Morphological Identification and Diversity Analysis of Fossil Diatoms from Diatomite Sangiran Central Java Indonesia

Abstract

Diatomite Sangiran is diatom fossil rich sediment. The aim of this research was to study the diversity of fossil
diatoms from Sangiran, Indonesia based on morphological characteristics. Samples were taken from lower, middle,
and upper sediment layers based on their different physical features with three replications each. Diatomite
extraction was performed following modification of Setty (1966) and frustule counting was accomplished by census
method. There were total 50 species found in diatomite layers. The diversity analysis showed that highest species
richness (21-22), diversity (1.35-1.47), and evenness index (0.44-0.48) were belong to the lower layer. The highest
frustule abundance (9.66x107-1.43x108 frustules/gram) and dominance index (0.67-0.72) were belong to the
middle layer. On the other hand, highest centrales:pennales ratios (0.73-1.11) were belong to the upper layer. The
sediment layers signified an obvious indication of gradual changes from marine to freshwater environment.
Dendrogram analysis using MINITAB.v.15.1.2 software denoted similarity between lower sediment layer and the
younger layers was 72.12%; while similarity between middle and upper layers 92.63%.
Keywords: diatom, diatomite, diversity, morphology, Sangiran