STATISTICAL STUDIES AND ECOLOGY OF BENTHIC FORAMINIFERA FROM TAMILNADU COAST, INDIA

The foraminif erans are the most diverse phylum of mieof aijna. Foraminif era are f oxmd in all marine environments, they may be planktic or benthic in mode of life. It has been estimated that the total number of foraminiferans species might be approximately 4000 living species of foraniinifera. The present paper deals with the distribution and diversity of marine foraminiferans all over Tamilnadu Coast. Foraminiferal distribution has been reported by many workers. Foraminiferans were the most abundant group of meiofauna at the sampling sites. The number species per station ranged from 11 to 32.


INTRODUCTION
The foraminif erans are the most diverse phylum of mieof aijna. Foraminif era are f oxmd in all marine environments, they may be planktic or benthic in mode of life. It has been estimated that the total number of foraminiferans species might be approximately 4000 living species of foraniinifera. The present paper deals with the distribution and diversity of marine foraminiferans all over Tamilnadu Coast. Foraminiferal distribution has been reported by many workers. Foraminiferans were the most abundant group of meiofauna at the sampling sites. The number species per station ranged from 11 to 32.

HISTORY AND DISTRIBUTION OF FOR AMINIFERANS
The recent reviews of Bhalla et al. (2007) and Khare et al. (2007) on foraminiferal studies in near shore regions of western and eastern coasts of India reveal that most of the studies are related to taxonomic and ecological aspects and palaeoenvironmental interpretations. A few studies have been undertaken along the eastern coast of India on applied aspects of Foraminifera. Taxonomic and ecological studies on foraminifera from west coast of India were carried out by some researchers. Bhalla & Nigam (1979) and Bhalla & Gaur (1987) worked on foram diversity of Calangute and Colva beach sands respectively. Bhalla & Raghav (1980) studied the ecologyof Foraminifera of Malabar coast and suggested that salinity is the chief governing factor. Raj & Chamyal (1998) (Gupta 1973;Rao et al., 1987;Saraswati 2007). To utilize these marine protists efficiently, adequate Knowledge of their diversity and distribution pattern in modern envirormient is of utmost importance. Therefore, a study of intertidal forams was undertaken comparing the east and west-coast and the sensitivity of forams to monsoons. This paper presents the scanning electron photomicrographs of inter tidal forams along the Indian coast, so as to benefit researchers in diverse areas who use Foraminifera.

Foraminif erans Diversity
A total of 37 species of foraminiferans as belonging to 21 families were recorded in the present study. The list is follows :

Diversity indices of foraminiferans
The diversity indices were lowest at stations 9 (Mandapam) and 11 (Rameswaram), which can be considered as indications of the stress at these sites. At station 11 is situated very close to Rameswaram temple. At statioiis 1,2 and 3 had higher values of diversity indices although it had very high density of foraminiferans. It must be also be stated the sediment here was fine sand. (Table-2 the ANOVA test at the p>0.05 level (Table 23). The fc-dominance curves for the foraminiferans species and stations show that in terms of dominance and diverse are similar (Fig. 4) The kdominance curves were significant different from the stations. At stations 9 and 11 are the most highly dominated. Probably because at stations 11 situated very close to Rameswaram temple, which was highly disturbing by tourist.Whereas stations 2 and 3 are the more diverse. It must be also be stated that sediment here was fine sand. Thus the foraminiferal population and diversity are highest in very fine grained sediments, while density secrease coarser grained sediments. These findings also support the results of Shannon-Wiener diversity index (H') and MDS analysis. The differences between the other stations are less amenable interpretation as the curves cross (
The other depth intervals of sandy sediments had 4-12 ind. 10 cm"^ and 0-15 ind. 10 cm"^ at 6-10 cm and 10-15 cm intervals respectively . In muddy sediments, it's range from 0 to 10 ind.lO cm"^ at 6-10 cm interval. However, it was totally absent in 10-15 cm depth interval in muddy sediments. Foraminiferans were most important aniong meiofauna, probably because all sampling sites situated in the marine envirorunent had fine sand. Similar observation was made by Varshney et al. (1984) and Nigam and Chaturvedi (2000). It is well known that foraminiferans occur mostly under high saline conditions with few species penetrating into the estuarine conditions (Gooday, 1988).