Dimensions:
Valve length: 12.5-25 µm
Valve breadth: 8-11 µm
Striae density: 27-36
(40 near apices)/ 10 µm

Ecology:
A cosmopolitan species found in alkaline waters, rarely becoming dominant.

Dimensions:
Valve length: 18-40 µm
Valve breadth: 12-24 µm
Striae density: 10-13/10 µm

Ecology:
A cosmopolitan species found in waters with moderate electrolyte content, sometimes occurring in brackish habitat.

Dimensions:
Valve length: 21 µm
Valve breadth: 4 µm
Striae density: 10-12/10 µm

Ecology:
A cosmopolitan species found in waters with elevated electrolyte content, tolerating critical to very heavy pollution.

Dimensions:
Valve length: 58-60 µm
Valve breadth: 17.5-18 µm
Striae density: 6-8/10 µm

Ecology:

Dimensions:
Valve diameter: 8µm
Valve mantle depth: µm
Striae density: µm

Ecology:
A Planktonic and benthic species found in eutrophic waters.

Dimensions:
Valve diameter: 5-15.5 µm
Valve mantle depth: 2.5-8 µm
Striae density: 4-7/10 µm

Ecology:
Found in both benthos and plankton of eutrophic rivers and lakes.

Dimensions:
Valve diameter: 8µm
Valve mantle depth: 7µm
Striae density: 8-21/10 µm

Ecology:

Dimensions:
Valve length: 66 µm
Valve breadth: 6-6.5 µm
Striae density: 5-9/10 µm

Ecology:
A cosmopolitan species widespread in very electrolyte-rich and brackish waters particularly near the coast. The cells form a unique type of mobile colony, in which individual cells slide to and fro with respect to each other. They are held together by interlocking grooves on the raphe sterna. The colony extends to form a linear array, where only the poles of the cells are touching then retracts to form a tabular array, with all the cells side by side.

Dimensions:
Valve length: 23-25 µm
Valve breadth: 8 µm
Striae density: 20-22/10 µm

Ecology:
A cosmopolitan littoral species found in a range of waters with moderate electrolyte content, as well as in damp mosses.

Dimensions:
Valve length: 27-36 µm
Valve breadth: 5.5-6.5 µm
Striae density: 18-20/10 µm

Ecology:
Cosmopolitan, ecology uncertain

Dimensions:
Valve length: 13-21/33 µm
Valve breadth: 8-13/18 µm
Straie density:  24-26/10 µm RV
: 20-23/10 µm RLV

Ecology:
Occurring in meso-to eutrophic flowing and standing waters. Found in abundance on plants, wood and stone.

Dimensions:
Valve length: 33 µm
Valve breadth: 18 µm
Straie density: /10 µm

Ecology:
A very widespread and common genus occurring in all waters. The frustules are epiphytic on filamentous algae or on aquatic plants, sometimes occurring so abundantly as to for a coating over the host surface. Cells of Cocconeis may also be found attached to stones and various other substrata.

Dimensions:
Valve length: 20-23
Valve breadth: 5-6
Striae density:  20-28/10 µm

Ecology:
A common characteristic indicator species for high levels of pollution. Found in strongly organically polluted waters, in particular effluent from sewage treatment works. It has a scattered occurrence in oligo- to eutrophic waters.

Dimensions:
Valve length: 70-98 µm
Valve breadth: 15-26 µm
Striae density: 18-20/10 µm

Ecology:
A cosmopolitan usually Epipelic species found in moderately to very electrolyte rich, eutrophic waters, resistant to critical and strong levels of pollution.

Dimensions:
Valve diameter: 5-28µm
Striae density: 6-10/10 µm

Ecology:
This taxon has a cosmopolitan distribution in the benthos and plankton of eutrophic, electrolyte rich lakes, rivers and streams.

