Results of phytoplankton investigations that were performed in May, July, August and October 2010 are presented in this paper. The investigated areas are in Boka Kotorska Bay on four locations: Kotor Bay-IBM, Tivat Bay, Hercegnovi Bay-two positions and one position on the open sea – Mamula. In this area the influence of the open sea and the land are expressed to the phytoplankton community. As a consequence of that quantities of phytoplankton are lower in the outer part and higher in the inner part. Diatoms are the most dominant species, which is very frequent in the eutrophic area.

Since the year 2004 the water reservoir Kraljevac has been recognized as a Special nature reserve. Investigations of the water reservoir were done during the autumn (November) of 2009 at three localities. on the basis of the results obtained in this study Kraljevac reservoir water is moderately polluted and correspond to classes 2nd and 2nd-3rd based on physical, chemical, microbiological and hydrobiological parameters.

In this work results from April to September 2009 are presented, which comprosed analyses of samples from 15 stations along Montenegrin coast. The main aim was to estimated level of eutrophication and phytoplankton community characteristic for eutrophic area. Maximum mean value of microplankton of 8.4 x 10**5 cells/l was noted in the inner part of Bokakotorska Bay. This area has maximal values throughout all period of investigation. It is result of waters dynamics and influence from the coast. In the open sea values were lower, about 10**4 cells/l. These results show that Montenegrin coast is an eutrophic region. Some phytoplankton organisms characteristic for eutrophic region were found also. The most abundant species was Thalassionema nitzschioides with maximum mean value of 8.4 x 10**5 cells/l.

In the scope of complex water quality analysis of the Bocac reservoir, as well as rivers which flow into and out of the Bocac reservoir (Vrbas, Crna Rijeka) during the period from May to September 2008, the contents and the dynamics of the phyto and zooplankton were analyzed as biological parameters. The qualitative contents of the phytoplankton includes 5 divisions of total 27 taxa from 16 species; the tributaries contain 30 taxa from 19 genuses. The zooplankton (Rotatoria, Cladocera and Copepoda) contain 22 taxa from 16 genuses; the tributaries contain 32 taxa from 19 genuses with huge dominance of the Rotatoria species. By saprobiological analysis, species of oligo and beta mezosaprobiological character previal.

Qualitative and quantitative phytoplankton analysis was determined using standard microscopic methods and high performance liquid chromatography (HPLC) in the Bay of Kotor, seasonally, from April 2008 to March 2009. Diatoms represents dominant group of microphytoplankton with maximum in spring period. Dinoflagellates reached maximum value in summer period, and followed by cyanobacteria bloom. Dominant biomarkers, fucoxanthin, alloxanthin, 19'-heksanoloksifukoxanthin, zeaxanthin and chlorophyll b, show a similar distribution as the appropriate phytoplankton assemblages during the researches in Kotor Bay.

Researches of the Zelengora natural lakes during 2008 were performed in Orlovacko, Kotlanicko and the Lake Donje Bare. Water quality analysis of natural lakes of Zelengora were based on preliminary examination of basic physical and chemical parameters, as well as microbiological parameters. In the scope of biological examinations, phytoplankton, zooplankton and benthic fauna were determined. Due to the lack of data on biodiversity of examined natural lakes and whole area of National park Sutjeska results obtained in this research could only represent the first step toward further examinations, as well as the nature and biodiversity preservation in the Republic of Srpska.

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.

Barje reservoir, established by damming of Veternica river, 30 km upstream from Leskovac town (Serbia), was intended for water supply of communities of Leskovac and Lebane. From its final formation and attaining of maximal volume (1995), long-year investigations have performed, and they included morphometric, chemical and biological parameters (phytoplankton, zooplankton, benthic fauna and ichthiofauna). The results of these hydrobiological investigations have showed that the reservoir Barje is unstable. In according to recommendation for continual following of condition of Barje reservoir, investigations of phytoplankton were repeated in spring and autumn aspects in 2005, and quality of the water was determined on the base of algae. The results of saprobiotic investigations show that the type of water is oligo-beta saprobic, but dense populations of eutrophic species (Fragilaria crotonensis and Closterium aciculare) indicate on deterioration of trophic conditions in this reservoir.

Influence of eutrophication to the phytoplankton community were studied in the inner part of Boka Kotorska Bay (Kotor Bay and Risan Bay) from September 2003 to August 2004. Kotor Bay and Risan Bay is very interesting area because the influence of natural and anthropogenic eutrophication are mixed very often. Microphytoplankton density is high (greater than 10**6 cells/cubic dm) what is characteristic eutrophic area, to the highest eutrophic area (greater than 10**7 cells/cubic dm). These values we stated in the surface, because in this layer were the best conditions. In same time we stated very high values: SiO2, oxygen saturation and chlorophyll a. The conclusion is: Boka Kotorska Bay and especially Kotor Bay (as a part of Boka Kotorska) has to be protected of dangerous consequences such as blooming. It is needed to regulate wastewater, their purification and permanent control physico-chemical and biological parameters, and especially phytoplankton component.