Effect of Domestic Sewage and Industrial Effluents on Biomass and Species Diversity of Seaweeds

Abstract

The effect of two chlor-alkali industry effluents and domestic sewage has been studied, in situ, on tropical seaweeds of the Okhamandal coast. Maximum biomass was observed at a distance of 400 and 5000 m away from the discharge points of the two chlor-alkali industries. Ulva lactuca and Rhizoclonium kochianum were most resistant while Caulerpa scalpelliformis, Halimeda tuna and Codium dwarkense were most sensitive. Species of Sargassum, Cystoseira and Gelidiella were completely eradicated due to the long term effect of the effluent from one chlor-alkali industry. Gracilaria corticata, G.foliifera and species of Hypnea produced good biomass under mildly polluted conditions and they may be cultivated in such areas. Algal species diversity (ASD) was not recorded up to 400 and 4000 m away from chlor-alkali industries outfalls as intensity of pollution was high in this region. The ASD increased as the distance from the outfall increased. In general, brown seaweeds were most sensitive to this type of pollution.Domestic sewage was much less inhibitory to seaweeds. Species of Ulva and Enteromorpha were maximum biomass producers while brown seaweeds were least productive in the near vicinity of the discharge. Species diversity was also high, in this area, as compared to the chlor-alkali industry effluents.Vertical distribution of seaweeds was not evident up to 400-4000 m away from chlor-alkali effluents outfall and up to 10m away from domestic sewage discharge points. Seaweeds showed characteristic vertical distribution after these distances. n ro uc on sewage and industrial effluents on Indian seaweed has Domestic sewage and industrial effluents affect the been published (Subbaramaiah and Parekh 1966, Tegrowth of seaweeds. The response ranges from stim-wari 1972, Sreeramulu et al. 1977, Umamaheswara ulation through indifference to total devastation. Spe-Rao 1977, Joshi et al. 1982, Tewari and Rao 1982, cies may respond uniformly or in diametrically op-Dhargalkar 1986. These studies were confined mostly posite ways (North et al 1972). The effect of such to the laboratory with analytical studies on selected complex effluents on temperate marine algae have species of seaweeds. The present study was underbeen studied in different parts of the world (Golubic taken to find out the effect of such complex wastes 1968, Borowitzka 1972, Littler and Murray 1975, Niel on tropical Indian seaweeds in situ.

Long-term changes in sublittoral macroalgal assemblages related to water quality improvement

“…Indeed, Cystoseira mediterranea assemblages did not show any evidence of recovery, as no significant changes were observed between 1982 and 1999. Brown algae, mainly those belonging to the order Fucales, are particularly sensitive to sewage and industrial waste (Littler and Murray 1975, Belsher and Boudouresque 1976, Kautsky et al 1986, Tewari and Joshi 1988, Bokn et al 1996, Díez et al 1999, Soltan et al 2001, Arévalo et al 2007. Other studies have shown a rapid increase in brown algae following reductions of industrial outlets (Bokn et al 1996, Soltan et al 2001).…”

Macroalgal community response to re-oligotrophication in Saronikos Gulf

“…Alterations of macroalgal community structure and composition as well as biodiversity loss due to high nutrient loads are well-documented and widespread phenomena (Arévalo et al 2007). For this reason, studies on marine macroalgae, particularly those in shallow waters, have been traditionally used to detect and evaluate anthropogenic effects on coastal ecosystems (Littler & Murray 1975, Tewari & Joshi 1988.…”

Regulation of spatial and seasonal variation of macroalgal biomass in a brackish, eutrophic lake

“…The high surface-area to volume ratio of these mass-forming macroalgae favours rapid nutrient uptake, high production and rapid growth rates, which enable them to outcompete the original vegetation (Littler and Littler 1980;Hein et al 1995;Pedersen and Borum 1997). Eutrophication effects on the benthic vegetation of coastal waters are reviewed by Schramm and Nienhuis (1996) for Europe and by Thorne-Miller et al (1983), Tewari and Joshi (1988), Brown et al (1990) and Valiela et al (1997) for other parts of the world.…”