Volume 47 (2018): Issue 1 (March 2018)

Relationships between chlorophyll-a (chl-a) concentrations and 16 physicochemical variables in temperate eutrophic Çygören and mesotrophic Ikizcetepeler reservoirs (Turkey) were determined using Principal Component Analysis (PCA). PCA was used to simplify the complexity of relationships between water quality variables. Principal component scores (PCs) were used as independent variables in the multiple linear regression analysis (MLR) to predict chl-a in both reservoirs. This procedure is called Principal Component Regression (PCR). In the eutrophic Çygören Reservoir, chl-a was significantly (p < 0.05) correlated with nitrite-nitrogen (NO₂), ammonium-nitrogen (NH₄), phosphate (PO₄), total suspended solids (TSS), pH, Secchi disk transparency, total dissolved solids (TDS) and total phosphorus (TP). In the mesotrophic Ikizcetepeler Reservoir, chl-a was significantly (p < 0.05) correlated with TSS, NO₂, chemical oxygen demand (COD), sulfate (SO₄), TDS, pH and the Secchi disk. In the eutrophic Çaygören Reservoir, six PCs explained 71% of the total variation in the water quality, while in the mesotrophic Ikizcetepeler Reservoir, six PCs explained 75% of the variation. This study has shown that PCR is a more robust tool than direct MLR to simplify the relationships between water quality variables and to predict chl-a concentrations in temperate reservoirs with different trophic states.

Screening of fourteen Baltic green algal strains provided basic data on their mass culture potential for the purpose of valuable biomass production with particular emphasis on lipid content. Selected microalgae were grown under non-stressed conditions in order to identify those characterized by efficient lipid production. The tested strains exhibited significant differences in growth patterns and lipid yields. Strains belonging to Chlorella and Stichococcus genera exhibited the highest growth rates, ranging from 0.39 d^-1 to 0.50 d^-1 and thus the highest final cell density (> 10⁷ cells ml^-1). Furthermore, five strains: C. minutissima BA-12, C. fusca BA-18, C. vulgaris BA-80, Monoraphidium sp. BA-165 and Chlorella sp. BA-167 were characterized by distinctively high lipid yield (> 60 mg l^-1). The same strains, together with C. vulgaris BA-02, were also shown as those with the highest volumetric lipid productivity, reaching > 30 mg l^-1 d^-1. The tested Baltic strains performed well in terms of lipid production compared to the literature data, still leaving a great spectrum of opportunities for further lipid yield improvement.

This paper presents the results of a study aimed at developing the extraction process and determining long-term stability of (E)-azastilbene derivatives in order to explore their possible use as preservative, antiseptic and disinfectant substances. The study was performed in three different matrices: distilled, surface and waste water. Test substances included bromide of (E)-N-(o-bro-mobenzyl)-4′-hydroxystilbazole-4 and chloride of (E)-N-(p-chlorobenzyl)-4′-hydroxystilbazole-4. The extraction process involved the use of three stationary phases: octyl, octadecyl and naphthylpropyl. The highest recovery values (amounting to approx. 95%) were obtained in the naphthylpropyl column for all of the above-mentioned matrices. A decline in the stability of the analysed derivatives after a 28-day period was below 14% in all matrix types.

The aim of this work was to present a morphological description and ecological characteristics of a rare species from the Gomphonema genus, occurring in calcium-rich waters, along with its new occurrence sites. The research was carried out in flowing waters of mountain and sub-mountain streams and rivers in Poland: the Wołosaty, the Wisłoka, the San and their tributaries. The occurrence of many rare and new to Polish flora species from the genus Gomphonema was recorded: G. cuneolus E. Reichardt, G. drutelingense E. Reichardt, G. innocens E. Reichardt,G. lateripunctatum E. Reichardt & Lange-Bertalot, G. lippertii E. Reichardt & Lange-Bertalot and G. calcifugum Lange-Bertalot & E. Reichardt. These species occur mostly in alkaline or close-to-neutral waters with medium or low electrolytic conductivity (78–530 μS cm^-1), low nutrient content and medium-to-high calcium ion content (12.4–76.4 mg l^-1). Despite the rare occurrence in other parts of the world, the studied Gomphonema species has found favorable conditions in unpolluted and calcium-rich stream beds with flysch strata. The literature data define G. calcifugum as a non-calciphilous species, but this study shows that it can develop in a wide pH range and in calcium-rich waters.

We have determined the timing of periodic events, such as leaf formation, flowering, fruiting and wintering of the aquatic plant Potamogeton alpinus. This study was performed in 15 watercourses situated in NW Poland in 2014–2015. Characteristics of the age stages were determined on the basis of 728 modules and phenological data were collected from permanent plots. In the study area, the plant appeared in week 12 of the calendar year, when water temperature in the streams was 5.4 ± 0.16°C. At that time, the first leafy juvenile shoots developed from winter buds. In week 22 (water temperature 13.9 ± 0.85°C), juvenile shoots became mature, whereas the first flowers were formed in week 24 (15.6 ± 1.04°C). The generative phase lasted twelve weeks with water temperature from 15.6 ± 1.04°C to 18.9 ± 3.23°C. Between weeks 37 and 44 (water temperature from 13.7 ± 0.77°C to 6.3 ± 1.05°C), senile shoots dominated in the population. From week 45 until week 11 of the next year (water temperature < 5.4 ± 0.16°C), the plants were in the winter resting stage. In our view, climate warming might disturb the phenology of P. alpinus, decreasing the probability of sexual reproduction of the species and the phenological distance between the Central European Plain and the Scandinavian populations.

