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1

Recognition of the vibriosis risk in Polish coastal waters of the Baltic Sea and public engagement in its mitigation

Rakowski Marcin, Mytlewski Adam, Piwowarczyk Joanna

Journal of Water and Land Development

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2023

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no. 59

291--297

EN

The surface water temperature in the Baltic Sea has been growing as a consequence of broader changes of the Earth’s climate, which contributes to the proliferation of natural bacterioplankton and new types of bacteria, such as Vibrio vulnificus, in the region. This pathogenic bacterium finds optimal conditions for growth primarily in warm brackish waters. Places particularly vulnerable to these bacteria include shallow Baltic coastal waters where the proliferation of Vibrio strains increases in summer. The growing temperature of coastal waters boost this phenomenon, posing a serious threat to human health and the coastal Baltic tourism. The BaltVib project implemented by marine microbiologists investigates the impact of the so-called “system engineers”, e.g. mussels, macroalgae, and seagrass, on the diversity and abundance of vibriosis. The research should help to develop strategies to mitigate the problem of excessive populations of vibriosis through nature-based solutions. In addition to environmental and health issues, public awareness of the phenomena and future threats are equally important and these are also addressed in the project. The article presents results of a survey conducted on the Polish coast involving 140 respondents interviewed concerning their awareness of the increasing population of pathogenic vibriosis. The survey helped to diagnose how local residents perceive the threat to human health posed by Vibrio vulnificus now and in the future, as well as possible impacts these bacteria might have on economic use of the coastal waters. The survey also investigated the level of acceptance for various methods used to mitigate negative environmental changes.

2

Epiphytic bacterial community composition on the surface of the submerged macrophyte Myriophyllum spicatum in a low-salinity sea area of Hangzhou Bay

Liu Qiao, Liu Mengmeng, Zhang Qi, Bao Yanlin, Yang Na, Huo Yuanzi, He Peimin

Oceanological and Hydrobiological Studies

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2019

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Vol. 48, No. 1

43--55

EN

In this study, we conducted a comparative analysis of the abundance and diversity of bacteria on the surface of the submerged macrophyte Myriophyllum spicatum, as well as in the surrounding water column and sediment in the low-salinity area of Hangzhou Bay, China. Bacterial clones from three clone libraries were classified into 2089 operational taxonomic units (OTUs), most of which affiliated with bacterial divisions commonly found in marine ecosystems. Alphaproteobacteria, Cyanobacteria and Gammaproteobacteria were the most abundant groups of bacteria on the surface of plants, in the water column and sediment, respectively. Epiphytic bacterial communities were more closely related to those in the sediment than bacterioplankton, and some species of epiphytic bacteria were found only on the surface of M. spicatum. The relative abundance of epiphytic bacterial genera associated with breakdown of organic compounds and with cellulose digestion was higher in October than that in July. These results suggested that bacterial communities on the surface of M. spicatum may originate from sediment bacterial communities and their specific structure was gradually formed on the surface of M. spicatum after being cultivated in low-salinity seawater.

3

Ocena stanu sanitarno-bakteriologicznego zbiornika wodnego „Balaton” zlokalizowanego w centrum Bydgoszczy

Kubera Ł., Małecka-Adamowicz M.

