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A total of 24 surface sediment samples were collected from Puravadaiyanar and Vettar estuary. In the Puravadaiyanar estuary, 47 foraminifera and in Vettar estuary, 26 benthic foraminiferal species have been identified. The species, Ammonia beccarii, A. tepida, A. dentata, Nonionoides elongatum, Elphidium advenum, E. discoidale, Cribrononion simplex, Trochammina inflata,and Quinqueloculina seminulumshows a prolific abundance in both region. Puravadaiyanar estuary records comparatively high value of organic matter in most of the stations. The contamination factor of the trace elements of sediment sample from the Puravadaiyanar estuary is Co>Pb>Cu>Zn>Ni>Fe>Mn>Cr and in Vettar estuary Co>Pb>Cu>Zn>Ni>Fe>Mn>Cr. Factor analysis clearly reveals that fine particles and organic matter control the distribution metals in the sediments and organic matter act as a metal carrier in this region. These studies indicate geogenic origin of most of the elements. The impact of heavy metal pollution on benthic foraminifera was very less in the study area.

The present study aims to understand the distribution of benthic foraminifera in surface sediments collected from Kottaipattinam to Kodiyakarai, Palk Strait southeast coast of India. The analysis reveals the presence of 79 species belonging to 42 genera, 24 families, 12 super-families, 19 sub-families, 5 sub-orders and, 5 orders have been reported and illustrated. Out of the total population count of 11,719 specimens, 705 were observed to be Rose Bengal-stained, and are considered to be living at the time of sample collection. Environmental parameters such as water depth, pH, bottom water temperature, dissolved oxygen, salinity, CaCO3, organic matter, sand, silt, and clay contents were determined to adopt standard methodology. Ammonia beccarii (Linnaeus) is the most abundant counterpart in the study area; followed by Asterorotalia trispinosa (Thalmann) and Ammonia tepida (Cushman). Besides that, Spiroloculina corrugata, Spiroloculina angulata, Quinqueloculina bicostata, Quinqueloculina echinata, Pyrgo depressa, Pyrgo laevis, Pseudotriloculina rotunda, Parrina brady, Cancris oblonga, Elphidium hispidulum, Elphidium norvangi, these species were not previously observed in this study site. The textural analysis reveals that the sediments are chiefly composed of sand with less clay and silt. The organic matter content shows a high loading factor in the study site followed by CaCO3. Further, the statistical analysis shows organic matter is major controlling factors in the study site and benthic foraminiferal assemblages are definitely bound to be influenced by the high volume of freshwater influx in the study site.

The present study encompasses a detailed investigation of downcore Holocene foraminifera and their assemblages to comprehend the ecology of the Bay of Bengal and compare it with that of the South China and Sulu Seas, at the same depth for all the three water bodies. Based on temperature and dissolved oxygen profiles, benthic foraminiferal abundance, and species diversity values, it is inferred that the Bay of Bengal is much better ventilated than either the South China or the Sulu Sea. The planktic/benthic (P/B) ratios are extremely low when compared with those reported elsewhere in the world. The absolute dominance of benthic foraminiferal species over their planktic counterparts is attributed to the effect of fragmentation and dissolution of the latter, as they are relatively more susceptible to this process. The very low P/B values are also indicative of water depth below the lysocline in this part of the Bay of Bengal.

Foraminifera have been successful inhabitants of every aquatic environment from deep oceans to brackish water lagoons, estuaries and even rarely in freshwater streams, lakes, etc. In order to know their distribution in different offshore habitats, the present study has been undertaken between Tuticorin and Tiruchendur, wherein 31 bottom sediment and water samples were collected. Benthic foraminiferal taxa belonging to four suborders (Textulariina, Miliolina, Lagenina and Rotaliina), 14 superfamilies, 25 families, 45 genera and 66 species have been identified; three planktonic species (suborder Globigerinina) have also been identified. An increase in total foraminiferal distribution with depth has been observed, except off Tiruchendur. Living/dead ratios range from 1.57% to 10.02%, indicating a low to moderate rate of sedimentation in this region. Off Punnaikayal and Tiruchendur, the rate of sedimentation is more at greater depths; at other stations, however, it is higher at relatively shallower depths. Based on this study, it is concluded that fluctuations in the distribution of foraminifera are mainly controlled by coastal morphology, wave dynamics, bathymetry and environmental parameters.

Benthic foraminifera have proved to be reliable proxies for understanding paleoenvironmental changes or paleoclimatic changes in the past geological history of the Earth, especially since the Cambrian when these unicellular protozoans began to evolve. Since then, foraminifers have been recorded as fossils and their abundant occurrence in the fossil record has aided in understanding the past history of the Earth. Within the Holocene, this group of microfossils has proved to be of immense utility, as their assemblages could be utilized for understanding past environmental changes, as they are so sensitive to variations in such ecological parameters as pH, depth of the water column, salinity, dissolved oxygen content, nature of substrate calcium carbonate and organic contents, which are the primary controlling factors over their species populations and diversity. The study area is a part of Kannur District, Kerala, India, about 5–7 km from the present-day shoreline. Trench samples (sub-surface) at varying depths up to 3.6 m, at Karakkeezhu and Kuduvathala, yielded a benthic foraminiferal assemblage that is characteristic of modern estuarinelbrackish water environments. This assemblage, typified by the dominance of Ammonia beccarii (Linnaeus) and its associated species, is suggestive of a shallow, probably sheltered, tidal flat environment with a possible connection to the Arabian Sea ∼5,000 to 5,500 years B.P. as revealed by 14C dates of both mollusk shells and sediment samples. The study has thrown open some intriguing questions, particularly with regard to the complete absence of arenaceous, agglutinated forms (Suborder TEXTULARIINA) and the poor representation of calcareous, imperforate taxa (Suborder MILIOLINA).