Distribution of Benthic Foraminiferal Assemblages in Nagavali River Estuary, Srikakulam, Andhra Pradesh
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Indian Journal of Geo-Marine Sciences Vol. 45(7), July 2016, pp. 875-881 Distribution of benthic foraminiferal assemblages in Nagavali river estuary, Srikakulam, Andhra Pradesh 1Greeshma A.G, 1Jagannadha Rao, M., 2Karuna Karudu, T*. & 1Mallikarjuna Rao, M 1Department of Geology, 2Delta Studies Institute, Andhra University, Visakhapatnam-530017, India *[E-mail: [email protected]] Received 04 April 2014; revised 16 May 2014 Fifteen sediment samples were collected from estuarine environment of Nagavali River Estuary and 237 foraminifera belonging to 23 species have been identified in the sediment samples. Faunal diversity 23% and distribution are 42% in this estuary. Q-mode cluster analysis revealed that the foraminifera could be grouped into 4 clusters. The Ammonia tepida, Noniondepressulum, Quinqueloculinaseminulum, Ammonia beccarii, Quinqueloculinasp., Nonionsp., are abundant species. Occurrence and distribution of foraminiferal assemblages studied in the Nagavali estuary sediments, infers that these sediments were deposited from marine to brackish environment. [Keywords: Foraminifera, hinterland, sedimentary environment, estuary, marine environment] Introduction Materials and Methods The East Coast of India is marked by major Sediment samples have been collected from 15 rivers, streams and drainage networks draining the stations in the Nagavali River estuary (Fig.1) using hinterland and joining the Bay of Bengal forming a Vanveen grab10. A 10 gm sample was soaked in varied sedimentary environments1-9. Nagavali water for 6 hours. The samples were washed over river estuary (18°10"-19°44"N and 82°53" - 63µm sieve and dried in the oven at 60°C. When ° 84 05"E) is located in the Srikakulam district, cooled carbon tetrachloride (CCl4) is added at AndhraPradesh. The river Nagavali is draining in room temperature and the floated foraminifera states of Orissa and Andhra Pradesh is a perennial were picked up using a stereo-microscope (Lieca river system originated in the Eastern Ghat 5M6). Systematic scheme has been followed for interland near Lakhbahal in the Kalahandi district identification and classification of foraminiferal of Orissa. It flows over a total distance of 256 kms genera11-12. Q-mode Cluster13-15 analysis has been initially through a hilly terrain in an N-E direction and debouches its sediments into the Bay of Bengal10 , near Kalingapatnam. Foraminifera are good indicators of environments of deposition. The scope of present investigation is to study the benthic foraminiferal abundance and distribution in Nagavali estuary using Q-mode cluster analysis. This is to understand the foramniferal distribution in terms of clusters and to establish the applicability of this tool in accessing statistical pattern of distribution and abundance of species. Fig. 1—Location map and sediment stations 876 INDIAN J. MAR. SCI., VOL. 45, NO. 7 JULY 2016 used to determine the natural grouping (cluster) 3. Araniar River Estuary4 2 among the foraminfera identified. 4. Chilika lake 5. Palk strait18 6. Cochin Estuary19 Results and Discussion 7. Present study To have an idea on occurrence of common There are 4 clusters of foraminifera are species, reported in other similar sedimentary identified in the Nagavali River estuary (Fig. 2). environments reported in literature has been given The cluster I comprises stations 6 and 10 dominant (Table 1). Distribution of different foraminiferal species include Ammonia tepida, species in the study area are (Table 2), Ammonia Quinqueloculinasp., Quinqueloculinaseminulum, tepida, Ammonia beccarii, Nonionsp., Noniondepressulum, Quinqueloculinaseminulum, Elphidium Crispum, Elphidiumadvenum, Noniongrataloupi, Asterorotaliatrispinosaare common species occur Uvigerinaproboscidea, Trochamminainflata, in Nagavali estuary and Godavari, Krishna, Pseudoeponides japonicas and Globigerina Araniar and Cochin estuary, Palk stait and Chilika bulloides. lake. Elphidiumcrispum, Asterorotaliatrispinosa, Cluster II covers sample stations 4, 5, 8, 11 and Ammonia beccarii, Ammonia tepida, Globigerina station 15, species observed are Ammonia tepida, bulloids, Quinqueloculinasp., Quinqueloculina Noniondepressulum, Quinqueloculinaseminulum, Seminulum, Florilusincisum, Pseudoeponides japonicas, Hanzawaiaconcentrica, Asterorotaliainflata, Hanzawaiaconcentrica, Triloculinaoblonga, Asterorotaliadentata, Nonionsp., Quinqueloculinalamarckina, Noniondepressulum, Noniongrateloupi, Quinqueloculinadilatata and Quinqueloculina Uvigerinaproboscidea, Trochamminainflata, vulgaris. Elphidiumadvenum, Pseudoeponides japonicas, Cluster III represents the stations 2, 3, 12, 13 Eponidesrepondus, Triloculinaoblonga, and station 14 with the species in order