Woda-Środowisko-Obszary Wiejskie

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2017

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T. 17, z. 1

63--73

PL

Zbiorniki wodne coraz częściej stają się integralną infrastrukturą dużych miast, pełniąc ważne funkcje estetyczne i rekreacyjne. Nie są one jednak objęte systematycznym monitoringiem mikrobiologicznym. Celem niniejszej pracy była ocena stanu sanitarno-bakteriologicznego zbiornika wodnego „Balaton” położonego w centrum Bydgoszczy. Analizy sanitarne obejmujące liczebność wybranych grup mikroorganizmów wykonane zostały zgodnie ze standardami Polskich Norm. Dodatkowo badania poszerzono o oznaczenie ogólnej liczby bakterii (OLB) oraz ocenę aktywności błony cytoplazmatycznej komórek bakterioplanktonu, wykorzystując w tym celu zestaw barwników fluorescencyjnych LIVE/DEAD® BacLightTM Bacterial Viability Kit. Wykonane badania wykazały, że zasadniczy wpływ na ilość drobnoustrojów miała pora roku. Największą liczbę bakterii psychrofilnych, mezofilnych oraz enterokoków kałowych odnotowano latem, a najmniejszą jesienią. Wyjątek stanowiły bakterie z grupy coli oraz Escherichia coli, których najmniejszą liczbę odnotowano w sezonie wiosennym. Podobne zależności stwierdzono na podstawie analizy ogólnej liczby komórek bakterii, wśród których aktywność błony cytoplazmatycznej wynosiła od 91,5% latem do 72,3% wiosną. Analiza taksonomicznego zróżnicowania dominujących szczepów bakterii wykonana metodą BIOLOG® wykazała, że wszystkie badane izolaty należały do klasy Gammaproteobacteria.

EN

Water reservoirs have become increasingly an integral part of infrastructure of big cities. They play an important aesthetic and recreational functions, but aren’t covered by systematic microbiological monitoring. The aim of this study was evaluation of sanitary and bacteriological condition of the “Balaton” water reservoir located in Bydgoszcz. Sanitary analysis includes the number of selected groups of microorganisms were made in accordance with the Polish Standards recommendations. The study was expanded to determine the total number of bacteria (TNB) and assessment the activity of cytoplasmic membrane of bacterioplankton. In this case was used fluorescent dyes LIVE/DEAD® BacLightTM Bacterial Viability Kit. The studies showed, that the season has a major impact on the distribution of bacterial populations. The highest average number of psychrophilic and mesophilic bacteria and also fecal enterococci was recorded in summer. The exceptions were coliform bacteria and Escherichia coli, which the smallest average number was noted in spring. Similar relationship observed based on the total number bacteria, among which cytoplasmic membrane activity varied from 91.5% in summer to 72.3% in autumn. The taxonomic analysis of dominant bacterial strains prepared using BIOLOG® method showed, that all examinated isolates belonged to Gammaproteobacteria class.

4

Bacterial community structure influenced by Coscinodiscus sp. in the Vistula river plume

Ameryk A., Hahnke R. L., Gromisz S., Kownacka J., Zalewski M., Szymanek L., Całkiewicz J., Dunalska J., Harder J.

Oceanologia

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2014

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No. 56 (4)

825--856

EN

The Gulf of Gdańsk is influenced by freshwater inflow from the River Vistula and by a wind-driven current along the coast. Bacterial communities from five stations along a salinity gradient were sampled during one day and analysed by terminal restriction fragment length polymorphism (T-RFLP), catalysed reporter deposition-fluorescence in situ hybridisation (CARD-FISH) and 16S rRNA gene libraries. On the day of sampling, we observed a probable current-driven seawater influx into the inner part of the gulf that separated the gulf into distinct water bodies. Members of the diatom Coscinodiscus sp. dominated one of these water bodies and influenced the bacterial community. The coexistence of typically freshwater and marine bacterioplankton populations in the Vistula river plume suggested an integration of some freshwater populations into the Baltic Sea bacterioplankton.

5

Impact of the inflow of Vistula river waters on the pelagic zone in the Gulf of Gdańsk

Wielgat-Rychert M., Ameryk A., Jarosiewicz A., Kownacka J., Rychert K., Szymanek L., Zalewski M., Agatova A., Lapina N., Torgunova N.

