Nature Environment and Pollution Technology

C. Raghunathan ¹, A. Tewari ², Y. Khambhaty ², J. T. Jothinayagam ¹

Affiliations
1 Marine Biological Station, Zoological Survey of India, 130, Santhome High Road, Chennai-600 028,Tamil Nadu, IN
2 Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, Gujarat, IN

Abstract

The range as well as mean values for numerical density, fresh weight and dry weight of the epiphytic fauna were lowest on Padina tetrastomatica from Okha and highest on Acrosiphonia orientalis from Diu. High species diversity of epiphytic fauna (>8.0) was observed on Caulerpa recemosa, Acrosiphonia orientalis, Padina gymnospora and Sargassum johnstonii. Some of the species of epiphytic fauna showed host specificity as they were recorded only on particular species of seaweeds. The maximum epiphytic fauna (27 species) was recorded on Caulerpa peltata and Veloniopsis pachynema. The similarity index between stations showed close resemblance for epiphytic fauna. Very high number of epiphytic faunal groups (15) were observed on Halimeda tuna, Caulerpa recemosa and Cystoseira indica. The foraminiferan, gastropod, polychaete, ostrocod and bivalve formed very high proportion (12.39-34.75%) of epiphytic fauna on these seaweeds. The minimum numerical density, and fresh and dry weight of seawater zooplankton were observed at Diu, and the maximum at Veraval. None of the species of zooplankton were common to all four places of study. The maximum percentage of numerical density was constituted by Hyperia medusarum, Conchoecia indica and Amhistegina lessonii at different stations. The species diversity of zooplankton ranged from 1.26 at Diu to 4.12 at Veraval whereas, similarity index ranged from 27.27 at Veraval to 41.67 at Okha. Most or all (at Dwarka) species of zooplankton were found in epiphytic form also. The epiphytic form at four stations were quite similar. However, the reverse trend was observed for zooplankton. The species diversity for epiphytic fauna at 4 stations of study varied in a narrow range while it varied widely for zooplankton. All the groups of zooplankton except Mysid were found in epiphytic form. The group diversity of zooplankton ranged from 0.95 at Diu to 3.90 at Veraval. The fresh and dry weights as well as numerical density of benthic fauna ranged from 4.37g.m^-2, 0.97g.m^-2 and 1387 per m^-2 at Veraval to 10.36 g.m^-2, 3.22 g.m^-2 and 5478 per m^-2 at Dwarka respectively. The Neries versicolar, Tubiculous polychaete, Amhistegina lessonii and Elphidium crispum showed maximum numerical density. The species diversity of benthic fauna was low as it ranged from 0.54 at Veraval to 1.63 at Dwarka. However, the similarity index showed nearly close resemblance between different stations. All the species of benthic fauna recorded from Okha and Veraval were also found in epiphytic form in these places. However, 18.75 and 22.22% benthic fauna at Diu and Dwarka respectively were not found in epiphytic form. The similarity index for plankton and benthic fauna indicated near close resemblance at all the stations except Okha. The species diversity of benthic form was significantly less than planktonic form at different places of study. Some of the species of epiphytic, seawater zooplankton and benthic fauna were specific for a particular station. However, quite a number of a species of fauna were common to all four stations of study. It may be concluded that the zooplankton from seawater and benthic (micro and meio) fauna had significantly influenced the composition of epiphytic fauna of seaweeds. Similarly benthic fauna has also influenced the composition of planktonic fauna of seawater and vice-versa.

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C. Raghunathan ¹, A. Tewari ², Y. Khambhaty ³, J. T. Jothinayagam ¹

Affiliations
1 Marine Biological Station, Zoological Survey of India, 130, Santhome High Road, Chennai-600 028, Tamil Nadu, IN
2 Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, Gujarat, IN
3 Central Salt andMarine Chemicals Research Institute, Bhavnagar-364 002, Gujarat, IN

Abstract

The soda ash industry effluent has significantly reduced the species diversity of epiphytic fauna and planktonic fauna of seawater, their numerical density, fresh and dry weight, total number of groups and group diversity as compared to control. However, the reverse trend was shown by benthos. Therefore, considerable degradation in the water quality of seawater as well as epiphytic and planktonic fauna has been observed due to discharge of effluent. Some of the species of epiphytic fauna were specific to effluent affected as well as control sites. The epiphytic molluscan larvae and fish eggs were observed only from effluent affected and control sites respectively. Quite a number of species showed host specificity under effluent affected as well as control conditions. The maximum numerical density on seaweeds under effluent affected and control conditions was shown by Copepods and Foraminiferans respectively. Most of the species of seawater zooplankton as well as benthos from effluent affected as well as control sites were also present as epiphytic forms on different seaweeds. The epiphytic fauna contained significantly higher number of groups and species diversity compared to zooplanktonic and benthic fauna. The Decapods were observed only in benthos whereas Cladocerans, Coelenterate larvae, Cyclopoids, Ostracods and Molluscan larvae were found only in epiphytic fauna. In general, most of the physicochemical parameters of effluent, diluted effluent as well as effluent affected seawaters were many magnitude to considerably high as compared to control seawater. However, magnesium in effluent as well as sulphate and phosphate in the effluent affected seawater showed reverse trend. In general, the effluent has significantly affected the species diversity and biomass production of epiphytic and planktonic fauna. The reduction in growth of epiphytic fauna and zooplankton in the effluent affected region is inhibited due to high concentration of different salts present in effluent affected seawater. However, such salts promoted growth and species diversity of benthos.

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