R-mode Cluster Analysis Research Articles

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The biodiversity of benthic foraminifera around the coral communities and the concentration of heavy elements (e.g., Mn, Fe, Cr, Cu, Ni, Pb, Zn, Cd, and Co) in Miskan Island and Al-Khiran coastline of Kuwait are used as an ecological indicator for the environmental and anthropogenic stresses occurred from February 2018 to February 2019. The study resulted in identifying 19 families, 6 orders, 29 genera, and 94 species. Using R-mode cluster analysis results in four assemblages and using Q-mode principal component analysis (PCA) distinguished three groups depending on the deep. The three main assemblages refer to different depths, Group A from 20 cm to 1 m depth; Group B from 1.5 to 2 m depth, Group C from 6 to 8 m depth. Al-Khiran coastline is characterized by anoxic conditions, confirmed by the existence of pyrite. Additionally, high water turbidity because of anthropogenic effects. The low number of benthic foraminifera on Miskan Island is due to the dissolution and calcification of foraminifera shells. The Island characterized by freshwater runoff from Iraq meets saltwater in the gulf, affecting the salinity. The turbidity is caused by sediment runoff and eutrophication. Both sites were considered relatively unpolluted compared with the nearest Iranian coast. However, the relatively high potentially toxic elements in some locations are due to the semi-restricted geographic characteristic and high anthropogenic activity. There is no clear abnormality in the identified species showing normal aperture, coiling, shape, and size.

Water Physico-Chemical Indicators and Metal Assessment of Teceu Lake and the Adjacent Groundwater Located in a Natura 2000 Protected Area, NW of Romania

This study closely analyzes the water quality dynamics of Teceu Lake, situated in a Natura 2000 protected area in Romania. The research investigates seasonal variations and interconnections with groundwater, assessing various ecological impacts. The main physico-chemical indicators of water, such as electrical conductivity (EC), dissolved oxygen (DO), oxygen saturation (OS), temperature, pH, turbidity, ammonium concentration (NH4+), nitrates (NO3−), nitrites (NO2−), orthophosphates (PO43−), water hardness, alkalinity (A), and chlorides (Cl−), were measured over the January–December 2022 period. Metal concentrations for both major metals (Na, K, Ca, Mg, Al) and trace metals (Li, Ga, Fe, Mn, Pb, Cu, Zn, Ni, Ti, Mo, Sr, Ba) were assessed. The evolution of the physico-chemical indicators revealed an increase in nutrient compounds (ammonium and phosphates) during the spring and autumn months. The EC values ranged from 180–444 μS/cm for the lake and 1575–2480 μS/cm for groundwater. The pH values (7.12–7.96) indicated a slightly alkaline environment. DO levels (6.79–11.21 mg/L) indicated good water quality. Chlorides exceeded levels in drinking water in some instances. Water hardness varied due to pH, temperature, and atmospheric pressure. Metal composition revealed diverse levels of aluminum, barium, nickel, copper, zinc, and manganese, which carries implications for environmental and human health. The water quality index (WQI) score, which is based on major ions, indicated that 93% of the groundwater samples were classified as excellent and good for drinking. WQI, based on the main physico-chemical indicators, revealed that 79.17% of the Teceu Lake-water samples and 41.66% of the groundwater samples gathered were classified as good quality; the difference indicated poor quality, especially in autumn. Q- and R-mode cluster analyses revealed distinct clusters for seasonal months and sampling points, suggesting shared sources and geological influences. Notable connections between physico-chemical indicators and metal content were identified, emphasizing the need for a tailored conservation strategy. Correlation analyses highlighted both positive and negative relationships between metal pairs. Understanding these parameters is vital for water resource management and preserving biodiversity in the region. The results of this study are important for monitoring pollution in Lake Teceu and might prompt local communities and authorities to take measures to reduce and prevent pollution.