Oceanologia

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2013

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No. 55 (4)

859--886

EN

The biomass, production, composition of autotrophic phytoplankton and hetero-trophic bacteria were studied along with environmental and biological parameters. Samples were taken from Vistula river water (at Kiezmark) and from the river plume to the outer stations in the Gulf of Gdańsk (Baltic Sea) in June 2005. The phytoplankton biomass gradient appeared to be simply the result of dilution of the river water in the sea water, whereas the bacterial abundance and biomass dropped between the river station and the first sea water stations, a decrease that cannot be explained by the dilution effect. The Vistula water stimulated the production mainly of bacterioplankton but also of phytoplankton in the river plume as compared to rates measured in Vistula waters and at the open sea stations. However, this stimulation did not result in a measurable increase in biomasses, probably because of the short retention time of water in the river plume. Phytoplankton production was correlated with phytoplankton biomass (Chl a), while bacterial production was correlated with phytoplankton production and phytoplankton biomass (Chl a).

6

Different antibiotic resistance of neustonic and planktonic bacteria in a freshwater coastal lake : implication for strain selection

Skórczewski P., Mudryk Z.

Polish Journal of Ecology

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2012

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Vol. 60, nr 1

153-162

EN

Antibiotic resistance of bacteria was observed in various aquatic environments including seas, rivers, lakes, coastal areas, surface water and sediments. The increased implementation of antibiotics into these environments through medical therapy, agriculture and animal husbandry has resulted in new selective pressures on natural bacterial aquatic populations. Antibiotic resistance of heterotrophic bacteria isolated from the surface microlayer and subsurface water of freshwater coastal polymictic and low-productive lake was studied. Antibiotic resistance was determined by the single disc diffusion method. The resistance level of bacteria to various antibiotics differed considerably. Bacteria were most resistant to ampicillin, ciprofloxacin, clindamycin, erythromycin and penicillin. Majority of bacterial strains showed resistance to 4.6 out of 18 antibiotics tested. As a rule, neustonic bacteria (antibiotic resistance index, ARI 0.44) were more resistant to the studied antibiotics than planktonic bacteria (ARI 0.32). 70-90% of neustonic bacteria were resistant to ampicillin, clindamycin and erythromycin, 60-70% of planktonic bacteria were resistant to ampicillin, ciprofloxacin and penicillin. Differences between pigmented and non-pigmented bacteria in their resistance to the tested antibiotics were observed. Above 40% of achromogenic bacterial strains were resistant to ampicillin, clindamycin and penicillin. Among bacterial strains characterised by their ability to synthesize carotenoids, more than 30% was resistant to ampicillin and ciprofloxacin. Bacterial resistance level to antibiotics depended on their chemical structure. Bacteria isolated from study lake were most resistant to quinolones and lincosamides while they were most susceptible to tetracyclines and aminoglycosides. Results presented in this paper indicate that antibiotics are a significant selection factor and probably play an important role in regulating the composition of bacterial communities in aquatic ecosystems. Adaptive responses of bacterial communities to several antibiotics observed in the present study may have possible implications for the public health.

7

Change in metazooplankton abundance in response to flood dynamics and trophic relations in Danubian floodplain lake (Kopački Rit, Croatia)

Palijan G., Galir A.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

777--787

EN

This study investigated relationships of hydrological variability and potential food resources for metazooplankton groups: rotifers, cladocerans, copepods and nauplii. Samples were collected monthly during ice-free season from March until November in 2006. Two sampling stations were chosen, the one located in Lake Sakadaš, as a segment of Kopački Rit floodplain (Croatia), and the other in the River Danube. Due to hydrological conditions we divided our samples into two hydrological groups which corresponded to: 1/ increased water level i.e. disturbed phase and 2/ decreased water level representing a more stable phase. Abundance of metazooplankton was not significantly different between hydrological groups in the River Danube. However, it was significantly different between hydrological groups in Lake Sakadaš (one-way ANOSIM R = 0.688, P = 0.024), where during a decreased water level higher abundance of metazooplankton was recorded. Rotifers were the most abundant metazooplankton group during the whole investigated period at both stations and between both hydrological groups comprising almost 99% of total metazooplankton abundance. Rotifers were significantly positively correlated with the total number of bacteria, as well as with ammonium and total phosphorous concentrations. The metazooplankton community in Lake Sakadas was negatively influenced by flooding, but not in the River Danube. Compared to the River Danube the investigated floodplain lake showed potential as a storage zone for metazooplankton development during more stable hydrological periods. During that time abundance of rotifers was related to the heterotrophic component of microbial food web. Hence, this investigation adds to the understanding of the metazooplankton dynamics in river-floodplain systems as well as of their relations with trophic levels under variable hydrological conditions.

