Volume 44 (2015): Issue 3 (September 2015)

Phytoplankton modify the optical properties of the seawater by altering the subsurface light field. Information on the accessory pigments present in the phytoplankton helps to differentiate major phytoplankton classes or taxonomic groups. The variability in the absorption spectra of phytoplankton and particulate matter of case 2 coastal waters of the Southeastern Arabian Sea were studied from June 2010 to November 2011. The phytoplankton specific absorption coefficient, at 440 nm and 675 nm, a*_ph (440) and a*_ph (675) varied from 0.018 to 0.32 m² mg^-1 and from 0.0005 to 0.16 m² mg^-1, respectively. The 4^th derivative spectra computed for each in vivo absorption spectrum showed that the amplitude of maxima obtained is proportional to the concentration of the chromoprotein which absorbed that wavelength. Regression of pigment concentration against the 4^th derivative spectral coefficient showed that the measurements of particulate absorption could provide quantitative information on chlorophyll α and other accessory pigment concentrations. Fucoxanthin and diadinoxanthin, the carotenoid pigments found in the diatoms were identified from the derivatives peaks. The study demonstrates the utility of using the 4^th derivative analysis as a tool to identify the dominating phytoplankton group and its pigment composition.

The paper reports the range extension of the Ponto- Caspian gammarid Dikerogammarus villosus (Sowinsky, 1894) and the first occurrence of this species in new areas of the Polish part of the Baltic Sea basin: the Śmiała Vistula and the Vistula Lagoon.

The studies additionally determine the osmoregulatory ability of the species under laboratory conditions within the salinity range of 2-22 PSU. Determination of the osmoregulation of the species shows that D. villosus is a hyperregulator at given experimental salinities and can function in a wide range of external salinities so it is potentially able to colonize various water bodies. Osmoregulatory capacity, which is an indicator of organism’s efforts to regulate the concentration of its body fluids, shows that for individuals from the Gulf of Gdańsk, 6 PSU is the best tolerated salinity. Osmoregulatory capacity is the lowest at this salinity value.

The range extension and potential osmoregulatory abilities of the species to spread to other waters are discussed in the context of pollution levels given in the literature with reference to the habitat and sensitivity of the species to e.g. fluoride and cadmium toxicity.

The American panopeid crab species Rhithropanopeus harrisii (Gould, 1841) is listed as an non-native species in European waters. In Poland, it occurred in the 1950s at two sites at the Baltic Sea coast, the Dead Vistula River (DVR) and the Vistula Lagoon (VL). Almost 50 years later, two additional populations were identified in the Gulf of Gdańsk (GG) and its inner part, Puck Bay (PB). In the present study, we sequenced and analyzed part of the mitochondrial cytochrome oxidase subunit I gene of the four Polish populations of R. harrisii in order to assess their genetic diversity and connectivity. The analyzed sequences of a length of 989 base pairs revealed eight different haplotypes. The highest number of haplotypes (n=6) was observed in the population from GG, whereas the lowest (n=3) in VL. The most common haplotype was recorded in 37% of the analyzed individuals. Pairwise Φ_ST values were mostly non-significant, with the exception of the comparison between DVR and VL (Φ_ST = 0.267; P < 0.05) and between PB and VL (Φ_ST = 0.194; P < 0.05), indicating a restricted gene flow or different sources of colonization.

Cormorants feed in aquatic ecosystems and transport a large amount of biomass and chemical substances to colonies or roosts situated on land adjacent to the water. This leads to significant enrichment of soils in nutrients. Some loads of nutrients may be transferred to a nearby lake. A long-term impact of cormorants may be followed by the destruction of vegetation beneath the colony. Within a few decades, cormorants lose places suitable for nesting or roosting and abandon the colonies. Then the content of nutrients in the soil decreases and natural regeneration of vegetation occurs. We found that despite the passage of several years since the abandonment of a cormorant colony, the concentration of nutrients in the soil remained high. Groundwater beneath the colony was also strongly enriched with nutrients. Thus, despite the absence of a bird being a source of nutrients, the area of the former colony constantly supplies nitrogen and phosphorus into the nearby lake. The occurrence of vegetation in the area of the former cormorant colony is limited to a few species. Nitrophilous black elder Sambucus nigra, usually creates a dense canopy preventing the light penetration, thereby reducing the growth of other plants.