Middle Eocene Nannofossil Assemblages Responding to Depositional Dynamics of the Elat Formation, Maluku

The Kei Besar Island is mainly composed of the Elat Formation carbonate rocks. This research was conducted to determine the nannofossils assemblages in the Elat Formation to interpret the depositional dynamics during its formation. Lithological observations and sampling for nannofossil analysis were carried out on three measured stratigraphic sections: Section 1 - Hollat, Section 2 - Ngurdu, and Section 3 - Mata Hollat. A total of 47 species assigned to 25 genera of nannofossils were identified in 45 selected samples. The succession of the Elat Formation in the study area formed at NP16 to N17 or Middle Eocene. Stratigraphic reconstruction supported by biostratigraphy analysis shows that Section 3 at the lower (NP16 to NP 17), Section 2 in the middle part (NP 17), and Section 1 at the upper (NP 17). R-mode cluster analysis of nannofossils defined four species clusters (assemblies A, B, C and D) that tend to occur together. Q-mode cluster analysis defined five depth-distribution clusters (1, 2, 3, 4, and 5), each deposited under similar conditions. Based on large foraminifera, the succession was formed in fore reef setting in neritic bathymetric zone. Coarsening and thickening upward supported by the nannofossil assemblages indicate depositional dynamics which tend to be shallower. Reworked fossils, commonly found at the lower of the Elat Formation, show the mechanism of turbid currents in early deposition.

The environmental significance and low-oxygen indicator potential of benthic foraminiferal assemblages in surface sediments off the Changjiang River (Yangtze River) Estuary, China

86 surface sediment samples and a core (CDZS38) from the Changjiang River Estuary (CRE) and its adjacent area were collected to investigate the environmental significance of foraminifera, and determine a microfaunal index for coastal hypoxia to be used for paleoenvironmental studies. Benthic foraminifera and their relationship with environmental parameters including grain size composition and total organic carbon in surface sediment samples were studied. The benthic foraminiferal assemblages were dominated by littoral species in the study area. R-mode cluster analysis identified three clusters based on the percentage of benthic foraminifera. Cluster 1 covers the transitional area between the Radial Sand Ridges of the South Yellow Sea and the CRE. The dominant foraminiferal assemblage is Ammonia beccarii vars.–Ammonia compressiuscula–Quinqueloculina spp., which is a good environmental indicator of an oligotrophic near-shore condition with a strong hydrodynamic force. Cluster 2 covers the inner-shelf off the CRE. The dominant foraminiferal assemblage of Cluster 2 is Epistominella naraensis–Bolivina cochei–Bulimina marginata, which can be used to represent a eutrophic, hypoxic inner-shelf environment. Cluster 3 covers the Hangzhou Bay, which is a typical macro-tidal river mouth. The dominant foraminiferal assemblage of Cluster 3 is A. beccarii vars.–E. naraensis–Ammonia convexidorsa, which is indicative of an environment that is strongly disturbed by tidal currents and influenced by substances from the Changjiang River. The occurrence of E. naraensis, B. marginata and B. cochei is always associated with the hypoxic region. With the correlation analysis with environmental parameters, these species can be considered low-oxygen foraminiferal assemblages (LOFA). We generated a low-oxygen foraminiferal index (the ratio of LOFA to the sum of LOFA and Euryhaline species) to explore the development of hypoxia at the inner-shelf off the CRE, and applied this index to the short core CDZS38. The result indicated that high LOFI values found for CDZS38 is consistent with the recorded trends in hypoxia and harmful algae bloom (HAB) for this area over the past 59 years, and reflect an increase in the hypoxic conditions over this time period.

