Aquatic plants have a major influence upon other Aquatic organisms, by altering both water chemistry and spatial structure of the habitat in shallow water bodies. Some of them, such as Stratiotes aloides L., may suppress algal growth. But how Aquatic plants would ultimately influence the heterotrophic community and the Aquatic ecosystem as a whole is far from clear. Our microcosm based study demonstrated that even a modest density of S. aloides caused a decline in phytoplanktonchlorophyll concentration and periphytic algae abundance, including cyanobacteria, whereas diatoms appeared to be immune to the plant influence. Photosynthetic rate remained unaltered despite decreased chlorophyll concentration. While bacterial counts remained largely unchanged, more bacteria were observed forming microcolonies as well as associating with particulate organic matter.Numbers of periphytic heterotrophic organisms did not differ significantly between the planted and plant-free control microcosms. Zooplankton diversity increased and cladocerans assumed a more prominent position within the microcosms with macrophytes. We assume that the presence of plant’s leads to increased importance of bacteria and protists in the functioning of the food webs. Therefore, decreasing of algal abundance does not involve reducing the number of heterotrophic planktonic and periphytic organisms.

Food interaction of waders and Aquatic organisms including species composition, food structure and preference as well as benthic macrofauna composition, substrate structure, TOM, biotic indices and interaction of macrofauna food constituents and waders were investigated in Khur-e-Musa from Dec. 1999 to Aug. 2000 (8 months). In this study 99 birds belonging to 5 families, 10 genera and 14 species were hunted from Dawragh and Zangee creeks. The highest abundance of waders belonged to dunlin, ringed plover and red shank. Analysis of gut contents revealed that the highest abundance of food item belonged to Eurycarcinus sp. gastropods, beetles and diptera. Birds composition revealed that the highest number in Dawragh and Zangee creeks belonged to dunlin, ringed plover, red shank (categorized as winter wading species) and little ringed plover (categorized as spring species index in breeding season). The highest abundance of macrofauna belonged to Eurycarcinus sp., gastropods, amphipods, polychaetes and bivalves. The bottom of estuaries was silty. Shannon index (1<H'<3) indicated the studied area was intermediately polluted. Species richness for birds and macrofauna in Zangee creek was higher than Dawragh creek. There was a positive correlation between bird's diversity and food items and this correlation in.Zangee creek was more than Dawragh creek.

The production and use of synthetic nanoparticles is growing rapidly, and therefore the presence of these materials in the environment seems inevitable. Titanium dioxide (TiO2) presents various possible uses in industry, cosmetics, and even in the treatment of contaminated environments. Studies about the potential ecotoxicological risks of TiO2 nanoparticles (nano-TiO2) have been published but their results are still inconclusive. It should be noted that the properties of the diverse nano-TiO2 must be considered in order to establish experimental models to study their toxicity to environmentally relevant species. Moreover, the lack of descriptions and characterization of nanoparticles, as well as differences in the experimental conditions employed, have been a compromising factor in the comparison of results obtained in various studies. Therefore, the purpose of this paper is to make a simple review of the principal properties of TiO2, especially in nanoparticulate form, which should be considered in Aquatic toxicology studies, and a compilation of the works that have been published on the subject.

Isolation of diverse chemical compounds from marine organisms implies a promising source of natural products. Oceans cover nearly 70% of the earth’s surface and over 90% of the volume of its crust. Marine environment contains a variety of species, many of which have no terrestrial counterparts. Recently, trends in search of new drugs emphasize that marine microorganisms could be potential productive sources of novel secondary metabolites.