Dimensions:
Valve length: 55-60 µm
Valve breadth: 18-18.5 µm
Striae density: 11-12/10 µm

Ecology:
A cosmopolitan species found in oligo- to mesotrophic waters with moderate electrolyte content. Occurs in the littoral zone of standing and flowing waters.

Dimensions:
Valve length: 30-40 µm
Valve breadth: 10-13 µm
Striae density: 10/10 µm

Ecology:
A cosmopolitan species found in oligo- to mesotrophic, alkaline waters with moderate electrolyte content.

Dimensions:
Valve length: 15-22 µm
Valve breadth: 5.5-7 µm
Striae density: 18-20/10 µm

Ecology:
A cosmopolitan species found in range of waters, including eutrophic, electrolyte rich and extremely polluted waters.

Dimensions:
Valve length: 20-22 µm
Valve breadth: 10 µm
Striae density: 10-11/10 µm

Ecology: Unknown

Dimensions:
Valve length: 36-38 µm
Valve breadth: 10-11 µm
Striae density: 8-9/10 µm

Ecology:
A cosmopolitan montane species found in weakly acidic waters.

Dimensions:
Valve length: 22-24 µm
Valve breadth: 7 µm
Striae density: 12/10 µm

Ecology:
A cosmopolitan species found in oligotrophic waters with moderate electrolyte content.

Dimensions:
Valve length: 4-6 µm
Valve breadth: 3 µm
Striae density: /10 µm

Ecology:
Cosmopolitan, found in a wide range of waters.
More ecology is Unknown.

Dimensions:
Valve length: 50-58 µm
Valve breadth: 8-9 µm
Striae density: 8-9/10 µm

Ecology:
Occurs in circumneutral waters, in pools and springs.

Dimensions:
Valve length: 17-25 µm
Valve breadth: 9-10 µm
Striae density: 20-25/10 µm

Ecology:
 A cosmopolitan Epipelic species occurring in waters with elevated electrolyte content. Tolerant to critical levels of pollution.

Dimensions:
Valve length: 280-320 µm
Valve breadth: 6-7 µm
Striae density: 7-9/10 µm

Ecology:
This cosmopolitan taxon is found in the benthos of rivers and lakes and is easily suspended in the plankton due to its relatively large surface area. Often found in mesotrophic to eutrophic waters together with F.ulna. Living cells are usually apically attached to a substratum by a mucilage pad or free living.

Dimensions:
Valve length: 100-365 µm
Valve breadth: 7-8.5 µm
Striae density: 8-10/10 µm

Ecology:
This cosmopolitan taxon is found in the benthos of rivers and lakes and is easily suspended in the plankton due to its relatively large surface area. Often found in mesotrophic to eutrophic, alkaline waters.

Dimensions:
Valve length: 140-210 µm
Valve breadth: 5.5-7 µm
Striae density: 8-10/10 µm

Ecology:
This cosmopolitan taxon is found in the benthos of rivers and lakes and is easily suspended in the plankton due to its relatively large surface area. Found in mesotrophic to eutrophic, alkaline freshwaters. Living cells are usually apically attached to a substratum.

Fragilaria ungeriana Grunow

Dimensions:
Valve length: 75-90 µm
Valve breadth: 8-9 µm
Striae density: 9-10/10 µm

Ecology:
Cells attached face to face. Found in tropical and sub-tropical, weakly alkaline, oxygen-rich waters.

Dimensions:
Valve length: 23-25 µm
Valve breadth: 7 µm
Striae density: 20-22/10 µm

Ecology:
A cosmopolitan species found in eutrophic, unpolluted or moderately polluted waters with average or slightly levated electrolyte content.

Dimensions:
Valve length: 40-70 µm
Valve breadth: 8.5-11 µm
Striae density: 9-12/10 µm

Ecology:
This taxon is able to tolerate extremely polluted conditions and is found in abundance in mining effluent.

Dimensions:
Valve length: 20-33 µm
Valve breadth: 6-8 µm
Striae density: 10-16/10 µm

Ecology:
A cosmopolitan species which is very wide spread in a range of waters, from small pools to lakes and rivers and generally considered to be tolerant to extremely polluted conditions.