8

Monsoon-driven dynamics of environmental factors and phytoplankton in tropical Sanya Bay, South China Sea

Wu M-L., Zhang Y-Y., Dong J-D., Cai C-H., Wang Y-S., Long L-J., Zhang S.

Oceanological and Hydrobiological Studies

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2012

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Vol. 41, No. 1

57-66

EN

In this work, we analyze environmental (physical and chemical) and biological (phytoplankton) data obtained in Sanya Bay during four cruises, carried out in January, April, August, and October. The main objective of this study was to identify the key environmental factors affecting phytoplankton structure and bacterioplankton in the bay. Results suggest that spatial variations in the phytoplankton community and bacterioplankton biomass are the result of nutrients. Temporal variation in the abundance of bacterioplankton and phytoplankton are affected by a combination of physical and biological factors, such as temperature and nutrients. The silicate, phosphate, and nitrogen phytoplankton require for growth may be co-limited. Monsoon winds (a southwestern monsoon during summer and a northeastern monsoon during winter) play important roles in controlling the phytoplankton community and bacterioplankton abundance in Sanya Bay, northern South China Sea.

9

Different impact of flood dynamics on the development of culturable planktonic and biofilm bacteria in floodplain lake

Palijan G.

Polish Journal of Ecology

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2010

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Vol. 58, nr 3

439-448

EN

Floodplains are lateral river extensions in which lotic, semi-lotic and lentic habitats are formed resulting in high habitat heterogeniety. Consequently biota development is highely influenced by its location within the floodplain and by the hydrological cycle. In the present paper the development of planktonic and biofilm bacteria associated with artificial substrates were investigated in the floodplain lake of the Danube River (Lake Sakadas, Croatia) during different hydrological situations. The aim of the study was to investigate if there was any difference in the bacterial development between two compartments - plankton and biofilm, and how the floods influence these communities. The samples were taken monthly (July.November 2007) from surface and bottom water layer (plankton) and exposed glass slides (biofilm) at two sampling stations. For these purposes bacterial abundance was estimated by the determination of number of colony forming units (CFUs). The development of bacterioplankton was equal between the sites and had its maximum at the time of falling water after the flood pulse. Bacterioplankton abundance correlated significantly with water properties, and it had predictable dynamics comparable with the previous results established in the same floodplain area (Kopacki Rit). The development of biofilm bacteria differed between the sites, and had its maximum prior to the flood pulse, or during the flood. The abundance of attached bacteria correlated with biofilm biomass while it was not significantly correlated with the water properties. Such results describe different development of planktonic and biofilm bacteria. Biofilm bacteria are more independent, compared to bacterioplankton, from the floodplain hydrology.

10

Hydrochemical properties, bacterioplankton abundance and biomass in the meromictic Lake Starodworskie in 2004

Tandyrak R, Parszuto K., Górniak D., Kośnik P.

Oceanological and Hydrobiological Studies

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2009

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Vol. 38, No.4

127-133

EN

Physicochemical and microbiological examinations were conducted on the meromictic Lake Starodworskie located in Olsztyn. The temperature profile revealed a characteristic, small increase in temperature at a depth between 13 and 14 m, and permanent anaerobic conditions in the deeper water layers. Accumulation of dissolved mineral substances enhanced the thermal stability of the lake waters; electrolytic conductivity values in the water deeper than 15 m oscillated within the range of 533 - 568 μS cm^-1.

