono również dla następnego okresu (IV 2007 – IV 2008). Wartości te są podobne do średniorocznej biomasy określonej dla wód otwartego Bałtyku oraz Zatoki Kilońskiej. Jednocześnie są niższe niż średnioroczna biomasa obliczona dla bardziej żyznych rejonów Bałtyku, takich jak Basen Arkoński czy też Basen Gdański.

12

Protozoan impact on bacterial biofilm formation

63%

Rychert K. , Neu T. R.

Biological Letters

|

2010

|

tom 47

|

nr 1

13

Pelagic respiration in the coastal zone of the southern Baltic Sea

51%

Rychert K. , Wielgat-Rychert M. , Woloszynek M. , Sojda G.

International Journal of Ecohydrology and Hydrobiology

|

2015

|

tom 15

|

nr 4

14

Importance of tintinnids and Mesodinium rubrum in communities of planktonic ciliates in the shallow brackish lakes Gardno and Lebsko (northern Poland)

51%

Rychert K. , Myszka M. , Wielgat-Rychert M. , Skuza E.

Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

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2017

|

tom 21

EN

Ciliates constitute an important trophic link in aquatic environments, because they are essential food sources for zooplankton and fish. In this study, the spatial differences in abundance and composition of ciliate communities in relation to varying water salinity were investigated. The study was conducted in the large, brackish, eutrophic lakes Gardno and Łebsko. In the studied lakes, no significant differences among ciliate communities were identified among sampling sites. Ciliate communities in Lake Łebsko were characterized by a high contribution of tintinnids, with mean values at particular sites between 32% and 36%. In Lake Gardno, where salinity was lower, the importance of tintinnid ciliates increased after a marine water intrusion into the lake. In both lakes, the importance of tintinnids in ciliate communities was higher than in adjacent fresh and marine waters. Shortly after wind-driven intrusions of marine waters (backwaters), the marine and brackish mixotrophic ciliate Mesodinium rubrum was observed in both lakes. Once, in the eastern part of Lake Łebsko, Mesodinium major (= Mesodinium rubrum forma major) was observed after a strong backwater when salinity reached 5.4 PSU.

PL

Orzęski stanowią istotne ogniwo troficzne w środowisku wodnym, ponieważ są ważnym źródłem pokarmu dla zooplanktonu i ryb. W prezentowanej pracy zbadano wpływ gradientu zasolenia na liczebność i skład zbiorowisk orzęsków. Badania prowadzono w dużych słonawych i eutroficznych jeziorach Gardno i Łebsko. Pomimo zróżnicowania przestrzennego zasolenia wody, nie wykazano istotnych różnic pomiędzy zbiorowiskami orzęsków obserwowanymi na poszczególnych stanowiskach. Zbiorowiska orzęsków w jeziorze Łebsko charakteryzowały się wysokim udziałem tintinnid, które wnosiły średnio na poszczególnych stacjach od 32% do 36% liczebności. W jeziorze Gardno, w którym zasolenie było niższe, znaczenie tintinnid wzrosło po intruzji wód morskich do jeziora. W obu badanych jeziorach znaczenie tintinnid w zbiorowiskach orzęsków było wyższe niż w przyległych wodach słodkich i morskich. Krótko po spowodowanych wiatrem intruzjach wody morskiej (cofkach) w obu jeziorach był obserwowany słono- i słonawowodny miksotroficzny orzęsek Mesodinium rubrum. Po silnej cofce, kiedy zasolenie we wschodniej części jeziora Łebsko sięgnęło 5,4 PSU, zaobserwowano tam Mesodinium major (= Mesodinium rubrum forma major).

15

Calculation of the photosynthetic quotient (pq) in the Gulf of Gdansk (southern Baltic)

51%

Wielgat-Rychert M. , Rychert K. , Witek Z. , Zalewski M.

Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

|

2017

|

tom 21

EN

The photosynthetic quotient (PQ) is defined as the molar ratio of oxygen released to the carbon dioxide assimilated during photosynthesis. Calculation of correct PQ values of natural phytoplankton populations is crucial for understanding of carbon budgets but often result in values that differ highly from the expected stoichiometric proportions of photosynthetic products. In the present study, measurements of primary production, that is, CO2 assimilation, performed with the standard isotopic method (14C) and oxygen release estimated during photosynthesis with the light-and-dark bottle method were compared to calculate PQ in the southern Baltic (Gulf of Gdańsk, Poland). The PQ average was 1.28 (ANOVA; F = 872; R2 = 0.92; n = 77; p < 0.001). Neither nitrogen source nor phytoplankton composition was noted to impact PQ values. Very high PQ values in the lower range of production rates (that cannot be explained by the stoichiometric proportion of photosynthesis products) were interpreted as artifacts related to the lower sensitivity of the oxygen method compared to that of the 14C method.

PL

Współczynnik fotosyntetyczny (PQ) definiowany jest jako molowy stosunek uwolnionego tlenu do węgla związanego w procesie fotosyntezy. Obliczenie poprawnej wartości PQ dla populacji fitoplanktonu występujących w środowisku jest zasadnicze dla sporządzenia poprawnego bilansu węgla, ale często obliczone z pomiarów wartości PQ różnią się znacznie od proporcji stechiometrycznych tlenu i węgla w produktach fotosyntezy. W niniejszej pracy przeprowadzono pomiary asymilacji węgla, czyli produkcji pierwotnej, przy użyciu standardowej metody izotopowej (z izotopem węgla 14C) oraz pomiary uwolnionego tlenu za pomocą metody jasnych i ciemnych butelek i na tej podstawie obliczono współczynnik fotosyntetyczny dla Bałtyku południowego (Zatoka Gdańska, Polska). Obliczona średnia wartość PQ wynosiła 1,28 (ANOVA; F = 872; R2 = 0,92; n = 77; p < 0,001). Nie odnotowano, aby wartości PQ zależały od rodzaju azotu wykorzystanego w procesie asymilacji (azot azotanowy czy amonowy) lub od składu fitoplanktonu. Bardzo wysokie wartości PQ obliczone w zakresie niskich wartości produkcji pierwotnej (wartości, które nie zgadzają się zupełnie z proporcjami stechiometrycznymi produktów fotosyntezy) zostały zinterpretowane jako artefakty wynikające z metodyki pomiarowej, ponieważ metoda tlenowa ma znacznie mniejszą czułość niż metoda izotopowa.

16

Latitudinal pattern of abundance and composition of ciliate communities in the surface waters of the Atlantic Ocean

51%

Rychert K. , Nawacka B. , Majchrowski R. , Zapadka T.

Oceanological and Hydrobiological Studies

|

2014

|

tom Vol. 43, No. 4

4436--441

EN

Abundance, biomass, and taxonomic composition of the ciliate community were studied in the surface waters along a transect between 50°S 61°W and 48°N 5°W (Atlantic Ocean, March-April 2011). The abundance of heterotrophic ciliates was low in the equatorial zone (280–320 cells l−1, 0.11–0.12 μg C l−1), but it increased toward both the northern and southern temperate zones with the maximum abundance observed at 44°S (2667 cells l−1, 0.82 μg C l−1). This pattern resembles the global distribution of oceanic primary production, which is low at lower latitudes and high in temperate zones. In temperate zones ciliate abundance peaks during spring and fall. Thus, because the present study was carried out during spring in the northern hemisphere and austral fall in the southern hemisphere, the ciliate abundance at higher latitudes was additionally elevated. Functionally autotrophic Mesodinium rubrum was only observed in the northern hemisphere and tropical waters. Its maximum abundance was observed at 48°N (1080 cells l−1, 1.14 μg C l−1). The most frequently observed ciliates were oligotrichs and choreotrichs. Other important ciliates were haptorids (including M. rubrum) and hypotrichs.

17

Dynamics of oxygen consumption during the formationof the anoxic zone in aquatic environment

51%

Rychert K. , Mendrzejewska B. , Kiestrzyn A.

European Journal of Biological Research

|

2018

|

tom 08

|

nr 4

18

Factors controlling pelagic production and respiration in a shallow polymictic lake

51%

Wielgat-Rychert M. , Rychert K. , Ficek D.

