During the first five months of 2007 at one station in front of the entrace the Bay of Boka Kotorska, it was collected mesozooplankton using Nansen net, mesh netting of 200 microns. Analyses included determination of biomass and qualitative composition. Data are given on the number of specimens per cubic meter as well as on the volume organisms. Qualitative composition showed domination Copepoda of zooplankton groups.

Explorations were done at the location Ilje, near Melenci. Novo Ilje 1 is a canal used for regulation of irrigation at the local fields. Novo Ilje 2 is a bog that dries out during the periods of low precipitation. Quantitative phytoplankton analysis of Novo Ilje 1 sample from 2003 determined that total amount of cells was 1.5 x 10**5 cell per liter. Total amount of cells in 2004 sample was 1.8 x 10**5 cell per liter. Quantitative phytoplankton analysis of Novo Ilje 2 sample from 2003 determined that total amount of cells was 1.7 x 10**5 cell per liter. Total amount of cells in 2004 sample was 3.1 x 10**5 cell per liter. Phytoplankton biomass in Novo Ilje 1 sample from 2003 was 2.6 x 10**8 cubic micrometer/l, and in 2004 sample was 1.09 x 10**8 cubic micrometer/l. Phytoplankton biomass in Novo Ilje 2 sample in 2003 was 3.06 x 10**8 cubic micrometer/l, and in 2004 sample was 1.62 x 10**8 cubic micrometer/l.

This paper shows the results of research of some phytoplankton and saprobiological characteristics of water in reservoir Grliste and the flowing rivers during the period of January 2001 to December 2007. During this period of researching, phytoplankton community was characterized by forms of Bacillariophyta, Chlorophyta, Cyanophyta, Chrysophyta, Pyrrophyta and Euglenophyta. Saprobiological analyses using bioindicatory species of algae showed oligosaprobic and beta-mezosaprobic characteristics of water in the reservoir. The analyses showed the poor water quality of Lesovacka and Lenovacka rivers which flow in reservoir. This water was determined as beta-mezosaprobic and alfa-mezosaprobic type. The phytoplankton was characterized by forms of Bacillariophyta, Chlorophyta, Pyrrophyta and Euglenophyta.

The results of researches of the degree of metals (Fe and Cu) of accumulation in certain species aquatic macrophytes and their organs which sampled in three lakes near city Kragujevac are exposed in this study. The results show variability of the degree of accumation of Fe and Cu among species, their organs and researched localities, and capacity of some aquatic macrophytes species and their organs which accumulate high level of mentioned metals from aquatic environment. Results obtained in this reserches pointed important role of macrophytes vegetation in bioindication and phytoremediation, and ability for use for monitoring pollutants, in studies of quality aquatic ecosystems and their protection, repairing and revitalization.

During the field research of phytocenous characteristics of the Moravica river flow and the influence of anthropogenic pollution, hygrophilous ass, Salicetum albae-fragilis (willow grove-shrubs in moist habitats) which grows in the middle reaches of the Moavica, has been found. The community develops in the middle reaches and it indicates highly polluted waters. The aim of this paper is to establish phytocenous contents of the community and ecological conditions of the habitat (indicatives of water quality of the Moravica river) based on ecological index of vascular plants.

During 2005-2006 the seasonal researches were taken place aiming to investigate the influence of the urban waste water on the qualitative and quantitative structure of the community of macrozoobenthos in Gabrovacka river. For this purpose five sites were determined and the sampling of the macrozoobenthos was organized on the seasonal level using Surber net.

In this work, the horizontal and vertical distribution of metals in the sediment of the DTD canal was studied, in a 6 km long polluted section between Vrbas and Bezdan. The assess sediment quality and the bioavailability of heavy metals, sediment samples were analyzed for total metal content, acid volutile sulphides (AVS) and simultaneously extracted metals (SEM). A high total metals content was determined (mainly Cu, Ni and Zn), which indicates that the sediment requires remediation. The AVS and SEM results show that in almost every profile, the molar concentration of metals is less than the molar concentration of sulphides, which suggests that in practice, the metals are not bioavailable. The high metals content of the sediment means that drudging of the canal will be necessary, during which, attention will have to be paid to avoid causing negative effects from the metals present in the sediment.

In the project Quality of Drinking Water of Banja Luka City, during 2007 the colony of zoobentos around the water factory is followed. The composition of colony is different in both season and horizontal profile. The quality of water in litoral area of river is much worse, because polluted water from ambiental settlement and that is indicated by major number of Tubificidae. During monitoring of the states there was a change of qualitative and quantitative composition of colony, also and the change of individual domination of taxons.

Aquatic biotopes are, due to their features, among the most disposed ecosystems to bioinvasion. Serbia waters are not an exception, with and increasing colonization by allochthnous organisms observed there during the last few decades. Non-indigenous aquatic species were found among plants, vertebrates and invertebrates. The aim of this work is to present the current status of aquatic ecosystems in Serbia in regard to biological invansions and to point up to the problem of introduction, presence and influence of aquatic non-indigenous species.