11

The impact of inundation-isolation cycles on the culturable bacterioplankton in the Danube River floodplain

Palijan G., Bogut I., Vidakovic J.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

391-401

EN

The investigation was conducted in the Kopacki Rit Nature Park (eastern Croatia) which is established to protect the floodplain area of the Danube River. The samples were collected monthly in four sites (channels and lakes) with increasing distance from the river. The aim of investigation was to examine trophic structure of culturable bacterioplankton in relation to inundation-isolation cycles on sampling sites with unequal degree of connection with the Danube river. A change in the ratio of copiotrophs (r-strategists) to oligotrophs (K-strategists) was expected as the different organic carbon sources emerged. The composition of variables was revealed by Principal Component Analysis of abiotic water properties (temperature, water depth, transparency, pH, electrical conductivity, dissolved oxygen, nutrient concentrations) and the chlorophyll-a concentration. Scores of significant components were used in a Multiple Regression as independent variables and the relationship between the scores and abundance of colony forming units (CFUs) was examined. Regression model was significant only for copiotrophs, and their relative dominance was noticed in couple of samples on more isolated sampling sites. In all other samples oligotrophs were a dominant group, especially during the flood pulses or drainage after it. Their elevated abundance was equally distributed in all groups revealed by Principal Component Analysis, and corresponds to the fluvial action. Also concerning the [eta] squared and R squared values from the two-way ANOVA (sites/samplings) oligotrophs are highly influenced by the sampling period i.e. inundation-isolation cycles. They are probably driven by the allochthonous organic matter provided by floods or have allochthonous origin itself. At the same time, copiotrophs are to some extent coupled with the established water properties, i. e. bottom-up controlled and their abundance is influenced by the localisation of sampling sites in the floodplain. These results describe the development of the conditions that promote habitat specific succession of the culturable bacterioplankton. Established differences had disappeared after additional inundation-isolation cycles.

12

Concentrations of heavy metals and bacterial numbers and productivity in surface and subsurface water layers in coastal lake Dolgie Wielkie

Antonowicz J., Mudryk Z., Trojanowski J., Dwulit M.

Ecological Chemistry and Engineering. A

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2008

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Vol. 15, nr 9

873-879

EN

Results of chemical and bacteriological examinations conducted for surface and subsurface water layers of coastal freshwater lake Dolgie Wielkie were presented. The obtained data indicated that there were substantial differences in concentrations of heavy metals, abundance and productivity of bacteria in the water layers studied. It was found that the highest concentration of heavy metals and the lowest counts of total and heterotrophic bacteria were recorded in the film layer. However, a higher level of secondary production than in neustonic bacteria was found for planktonic bacteria. The results justify a conclusion that heavy metals accumulated in the surface layers may have a significant inhibitory effect on counts and productivity of neustonic bacteria.

PL

Przedstawiono wyniki chemicznych i bakteriologicznych badań powierzchniowych i podpowierzchniowych warstw wody przymorskiego słodkowodnego jeziora Dołgie Wielkie. Uzyskane wyniki wykazały istotne różnice w stężeniu metali ciężkich, liczebności oraz poziomie produkcji bakterii w badanych warstwach wody. Wykazano, że największe stężenie metali ciężkich, najmniejsza ogólna liczebność bakterii oraz liczebność bakterii heterotroficznych notowane było w filmie powierzchniowym. Jednakże wyższy poziom wtórnej produkcji obserwowano u bakterii planktonowych niż neustonowych. Uzyskane wyniki upoważniają do stwierdzenia, że metale ciężkie zakumulowane w powierzchniowych warstwach wody mogą mieć istotny inhibitorowy wpływ na liczebność i produktywność bakterii neustonowych.

