Components of the Subsurface Sediments with Emphasis of Diatoms Frequency and Their Palaeoecological Significance at the Tennis Island and Its Environs, Western Port Said, Egypt

Abstract

Objective: The study gives a view of the major textural and compositional components of subsurface sediments around Tennis Island and its environs. It provides data on distribution and frequency of diatoms in the subsurface sediment as well as describes and combines the achieved results of paleo-environment processes and its response to water level change. Methodology: Twelve subsurface sediment samples were collected to show major textural and compositional components as well as describing diatom flora around a unique natural ecosystem called Tennis Island. Results: The grain size analysis of the collected samples revealed a high content of fine sand, mud (silt and clay) and characterized by low organic matter (average 10.4%) and widely varied content of CaCO3, with an average of 53.8%. 39 diatom species belonging to 25 genera were identified. Analogue for the island with high proportion of Planktonic species compared to benthic ones was established. Planktonic species represented by dominant forms like Cyclostephanos dubius; Cyclotella meneghiniana and Cyclotella stelligera. The non Planktonic species were Navicula alpina; Campylodiscus spp. and Diplonies bombus; while the other benthic forms were often sparse. Island is influenced by water input from the sea and drains from the south. Conclusion: The study revealed that diatoms experience climate change directly and indirectly through changes in sea water level, tectonic activity and trophic status.