Ekologija

Improvement of phosphorus removal in the wastewater treatment

Marina Valentukevičienė — 2015-03-16

This research study is dedicated to sustainable use of backwash residual from groundwater treatment plants. A high concentration of phosphorus ranging from more than 12 mg/l was detected after primary sedimentation of domestic wastewater and cannot be removed with the existing biological reactors at wastewater treatment plants (Vilnius, Lithuania). Previous research results showed that the high levels of nitrogen compounds are also connected with phosphorus substances. A new reused material is presented in this article for the removal of phosphorus substances from wastewater by use of iron saturated backwash solids obtained from groundwater treatment plants. The treated wastewater quality increased during the treatment that used the 1 g/l dosage of backwash residual from groundwater treatment filters: phosphorus compounds concentration decreased by 98%. All results obtained from this research can be used with the background of sustainable development approach, when backwash residuals from gravitational filters can be collected and used for the removal of phosphorus compounds from domestic wastewater.

Recent advances in vector studies of avian haemosporidian parasites

Rita Žiegytė — 2015-03-16

Many recent studies addressed morphological and molecular characterization, distribution, genetic diversity and evolutionary relationships of avian haemosporidian parasites (Haemosporida). However, the information about relationships between bird haemosporidians and their vectors remains fragmentary and scarce. Experimental studies on this subject are few. Recent advances in vector research of avian haemosporidians (Haemosporida) have been briefly reviewed in regard to the experimental studies, which have been carried out at the Nature Research Centre, Vilnius, during the last five years, with particular attention to widespread species of Plasmodium and Haemoproteus parasites. New information about vectors of avian malaria parasites and haemoproteids is provided and discussed. We point out high virulence of widespread Haemoproteus species for bloodsucking insects of the Culicidae and Ceratopogonidae, and call for additional studies on this subject. Due to widespread abortive sporogonic development in bloodsucking insects, Polymerase Chain Reaction (PCR)-based diagnostics should be carefully used in vector research of haemosporidians because it detects parasites in blood-sucking insects for several weeks after initial infection, but does not distinguish abortive parasite development. That questions vector studies, which are based solely on PCR-based tools. Demonstration of infective sporozoites in insects is essential for definitively demonstrating the insects are vectors. Because of the complicated life cycles of haemosporidians, microscopic approaches and experimental research remain essential and should be applied in parallel with PCRbased detection tools in vector studies, particularly in wildlife.

Teofilį Zubavičių prisimenant

Jurgis Stašaitis — 2015-03-16

Prieš 100 metų gimė žymus gamtininkas ir gamtosaugininkas Teofilis Zubavičius (1904–1993), pažinojęs visus Lietuvoje gyvenančius paukščius, puikiai skirdavęs visų jų balsus, išmanęs slėpiningiausius sparnuočių gyvenimo niuansus.

Recent doctoral theses (ecology and environmental sciences) in Lithuania

Virginija Kalcienė — 2015-03-16