Sumuury: Wat,er pollution exerts a. pressurc of ~electioii oil algal popiilations. I n spite of a possible adaptation, often rz changed diversity ant1 sociological structure rrwilt, from which other effects on higher levels of the nutrient chain inny rinamte. There a,re represented some biological indices for characterizing algal coniinunit~ies which niay serve as a biological measnre of pollution and selfpiirificntion, t,he problem of diversit'y bring especially taken into account. Moreover, algal tests are irsed for rcprc~senting the troplric. sit,uation and for det,errniniirg the limit.ing nutrient, hiit, also for det~ei~inining the toxic influencing of biocenosis by hydrocarbons, too. Special a,ttention is paid to heavy niet,als mit'h regard to thcir synergistic action and bioaccunirilatioii. On the ot,lier hand, tht. inass cut ture of algae is a valrtltble method of wast.cwater t,reat,rnent, and the recovery of valua.ble iiiat,er.ials, a.iid a l p e ponrls provide a n impoi~tant, t,c.chniqne for advanced wast.cwnter purificat ion,
IntrodiwtionApart troin being the universal mediiiiii for all hiological reactions, nater is IJY far t he largest resource used by iiian. Indiscrinunnte abuse of water as a rcwilt of the increase in the hunian population and the growth of industries has been continiiously contributing t o the qualitative deterioration of our inland waters. The sea is the ultiiiiate sink for waterborne pollutants arid duc to its large inass of water it lessens the severity of pollution by dih~l1oi1. Despite receiving various contaniinants, the cheniical coiiiposition of sea ater remains essentially constant though there niay bc minor local fluctiiations. However, if we continue to discharge inore and inore pollutants into the sea, the day inny not be far off when the sea water Loiiiposition will c h i a t e from its present averages. Keeping in view the alarming water pollution problems, considerable attention has been given during the past several years to visualize and define its consirquences, with particular cniphasis on surreillance and monit ormg aspects.=\ fcw decades ago even in developed countries it had been a coniiiioii practice t o einploy only cheinical criteria in water pollution studies, thus coiiipletely ignoring the biological inforinatiop which is certainly of much use while interpreting the sigiiificance of the physico-chemical observations (HYNES). The importance of utilizing hiological information t o supplement chemical findings for a better evaluation of ~)ollutional conditions has been established only in recent years.Algae are prevalent in all water bodies including ponds, reservoirs, lakes, streanis, rivers and oceans. Being the principal primary producers in aquatic ecosystems, 56'