Diatoms

Diatoms refer to the main group of algae and which are normally the most common members of phytoplankton family. Even though most diatoms are unicellular, they are also known to exist as colonies. Palaeo-sedimentary analysis refers to the way up criterion, structure or geopital indicator observed in volcanic or sedimentary rocks making it possible to ascertain whether they have been overturned through deformation or they are right way up.

Diatom analysis of sediments is a main Palaeo-ecological method for reconstruction of past environmental impacts. Pre-requisites include the fact that changes in the abundance of living diatom and in the composition are recorded faithfully in sediments and subsequent analysis can be accurately depicted. Results obtained from diatom analysis give room for reconstruction of various environmental variables which include PH, Palaeo-temperature of surface waters, conductivity or salinity, water productivity and depth and variation in fresh water inflow (Smol, J, et al, 2010, p.600)  

Some of the five different diatom species include Digitoradiata Navicula, Aulacoseira islandica, Tabellaria Flocculosa, Fragilaria ulna, Epithemia Adnata var Parcellus. The following are the species and their appropriate keys:

Digitoradiata Navicula- Taxonomic classification

Chromista (Kingdom) Harosa (Sub-Kingdom) Heterokonta (infrakingdom) Ochrophyta (phylum) Khakista (Subphylum) Bacillariophyceae (Class) Bacillariophycidae  (subclass) Bacillariophycanae (Superordr) Naviculales (Order) Naviculaceae (Family) Navicula (genus).

This diatom species is found in the marine environment.

Aulacoseira islandica-Taxonomic classification

Empire-Eukaryota

Kingdom-Chromista

Sub-kingdom-Harosa

Infrakingdom-Heterokonta

Phylum-Ochrophyta

Subphylum-Khakista

Class-Bacillariophyceae

Sub-class-Coscinodiscophycidae

Superorder-Coscinodiscanae

Order-Aulacoseirales

Family –Aulacoseiraceae

Genus- Aulacoseira

Tabellaria Flocculosa-Taxonomic Classification

Empire-Eukaryota

Kingdom-Chromista

Sub-kingdom-Harosa

Infrakingdom-Heterokonta

Phylum-Ochrophyta

Subphylum-Khakista

Class-Bacillariophyceae

Sub-class-Fragilariophycidae

Superorder- Fragilariophycanae

Order-Tabellariales

Family – Tabellariaceae

Genus-Tabellaria

This is a freshwater species.

Fragilaria ulna-Taxonomic Classification

Empire-Eukaryota

Kingdom-Chromista

Sub-kingdom-Harosa

Infrakingdom-Heterokonta

Phylum-Ochrophyta

Subphylum-Khakista

Class-Bacillariophyceae

Sub-class-Fragilariophycidae

Superorder- Fragilariophycanae

Order-Fragilariaceae.

Family – Flagilariaceae

Genus-Flagilaria.

This is also a freshwater species.

Epithemia Adnata var Parcellus-Taxonomic Classification

Empire-Eukaryota

Kingdom-Chromista

Sub-kingdom-Harosa

Infrakingdom-Heterokonta

Phylum-Ochrophyta

Subphylum-Khakista

Class-Bacillariophyceae

Sub-class-Bacillariophycidae

Superorder- Bacillarianae

Order-Rhopalodiales.

Family – Rhopalodiaceae

Genus-Epithemia

This species is normally found in neutral to high PH environments

This is also a freshwater species.

Due to the siliceous composition of diatoms, they can only be well preserved in stratigraphic deposits in which they can be used in inferring both qualitative and quantitative environmental conditions of the past. Lack of such conditions therefore makes such analysis to be difficult and thus in order to improve the quality of the data collected, it is essential that such conditions are provided.