Polish Journal of Ecology

|

2010

|

tom 58

|

nr 2

EN

Shallow lakes, defined as ‘nonstratifying’, polymictic water bodies are usually eutrophic and highly productive, and more turbid than deeper lakes due to bottom sediment resuspension. Gross primary production (GPP) and total planktonic community respiration (TCR) were measured in a very shallow (on average 1.2 m deep) and large (area 25 km²), polymictic, eutrophic Lake Gardno (Baltic coastal lake, Northern Poland) with the light-and-dark bottle method. The aim was to compare GPP to TCR ratio in the pelagic zone in a course of a year and identify factors governing these processes. Identified factors governing GPP were light conditions and temperature, with Q₁₀ = 2.23 in the 2–24.5°C temperature range, whereas TCR was driven by water temperature (Q₁₀ = 2.15 in the same temperature range) and by organic matter content in water. TCR was correlated with total suspended matter (effect of bottom sediment resuspension due to wind action in a very shallow lake), however not with chlorophyll content. During two-year measurement period (years 2006 and 2007), annual GPP amounted to 402 and 471 g C m⁻², and TCR amounted to 192 and 223 g C m⁻² respectively. Lake Gardno pelagic system seemed to be net autotrophic on annual basis; GPP to TCR ratio = 2.1. Part of the organic matter produced in pelagial is probably deposited in bottom sediments decomposed there. Wind induced resuspension increases matter content in water (measured here as TSM content) and thus contributes to pelagic respiration processes (TCR).

19

Impact of the Słupia River waters on microbial communities in the port of Ustka and adjacent Baltic Sea waters

51%

Rychert K. , Wielgat-Rychert M. , Lemańczyk Ł.

Oceanological and Hydrobiological Studies

|

2018

|

tom Vol. 47, No. 4

429--438

EN

The distribution of bacterial and ciliate abundance, ciliate community composition and other parameters were studied during summer along a transect from the mouth of the Słupia River to offshore waters (southern Baltic Sea). Bacteria were examined under an epifluorescence microscope and ciliates were observed under an inverted microscope. Two water masses were identified along the transect. Less saline waters in the river mouth and in the surface layer in the port of Ustka were characterized by high bacterial abundance (5.51–6.16 × 106 ml-1) and low ciliate abundance (0.34–0.90 cells ml-1). More saline waters in the near-bottom zone in the port of Ustka and in the surface layer outside the port contained smaller numbers of bacteria (0.99–2.14 × 106 ml-1) and larger numbers of ciliates (2.65–5.40 cells ml-1). The differences were statistically significant. The separation of the two water masses indicated that the Słupia River exerted a minor impact on the marine waters. The ciliate community composition changed along the transect studied. The main statistically significant difference observed was the low contribution of oligotrichs and choreotrichs to ciliate biomass (3–4%) in less saline waters and their dominance (45–80% of ciliate biomass) in more saline waters.

20

Nutrient fluxes and their impact on the phytoplankton in a shallow coastal lake

45%

Wielgat-Rychert M. , Jarosiewicz A. , Ficek D. , Pawlik M. , Rychert K.

Polish Journal of Environmental Studies

|

2015

|

tom 24

|

nr 2

EN

Data on nutrient concentrations and phytoplankton growth was analyzed in Lake Gardno, representing a separate group of coastal lakes within the Polish abiotic typology according to the Water Framework Directive. The aim of this work was to identify sources of nutrient variability in lake water and consequences of this variability for phytoplankton growth. Phytoplankton composition was dominated by green algae, present in high biovolumes throughout the year, and cyanobacteria, whose elevated biovolumes were noted at temperatures above 13ºC. Production of phytoplankton was often light-limited throughout the vegetation period (changing on a day-to-day basis). Low N-to-P ratio, the presence of nitrogen-fixing cyanobacteria, and Carlson’s trophic state indices (TSI) analysis indicated also possible nitrogen limitations of primary production during the vegetation period. No phosphorus limitation was indicated. Possible nitrogen limitation was a result of in-lake modification of the N-to-P ratio compared to external N-to-P ratio in nutrient loads discharged by the freshwater inflow. Lake Gardno was a substantial sink of nitrogen discharged by the Łupawa River, probably due to denitrification. Nutrient budget for the 2006-08 period revealed 50% loss of nitrogen in a lake, whereas the phosphorus budget did not reveal substantial phosphorus retention. From a management perspective, the study indicates the importance of reduction of phosphorus loads discharged to the lake, which could prevent further development of cyanobacterial blooms stimulated by low N-to-P ratio.