To date, no studies have been conducted on macroinvertebrate communities in coal mine settling ponds used for temporary retention of saline mine waters. The objective of the research was to evaluate which habitat – Ruppia maritima, Phragmites australis or sediments without macrophytes – is the most favorable for the abundance and biomass of macroinvertebrate communities. The study was carried out in a hyposaline settling pond located in a mining and urban area in southern Poland. At this time, it is the only inland locality of R. maritima in Poland.

In the studied coal mine settling pond, the non-native, euryhaline amphipod Gammarus tigrinus dominated in the communities on all the habitats. The abundance of other taxa was small and similar on each type of substrate; only Corixidae were much more abundant on the widgeongrass beds. The highest abundance and biomass of macroinvertebrates was recorded at the sites with R. maritima. Our study highlights the importance of coal mine settling ponds as a substitute habitat for salt-tolerant invertebrates.

We present the first report and description of the pinnate diatom Haslea sp. from the northeastern Adriatic Sea, Croatia, producing a blue pigment. This organism is very similar to the well-known Haslea ostrearia, the first described “blue” diatom producing marennine, i.e. the pigment involved in the greening of oysters, and recently described H. provincialis. However, the Croatian diatom slightly differs from other Haslea species in its morphology and 18S rRNA sequence. The discovery of Haslea sp. from Croatia confirmed the possible existence of more species among the representatives of blue Haslea species, as previously assumed. The discovery of several genetically distinct populations of Haslea ostrearia, new species H. karadagensis, H. provincialis and Haslea sp. from Croatia, suggests that species richness in the group of “blue” diatoms is probably underestimated and still more new blue diatoms remain undiscovered. This also raises questions about previously published reports and observations of Haslea distribution in the Mediterranean Sea whether these organisms really belong to H. ostrearia.

The paper presents the results of research on the reproductive biology of Syngnathus abaster – a species distributed in Çandarli Bay. For this purpose, seine nets were collected from a depth of 0.5–2 m in 15 minute periods between April 2013 and March 2014, and a total of 185 individuals were sampled. It has been determined that 94 individuals (50.81%) were females, 79 were males (42.70%) and 12 were immature (6.49%). The sex ratio was 1:0.84. The average length values in female, male and immature individuals were 111.5 ± 7.35, 109.9 ± 11.08 and 79.8 ± 5.30 mm, respectively. The maximum mean surface water temperature is in spring and summer seasons. When Gonadosomatic Index (GSI%) values were examined, the spawning period of the species was indicated as spring and summer. Three groups of species were identified as maturing (diameter: 0.61–1.20 mm), mature (diameter: 1.21–1.70 mm) and hydrated oocytes (diameter: 1.71–2.10 mm) in ovaries of female individuals. The number of eggs in the brood pouch of pregnant male fishes was on average 48 (mean ± SD = 48 ± 14.09 eggs, range: 23–78 eggs). The hydrated oocyte/total length relationship was: y = 0.8651x – 84.332 (n = 14, r² = 0.64) and the number of eggs/total length relationship in the brood pouch of pregnant males was: y = 1.0168x – 67.715 (n = 33, r²=0.58).

A new large population of the Asian clam Corbicula fluminea (O. F. Müller, 1774) was found within a reach (ca 210 km long) of one of the largest European rivers, the Vistula. The largest population and the largest individuals were found at the outlet of a channel collecting heated water from the cooling process at the Połaniec power station and adjacent parts of the river. In the northern part of the study area, bivalves occurred at the channel margins, in groyne fields, and in the shallows of sand banks or sandbars. The clams were less numerous in places where the river was regulated with straightened banks and stone ripraps. Twenty-five other taxa of mollusks were found altogether at the sampling stations where Corbicula was observed, including other non-indigenous mollusk species.

The breaking wave phenomenon significantly takes part in the mechanisms of mass, heat and gas exchange at the air-water boundary and depends on the wind velocity. Some of the energy dissipated during this process is converted into underwater sound emitted by oscillating gas bubbles and bubble plumes. However, the underwater noise accompanying the lowest wind speed conditions has received only little attention. This report describes a study aimed at advancing the knowledge of underwater noise emission from air bubbles injected during small-scale breaking events occurring on the water surface. Results of model experiments performed in a small tank are presented. The object of the research is the relationship between the generated noise and the dissipated potential energy of water poured into a tank filled with water of varying physical water properties. Additionally, the impact of various water properties such as salinity, surface tension or microscale gas bubbles was examined. The experiment revealed that noise spectra are affected by different water properties and most likely reflect the varying efficiency of bubble formation and bubble size spectra.