of Quinqueloculinalamarckina, Quinqueloculina abundance are Ammonia tepida, Ammonia vulgaris and Quinqueloculinadilatatahas. Out of beccarii, Asterorotaliatrispinosa, Quinqueloculina the abundance of different species in all 15 sp., Quinqueloculina Seminulum, stations, Ammonia tepidarecorded first place, Asterorotaliainflata Elphidiumadvenum, Noniondepressulum and Quinqueloculina Elphidiumcrispum and Noniondepressulum. Seminulum recorded second and third place Cluster IV comprises station 1, 7 and station 9, respectively. The dominance in percentage has dominant species are Ammonia tepida, been indicated (Table 3). To understand the Noniondepressulum, Elphidiumcrispum, relationship between the foraminiferal Asterorotaliatrispinosa, Ammonia beccarii, composition and distribution the cluster analysis Quinqueloculinasp., Quinqueloculina Seminulum, has been adopted and the data are analyzed using Florilusincisum, Hanzawaiaconcentrica, Q- mode analysis. Asterorotaliainflata, Asterorotaliadentata, Table 1— Benthic foraminiferal record in estuaries Nonionsp., Eponidesrepondus and Triloculinaoblonga. S.No Species Name 1 2 3 4 5 6 7 Cluster I stations have 42% of species. Cluster II 1 Ammoniabeccarii having stations with medium 23% of species. 2 Ammonia tepida Cluster III and IV having stations are with 19 and 12% in species, which signify transformation of 3 Quinqueloculinaseminulum brackish to marine environment3. Planktonic 4 Elphidiumcripsum species like Globigerina bulloides has been recorded to occur in stations 6 and 10. Their 5 Asterorotaliatripsinosa presence in the estuary suggests their transportation through inflow of sea water from 1. Godavari River Estuary1 the Bay of Bengal by tidal currents2. 2. Krishna River Estuary1 GREESHMA et al.: DISTRIBUTION OF BENTHIC FORAMINIFERAL ASSEMBLAGES IN NAGAVALI RIVER 877 Table 2— Spatial Distribution of Foraminifera in Nagavali River Estuary Species Names St1 St2 St3 St4 St5 St6 St7 St8 St9 St10 St11 St12 St13 St14 St15 Elphidiumcrispum 1 1 Asterorotaliatrispinosa 1 1 1 Ammonia beccarii 2 1 2 2 Ammonia tepida 1 1 1 5 6 33 2 9 3 13 2 1 1 2 3 Globigerina bulloids 1 1 Quinqueloculinasp., 1 2 3 QuinqueloculinaSeminulum 2 1 3 3 1 3 2 1 Florilusincisum 1 2 1 Hanzawaiaconcentrica 1 1 1 1 Asterorotaliainflata 1 1 Asterorotalia dentate 2 Nonionsp., 1 2 1 2 Noniondepressulusm 5 1 1 4 4 3 4 4 4 2 3 Noniongrateloupi 2 2 Uvigerinaproboscidea 1 1 Trochammina inflate 3 Elphidiumadvenum 1 1 1 Pseudoeponides japonicas 1 2 2 Eponidesrepondus 1 Triloculinaoblonga 1 1 1 Quinqueloculinalamarckina 1 1 Quinqueloculina 1 vulgaris Broken shells 2 3 4 4 5 8 5 5 4 Quinqueloculinadilatata 1 Total 17 10 9 7 8 59 13 21 17 37 4 8 12 8 7 Relative% 7.6 3.5 2.5 3.5 4.0 27.9 6.5 8.1 8.7 14.7 2.0 1.5 3.5 2.0 2.5 Species diversity 15 7 5 7 8 55 13 16 17 29 4 3 7 4 7 878 INDIAN J. MAR. SCI., VOL. 45, NO. 7 JULY 2016 Table 3— Foraminifera and their order of Abundance Species Names Abundance Percentage Ammonia tepida 83 42.13 Noniondepressulus 35 17.76 Quinqueloculinaseminulam 16 8.12 Ammonia beccarii 7 3.55 Nonion sp. 6 3.04 Quinqueloculinasp. 6 3.04 Pseudoeponides japonicas 5 2.53 Florilusincisum 4 2.03 Hanzawaiaconcentrica 4 2.03 Noniongrateloupi 4 2.03 Asterorotaliatripsinosa 3 1.52 Elphidiumadvenum 3 1.52 Triloculinaoblonga 3 1.52 Trochammina inflate 3 1.52 Asterorotalia dentate 2 1.01 Asterorotalia inflate 2 1.01 Elphidiumcripsum 2 1.01 Globigerina bulloids 2 1.01 Quinqueloculinalamarkina 2 1.01 Uvigerinaproboscidea 2 1.01 Eponidesrepondus 1 0.50 Figure 2— Q- mode cluster analysis of Nagavali estuary. Quinqueloculinadialata 1 0.50 Quinqueloculina vulgaris 1 0.50 Foraminiferal species Total 197 99.9 A total of twenty three foraminiferal species belonging to 9 families have been The significant variation in the distribution and identified in Nagavali estuary sediments assemblages of foraminiferal species in Nagavali present as table.4 estuary may be due to the rate of sedimentation as well as due to the postmortem transportation by Table 4— Names of family and species tidal currents and other related (salinity, River Family Species Names Trochamminidae Trochamminainflata influence etc.) factors. Quinqueloculinalamarckina Quinqueloculina vulgaris Benthic foraminiferal species are abundant in Quinqueloculinadilatata Hauerinidae Quinqueloculinaseminulum cluster I signify the less river influence and Quinqueloculinasp., characterized by brackish to marine environment. Triloculinaoblonga Globigerinidae Globigerina bulloids Noniondepressulum The stations of cluster III 2, 3, 12, 13 and Pseudoeponides japonicas station 14 have 40 broken shells. The higher Nonionidae Noniongrateloupi number of broken shells and less abundance of Nonionsp., Florilusincisum foramniferal species of cluster III suggest river Ammonia beccarii flow affected the distribution offoraminiferal Asterorotaliatrispinosa