Andrzej Górniak

Long-term variations of phytoplankton primary production in a shallow, polyhumic reservoir

Multiannual and seasonal variation of phytoplankton primary production parameters were investigated in a polymictic, polyhumic dam reservoir. High values of the gross production indicate increasing eutrophication of reservoir waters already from the first years of its existence. The predominance of the total respiration over the net production is caused by substantial natural loads of dissolved organic matter fed to the reservoir from the peaty-forest catchment.

Morphological Variation in Daphnia Cucullata Sars with Progressive Eutrophication of a Polymictic Lowland Reservoir

Morphological variation in Daphnia cucullata Sars was studied from 1994 to 2001 when fast increasing water trophy of the Siemianówka Reservoir was related to high TP and chlorophyll concentrations. During this period, D. cucullata biomass, as well as its contribution to the total cladocerans biomass clearly decreased. We found that among the six morphological parameters analyzed in D. cucullata, body length, height of the head and length of the tail spine had a tendency to decrease. The maximum values of these traits and carapace length also decreased. The morphology of D. cucullata appeared to be influenced by factors such as food availability, fish predation and an exclusive presence of D. cucullata among Daphniidae species. Increased water mixing in the reservoir may have also affected the changes in the head inclination of D. cucullata.

Influence of catchment characteristics and hydrology on dissolved organic carbon in rivers in north-eastern Poland

Dissolved organic carbon (DOC) plays an important role in many biogeochemical cycles. Nurrients and metals, in the form of DOC-mineral complexes, can migrate in freshwaters (REUTER & PERDUE 1977). Dissolved forms of organic carbon are sources of energy for stream ecosystems (WETZEL & MANNY 1977, MEYER 1990). In recent years, a number of papers have been published on the export of DOC from different catchments (MEYBECK 1993, HorE et al. 1997). Many data clearly show the important role of catchment characteristics in influencing riverine carbon concentrations and losses (ECKHARDT & MooRE 1990, CLAIR et al. 1994). Only a small number of these publications have, however, considered the influence of the hydrological parameters of rivers on DOC concentrations. To date, we have only a small amount of data from Polish rivers (BARALKIEWICZ & SIEPAK 1994, PEMPKOWIAK & KUPRYSZEWSKI 1978). The aim of this study was to examine spatial variations of DOC in rivers of contrasting catchment size, river flow and land-use.

Zoosporic fungi and fungus-like organisms in the Siemianówka dam reservoir

Abstract: The occurrence of fungi in the Siemianowka dam reservoir and in the river Narew downstream and upstream of the reservoir was investigated, during the spring, summer and autumn months, taking into consideration many physicochemical factors of water. Phytoplankton chlorophyll a content was also determined. Eighty-seven fungal species, including 71 fungus-like organisms (Straminipila) and 16 species of true fungi were identified. Most species were found in the river Narew upstream of the reservoir, the fewest inside it. The latter finding can be correlated with cyanobacterial blooming recurring every year. The greatest number of species developed in the spring months, the smallest in the summer period. The surface layer of the reservoir was poorer in species than its deeper layers. Moreover, 6 rare species were detected, including Aphanodictyon apiculatum which is recorded for Poland for the first time.

Summer phytoplankton in selected lakes of the East Suwałki Lakeland in relation to the chemical water parameters

Abstract The study covered a complex of 16 lakes of the East Suwałki Lakeland, distinguished by high differentiation of morphometric parameters determining their polymictic or dimictic character. In half of the lakes studied, the occurrence of summer water thermal stratification was observed. It strongly influenced the vertical qualitative and quantitative diversification of phytoplankton. The majority of the lakes studied were classified as eutrophic waters. Only lakes Szelment Wielki and Pejcze had the Carlson chlorophyll index at the boundary of mesoeutrophy. In the case of the majority of the lakes, the concordance of all the trophy indices was recorded. In 6 mesoeutrophic lakes, the character of water was only suggested by phytoplankton parameters

Development of crustacean plankton in a shallow, polyhumic reservoir in the first 20 years after impoundment (northeast Poland)

Abstract Multiannual changes of structure and biomass of crustacean zooplankton were studied in the shallow, lowland, polyhumic Siemianówka Reservoir on the upper Narew River in northeast Poland. High ammonium and soluble reactive phosphorus ion availability for phytoplankton, low water transparency, and high dissolved oxygen concentration resulted in humoeutrophication and caused an intensive development of summer cyanobacteria. We compiled and analyzed long-term (1993–2011) crustacean zooplankton community data and chlorophyll a concentrations. Zooplankton biomass and structure in the summer were related to the intensity of the cyanoprokaryota blooms. As chlorophyll a concentration increased, crustacean zooplankton biomass decreased and smaller crustacean species dominated the zooplankton structure. Large species of crustaceans (Daphnia longispina, D. magna, and Eudiaptomus graciloides) disappeared from the reservoir after filamentous cyanobacteria dominated the phytoplankton. Long-term studies suggest that phytoplankton with strong dominance of filamentous cyanobacteria shape the crustacean community but are probably an insignificant food source for the crustacean zooplankton in the Siemianówka Reservoir.