Application of geostatistical techniques in the assessment of groundwater contamination in the Afigya Kwabre District of Ghana

Geostatistical techniques have been applied to successfully assess the groundwater quality in the Afigya Kwabre District of Ghana. Forty boreholes were sampled for physicochemical and bacteriological characteristics of the groundwater. Principal component analysis revealed that seven components contain 81.01% of the variation of the original variables. Factor 1 accounted for 31.34% of the total variance, factor 2 accounted for 10.97%, third and fourth factors explained 8.41% and 8.19%, the fifth factor showed 8.13% while the sixth and seventh components showed 7.76% and 6.21% variances, respectively. R-mode cluster analysis showed five clusters. Cluster 1 was made of Na+, Cl−, TH, SiO2, HCO3− and TDS. Cluster 2 and cluster 3 contained dissolved oxygen (DO), pH, K+ and F−, Br, respectively. Cluster 4 was made of PO43− and NO3−and Cluster 5 had Ca2+, Mg2+, Total. coli, Fecal. coli, SO42−, and salinity. Correlation analysis revealed a strong positive correlation between EC and TDS, Mg2+, Ca2+, Mn, Na+, TH, HCO3−; pH and Ca2+, HCO3−; Mg2+ and Ca2+, Na+, TH, HCO3−, Fe; Ca2+ and Na+, TH, HCO3−; Cu and PO43−; Mn and Na+; F− and SO42− as well as NO3− and PO43−. The study revealed the impact of both natural processes such as rock mineral weathering, ion exchange, and anthropogenic activities such as application of agrochemicals on farmlands and improper waste disposal on the geochemistry of the groundwater. Generally, the groundwater in the District has a low pH. However, it is generally suitable for domestic use with exception of a few samples with high Fe, F-, Pb concentrations and Escherichia coliform and fecal coliform contaminations. The study has shown that the geostatistical technique is useful in determining the state of water contamination, the extent of contamination, and possible source of contaminants, as well as presenting a guideline for effective groundwater resource management.

Recent Ostracoda from the shelf sediments of Southwestern part of Bay of Bengal: Implication on Microenvironments

A detailed study on Recent Ostracoda was carried out in twenty-six surface sediment samples collected from shelf region of the Southwestern part of Bay of Bengal. A total of 21 species of Ostracoda belonging to 18 genera have been identified, of which, seven species are abundant (>5%). The Q-mode and R-mode cluster analyses of the abundant species resulted in two assemblage defining different microenvironments. The shallowest assemblage (I) from 10 to 80 m water depth is characterised by Hemikrithe Orientalis, Pterygocythereis chennaiensis and Lankacythere multifora which are associated with sand to slightly muddy sand. The second assemblage (II) from 80 to 200 m water depth is associated by Keijella reticulata, Bairdoppilata paraalcyonicola, Actinocythereis scutigera and Stigmatocythere indica and the nature of sediments varies from slightly muddy sand to slightly sandy mud. The sediments from 50-100 m water depth are foundto contain higher concentration of organic matter (TOC and TN) suggesting the high productivity zone. The C/N ratio value ranges from 4 to 8 in 52% of sediment samples indicating both marine and terrestrial source. The shallower part of the seafloor up to 30 m depth is dominated by sandysediments, reflecting the occurence of high-energy conditions. The higher mud content in the deeper part is due to the prevalance of low energy condition. The carapace-valve ratio (1:9) indicates that the study area experiencing a slower rate of sedimentation. Our study results revealed that the distribution of Ostracoda in the Southwestern part of Bay of Bengal is controlled by the type of sediment, depth and physicochemical parameters of the bottom water.

Benthic foraminifera as bio-indicator of Mangrove ecosystem quality: A case study from Abu Ghoson area, Red Sea Coast, Egypt

The assemblages of benthic foraminifera were studied in surface sediment samples collected along two transects from the mangrove swamp and the intertidal flat zone in Abu Ghoson area, the Red Sea coast of Egypt, to validate and support their use as bio-indicators of ecosystem quality. Using Q-mode and R-mode cluster analyses, three biotopes following the bathymetric and environmental gradients have been documented. The seaward intertidal flat stations were dominated by larger symbiont-bearing foraminifera (Peneroplis planatus, Peneroplis pertusus, Sorites orbiculus, Coscinospira spp., and Amphisorous spp.). This biotope reflects the oligotrophic environment. Assemblage of smaller miliolids and rotaliids is diversified and characterized the swamp stations and the closest intertidal stations. The assemblage from the most landward semi-closed swamp station was distinguished by stress-tolerant taxa, especially Ammonia tepida, found in high percentages, though relatively low diversity.

