ACROSS

The Main Water Resources of The Republic of Moldova

2024-04-01T15:38:23+00:00

The Republic of Moldova has a small area and no direct access to the sea or ocean, so its water resources are limited and are represented by surface and underground waters. However, it has an access point to the Danube River on a 430-meter stretch, at the country's southernmost point (Giurgiulești village), which offers potential access to the Black Sea. The country’s main sources of water include rivers, lakes, and groundwater. 3,621 rivers and streams represent surface waters with a total length of approximately 16,000 km and 4,261 natural lakes and artificial basins. Underground water is represented by over 7,000 artesian wells and about 179,574 wells fed from the water table. It should be noted that, in recent years, the Republic of Moldova has faced a series of problems related to water quality, including the pollution of rivers and lakes. In this sense, a more effective management of water resources is needed to ensure an adequate and sustainable drinking water supply.

The Zooplanktonic Communities of Cârja And Mălina Farms (Romania)

2024-04-01T15:35:58+00:00

Zooplankton communities represent an important link in the aquatic food web with an important role in the transmission of matter and energy from producers to consumers. Also, they are excellent indicators of water quality and their functioning through their central position in the food web. This study presents the taxonomic composition, abundance, and spatio-temporal distribution of zooplankton communities in two pond ecosystems with different water supply sources, in two seasons (spring and autumn). Diversity and similarity for the three zooplankton groups between the two fish farms were also calculated. The study was conducted in 2020.

The zooplankton taxonomic groups identified in the samples taken were: Rotifers, Cladocera and Copepods. In the Mălina aquatic ecosystem, species from the Cladocera taxonomic group dominate, with the species Daphnia cristata, Daphnia longispina and Daphnia cuculata, while in the Cârja aquatic ecosystem, species from the Rotifera taxonomic group dominate, namely Brachionus angularis, Brachionus rubens, Brachionus urceolaris and Trichocerca tigris.

Comparing the diversity of the two aquatic ecosystems (which are water supplied by distinct rivers), we conclude that the Mălina farm has the greater diversity for all three groups of zooplankton.

Using the Sorenson Diversity Index (IS) to see the degree of similarity of the taxonomic composition between the two aquatic ecosystems studied, it was observed that for the Rotifera group, the similarity is 56%, for the Cladocera group 50% and for the Copepoda group 80%.

The Structure of Algal Communities in the Parches Aquatic Ecosystem, Tulcea County (Romania)

2024-04-01T15:35:59+00:00

Phytoplankton represents one of the most important communities of organisms for life in aquatic environments. It is a type of autotrophic pelagic organism that is unable to oppose the action of currents and is therefore widespread in all types of aquatic ecosystems. They are important for ecosystems and biodiversity development because they are primary producers. This means that they form the basis of food webs in aquatic environments.

The present paper presents information about the phytoplankton structure in the Parches aquatic ecosystem, Tulcea County (Romania). Phytoplankton samples were taken in September 2021, at the end of the vegetative season, from 4 stations. Phytoplankton was present in all the stations we analysed. By processing the phytoplankton samples taken, four taxonomic groups were highlighted, namely: Baccilariophyceae, Euglenophyceae, Chlorophyceae and Cyanophytes. A total of 58 species belonging to the four taxonomic groups were identified. The dominant species are Cymatopleura solea, Cocconeis placentula, Melosira granulate.

In the samples taken in September 2021, the abundance of Bacillariophyceae varies between 52-69%, followed by Chlorophyceae between 14 and 28%, and Euglenophycin between 9 and 14%. Cyanophytes had the lowest abundance between 0 and 10%.

The number of taxa and specimens identified in the phytoplankton structure shows a good diversity of the phytoplankton community during the study period.