13

Impact of humic substances on bacterioplankton in eutrophic lake

Burkowska Aleksandra, Donderski Wojciech

Polish Journal of Ecology

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2007

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Vol. 55, nr 1

155-160

EN

This paper presents the results of resarch on impact of humic substances (HS) on bacterioplancton in eutrophic Lake Jeziorak (north-eastern Poland). In cultures of natural bacteria from the lake water, enriched with 0, 5, 10, 25 and 50 mg dm[^-3] of HS (natural HS - isolated from lake water or commercial HS - sodium salt of humic substance; Sigma-Aldrich), were determined the following parameters: total number of bacteria (TNB), number of heterotrophic bacteria (CFU), bacterial production (BP) (measured with [[3]H]methyl thymidine method) and general activity of esterases. Natural HS had a more positive impact on bacterial growth, bacterial production and activity of esterases than the commercial preparation HS. The highest TNB and CFU was observed when the water was enriched with 25 mg dm[^-3] of natural HS. Ali concentrations of the natural HS stimulated bacterial production. The activity of hydrolytic enzymes increased with rising concentrations of natural HS.

14

Neustonic versus planktonic bacteria in eutrophic lake

Kalwasińska A., Donderski W.

Polish Journal of Ecology

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2005

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Vol. 53, nr 4

571-577

EN

This paper presents the results of research on the number, the rate of secondary production and physiological properties of neustonic (surface microlayer SM ≈ 250 μm) and planktonic (subsurface water SSW ≈ 10-15cm) bacteria of the eutrophic lake (TP 30-99 μg l-1; TN 0.94-1.76 mg l-1; chlorophyll a 26.4-56.9 mg l-1; water transparency 1.2-1.9 m). It was found that the total number of neustonic bacteria (TNB) varied from 1.28 × 106 to 1.98 × 106 cells ml-1 and was from 1.4 to 2.0 times higher than the number of planktonic bacteria (P <0.001). TNB range for planktonic bacteria oscillated between 0.75 × 106 and 1.45 × 106 cells ml-1. The number of heterotrophic neustonic (SM) bacteria (CFU 22°C) was also higher by 2.0 to 13.3 times (P <0.001) being between 1.48 and 12.5 × 103 cells ml-1 while the CFU of bacteria in the SSW oscillated between 0.35 to 0.94 × 103 cells ml-1. Both the values of TNB and CFU displayed a distinct seasonal variation (P <0.001). However, the rate of secondary production of planktonic bacteria was higher (from 1.1 to 6.0 times) than the rate of production of neustonic bacteria (P <0.05) and displayed seasonal variability (P <0.001). The rate of secondary production in subsurface water ranged from 0.676 to 1.265 μgC l-1 h-1 while in surface microlayer from 0.118 to 0.597 μgC l-1 h-1. In neuston the bacteria decomposing fat and DNA were more common than in plankton (P <0.05).

15

Interaction of estuarine bacterioneuston and bacterioplankton with elevated mercury concentrations

Mudryk Z. J., Dwulit M.

Polish Journal of Ecology

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2004

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Vol. 52, nr 3

301-310

EN

The effect of different concentrations of mercury on the number and respiratory activity of neustonic and planktonic bacteria derived from estuarine Lake Gardno (Baltic Coast, Poland) was studied. The laboratory experiments demonstrated that mercuric ions (Hg^2+) exhibited toxic effects on abundance and oxygen uptake of neustonic and planktonic bacteria. Bacterioneuston and bacterioplankton showed different responses to the mercuric ions. The neustonic bacteria showed higher levels of tolerance to various concentrations of Hg (10-15 mg dm^-3) in the culture medium than the planktonic ones (<10 mg dm^-3). It was found out that the bacteria isolated from freshwater zone of Lake Gardno were more tolerant to the increasing concentration of mercury ions (10-20 mg dm^-3) than bacteria isolated from the seawater and mixed zones of lakes. Non-pigmented bacteria from all layers and zones were more tolerant to the higher Hg^2+ concentrations than pigmented ones. High concentrations (above 8 [mi]g cm^-3) of mercury chloride in the respiratory substrate blocked completely oxygen uptake by neustonic and planktonic bacteria.