Ecology:
Species of Gomphonema are very common epiphytes found attached to substrata by branched, gelatinous stalks originating at their narrow, or base, end. They occur in a wide range of mostly fresh waters including those enriched with sewage.

Dimensions:
Valve length: 52-56 µm
Valve breadth: 11-12.5 µm
Striae density: 11/10 µm

Ecology:
A cosmopolitan species found in circumneutral waters with moderate electrolyte content.

Dimensions:
Valve length: 90-110 µm
Valve breadth: 6-7.5 µm
Striae density: 16/10 µm
Fibulae density: 8/10 µm

Ecology:
A cosmopolitan species found in waters with very high electrolyte content.

Dimensions:
Valve length: 23-25 µm
Valve breadth: 5.5 µm
Striae density:  16-23/10 µm

Ecology:
Occurs in weakly alkaline waters with moderate to elevated electrolyte content and may also occur in critically polluted waters. Found mostly as an epiphyte, commonly found associated with Lemna spp. (duckweed).

Dimensions:
Valve length: 16/18 µm
Valve breadth: 5.5/6 µm
Striae density: 20-24/10 µm

Ecology:
A cosmopolitan species found in oligo- to dystrophic circumneutral to slightly acidic, electrolyte poor waters.

Dimensions:
Valve length: 26-40 µm
Valve breadth: 5-8 µm
Striae density: 13-15/10 µm

Ecology:
Cosmopolitan, found in eutrophic waters, tolerant to critical levels of pollution.

Dimensions:
Valve length: 21-26 µm
Valve breadth: 5.5-7 µm
Striae density: 9-10/10 µm

Ecology:
Cosmopolitan, very common in eutrophic to hypereutrophic fresh waters with moderate to highly electrolyte content. Also found in brackish waters. Tolerant of strongly polluted conditions. A good indicator species for these conditions.

Dimensions:
Valve length: 29-52 µm
Valve breadth: 6.5-11 µm
Striae density: 9-15/10 µm

Ecology:
A cosmopolitan eutrophic species. Tolerant to critical levels of pollution.

Dimensions:
Valve length: 28-32 µm
Valve breadth: 6-7 µm
Striae density: 14-16/10 µm

Ecology:
Cosmopolitan in eutrophic, electrolyte-rich waters. Tolerant of strongly polluted conditions.

Dimensions:
Valve length: 23.5-25 µm
Valve breadth: 6-7 µm
Striae density: 14-16/10 µm

Ecology:
A cosmopolitan Epipelic species. Occurs in eutrophic waters with moderate electrolyte content. Tolerant of dessication and strongly polluted conditions.

Dimensions:
Valve length: 20-22 µm
Valve breadth: 5-6 µm
Striae density: 10-13/10 µm

Ecology:
Cosmopolitan, common in heavily eutrophied, electrolyte-rich to brackish water. Very pollution tolerant, often the dominant species in industrially impacted waters.

Dimensions:
Valve length: 40-100 µm
Valve breadth: 10-15 µm
Striae density: 8-11/10 µm

Ecology:
Cosmopolitan but infrequent. Epilithic, Epipelic, as well as on detritus and macrophytes. Occurring in eutrophic waters and tolerant of critical levels of pollution.

Dimensions:
Valve length: 28-32 µm
Valve breadth: 66.5 µm
Striae density: 14/10 µm

Ecology:
A tropical to sub-tropical species, found commonly in alkaline waters.

Dimensions:
Valve length: 25-30 µm
Valve breadth: 4.5 µm
Striae density: 12/10 µm
Fibulae density: 6/10 µm

Ecology:
Found in eutrophic waters over a range from electrolyte- poor to electrolyte -rich waters.