Polycystine Radiolarians Vertical Distribution in the Subtropical Northwest Pacific during Spring 2015 (KS15-4)

Polycystine radiolarian remains were collected during Expedition KS15-4 in a plankton tow sample from 0 to 3000 m water depth at station (Sta.) 1 (30°28.8537′N, 132°24.9532′E). Obtained data from this site provide precious information about radiolarian assemblages living at deep-water depths. Based on R-mode cluster analysis, the surface water is characterized by well known subtropical species such as the Tetrapyle circularis/ fruticosa group and Didymocyrtis tetrathalamus. The subsurface water depths (200–500 m) are characterized by species such as Siphonosphaera abyssi. The intermediate-water depths (500–1000 m) are characterized by relatively high abundances of Larcopyle weddellium and Actinomma boreale, while species such as Cycladophora davisiana inhabit mainly water depths below 2000 m and the Carpocanarium papillosum group inhabits the deep-water depths between 1000 and 2000 m.

Variation in the eastern North Pacific subtropical gyre (California Current system) during the Middle to Late Miocene as inferred from radiolarian assemblages

Abstract The California Current has influenced the primary productivity along the California margin, which plays a significant role in global carbon cycles. Although previous studies have explored the response of the California Current to climate change since the Pliocene, comparatively little is known about that during the Middle and Late Miocene when the paleoclimate changed significantly. Here, we present variations of the California Current based on new data of radiolarian fossil assemblages integrated with previously published data from the Middle to Late Miocene, and show that the California Current was strengthened from 12.3 to 10.5 Ma, 9.0 to 8.2 Ma, and 7.2 to 6.9 Ma at ODP Site 1021. The biogenic opal declined during periods of increased strength of the California Current from the Middle to Late Miocene at Site 1021 in offshore area. These data suggest that the biogenic opal decreased at Site 1021 in offshore area due to the deep nutricline depth by the strengthened California Current. R-mode cluster analyses divided into three major assemblages; surface/warm, cool/surface to thermocline, and intermediate-deep water taxa. The pronounced faunal changes of radiolarian assemblages to the dominance of intermediate-deep water taxa might reflect an initiation of the modern-type California Current system since ca. 10.5 Ma in the early Late Miocene due to the tectonic changes (e.g. partial closing of tropical gateways and uplift of the Himalaya and the Rocky Mountains) and/or significant high latitude cooling.

Impacts of culture-wise shrimp farming activities on hydrogeochemistry: a case study from Chidambaram taluk, Cuddalore district, Tamil Nadu, India

Shrimp farming is one of the most important aquaculture practices in terms of area, production, employment and foreign exchange generation in India. In recent years, the growth and intensification of shrimp farms in the study area have been explosive, and setting up of new shrimp farms along the coastal areas has also become a matter of apprehension among the environmentalists. An extensive survey made by environmentalists elsewhere shows mixed opinion, but ascertains the real scenario as facts. A total of about 46 groundwater samples were collected in five phases: pre-culture, summer culture, immediately after summer harvest (IASH), winter culture and immediately after winter culture, respectively. The results revealed that the high value of TDS, Na, Cl and Br is observed in IASH, and also, the spatial distribution map confirmed that higher concentration is observed near to the creek and sea. Moreover, the abundance of these ions is in the following order: Na > Ca > Mg > k and Cl > HCO3 > SO4 > CO3 > NO3 > Br for different culture periods, respectively. Piper diagram depicts that the groundwater was controlled by ion exchange reactions. Further, Chadha’s classification revealed that the reverse ion exchange was the dominated feature, and it is supported by various ionic indices such as Na/Cl versus EC, (Ca + Mg) versus (SO4 + HCO3), (Na–Cl) versus (Ca + Mg–HCO3–SO4), (Ca + Mg) versus Cl and Na/Cl versus Cl, respectively. The result of factor analysis shows that most of the variations are elucidated by the seawater intrusion, rock–water interactions and anthropogenic activities during different culture periods. The spatial distribution map of factor scores clearly delineates that the positive values are observed near to the creek and sea and in that, shrimp farming area is not predominated. R-mode cluster analysis shows that groundwater quality does not vary extensively as a function of culture periods. Moreover, Q-mode classification consists of two clusters: the first cluster has a high saline water concentration comprising samples location near to the creek and sea. The second cluster mainly depends upon rock–water interactions and the majority of shrimp farming area are grouped under these categories. The above statements clearly indicate that groundwater parameters mainly depend upon the geological process and that shrimp farming cannot be targeted as the root cause for groundwater salinization.