16

Effect of some heavy metals on neustonic and planktonic bacteria isolated from the Deep of Gdańsk

Mudryk Z., Donderski W., Skórczewski P., Walczak M.

Oceanological Studies

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2000

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Vol. 29, No. 1

89-99

EN

The effect of different concentrations of heavy metal ions Hg+2, Cd+2, Zn+2, Cu+2 on growth and respiratory activity of neustonic and planktonic bacteria derived from the Deep of Gdańsk was studied. The laboratory experiments demonstrated that all heavy metals examined exhibited toxic effects on the development and oxygen uptake by neustonic and planktonic bacteria. This effect depended on the kind of the metal and its concentration.

17

Composition and abundance of picoplankton in the coastal zone of the Gulf of Gdańsk

Gławdel M., Mackiewicz T., Witek Z.

Oceanological Studies

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1999

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Vol. 28, No. 1-2

17-30

EN

With the aid of epifluorescence microscopy, picoplankton (0.2-2mum) in the coastal zone of the Gulf of Gdansk (southern Baltic) was studied from March to December 1997. The main portion of the picoplankton biovolume was comprised of bacteria, making up on average 70% of picoplankton. Autotrophic picoplankton (APP) prevailed over the bacterioplankton only in late August and early September. The main components of APP were cyanobacteria. The APP proportion in the total phytoplankton biomass was highest in summer. The assessment of this share in terms of quantity varied depending on the picoplankton separation method. In the microscopic analysis of unfiltered samples, all cells 2mum were counted as picoplankton, including colony-forming types. Based on the analysis of unfiltered samples, the amount of APP in the overall phytoplankton biomass was assessed at 16-22% in summer, and 0.5-6% in the remaining period. Initial filtration of samples through a 2mum filter caused great losses in APP, resulting mainly in the elimination of colony-forming cyanobacteria cells from samples. Prefiltered samples were also contaminated by cells 2mum. In prefiltered samples the APP proportion in the total phytoplankton biomass was 1-7% in summer and 0.2-3% in the remaining period.

18

The abundance, biomass and production of bacterioplankton in the Pomeranian Bay

Ameryk A., Mudryk Z., Podgórska B.

Oceanologia

|

1999

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No. 41 (3)

389-401

EN

A microbiological investigation was carried out in the Pomeranian Bay in 1996-1997 to determine the spatial and seasonal changes in the numbers, biomass and productivity of bacterioplankton. Substantial differences in the spatial distribution of bacterioplankton populations were found. At the stations in the coastal zone of the Pomeranian Bay numbers, biomass and production of bacteria were high, with maximum values noted at the mouth of the river Swina. This is indicative of the significant impact of riverine waters on the bacterioplankton in the Pomeranian Bay. Seasonal fluctuations and bacterial microflora activity were recorded. The dynamics of the changes showed that most of the bacteriological parameters examined reached their maximum in summer while minimum values were noted in winter.

19

Occurrence and distribution of bacteria decomposing organic phosphorus compounds in the surface seawater layers

Mudryk Z.

Oceanological Studies

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1998

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Vol. 27, No. 3

45-55

EN

The ability of neustonic and planktonic bacteria inhabiting the Gdańsk Deep to decompose organie forms of phosphorus was studied. It was found that bacteria hydrolysed phytin and DNA most actively, while only smali percentage of bacterial strains studied was able to depolymerize glycero-phosphate. Significant differences in the intensity of minerahzation of organie phosphorus compounds between ncustonic and planktonic bacteria were observed. This process was characterised by consid-erable diel fluctuations. It was also found that in the microlayer, the activity of alkaline phosphatase was higher than of acid phosphatase.