The in situ growth rates of dinoflagellates along the Karachi coast off Pakistan was studied by the size fractionated method during winter (February 2006) and summer (May 2007). The growth rate per day ranged from -2.87 to 2.3 d^-1 (20 species) in winter and from 1.20 to 1.95 d^-1 (13 species) in summer. Growth rates (μ_max d^-1) of the dominant species were as follows: Prorocentrum gracile, Prorocentrum minimum, Prorocentrum arcuatum (1.0-1.10), Protoperidinium steinii (0.92), Gonyaulax spinifera (0.69), Dinophysis acuminata (2.3), Dinophysis caudata (0.92), Ceratium lineatum, Prorocentrum micans (1.95), Gyrodinium sp. (1.88), Ceratium furca (1.70), and Alexandrium ostenfeldii (1.34). The declining growth rates were observed for Pyrophacus stein (-1.10), Scrippsiella trochoidea (-1.61 to -0.82), Prorocentrum donghaiense (-1.94) and Karenia mikimotoi (-2.48). Our results suggest that a higher temperature induce an increase in dinoflagellate growth rates.

Rotifer diversity was studied in three different types of artificial water bodies situated in one of the largest cities in Poland. The bodies of water were as follows: a fountain in a city park, the Nowa Huta dam reservoir, and the Bagry gravelpit. The lowest number of rotifer species (23) was noted in the urban fountain, and the highest (36) in the Bagry gravel-pit lake. Rotifers’ communities in the investigated water reservoirs showed different levels of diversity and density. The most numerous species in the dam reservoir was Trichocerca similis (2511 ind. l^-1) and in the Bagry gravel-pit lake was Polyarthra dolichoptera (2634 ind. l^-1). However, the most abundant species in the fountain was Brachionus urceolaris (863 ind. l^-1). The highest values of Shannon and evenness diversity indices were found in the Bagry gravel-pit lake (H’ = 2.521, J’ = 0.783), while the lowest in the urban fountain (H’ = 0.568, J’ = 0.258). The DCA analysis (Detrended Correspondence Analysis) showed that the diversity of rotifers communities in the studied reservoirs was related to the concentration of magnesium and calcium, and to water conductivity.

Effects of marine aluminum (Al) on phytoplankton are controversial, making it important to elucidate the mechanisms underlying Al effects. This study was aimed at identifying the effects of Al on the growth, chlorophyll a (chl a) content and the antioxidant mechanism of cyanobacteria Synechococcus sp. WH7803. The growth rate increased from 0.33 to 0.52 d-1 in media with the increasing Al concentration from 0.2 (control) to 20 μmol l^-1 and almost saturated to 0.44 d^-1 at ~ 0.5 μmol Al l^-1. The higher growth resulted in the higher biomass in both stationary and decay phases in the conditions of higher Al content. Chl a per cell reached 10.19 μg cell^-1 in the exponential phase at 20 μmol Al l^-1, approximately 1.6 and 3.1 times higher than those in stationary and decay phases, respectively, and chl a per cell showed a similar pattern as a growth rate when plotted with Al content. Al addition increased the cellular methane dicarboxylic aldehyde (MDA) content in the exponential phase and decreased the superoxide dismutase (SOD) activity in the decay phase. In particular, our results indicated a positive relationship between chl a per cell and the growth rate, suggesting the stimulation of increasing Al on the growth of Synechococcus is related to the enhancement of cellular chl a content.

The state of a fragment of the southern Baltic Sea shore was assessed on the basis of historical maps, aerial images, the digital elevation model and the data on the geological structure of the nearshore bottom. The alternate erosion and accumulation sections of the coast were observed. They are moving toward the east related to the migration of mega beach cusps. The infrastructure of the military training ground located in the western part of the study area is threatened with abrasion. In 1889-2012, the nearby seashore retreated by an average of 257±11.5 m. The recorded average rate of changes for the period of 1989-2012 was -2.6±0.22 m year^-1. In the eastern part of the study area, at the bottom of the nearshore, a thick layer of sand determines the development of new accumulation sections of the coast. The state of the seashore, recognized in this paper, will change due to the construction of four concrete sea-walls. Their operation will disrupt the natural processes described in these studies.