Evaluation of Physicochemical Characteristics in Drinking Water Sources Emphasized on Fluoride: A Case Study of Yancheng, China.

In this study, the concentration of fluoride and the associated health risks for infants, children, and adults were analyzed and compared for three drinking water sources in Yancheng City, Jiangsu Province, China. To analyze the relationship between the water quality parameters of pH, fluoride (F−), sulfate (SO42−), chloride (Cl−), total dissolved solids (TDS), total alkalinity (TAlk), sodium (Na+), and potassium (K+), statistical analyses including correlation analysis, R-mode cluster analysis and factor analysis were performed based on monthly data from the year 2010 to 2015. The results indicated: (1) Fluoride concentrations in the drinking water sources ranged from 0.38 to 1.00 mg L−1 (mean = 0.57 mg L−1) following the order of Tongyu River > Yanlong Lake > Mangshe River; (2) fluoride concentrations in 22.93% of the collected samples were lower than 0.5 mg L−1, which has the risk of tooth cavities, especially for the Mangshe River; (3) the fluoride exposure levels of infants were higher than children and adults, and 3.2% of the fluoride exposure levels of infants were higher than the recommended toxicity reference value of 122 μg kg−1 d−1 as referenced by Health Canada, which might cause dental fluorosis issues; (4) the physico-chemical characteristics are classified the into four groups reflecting F−- TAlk, Na+-K+, SO42−-Cl−, and pH-TDS, respectively, indicating that fluoride solubility in drinking water is TAlk dependent, which is also verified by R-mode cluster analysis and factor analysis. The results obtained supply useful information for the health department in Yancheng City, encouraging them to pay more attention to fluoride concentration and TAlk in drinking water sources.

Integration of hydrochemical, GIS, and remote-sensing data for assessment of shallow groundwater aquifers in Wadi Nisah, Central Saudi Arabia

Groundwater samples were collected in May 2015 from 23 wells distributed in the western part of Wadi Nisah, mainly used for irrigation. Calculation of saturation indices showed that the samples were generally undersaturated with respect to halite, gypsum, anhydrite, calcite, and aragonite. Groundwater facies analysis showed that most of the collected samples were dominated by Ca–Na–SO4-type water. This water type indicates rock–water interaction, mainly gypsum dissolution. The second major water type was Na–Ca–SO4. Evaporation is the major process that controls the groundwater chemistry in the study area. Principal component analysis resulted in the extraction of two principal components. All the elements analyzed showed significant positive factor loading in the first principal component (PC1) except NO3 and Pb which showed high negative loadings in the second principal component (PC2). R-mode cluster analysis identified two groups of variables. The variables in Group 1 are the result of rock–water interaction and contamination by human and agricultural activities. Variables in Group 2 represent the dissolution of evaporite minerals. The total dissolved solids’ (TDS) results demonstrated that the water samples could be classified as either brackish or freshwater. The high TDS concentration in the brackish samples could be a result of soil–water interaction. Moreover, human activities, especially those producing agricultural and household wastewater, can increase TDS in groundwater. Remote-sensing results demonstrated that the areas of agricultural and urban land use have increased with time and have contributed to groundwater pollution.

