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This paper aims to assess the level of perceptions of stakeholders on algal blooms in aquatic systems of Danube Delta in order to apprehend potential adaptation and mitigation strategies for the future, and to analyze for political targets and deficits. Hence, by means of questionnaires were engaged 24 stakeholders representing natural resource managers, local authorities, scientists, NGO’s. Even though the results indicated that not all stakeholders are aware with algal bloom terminology, stating a lack of institutional communication and availability of information to the public in the area, it was an overall consensus that the phenomenon represents more than a serious issue for deltaic aquatic ecosystems. The level to which national, regional and local resources can be focused on treating algal blooms issues depends in part of the strengths and interests in the area.

This study presents the drinking water supply system quality analysis in the context of the presence and distribution of eukaryotic assemblage, specifically the presence of algae in 10 specific sites (water treatment plants and fountains) from the Danube Delta. The analysis comes with a new approach based on stakeholders involvement and understanding of the new emerging problems generated by the presence of algae in the water supply system. In order to upgrade the water quality it is needed an improvement on the management of the water supply systems, with direct connection to the management of presence of algae or the occurrences of algal toxins in drinking water sources. Taking into consideration that Romania have no regulation dealing with the occurrence or the presence of algae or algal toxins in recreational or drinking water sources, it is important for all the stakeholders (local communities, local authorities, regional and national authorities etc.) to be informed about the the possibility of their occurrence in drinking or recreational waters, by creating a virtual space where they have access to the researches in this area.

The present paper includes details related to the evolution (in 1993 – 2012 period) of some qualitative and quantitative features of the volumes of the journal entitled “ Scientific Annals of the Danube Delta Institute”. In the respective twenty years, there were published 798 original articles, but the number of articles / volume decreased along the analysed period (R 2=0.7405) (the most obvious decrease was in case of the articles with subjects related to natural resources and socio-economic aspects). A positive characteristic of the journal evolution was the decrease in percentages/volume of works with few references (the articles without any references being totally eliminated since 2004, inclusively). Other positive aspects of the journal development (in the same two decades) can be considered the increases in some elements of the journal, as follows: percentage of articles that contain lists of references (R2 =0.7322), details related to the authors (R2=0.5179),abstracts (R 2=0.5578) and key words (R2=0.7971), number of articles with high number of references (R2=0.3446 in case of articles with 26 – 30references, respectively R2=0.267 in case of articles with more than 30 references) and their percentage / volume (R 2=0.474 in case of articles with 26 – 30 references, respectively R 2=0.4849 in case of articles with more than 30 references).

Ciuperca Lake, located in the floodplain area of the lower Danube, suffered a lot of interventions over time due to human activity. Man-made interventions started in 1830 and during the time changes have been made in shape, functions and role of the lake and the surrounding wetlands. Drainage, cleaning the lake, concrete banks on the lake shores transformed Ciuperca Lake from natural lake into a flood-protection area for the city and later into a recreational area for the citizens. Since 2011 the lake has been used as a recreational bathing area of Tulcea city. Due to these aspects two problem arise: the lack of information for the local authorities on water quality and on the dangers for exposing the population to the blooming of algae (if these later ones would take place). The phytoplankton of Ciuperca Lake is dominated by cyanobacteria having a wide range of temperature tolerance, their presence in water being recorded even under the ice coverage and has a great development-potential. The author’s assessment on hazard status and alert level could provide a pertinent analysis of the results of the rehabilitation program for improving the water quality of Ciuperca Lake and a better understanding of the necessity to include the inland water used for recreational purpose into a national monitoring program.

The impact of inorganic nutrient enrichment on reophillic ecosystems has been observed and intensively studied in many rivers. Due to the scarcity of information on ecological conditions in the channel-network of the Danube Delta it is very important to have reliable information on the trend of the abiotic and biotic quality elements in the Danube River and channel system – in order to fulfill the Water Framework Directive objectives and to implement the rehabilitation projects in area affected by nutrient pollution. The purpose of this paper is to present, analyze and discuss the results of evaluation of nutrient variation and phytoplankton quantification obtained in Fortuna area - one of the seven reconstructed areas of the Danube Delta Biosphere Reserve. In order to improve the quality of data on phytoplankton biomass distribution from Fortuna area, in the summer of 2008 there has been used a submersible spectrofluorometer with automatic algae class determination and chlorophyll analysis (bbe Fluoro Probe). According to the results of analyses on relation between phytoplankton communities and water-column, the phytoplankton development in the channel network of the Fortuna reconstructed area seems to be influenced mainly by nitrogen concentration than by phosphorus concentration, as in case of phytoplankton development in Danube Delta’s lakes

The Danube Delta National Institute for Research and Development, although evolved from an entity established in 1926, launched its first scientific journal in 1978, but the respective publication had irregular issuance. In 1993 the institute launched the first issue of a new periodical which nowadays is entitled “Scientific Annals of the Danube Delta Institute”. In 1993 – 2011 period there were published 17 volumes and, excepting two years (2000 and 2001), the journal had a yearly issuance. Till 2011 there were published in the journal 774 articles, most of them (509 articles) in 1993 – 1999 period. A total number of 447 persons contributed (as single author, as first author or as co-author) with articles, most of the articles having one author (250 articles) or two authors (212 articles). Works written in Romanian were the most frequent ones (449 articles – out of which 447 were published till 1999, inclusively), meanwhile the works written in English are the second most frequent ones (319 articles – out of which 263 published since 2002, inclusively). The average length of the articles published in 1993 – 2011 period is 6.78, the highest average number of pages/article (12.93 pages/article) being recorded in case of the most recent volume (published in 2011).

