Empirical relationships between phytoplankton and zooplankton biomass in Indian Ocean

19-23Empirical models based on regression analysis are derived using published values of phytoplankton and crustacean zooplankton biomass from Indian Ocean. Three regression models are derived. There is significant correlation between zooplankton and temperature, zooplankton and phytoplankton, zooplankton and PO4-P and phytoplankton and PO4-P. Linear regression model is found to be significant at 1% level of significance. Since zooplankton and phytoplankton are significantly positively correlated, zooplankton biomass can be predicted from the phytoplankton biomass using this model. Using multiple regression model it is found that at lower and medium levels, temperature is the prominent factor and at higher level it being PO4-P followed by phytoplankton, at all levels of concentration of phytoplankton. At the higher level of phytoplankton production ecological efficiency reaches its asymptotic value and almost remains a constant for further increase

Auto-correlograms and auto-regressive models of trace metal distributions in Cochin Backwaters

236-238Auto-correlation technique has been applied to study fluctuations in concentration profiles of chemical species in Cochin Backwaters (Kerala, India). No stability in time can be detected for particulate Mn at all stations, for Fe at stations 1,2 and 3 and for Zn at stations 1 and 4. The stability in time for the concentration profiles increases as Fe ~ Mn Tx indicate absence of isopattern and for such metals it is found that there is no stability in time

Communities and coexistence of benthos in northern limb of Cochin backwaters

249-254Occurrence and coexistence of benthic communities of 9 stations in the northern limb of Cochin backwaters where an industrial belt (mostly chemical industries) is located are studied. Polychaetes with 30 species are the most common among groups present at all the stations. Capitella capitata which showed high density near the effluent discharge site is proposed as an indicator of pollution. Dendronereis aestuarina present at all stations and in high densities at sts 5, 6 and 8, can be considered as a pollution resistant species. Lycastis indica, Paraheteromastus tenuis, Telehspia annandalei, chironimid larvae and Pendora flexosa present at st 8, even-though in very low numbers, can be treated as pollution tolerant species. The number and the size of the clusters show a steady decline from sts 1 to 8. Maximum affinity is for adjacent stations and never exceeded 60%. Negative affinity indices obtained are deemed indicative of the varied environmental conditions. Results indicate limited spatial migration and possible niche separation

Distribution of planktonic Foraminifera in waters of the submarine coral banks in southeast Arabian Sea during winter

233-245Twentyfive species of planktonic Foraminifera are recorded from 36 plankton tows collected from waters of the submerged coral banks-Bassas de Pedro, Sesostris and Cora Divh-located at northern end of the Laccadive group of islands in southeastern Arabian Sea. High standing stocks of these organisms are found in plankton tows north of 13-degrees-N where upwelling indicator species namely Globigerina bulloides and Neogloboquadrina dutertrei are observed. Most of the spinose species show higher concentrations in 0-10 m than in 0-200 m tows. Although they form a major component of the fauna, non-spinose species show an increase in relative abundance in December as compared with studies of other winter months in the Arabian Sea and are represented chiefly by those of Globorotalia and Globigerinita. Distribution of species in plankton tows reveals that Globigerinoides ruber, G. sacculifer and Globigerinita glutinata are the most dominant forms, while less dominant species being Globigerinella aequilateralis and Globorotalia tumida. Foraminiferal fauna in general depicts closer affinity with that of equatorial waters of the world and is typical of a tropical reef region under peak winter conditions

Ecology and distribution of Recent planktonic Foraminifera in eastern part of Arabian Sea

25-35Thirty species of living planktonic Foraminifera have been studied from 97 plankton tows collected from the eastern Arabian Sea with an accent on their ecological and distributional aspects. Species density is higher with less dominance in the deep (0-200 m) than in the surface (0-10 m) tows. Further, latitudinal gradient of some species which have a definite bearing on hydrography of the sea, has been outlined. Relative production of planktonic Foraminifera shows that it is high in the southern Arabian Sea south of 15-degrees-N, but low in the northern one from 15-degrees-N northwards based on mean total specimens occurring in plankton samples of the areas of study

Atypical behaviour of dissolved silicate in the Cochin Backwaters and Periyar River