Nitzschia capitellata Hust

Dimensions:
Valve length: 40 µm
Valve breadth: 4.5 µm
Striae density: 23-40/10 µm
Fibulae density: 12/10 µm

Ecology:
A wide spread species found in electrolyte rich and brackish waters. Tolerant to extremely polluted conditions.

Dimensions:
Valve length: 31.5-35 µm
Valve breadth: 4-5 µm
Striae density:  (32) 38-42/10 µm
Fibulae density: 10-13/10 µm

Ecology:
A cosmopolitan species found in brackish coastal waters as well as in electrolyte-rich inland waters. In large rivers systems this species may be associated with industrial effluents and is tolerant of strongly polluted conditions.

Dimensions:
Valve length: 11-30 µm
Valve breadth: 2-4 µm
Striae density: 16-18/10 µm
Fibulae density: 9-10/10 µm

Ecology:
A cosmopolitan species found in electrolyte rich and brackish waters. Tolerant to fluctuations in osmotic pressure and of critical levels of pollution.

Dimensions:
Valve length: 30-60
Valve breadth: 2.5-3.5
Striae density: 16/10 µm
Fibulae density: 8/10 µm

Ecology:
A cosmopolitan species occurring in very electrolyte-rich to brackish waters.

Nitzschia pumila Hustedt

Dimensions:
Valve length: 62-66 µm
Valve breadth: 4.5-5 µm
Striae density: 14/10 µm
Fibulae density: 8/10 µm

Ecology:
Little is known of this species except that it occurs in alkaline lakes.

Nitzschia sigma (Kutzing) W Smith

Dimensions:
Valve length: 35-1000 µm
Valve breadth: 4-15(26) µm
Striae density:  (15) 19-38/10 µm
Fibulae density: (3)7-12/10 µm

Ecology:
A cosmopolitan species found in eutrophic, electrolyte-rich inland waters and extending into brackish estuarine and coastal biotopes.

Ecology:
Nitzschia is a large, diverse and ecologically versatile Genus. They are mostly benthic but include Planktonic taxa (e.g. N. acicularis (Kutzing) W Smith). The genus can yield much ecological information since several taxa are indicative of nutrient enrichment (eutrophication), while other are useful indicators of elevated salinities. Nitzschia may also occur in oligotrophic waters, but they are rarely a major component of these assemblages.

Dimensions:
Valve length: 35 µm
Valve breadth: 3.5 µm
Striae density: 16/10 µm
Fibulae density: 14/10 µm

Ecology:
A cosmopolitan species found in eutrophic waters with moderate to moderately high electrolyte content. Also occurring supralittoral sites, tolerant to osmotic fluctuations and strongly polluted conditions.

Dimensions:
Valve length: 15-45 µm
Valve breadth: 2.5-7 µm
Striae density: (16) 17- 19(20) /10 µm /10 µm
Fibulae density: 3.56(7)/10 µm

Ecology:
A common species in eutrophic electrolyte rich waters and tolerating extremely polluted conditions.

Dimensions:
Valve length: µm
Valve breadth: µm
Striae density: /10 µm

Ecology: Unknown

Dimensions:
Valve length: 79-80 µm
Valve breadth: 14 µm
Striae density: 8/10 µm

Ecology: Unknown

Dimensions:
Valve length: 42-46 µm
Valve breadth: 8-8.5 µm
Striae density: 8/10 µm

Ecology:
Cosmopolitan in distribution

Ecology:
A very common benthic genus living on stones and sediment mainly in freshwater, they are often abundant especially in acid waters. Cells of Pinnularia may also be washed into the plankton.

Dimensions:
Valve length: 70-93 µm
Valve breadth: 13-15 µm
Striae density: 10-11/10 µm

Ecology:
Cosmopolitan, common Pinnularia in oligo- to mesotrophic waters with low to moderate electrolyte content.

Dimensions:
Valve length: 15-25 µm
Valve breadth: 6.5-7 µm
Striae density: 12-16/10 µm

Ecology:
Occurring in circumneutral to alkaline waters with low to moderate electrolyte content. More often attached to plants than stones.