Benthic foraminiferal paleoecology of the Maastrichtian succession at the Kharga Oasis, Western Desert, Egypt

The present work deals with the benthic foraminiferal investigations and analyses of the Maastrichtian succession from two sections in the Kharga Oasis (Naqb El-Rufuf and Gabal Teir), to evaluate the prevailing paleobathymetric and paleoenvironmental conditions. Three benthic foraminiferal assemblages have been distinguished by the R-mode cluster analysis. The first two clusters are dominated by simple-walled and complex-walled non-calcareous agglutinated foraminifera, respectively; while the third assemblage is characterized by calcareous agglutinated and calcareous benthic foraminiferal species. The Q-mode Detrended Correspondence Analysis (DCA) of the studied samples indicates five main groups designated as five biofacies (IV), each with a characteristic faunal structure. The overall dominance of the non-calcareous agglutinated foraminifera and the sporadic occurrence of the calcareous benthic foraminifera suggest deposition in a shallow water environment of restricted brackish, lagoonal, and littoral setting with occasional marine incursions. The distribution of the identified benthic foraminiferal species suggests deposition under oxygen-depleted conditions with high organic matter flux. Surficial epifaunal taxa dominate the benthic assemblages at certain intervals suggesting episodes of stagnation and elevated position of the redox boundary relative to the water/sediment interface.

Foraminiferal evidence of anthropogenic pollution along the Nile Delta coast

Twenty-four sediment samples were collected from six coastal areas along the Nile Delta coast, including Abu Qir Bay, Rosetta estuary, Abu Khashaba, El Burullus fishing port, El Gamil inlet and Damietta Harbor. Environmental parameters such as grain size, total organic matter, calcium carbonate and seven heavy metals concentration have been investigated. Seventy-two foraminiferal species were identified and counted. The study area has low foraminiferal density but diversified foraminiferal assemblages. Q-mode and R-mode cluster analyses have been applied to assess the relationship between foraminiferal assemblages and the measured environmental factors. Different diversity indices [e.g., species richness (S), Shannon index, Simpson index, Fisher alpha index, and Dominance] have been examined. The statistical results allowed the recognition of different species assemblages corresponding to different sub-environments, which reflected the prevalent ecological and pollution conditions. There are two main recognized clusters dividing the sampling stations into less polluted cluster (A) at El Burullus fishing port, El Gamil inlet and Abu Khashaba and highly polluted cluster (B) at Abu Qir Bay and Damietta Harbor. Ammonia tepida, Ammonia beccarii, Triloculina trigonula, Quinqueloculina lata, and Quinqueloculina spp. are recognized as pollution tolerant species, while Ammonia parkinsoniana, Porosononion spp., Buccella spp., Ammonia spp., and Ammonia sp1 are recognized as pollution-sensitive species. A high percentage of deformed specimens was recorded in the polluted areas especially in Damietta Harbor.

Faunal and stable isotopic analyses of benthic foraminifera from the Southeast Seep on Kimki Ridge offshore southern California, USA