The method introduced in this study for future projection of coastline changes hits the vital need of communicating the potential climate change impact on the coast in the 21th century. A quantitative method called the Dynamic Equilibrium Shore Model (DESM) has been developed to hindcast historical sediment mass budgets and to reconstruct a paleo Digital Elevation Model (DEM). The forward mode of the DESM model relies on paleo-scenarios reconstructed by the DESM model assuming stationary wind-wave climate. A linear relationship between the sea level, coastline changes and sediment budget is formulated and proven by the least square regression method. In addition to its forward prediction of coastline changes, this linear relationship can also estimate the sediment budget by using the information on the coastline and relative sea level changes. Wind climate change is examined based on regional climate model data. Our projections for the end of the 21st century suggest that the wind and wave climates in the southern Baltic Sea may not change compared to present conditions and that the investigated coastline along the Pomeranian Bay may retreat from 10 to 100 m depending on the location and on the sea level rise which was assumed to be in the range of 0.12 to 0.24 m.

An excess of nitrogen and phosphorus causes an increase in productivity, leading to degradation of a water reservoir. In order to reduce the eutrophication, protective and restoration methods are used. The objective of the paper was to determine the hourly and daily variability in nitrogen and phosphorus compounds in a lake restored by the hypolimnetic withdrawal method. In the epilimnion, the organic form dominates: 97% of P_tot and 75% of N_tot. Hourly variations in the concentration of the investigated compounds indicate that the highest values occurred at night and in the morning, whereas lower measurements were recorded at noon and in the evening. Such a distribution of the concentrations of nutrients during a day is strongly associated with photosynthesis. Along with depth, the proportion of this form decreased in favor of mineral forms. A high content of mineral phosphorus (70%) and ammonium ions (75%) in the hypolimnion results from their release from bottom sediments under anaerobic conditions. As a result of the generated thermocline, they are blocked and accumulated. At the experimental station, the concentration of mineral compounds was at a lower level than at the reference station since their amount was systematically reduced by the outflow of over-fertilized waters from the hypolimnion.

The macroalgae representing the cosmopolitan Ulva flexuosa Wulfen species have been found in inland water ecosystems of Europe since the mid-1800s. The presence of the Ulva genus in waters of inland salt marshes was explained by high salinity of water in such systems. However, Ulva flexuosa thalli were found in lakes and rivers having no supply from strongly mineralized sources, either of natural or anthropogenic origin. The study focused only on populations of Ulva flexuosa subsp. pilifera (Kűtz.) M.J. Wynne and Ulva flexuosa subsp. paradoxa (C. Agardh) M.J. Wynne occurring in inland ecosystems isolated from seawater. The differentiation of inland U. flexuosa subsp. pilifera and subspecies paradoxa was assessed by using classical morphological data and molecular techniques. We found that only two subspecies of Ulva flexuosa Wulfen occur in inland water ecosystems of Poland. On the basis of the analysis combining morphological features with the ITS region and rbcL gene sequences, a small degree of differentiation of the two inland taxa was demonstrated. These two subspecies have high differentiation of the habitat niches. U. flexuosa subsp. paradoxa settled in habitats featuring high salinity levels, and the second subspecies pilifera occurred only in fresh waters.

The study was conducted from 2000 to 2003 in the tailwater of the Drzewieckie Lake, an artificial reservoir in Central Poland. Short-term peaks in water flow were generated for the purpose of the operation of a whitewater slalom canoeing track built just downstream of the dam. In 2002, the reservoir was drawn down. The patterns in habitat samples were recognized with a Kohonen’s unsupervised artificial neural network (SOM). The SOM spatial gradient was stronger than the SOM temporal gradient, which shows that the removal of the studied dam did not have a destructive impact on habitats’ features, as shown in other studies, and that the patchy nature of the riverbed has been maintained. The complete emptying of the Drzewieckie Lake took place at the beginning of the vegetation season, which allowed plants to cover the exposed bottom of the reservoir and, consequently, reduce the downstream flow of organic matter accumulated there. Patterns in the displacement of aquatic macrophytes, inorganic substratum and different fractions of particulate organic matter are discussed. The amount of dissolved oxygen decreased because of the lack of intensive water discharge from the reservoir into the river, which would result in high water turbulence. Results of this study are important for planning the ecologically sound dam removals.

A single female of Litarachna duboscqi Walter, 1925 was collected on the coast of the island of Tenerife (Canary Islands) extending the currently known distribution of this species by more than 2000 km southwestward into the eastern Atlantic.