The present paper is dealing with the responses of phytoplankton community to the thermal gradient and the trend of development of Danube river phytoplankton population, measured in real-time using a submersible spectrofluorometer with automatic algae class determination and chlorophyll analysis. Depth profiles of the distribution of spectral algal groups have been recorded during field investigations carried out along Danube between Rasova(Danube Km 310.3) and Capidava (Danube Km 279) in order to reveal if the phytoplankton development is influenced by the warm water discharged from Nuclear Power Plant Cernavodă. A total number of 214 measurements (temperature, transparence, depth of measurements and phytoplankton biomass) have been performed in 2010 - 2011. Variation of phytoplankton along the investigated sector Danube does not have significant perturbation compared with general development of phytoplankton in the lower Danube river. Phytoplankton biomass decline under the influence of warm water discharges was not recorded during the entire sector of the thermal plume, sometimes being recorded an increase of the phytoplankton biomass which slightly exceeded the threshold of blooming for lotic ecosystems. The increasing or decreasing of chlorophyll-a concentration seams to be related more to the natural biological cycle than to the influence of discharged warm water. Phytoplankton populations from Danube River have a high capacity to adapt to the modification of the temperature. The variation of temperature dose not influence the natural algal class’s composition.

The present paper presents the results of 10 years of phytoplankton monitoring in the Danube Delta Biosphere Reserve.

In order to improve the water-quality monitoring program developed in the Danube Delta, during 2008 there was tested a new system for assessing the development of phytoplankton biomass. The present paper contains the preliminary data obtained with the use of a submersible spectrofluorometer, sampling sites being along the main branches of the Danube (Dunărea Veche, Sulina and Sfântu Gheorghe), respectively various channels from the so-called “fluvial delta” – western half of the Danube Delta: Sontea, OlguŃa, Crisan, Litcov, Perivolovca channels and some smaller channels that are around the most relevant lakes of the Isac-Uzlina lake-complex.

The present paper contains an analysis of the available information dealing with the diversity of algae from Danube Delta Biosphere Reserve. Undesirable mistake: wrong nominalization of the scientific names which have been found in reference sources or synonyms of the species have been crowed out from the revised checklist.

The present paper includes the results of a preliminary ecological study of how phytoplankton diurnal development is related to water-column variables. The recorded data set was analyzed by a multivariate procedure using PRIMER6 statistical program with the following steps: transformation of the phytoplankton datachoosing square root option, creating a triangular resemblance matrix based on Bray Curtis similarity, diagnosis of the environmental variables based on Pearson correlation coefficients using Draftsman plot option before normalizing the data, creating a triangular resemblance matrix based on Euclidean distance and linking the phytoplankton assemblage to environmental variables to find the ‘best’ match which reflects the degree to which the chosen abiotic variables explains the phytoplankton diurnal pattern.

The authors performed an assessment of the frequencies of quality classes and degrees of eutrophication of various waters from the Danube Delta Biosphere Reserve, in the 2001 – 2007. For theanalyses there were taken into account the following elements: concentration of phosporus, concentration ofammonium and characteristics of algal blooms.

The present work includes a model for assessing the ecological status of shallow lakes, based on the principle of the integrative method used previously in Finland, Sweden, Estonia, Denmark, Germany,Poland, Great Britain and Holland. The authors included into the respective method those elements that are local-specific to the Danube Delta, taking also into account the current Romanian national legislative framework and the recommendations of the Water Framework Directive.

Based on informations from various bibliographical references, the authors present the list of 945 zooplankton species ever recorded in the Danube Delta Biosphere Reserve. There are also remarks related tothe taxonomical position of some species.

During five years of investigation there have been carried out observation on ecological value of the diatoms from Danube Delta’s lakes. The present study provide new data on their sensitivity to environmental conditions.

The term ”plankton” refers to those microscopic aquatic forms having little or no resistance to currents and living free-floating and suspended, in open or pelagic waters. Phytoplankton development has different consequences depending on biomass quality and quantity, the overgrowth result being eutrophication process. The eutrophication intensity can cause both a lower water transparency, by excessive algal growth, to fish death in the area. In this study, it was presented the ecological status and phytoplankton biomass dynamic, in the Danube branches from upstream to downstream. The measurements have been made in 2013, in March, June, September and November, using spectrofluorometer for algal biomass determination and a microscope for qualitative analyses of phytoplankton species. Shannon-Wiener index was calculated to compare phytoplankton species diversity. Also, the biodegradable organic matter loading the ecosystem was determined by computing the Saprobic index. The values obtained do not exceed the eutrophication limits according to the Water Framework Directive, transposed into Romanian legislation by Order 161/2006, with normal concentrations for rheophile ecosystems, as Danube's branches. In this area, water currents and high water turbidity inhibit phytoplankton growth, in contrast to lacustrine ecosystems, where light penetration to depths favors the development of different phytoplankton groups.