We investigated the benthic foraminiferal faunal and stable carbon and oxygen isotopic composition of a 15-cm push core (NA075-092b) obtained on a Telepresence-Enabled cruise to the Southeast Seep on Kimki Ridge offshore southern California. The seep core was taken at a depth of 973 m in the vicinity of a Beggiatoa bacterial mat and vesicomyid clams (Calyptogena) and compared to previously published data of living assemblages from ~ 714 m, four reference cores obtained at ~ 1030 m, and another one at 739 m. All of the reference sites are also from the Inner Continental Borderland but with no evidence of methane seepage.No endemic species were found at the seep site and most of the taxa recovered there have been reported previously from other seep or low oxygen environments. Q- and R-mode cluster analyses clearly illustrated differences in the faunal assemblages of the seep and non-seep sites. The living assemblage at Southeast Seep was characterized by abundant Takayanagia delicata, Cassidulina translucens, and Spiroplectammina biformis, whereas the non-seep San Pedro Basin reference assemblage was comprised primarily of Chilostomella oolina and Globobulimina pacifica. Density and species richness were lower at the seep site compared to the non-seep site, reflecting the harsher living conditions there. The dead assemblage at the seep site was dominated by Gyroidina turgida compared to Cassidulina translucens at the ~ 1030 m non-seep site and Cassidulina translucens, Pseudoparrella pacifica, and Takayanagia delicata at the 739 m non-seep site. Density was three times lower at Southeast Seep than at the non-seep sites of comparable water depth but species richness was ~ 30% higher. Stable carbon isotopic values were considerably depleted in the seep samples compared to the non-seep samples, with a progression from lightest to heaviest average δ13C values evident at the seep site reflecting microhabitat preference and vital effect: the deep infaunal species of Globobulimina, the shallow infaunal species Uvigerina peregrina, the epifaunal species Cibicidoides wuellerstorfi, and the shallow infaunal but aragonite-shelled species Hoeglundina elegans. The δ13C values downcore among each benthic species indicates ongoing fluid seepage through at least the last 3800 cal yr B.P. at Southeast Seep. Besides the continual local seepage, evidence from δ13C values of planktic foraminifera in the seep core suggest two pulses of methane (at 3000 and 3700 cal yr B.P.) were released that were large enough to influence much of the water column. Paired benthic and planktic foraminiferal stable oxygen isotope records provide evidence that there were no paleoenvironmental changes such as increased bottom-water temperature or changes in oxygen isotopic composition of bottom and pore waters during this 3800-year record to induce the methane releases. Instead, Southeast Seep appears to be the result of local faulting providing pathways for fluid to flow to the seafloor at a fault stepover or transpressional bend in the regional strike-slip system.

Cluster analysis of benthic foraminiferal morpho-groups from the western margin of India reflects its depth preference

Q-mode and R-mode cluster analyses have been carried out on the census counts data of 68 genera and one ‘other genera’ of benthic foraminifera from 32 stations off Mangalore-Cochin sector, west coast of India, to study the ecological preferences, especially the effect of depth on external test morphology of benthic foraminifera. We report that benthic foraminiferal distribution in the central western continental margin of India, can be grouped into three clusters. Cluster A is predominantly represented by angular-asymmetrical forms, cluster B is dominated by rounded-symmetrical forms, whereas cluster C includes both rounded-symmetrical and angular-asymmetrical forms. From the spatial distribution of cluster A-C-B, we report that with decreasing depth, there is a gradual tendency among benthic foraminifera to become more symmetrical from angular-asymmetrical. The observed morphological changes in benthic foraminifera are attributed to the sediment turbulence. The spatial distribution of benthic foraminifera indicates that the angular-asymmetrical morpho-group indicates relatively deeper water while rounded-symmetrical forms suggest shallow environment. Therefore, the temporal variation in the relative abundance of these benthic foraminiferal morpho-groups, can be used for paleo-depth reconstruction.

Foraminíferos e Tecamebas Bentônicos do Estuário do Rio Godineau, Golfo de Paria, Ilha de Trinidad

In the Godineau River Estuary, located in Trinidad Island (off the northeast coast of Venezuela), were found 114 taxa of foraminifera and 17 of thecamoebians in the dead fauna. Most of the identified foraminiferal species were rare because they were transported from the Gulf of Paria to this estuary. The autochthonous foraminiferal assemblage was represented by several tropical estuarine species such as Ammonia tepida, Ammotium salsum, Arenoparrella mexicana, Cribroelphidium excavatum, Ammonia parkinsoniana, Haplophragmoides wilberti, Miliammina fusca and Ammotium cassis. The thecamoebians assemblages, found in the inner part of this estuary, were dominated by Cyclopyxis spp., Centropyxis spp., Difflugia corona and Difflugia urceolata. The relative abundance of the main species of foraminifera and thecamoebians were analyzed through Q-mode and R-mode cluster analyses. Statistical results revealed the presence of three different environments in the Godineau River Estuary related to different hydrodynamic conditions and more or less oceanic or fluvial influence. The first sector represents the most confined region of the estuary and was mainly composed by agglutinated foraminifera together with thecamoebians. The second sector was located in the middle part of the estuary and was associated with the presence of brackish waters. The third sector denotes the outermost part of the estuary characterized by the greatest hydrodynamic activity and highest oceanic influence within the estuary. This sector was marked by the occurrence of a large number typical-marine foraminifera species.