Dimensions:
Valve length: 85-88 µm
Valve breadth: 11.5-12.5 µm
Striae density: 22-25/10 µm

Ecology:
Cosmopolitan, found in brackish and saline inland waters.

Dimensions:
Valve length: 29 µm
Valve breadth: 11 µm
Striae density: 14/10 µm

Ecology:
A cosmopolitan species found in standing and slow flowing waters, especially springs, of moderate to high electrolyte content.

Dimensions:
Valve length: 32-34 µm
Valve breadth: 7-7.5 µm
Striae density: 14 /10 µm

Ecology :
The genus may be found in fresh waters as well as brackish waters. Species of this genus are found mostly in the benthos.

Dimensions:
Valve length: 25-29 µm
Valve breadth: 9-10 µm
Striae density: 20/10 µm

Ecology: Unknown

Dimensions:
Valve length: 15-32 µm
Valve breadth: 6-10 µm
Striae density: 7-14/10 µm

Ecology:
A cosmopolitan species found in a broad spectrum of electrolyte rich waters with some populations found under strongly polluted conditions.

Dimensions:
Valve length: 33.5 µm
Valve breadth: 10 µm
Striae density: 6/10 µm
Fibulae density: 5.5-8/10 µm

Ecology:
A cosmopolitan species found in eutrophic waters with moderate electrolyte content.

Surirella species

Ecology:
It is a large and common freshwater to marine genus. Cells found in the benthos of hard waters, are rarely planktonic, and seldom abundant. Some species may tolerate very nutrient-rich conditions.

Dimensions:
Valve length: 65-120 µm
Valve breadth: 27-35 µm
Striae density: 3/10 µm

Dimensions:
Valve diameter: 10-11 µm

Ecology: Unknown

Dimensions:
Valve length: µm
Valve breadth: µm
Striae density: 9-12/10 µm
Fibulae density: 7-10/10µm

Ecology:
A cosmopolitan species commonly occurring in eutrophic waters with elevated electrolyte content. Favours standing waters.

Dimensions:
Valve diameter: 7-8 µm
Striae density: 7/10 µm

Ecology:
Found in freshwater in the plankton of inland rivers and lakes.

Dimensions:
Valve diameter: 6-6.5 µm
Valve mantle depth: 4-8 µm
Striae density: 8-21/10 µm

Ecology:
Found in freshwater in the plankton of inland rivers and lakes.

Dimensions:
Valve diameter: 22-27 µm

Ecology: Planktonic, freshwater taxa. Ecology Unknown

Dimensions:
Valve length: 95-140 µm
Valve breadth: 7.5-9.5 µm
Striae density: 9/10 µm

Ecology: Unknown

Dimensions:
Valve length: 7 µm
Valve breadth: 4 µm
Striae density: 24-30/10 µm RV
                         : 20/10 µm RLV

Ecology:
This cosmopolitan species has very wide ecological amplitude and is found in many different types of water including industrial and other wastewater. It is also able to grow under very low light and can tolerate temperatures of up to 40˚C. The optimum growth conditions for this taxa are alkaline water with moderate to elevated electrolyte content.

Dimensions:
Valve length: 23 µm
Valve breadth: 9-10 µm
Striae density: 10-11/10 µm

Ecology:
Found in well-aerated clean or mildly polluted water with moderate electrolyte content.

Dimensions:
Valve length: 25 µm
Valve breadth: 8 µm
Striae density: /10 µm

Ecology:
Craticula species tend to be associated with fresh to brackish waters and some species are very tolerant to elevated levels of organic pollution. This taxa occurs as single cells in the benthos, but may be washed into the plankton.

Dimensions:
Valve length: 19-28 µm
Valve breadth: 9-10 µm
Striae density: 10-16/10 µm

Ecology:
A cosmopolitan species found in wide range of waters, in unpolluted to slightly polluted waters with moderate to high electrolyte content.