Riverine water transformation during retention in small lowland reservoirs.

Riverine water transformation during retention in small lowland reservoirs Six small dam reservoirs in northeastern Poland, with different hydrologic and catchment characteristics were selected for research from March to October (2001-2003). There was a significant correlation between DOC and TP in the reservoirs and the water retention time (WRT). The highest values of electrical conductivity (EC) were recorded in reservoirs with an agricultural basin. In almost all reservoirs a statistically significant decrease of EC, compared to inflowing waters, was noted. Nitrates were substantially reduced in afforested catchment reservoirs. The highest TP concentration was recorded in a newly flooded reservoir. In reservoirs with long retention time, phosphorus sedimentation takes place more intensively. This caused phosphorus reduction in outflowing waters.

Results of biomanipulation of a humic reservoir after four years of study

Cyanobacterial blooms dominate eutrophic lakes and reservoirs where anthropogenic nutrient water enrichment has occurred and cause serious problems for water utilization or recreation (SAGEHASHI et al. 2000). Limnological studies of eutrophication of reservoirs in seminatural catchments are very rare, as are scientific restoration studies o f reservoirs with alkaline and high-coloured water. The Siemianówka Dam Reservoir (SDR) was created in 1990. Absence of effective top-down regulation caused rapid eutrophication in the SDR from the first years after filling. In 2000, a restoration project was applied (GóRNIAK et al. 2002). The gradual decrease in fish biomass from 600 k g/ha to 300 kg/ha was the main biomanipulation activity, as well as a decrease in water volume in the reservoir (SMAKULSKA & GóRNIAK 2004 ). In this paper we present the first hydrochemical results ofbiomanipulation effects on this shallow, humic dam reservoir where in summer 1999 chlorophyll concentrations approached 1000 mg chl a/m3 (GóRNIAK et al. 2002).

The variability of summer phytoplankton in different types of lakes in North East Poland (Suwałki Landscape Park)

Abstract This study describes summer phytoplankton communities in 27 lakes in the Suwałki Landscape Park (SLP) using in situ fluorescence methods. Low chlorophyll-a concentrations were noted in most of the studied lakes, particularly in the deepest lakes with highest surface area. Green algae, diatoms and cryptophyta were dominant components of lake phytoplankton. Higher chlorophyll-a concentrations in the shallow or more eutrophicated lakes were connected with an increase of cyanobacteria and cryptophyta concentrations as well as with a decrease in the share of diatoms inphytoplankton structure. Vertical distribution of phytoplankton in stratified lakes revealed the presence of deep chlorophyll layers just below the thermocline where the maximum concentrations of phytoplankton were up to 15 times higher than in the epilimnion zone. The deepest maximum concentration of phytoplankton was noted at a depth of 16.5 metres in Lake Jeglówek. In some lakes two or three significant increases of phytoplankton concentration in the vertical profile were observed, caused by intensive development of different algae groups.

Boron and manganese fractions in dystrophic lake waters (Wigry National Park, NE Poland)

Abstract Physicochemical studies in four dystrophic lakes (Suchar Wielki, Suchar II, Suchar IV, and Wądołek) were carried out in Wigry National Park, NE Poland. Total manganese concentrations oscillated within the range of 386.6-647.5 μg Mn dm-3, while those of soluble reactive manganese, 112.5-328.2 μg Mn dm-3. Fairly high boron contents were recorded in the studied lakes, which amounted to 0.09-2.20 mg B dm-3. The increase in dissolved reactive manganese (DRMn) and decrease in dissolved boron concentration with the lake depth were observed. Almost half (47%) of the total manganese pool was composed of dissolved reactive soluble fraction (DRMn), then dissolved organic form (DOMn, 41%), whereas the particulate fraction (PMn) made up the smallest share (12%). Microbial decomposition of lake organic matter disappears and requirements of authotrophic plankton for Mn2+ decreases when the water temperature drops, thus the fraction prevails. The following regularity was recorded in all analysed dystrophic lakes: iron concentration decreases along with the depth, hence boron content can also be observed due to precipitated borates to bottom sediments, where they are accumulated.