Foraminíferos e Tecamebas Bentônicos do Estuário do Rio Godineau, Golfo de Paria, Ilha de Trinidad

In the Godineau River Estuary, located in Trinidad Island (off the northeast coast of Venezuela), were found 114 taxa of foraminifera and 17 of thecamoebians in the dead fauna. Most of the identified foraminiferal species were rare because they were transported from the Gulf of Paria to this estuary. The autochthonous foraminiferal assemblage was represented by several tropical estuarine species such as Ammonia tepida, Ammotium salsum, Arenoparrella mexicana, Cribroelphidium excavatum, Ammonia parkinsoniana, Haplophragmoides wilberti, Miliammina fusca and Ammotium cassis. The thecamoebians assemblages, found in the inner part of this estuary, were dominated by Cyclopyxis spp., Centropyxis spp., Difflugia corona and Difflugia urceolata. The relative abundance of the main species of foraminifera and thecamoebians were analyzed through Q-mode and R-mode cluster analyses. Statistical results revealed the presence of three different environments in the Godineau River Estuary related to different hydrodynamic conditions and more or less oceanic or fluvial influence. The first sector represents the most confined region of the estuary and was mainly composed by agglutinated foraminifera together with thecamoebians. The second sector was located in the middle part of the estuary and was associated with the presence of brackish waters. The third sector denotes the outermost part of the estuary characterized by the greatest hydrodynamic activity and highest oceanic influence within the estuary. This sector was marked by the occurrence of a large number typical-marine foraminifera species.

CHEMICAL DETERMINATION OF HEAVY METALS IN PB AND ZN CONCENTRATES OF TREPÇA (KOSOVO) AND CORRELATIONS COEFFI CIENTS STUDY BETWEEN CHEMICAL DATA

Kosovo ore deposits are located in the Trepca belt which extends for over 80 km. The concentrate produced by the flotation process of the Trepca metallurgical corporation contains a considerable quantity of valuable metals, such as Pb, Zn, Fe and minor accompanying metals such as Cd, Cu, As, Sb, Bi, Ag, Au, etc. The subject of this work was to assess the concentration of major and minor metals in lead and zinc concentrates of Trepca and to study the correlation coefficients between metals. Chemical determination of concentrates was performed by using atomic absorption spectroscopy (AAS). In the content on lead concentrate samples, the following were found: Pb>Fe>Zn> Ag> As>Sb>Cd. In the content of zinc concentrate, the following were found: Zn>Fe>Pb>Ag>As>Cd. The program “Statistica ver. 6.0” has been used for calculations of basic statistical parameters, relationships between data and cluster analysis of R-mode. R-mode cluster analysis on lead concentrate samples showed that Pb has the closest linkages with Fe and they form one branch of the dendogram. On the zinc concentrate samples, Zn has the closest linkages with Fe and they form one branch of the dendogram.

Late Quaternary palaeoenvironmental changes in the Aegean Sea: interrelations and interactions between North and South Aegean Sea.

The present study describes the Late Quaternary palaeoenvironmental evolution and the main palaeoceanographic changes of the Aegean Sea reconstructed using planktonic foraminifera. This approach, including Q-mode and R-mode cluster analyses, gives an insight into the relationships between sea surface environmental changes between north and south Aegean, and furthermore serves as a baseline data set for palaeoclimatic and palaeoceanographic reconstructions of the eastern Mediterranean Sea.