Date of Award

1999

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Abdelrahman AI-sharhan

Second Advisor

christopher G. Kendall

Third Advisor

Dr. Osman Abdul Ghani

Abstract

Twenty samples of sea water and twenty samples of sediment were collected from the off shore area of Ras AI-Khaimah to find out the relationships between environmental parameters, abundance of foraminifera, and ratio of living to dead foraminifera.

Analysis of sea water for the environmental parameters includs, temperature, salinity and nutrient salts (nitrate, nitrite, silicate, phosphate and amonia). Organic mattar, and total carbonate were measured in the bottom sediments. Grain size analysis of the bottom sediments was done using seiving method. The foraminiferal species were picked, counted and photographed using the SEM. The ratio of dead to living forams was calculated. Rose Bengal dys was used to differentiate between dead and living foraminiferal tests.

The maximum grain size value was found at station 20, while the minimum was at station 4. The average grain size is 1.24 Φ. Relationships were observed between mean size and the other parameters. The standard deviation (sorting) rangeds between moderately sorted to poorly sorted. Skewness ranges between 0.22 and -0.46.

Complete linkage cluster analysis shows that the study area can be clustered into three groups. Group I includes stations numbers 20, 13, 5, 14, 11 and 3, group II contains stations numbers 7, 4, 16, 17, 18, 12 and 2, while group III contains stations numbers 15, 19, 9, 8 and 6. Grain size parameters indicates no indication about the similarities or dissimilarities between different stations.

The highest water temperature was recorded at station 20 (27.4 salinity ranges between 34.95 and 35.86.

For the organic matter station 7 shows the maximum content of organic matter, while station 17 has the minimum. For the nutrient salts, station 9 shows the maximum value for PO4 while station 4 has the lowest. For SiO3, station 1 presents the maximum value. On the other hand station 14 presents the lowest value in SiO3. Station 2 shows the lowest value for NO3 while stations 16 and 17 have the maximum values. The maximum value of NO2 is found at stations 11 while the minimum value is found at station number 7 and 20.

The high phosphate concentrations that have been recorded is a response to the decay of phytoplankton and excretion of considerable amounts of phosphate by aquatic organisms. On the other hand, the decrease in phosphate concentrations can be related to the decrease in the internal influx of phosphate, with an increase in consumption by phytoplankton. The high silicate values that have been found in the extreme east and off the Al-Khor opening is probably due to increase of the dissolution rate of diatom frustules and their fragments in the bottom sediments. The low values for nitrite may be attributed to the increase of nitrite oxidation to nitrate and its reduction to ammonia.

Station 8 showes the maximum foraminiferal individuals (39 1 individuals) while the minimum number (25 individuals) is found at station 2.

The must common foraminifera are the agglutinated forams, porcellaneous forams are the second in abundance; while the hyaline shells are less common.

The maximum number of dead foraminiferal individuals is 277 (station 13), while the minimum number is 5 individuals (station 2).

Peneropolis plantus, Quinqueloculina neastrictula, Quinqueloculina cooki, Triloculina sp., Ammonia beccarii, Elphidium crispum and Texularia sp. are the main foraminifera assemblages found in the study area. Other Milliolina, Textularina and RotalIina also occur.

The differences in the percentage of living foraminiferal tests may be a response to the nature of the bottom with the low values occurring in areas covered with seagrasses and halophytes. On the other hand, high percentages of living forams occur where algae, seagrasses and other plants disappear. Another possibility may be caused by the short lifespan of the benthic foraminifera. Another possible reason is the fact that some dead foraminiferal tests may be either recent deceased where the red color may be caused by the effect of Rose Bengal on the protoplasm.

Temperature and salinity have little influence on the distribution of the foraminiferal tests. Except for silicate, no relationship can be noticed. With the decreasing of the silicate, both living and total foraminiferal species slightly decrease.

Most of the foraminiferal assemblages fall within the normal marine to hypersaline marine marshes.

During the present study, some stations contain high percentages of blackened foraminifera that could be attributed to the decomposition of organic matter as well as to the effect of pollution. It also may be due the reducing conditions beneath the sediment surface.

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