Dimensions:
Valve length: 17.5-20 µm
Valve breadth: 5.5-7 µm
Striae density: 9-11/10 µm

Ecology:
Cosmopolitan, found in eutrophic to hypereutrophic waters with moderate to high electrolyte content. Tolerant to strongly polluted conditions. A good indicator for such anthropogenically impacted waters.

Dimensions:
Valve length: 28-32 µm
Valve breadth: 6-9 µm
Striae density: 12-14/10 µm

Ecology:
Navicula is found in all types of waters ranging from oligotrophic to eutrophic. Cells inhabit the plankton or benthos. In benthic habitats the cells may occur singly, in films on submerged substrates and sediments, or as colonies within a mucilage tube (e.g., N. recens). Navicula like many other raphe bearing diatoms secretes mucilage from the raphe to enable the cells to glide along a substratum.

Dimensions:
Valve length: 28-35 µm
Valve breadth: 6.5-7 µm
Striae density: 13-14/10 µm

Ecology:
A cosmopolitan species found in eutrophic, brackish waters or those with very high electrolyte content. Tolerant to critical levels of pollution.

Dimensions:
Valve length: 45-52 µm
Valve breadth: 7-9 µm
Striae density: 10-14/10 µm

Ecology:
Cosmopolitan, but mostly in the tropics. Epipelic in circumneutral waters with a moderate electrolyte content.

Dimensions:
Valve length: 34-46 µm
Valve breadth: 6-8.5 µm
Striae density: 10-12/10 µm

Ecology:
This taxon is wide spread.

Dimensions:
Valve length: 48-50 µm
Valve breadth: 9 µm
Striae density: 12/10 µm

Ecology: Unknown

Pinnularia conica Gandhi

Dimensions:
Valve length: 48 µm
Valve breadth: 9-9.5 µm
Striae density: 9/10 µm

Ecology: unknown

Dimensions:
Valve length: 11-13 µm
Valve breadth: 2-3.5 µm
Striae density: 8-12/10 µm

Ecology: Unknown

Dimensions:
Valve length: 21-23 µm
Valve breadth: 5-5.5 µm
Striae density: 8-12/10 µm

Ecology: Unknown

Dimensions:
Valve length: 35-37.5 µm
Valve breadth: 10 µm
Striae density: 11-12/10 µm

Ecology:
A cosmopolitan species found in oligo- to mesotrophic waters but not tolerant to critical levels of pollution. Attached to the substratum by dichotomous mucilage stalks.

Dimensions:
Valve length: 28 µm
Valve breadth: 4 µm
Striae density:  4-11/10 µm

Ecology:
A cosmopolitan species favouring periodically dry habitat, including soils and rock crevices. Widespread in a range of rivers, but probably washed in from soils.

Dimensions:
Valve length: 65-110 µm
Valve breadth: 6.5-8 µm
Striae density:  >40/10 µm
Fibulae density: 6-8/10 µm

Ecology:
A commonly occurring species found in brackish coastal and inland waters.

Dimensions:
Valve length: 11-30 µm
Valve breadth: 2-4 µm
Striae density: 16-18/10 µm
Fibulae density: 9-10/10 µm

Ecology: Unknown

Dimensions:
Valve length: 60-100 µm
Valve breadth: 4-7 µm
Striae density: 20-33/10 µm
Fibulae density: 7-13/10 µm

Ecology:
Found in the littoral zone of large eutrophic rivers and lakes with moderate to high electrolyte content. This species does not tolerate more than critical levels of pollution.

Nitzschia gracilis Hantzsch

Dimensions:
Valve length: 30-110 µm
Valve breadth: 2.5-4 µm
Striae density: 38-42/10 µm
Fibulae density: 12-18/10 µm

Ecology:
A cosmopolitan species found in eutrophic, electrolyte- rich waters but not tolerating more than moderately polluted conditions.