Teresa Ozimek

Growth and nutrient uptake by two species of Elodea in experimental conditions and their role in nutrient accumulation in a macrophyte-dominated lake

The capacity of Elodea nuttallii (Planch.) St. John and Elodea canadensis Michx. to remove nitrogen from water was evaluated in laboratory experiment. The growth rate of plants and their effect on the nitrogen level of hypertrophic Lake Zwemlust (the Netherlands) as well as on lake water enriched with nitrogen were investigated. The plants grew best in water enriched with up to 2 mg NH4-Nl−1 and 2 mg NH4-Nl−1 plus 2 mg NO3 Nl−1. During a 14 day experiment, plants absorbed from 75% to 90% of nitrogen. Higher nitrogen concentration than 4 mg l−1 had a negative effect on growth of both species. Elodea nuttallii and E. canadensis prefer NOinf4/p+ over NOinf4/p− when both ions were present in water in equal concentrations.

Long-term changes of the submerged macrophytes in eutrophic lake Mikołajskie (North Poland)

Abstract On the basis of quantitative observations of submerged macrophytes over the past 17 years, it has been found that their distribution, frequency and presence in Lake Mikolajskie are all affected by eutrophication. The area occupied in the littoral zone has been reduced markedly and, as the degree of eutrophication became more advanced, the lake has changed from a Chara-type to a Potamogeton-type lake.

The effect of sewage sludge flooding on growth and morphometric parameters of Phragmites australis (Cav.) Trin. ex Steudel

Abstract Phragmites australis is the most frequently used species in constructed wetlands (CW) for dewatering and mineralization of sludge. Such CW create a very hostile environment for plants because their roots are exposed to permanently anaerobic conditions. Our working hypothesis assumed a simple relationship between the success of reed in colonising sludge flood stands and maximalisation of shoot oxygen production and transport to rhizomes and roots. Morphometric parameters and density of common reed shoots growing in reed bed systems inundated with sewage sludge were investigated. It was proved that flooding with sewage sludge significantly influenced characteristics of common reed populations. In comparison with natural stands, on stands treated with sewage sludge, maximal density of shoots was higher, biomass was twice as high, shoot diameter was significantly greater, and leaf weight ratio of an individual shoot was also significantly higher. Tendency to shorten shoots was noted. Growing period was longer for reed shoots treated with sewage sludge than on natural stands.

Effects of filamentous algae on submerged macrophyte growth: a laboratory experiment

Abstract Elodea canadensis Michx. and Potamogeton pectinatus L. were cultivated in the laboratory in the presence and absence of filamentous algae ( Cladophora glomerata (L.) Kutz.) for 20 or 30 days. In treatments without algae, macrophyte biomass increased in all cases (from 17 to 76% of initial fresh weight). In the presence of algae, Elodea lost weight (35–57% of initial weight), no significant differences in biomass were observed in the case of Potamogeton . Algae decreased growth of new shoots and accelerated decay of old shoots. Chlorophyll a was significantly lower in macrophytes growing with algae than in plants grown alone.

Further long-term changes in the submerged macrophyte vegetation of the eutrophic Lake Mikolajskie (North Poland)

Abstract On the basis of quantitative sampling of submerged vegetation, repeated in Lake Mikolajskie a further 10 years after the last survey, and compared with 1980, 1971 and 1963, continuing changes are reported. There was a further decrease of the depth range and thus of the colonized area. The frequency and percentage contribution of some formerly abundant species diminished, as the submerged vegetation continued to change to a Myriophyllum-Potamogeton assemblage.

Aspects of the ecology of a filamentous alga in a eutrophicated lake

In the eutrophic Lake Mikolajskie macrophytes disappearing from the deeper parts of the littoral are replaced by Vaucheria dichotoma Ag. This forms a belt at 3.0–4.5 m to which depth only 1% of surface light penetrates. The zone of V. dichotoma has a layered structure. Some filaments are covered in mud and receive no light, but are alive and photosynthesize when transferred to light. V. dichotoma prefers fertile environments with a high content of phosphate-phosphorus and ammonium-nitrogen. It is evergreen and its biomass changes relatively little during a year.

