Intertidal foraminifera from Miramar-Caranzalem Shoreline, Goa

Occurrence of foraminifera in the beach sediments of west coast of India has been reported 1 -3. In the present paper occurrence of various types of foraminifera and the inter-relationship of various parameters that influence their productivity and diversity are reported. The intertidal zone of Miramar-Caranzalem shoreline (Fig.l) is influenced by high-energy waves and variable (0.5-2 m) amplitudes of spring and neap tides. During monsoon, the flooding and ebbing of the tides is very high. The surface temperature of water varies from 26.1° to 30.1°C during high and low tides whereas the bottom temperature" ranges from 23.5° to 30.4°C. The monsoon-nonmonsoon temperature variation is considerable (29.2°-30.6°C during premonsoon, 26°-30°C during monsoon, and 26.5°27°C during postmonsoon periods"). The salinity ( x 10 -3) varies from 34-36, 10-35 and 32.2-35.6 respectively during premonsoon, monsoon and postmonsoon periods. The suspended load (mg.l -1) during premonsoon is < 50, while during monsoon it is 100 and ranges from 5-50 in postmonsoon periods. Several sediment samples were collected periodically during monsoon-nonmonsoonal period (June-Dec. 1982),along 6 traverses (Fig. 1). The sample is medium textured, medium grained, and sandy. Quantitative analysis of all samples was carried out following wellknown standard methods. Entire and broken tests of foraminifera were counted out of 1g dry weight of each sample and the species identified. A total of 44 benthic and one planktonic species of foraminifera were recorded (Table 1). Rotaliina, composed of 29 species, constituted 90.61 to 95.18%, while Miliolina, composed of 11 species, and Textulariina, composed of 5 species, constituted 2.75 to 6.15% and 0.59 to 3.24% respectively. Rotaliina composed of species of Ammonia, Asterorotalia and Elphidium (Table 1)having a habitat depth of 0-50 m; and Rosalina and Nonion having a habitat depth of 0100-180 m are endemic to the region. Species of Eponides, Nonionella, Cibicides and Bulimina having a habitat depth of 0-1000-6000 m are also seen. Bolivina, a cosmopolitan species which prefers a muddy substratum and restricted to bathyal to marginal marine conditions is encountered here thus indicating transport from long distances towards the shore. Among others it was reported that Ammonia beccarii and its variants, Elphidium crispum, and Eponides repandus occur in the beach rock along Goa coast" in the surf zone at a height of 40 m suggesting eustatic movements in the area. Textulariina composed of species of Ammobaculities and Trochammina (Table 1) which are typical of hyposaline, intertidal, marsh and lagoonal environ-ment occur as endemic species also. Textularia which is a lone species may be a transported fauna. The variation in the density of the suspended load (which includes dead tests of foraminifera) in the waters of monsoon and nonmonsoonal periods is a direct