This chapter will present an overview of cyanobacterial harmful algal blooms (cyano-HABs) and biotic and abiotic factors, as well as various aspects associated with these worldwide ecological bursts. The exact causes of the cyanoHABs are still not well defined, but eutrophication and climate change (temperature increase, light intensity variation, etc.) are the two assumed main factors that may promote the proliferation and expansion of cyanobacterial blooms. However, these premises need to be profoundly investigated as the optimal combination of all factors such as increased nutrient loading, physiological characteristics of cyanobacterial species, and climate effects which could lead to the blooming pattern will require robust modeling approaches to predict the phenomena. Negative issues associated with cyanoHABs are diverse including the toxic products (cyanotoxins) released by certain taxa which can damage the health of humans and animal habitats around the related watershed as well as generate a huge water quality problem for aquatic industries.

Belhiouani H, El-Hadef El-Okki M, Afri-Mehennaoui FZ, Sahli L. 2019. Terrestrial gastropod diversity, distribution and abundance in areas with and without anthropogenic disturbances. Biodiversitas 20: 243-249. The objective of this study was to establish an inventory of terrestrial gastropods from different sites in the northeast of Algeria. Several points were sampled from five various areas relatively affected by human activity. Areas prospected were an industrial area (El-Hadjar, Annaba), a mining area (Djebel Hamimat, Oum-El-Bouaghi), an urban area (B’kira, Constantine), a mountainous area (Ibn Ziad, Constantine) and a sub-mountainous area (Ibn Badis, Constantine). A total of 11 species and 2632 individual land snails belonging to six molluscan families (Helicidae, Hygromiidae, Sphincterochilidae, Achatinidae, Enidae, and Pomatiidae) and 10 genera were found in all habitats. The highest density was recorded in the mountainous area with 1270 individuals and 10 species, whereas the lowest value was recorded in the mining and the industrial areas with 3 and 4 species respectively. The malacofaunal diversity was also determined, Shannon’s index, Simpson’s index, and equitability index are higher in the mountainous zone of Ibn Ziad with 1.87, 0.82 and 0.78 respectively, and lower in the mining area of Djebel Hamimat, with 0.60, 0.33, and 0.54. The dispersion and density of species appear to be contingent upon several factors among which soil properties, height, climate conditions and certainly anthropogenic disturbance.

This study sought to assess sediment contamination by trace metals (cadmium, chromium, cobalt, copper, manganese, nickel, lead and zinc), to localize contaminated sites and to identify environmental risk for aquatic organisms in Wadis of Kebir Rhumel basin in the Northeast of Algeria. Water and surficial sediments (0-5 cm) were sampled in winter, spring, summer and autumn from 37 sites along permanent Wadis of the Kebir Rhumel basin. Sediment trace metal contents were measured by Flame Atomic Absorption Spectroscopy. Trace metals median concentrations in sediments followed a decreasing order: Mn > Zn > Pb > Cr > Cu > Ni > Co > Cd. Extreme values (dry weights) of the trace metals are as follows: 0.6-3.4 microg/g for Cd, 10-216 microg/g for Cr, 9-446 microg/g for Cu, 3-20 microg/g for Co, 105-576 microg/g for Mn, 10-46 microg/g for Ni, 11-167 microg/g for Pb, and 38-641 microg/g for Zn. According to world natural concentrations, all sediments collected were considered as contaminated by one or more elements. Comparing measured concentrations with American guidelines (Threshold Effect Level: TEL and Probable Effect Level: PEL) showed that biological effects could be occasionally observed for cadmium, chromium, lead and nickel levels but frequently observed for copper and zinc levels. Sediment quality was shown to be excellent for cobalt and manganese but medium to bad for cadmium, chromium, copper, lead, nickel and zinc regardless of sites.

This paper focuses on evaluating the degree of three metal pollution (Cu, Zn and Pb) in the sediments of Béni Haroun dam, located in northeastern of Algeria. For this reason, the superficial sediments were sampled at five stations, and the samples were taken at different seasons of the year. The results show low Cu and Zn levels which reflect natural conditions in relation to the area of geological nature. It also highlights the presence of Pb contamination (2.29 to 91.86µg/g). This result was also confirmed by various indices, including the geoaccumulation index (Igeo) and the contamination factor (FC). The Igeo values for Pb show moderate contamination of the Bge2 and Bge3 stations. CF values indicate moderate to considerable contamination for most stations by Pb. However, low or absent of Zn contamination was noted in all stations except for the Bge5. The correlation matrix and the PCA between all metal elements indicates that they were derived from similar sources. The contamination sources would probably establish a significant relationship between runoff and the erosion of agricultural lands. It is therefore an anthropogenic metal pollution related to agricultural activity using fertilizers and pesticides. Keywords: Heavy Metal Pollution, Béni Haroun dam, sediment, Enrichment factor RésuméCette étude porte sur l'évaluation du niveau de contamination des sédiments du barrage Béni Haroun, situé dans le nord-est de l'Algérie, par

SUMMARYThe aim of this article is to assess the level of trace metal contamination of sediment and to evaluate the environmental water quality based on the distribution of benthic organisms at stations along the Rhumel river and its principal tributary Boumerzoug river selected in urban areas (Constantine, Algeria). Fresh sediment samples and benthic organisms were collected from 10 sites on three occasions (December 2000, February 2001 and April 2001. Four trace metals-manganese (Mn), lead (Pb), chrome (Cr), and cadmium (Cd)-were measured in surface sediment and in the fauna using a flame or flameless atomic absorption spectrophotometer. In addition, chemical water parameters, pH, dissolved oxygen (DO), conductivity (EC) and sediment variables, pH, loss on ignition (LOI) and grain size were determined. The differences in species composition of the benthic community and the biotic index variation were used to reveal disturbance in watercourses.Principal component analysis (PCA) was used to identify the relationship between the sediment variables, water chemistry and distribution of benthic invertebrate communities. The results of PCA indicate that there are several significant correlations between trace metals which suggest their common origin (anthropogenic or natural sources). Besides, the PCA results suggest the following trend: the biotic index, communities' distribution of macroinvertebrates and dissolved oxygen were unconnected to from both sediment and fauna trace metals concentrations.