Biomass and distribution of underground parts of Potamogeton perfoliatus L. and P. Lucens L. in Mikołajskie Lake, Poland

Abstract The rhizomes of Potamogeton lucens penetrate the lake bottom to a maximum depth of 20 cm (on average to a depth of 9 cm), thus exceeding the average depth of penetration by rhizomes of Potamogeton perfoliatus by a factor of 1.5–4.5. The contribution of the biomass of underground parts to the biomass of the whole plant is on average 49% for P. lucens and 39% for P. perfoliatus , independent of the structure of the lake bottom. There is a positive correlation between the biomass of underground and above-ground parts. Field experiments show a similar rate of increments and losses in rhizome biomass of both species of pond weed.

Glyceria maxima (Hartm.) Holmb. in ponds supplied with post-sewage water

Abstract Glyceria maxima (Hartm.) Holmb. growing in a pond supplied with post-sewage water (sewage after biological and mechanical treatment) grows very well, attaining a high biomass of 1.5 kg dry weight/m 2 of an overgrown surface, and accumulating large amounts of different elements, e.g. 46.2 g N, 7.9 g P and 31.1 g K/kg dry weight of plants. The plant offers possibilities for the purification of waters polluted by municipal and industrial waste.

Duckweed does not improve the efficiency of municipal wastewater treatment in lemna system plants / Rzęsa nie poprawia efektywności oczyszczania ścieków komunalnych w oczyszczalniach typu Lemna System

Abstract This study investigated the operation of three full-scale Lemna System surface fl ow municipal wastewater treatment plants, built according to the Lemna Corporation design. These plants consist of two ponds, the first aerated and the second for duckweed, with a barrier grid in the latter to ensure uniform plant distribution across its area. According to designers duckweed improves the efficiency of wastewater treatment. The three treatment plants are situated in central Poland and they differ in the occurrence of duckweed, two of them, located in Raków and Bąkowiec, operate without duckweed. and the third in Falęcin Stary, Lemna minor covers ca. 90% of second pond surface. The efficiency of Lemna System wastewater treatment was found not to differ between the plants with and without duckweed. The aerated pond played the main role in reduction of pollutants in the investigated Lemna Systems Streszczenie Badania prowadzono w trzech czyszczalniach hydrofi towych z powierzchniowym przepływem ścieków typu Lemna System, zbudowanych według projektu Lemna Corporation. Składają się one ze stawu napowietrzanego i stawu rzęsowego wyposażonego w system barier mających na celu równomierne rozmieszczenie roślin. Stawy poprzedzone są osadnikiem wstępnym. Według projektantów odpowiednia praca tych oczyszczalni związana jest z występowaniem rzęsy na powierzchni stawu rzęsowego. Badano efektywność oczyszczania ścieków komunalnych w trzech oczyszczalniach Lemna System usytuowanych w centralnej Polsce ze szczególnym uwzględnieniem roli stawu rzęsowego i samej rzęsy. Oczyszczalnie różniły się między sobą występowaniem rzęsy. W dwóch z nich (w Rakowie i Bąkowcu) w trakcie całego okresu badań rzęsa nie występowała, natomiast w trzeciej (w Falęcinie Starym) w okresie wegetacyjnym pokrywała do 90%.powierzchni stawu. Efektywność oczyszczanie ścieków nie różniła się w oczyszczalni z rzęsą i bez rzęsy. Rzęsa nie wpływała istotnie na efektywność oczyszczania ścieków. We wszystkich oczyszczalniach główną rolę w redukcji zanieczyszczeń odgrywał staw napowietrzany

The losses and increments of rhizomes of Potamogeton lucens L. in the littoral of mikołajskie lake (Poland). Field experiments

Abstract A field experiment in which Potamogeton lucens L. was transplanted was carried out in order to determine the losses and increments of rhizomes under natural conditions during the vegetation season. The losses of rhizomes separated from the aboveground parts and placed in bags were also determined. The losses from rhizomes separated from aboveground parts were greater than from transplanted plants; after 38 days the losses of rhizomes in bags were 80%, while those of transplanted plants were only 52% of initial biomass. It has been found that the rate of increment to rhizomes is not constant over the entire vegetation season; the highest increment takes place after the plants have flowered and fruited.