60-63Dissolved silicate was determined for 1 y (1982-83) covering a wide range of salinity from the estuarine mouth to the fresh water region. Silicate concentration ranged between 0.03 and 4.75 mgl-1. Silicate-salinity relationship was linear and inverse in the salinity ranges 0-5 x 10-3 and 5-35 x 10-3. Since variability in the distribution of silicate explained by the significant linear regression model was small in the subranges of salinity 5-20 and 20-30 x 10-3, a curvilinear regression model was fitted and it gave a good fit at 5% level (P> 0.05). The expected removal of silicate at salinity range 0-5 and 5-35 x 10-3 given by linear relationship was 28.8 and 51.1% respectively. In 5-20 and 20-30 x 10-3 salinity the expected removal as given by curvilinear relationship was 31.94 and 6.068% respectively

Pigmented epidermal cyst with dense collection of melanin: A rare entity - Report of a case with review of the literature

Epidermal cyst is a very common benign cystic lesion of the skin. It is usual to find ulceration of the lining epithelium, rupture of the cyst wall with chronic inflammation and foreign body giant cell reaction. But, it is very rare to see an epidermal cyst with marked accumulation of melanin pigment. Only a few cases of pigmented epidermal cyst with dense collection of melanin pigment have been published in the literature. Here, we are reporting a case of ruptured epidermal cyst with keratin granuloma formation and showing dense collection of melanin pigment

Living Planktonic Foraminifera of the Wadge Bank, Northern Indian Ocean

67-70Twenty three species of living planktonic Foraminifera belonging to 11 genera have been studied from the Wadge Bank area off southern tip of the Indian peninsula. The fauna is characterized by species such as Globigerinoides conglobatus, G. sacculifer, Pulleniatina obliquiloculata, Globorotalia flexuosa, G. menardii, G. theyeri, G. tumida, G. ungulata and Globoquadrina conglomerata, due to tropical influence on the coastal waters. Presence of Globigerina bulloides and Neogloboquadrina dutertrei suggests coastal upwelling and these species are more abundant in relatively cool waters of the nearshore sites. All the species typical of tropical upwelling assemblage are encountered in the region. The role of some ecological parameters like temperature and salinity as possible controlling factors in distribution patterns of the fauna, has also been elucidate

Effects of eyes talk ablation on moulting and growth of penaeid prawn <i>Metapenaeus dobsoni </i>(de Man)

403-412Penaeid prawns M. dobsoni of two different size ranges were ablated both unilaterally (UEA) and bilaterally (BEA) and subjected to individual study. The UEA prawns consumed almost the same amount of food as the control prawns in the size group, 35-40mm, but consumed about 57.8% more food than the control prawns in the larger size group, 48-53mm. Growth was estimated as length and weight changes and significant variation was observed. The moult rate and dry moult weight showed marked differences. Average intermoult period increases with second ablation. Dry weight of moult in every succeeding moult was found to decrease irrespective of the level of ablation. Unilateral eyestalk ablation resulted in increase in dry weight whereas bilateral eyestalk ablation reduced the dry weight of moult and this decrease in the rate increased after each subsequent moult. In the larger size group, values of protein efficiency ratio (PER) were almost same as that of the lower size group. The UEA prawns exhibited highest conversion efficiency. The production rate of UEA prawns was 84% more than that of the control whereas BEA prawns indicated negative production. The same trend followed for net growth efficiency also. The results suggest that unilateral eyestalk ablation can be resorted to accelerate growth and conversion efficiency. Eyestalk ablation has been frequently resorted in matured forms for inducing maturation of gonads. For the first time attempts have been made to compare between the effects of removing one eyestalk versus two and changes taking place in juvenile forms especially in their physiology related to growth

Distribution of foraminifera in the lagoons of certain islands of the Lakshadweep archipelago, Arabian Sea

161-178A total of 107 foraminiferal species belonging to 29 families and 48 genera have been identified from the lagoonal sediments of Agatti, Kavaratti, Suhelipar, and Minicoy atolls of Lakshadweep. The fauna is dominated by calcareous Foraminifera, but arenaceous forms are very rare due to coarse nature of the deposits. Of the families observed, Miliolidae, Calcarinidae, and Amphisteginidae are most abundant and 2 species, Calcarina calcar and Amphistegina radiata are the most dominant. Planktonic Foraminifera are very rare and those few present in the lagoons have been transported by water currents through passages of the reef. In general, Foraminifera of the coral reefs in the coastal waters of Indian peninsula are similar in their species composition. Larger foraminiferids and typical coral-reef species of the fauna from Lakshadweep have been reported. The role of Foraminifera as reef-builders and their distribution as related to ecology are evaluated. The data suggest that there is a similarity of the reef faunas from tropical Indo-Pacific and Atlantic Oceans