Table 1. Abiotic Factors of Loktak Lake (2002-04)

Abiotic Factors	Range	Mean ± SD
Air temperature ºC	16.4 - 30.8	23.4 ± 4.1
Water temperature ºC	14.5 - 28.5	21.4 ± 4.0
Rainfall mm	0 - 370.4	112.1 ±1 16.8
pH	6.01- 6.74	6.38 ± 0.23
Specific Conductivity µS/cm	75.0 - 132.0	98.9 ± 19.7
Dissolved Oxygen mg/l	4.6 -9.0	6.2 ± 1.1
Free CO₂ mg/l	6.0 - 13.0	9.5 ± 2.1
Alkalinity mg/l	10.0 - 25.0	16.0 ± 4.4
Hardness mg/l	24.0 - 54.0	38.1 ± 8.2
Phosphate mg/l	0.12 - 0.32	0.23 ± 0.12
Nitrate mg/l	0.27 - 0.42	0.34 ± 0.04
Sulphate mg/l	0.54 - 0.99	0.86 ± 0.12
Silicate mg/l	8.40 - 12.70	10.4 ± 1.2
Chloride mg/l	10.0 - 20.1	14.9 ± 3.1
Dissolved organic matter mg/l	0.91 - 2.1	1.38 ± 0.40
Total dissolved solids mg/l	0.20 - 0.81	0.46 ± 0.22

Table 2. Temporal variations of Phytoplankton of Loktak Lake

	2002-03	2003-2004	Study period
QUALITATIVE Chlorophyta > Bacillariophyta > Dinophyta = Cyanophyta = Euglenophyta > Chrysophyta
Phytoplankton	75 species	71 species	75 species
% Similarity	50.0-83.2	64.5-84.0	50.0-84.0
Monthly Richness
Phytoplankton	37 – 57 47 ± 6	45 – 54 49 ± 3	37 – 57 48 ± 5
Chlorophyta	24 – 40 33 ± 5	30 – 42 35 ± 3	24 – 42 34 ± 4
QUANTITATIVE Chlorophyta > Dinophyta > Bacillariophyta
Phytoplankton n/l	155 – 369 206 ± 58	158 – 323 220 ± 53	155 – 369 213 ± 56
% composition	38.0-60.0 45.1 ± 6.5	34.8-54.8 42.9 ± 5.8	34.8-60.0 44.1 ± 6.3
Species Diversity	2.520-3.805 3.283±0.354	2.876-3.741 3.507±0.259	2.520-3.805 3.404±0.329
Dominance	0.074-0.523 0.283±0.123	0.055-0.409 0.158±0.103	0.055-0.523 0.180±0.118
Evenness	0.698-0.941 0.853±0.074	0.739-0.956 0.902±0.064	0.698-0.956 0.879±0.075
Different groups (n/l)
Chlorophyta n/l	78 – 137 111 ± 20	104 – 155 119 ± 15	78 -155 115 ± 18
% composition	34.7-77.3 56.2 ± 12.6	38.1 -5.8 56.5 ± 8.3	34.7-77.3 56.2 ±10.5
Dinophyta n/l	13-193 53 ± 48	17 – 138 49 ± 36	13 – 193 51 ± 43
% composition	6.9 – 52.3 22.8 ± 12.5	10.4-49.3 20.5 ± 0.9	6.9– 52.3 22.0 ± 11.8
Bacillariophyta n/l	11 – 44 31 ± 10	17 – 55 38 ± 11	11 – 55 35 ± 11
% composition	6.7 – 21.8 15.4 ± 3.7	10.5 – 22.4 17.3 ± 3.0	6.7 - 22.4 16.3 ± 3.5
Euglenophyta n/l	2 - 12 7 ± 3	3 – 13 7 ± 3	2 – 13 7 ± 3
% composition	0.5 – 5.9 3.4 ± 1.7	1.3 – 4.1 3.0 ± 0.9	0.5 – 5.9 3.2 ± 1.4
Cyanophyta n/l	1 – 7 3 ± 2	3 – 7 5 ± 2	1 – 7 4 ± 2
% composition	0.3 – 4.3 1.5 ± 1.4	0.6 – 5.1 2.8 ± 1.4	0.3 – 5.1 2.1 ± 1.5
Chrysophyta n/l	0 – 1	0 – 4 2 ± 1	0 – 4 1 ± 1
Important taxa (n/l)
Ceratium hirudinella	4 – 193 43 ± 52	5 – 130 39 ± 37	4 – 193 41 ± 45
Closterium spp.	8 – 4 21 ± 8	17 – 43 29 ± 9	8 – 43 25 ± 9
Staurastrum spp.	5 – 30 17 ± 7	11 – 24 18 ± 4	5 – 30 18 ± 6
Gonatozygon spp	6 – 25 13 ± 6	7 – 26 17 ± 6	6 – 26 15 ± 6
Micrasterias spp.	1- 26 10 ± 7	3 – 15 10 ± 3	1 – 26 10 ± 6
Cosmarium spp.	2 – 8 5 ± 2	2 – 11 6 ± 3	2 – 11 6 ± 2

Table 3. Phytoplankton community similarities (Sorenson’s index) 2002-03

	Nov	Dec	Jan	Feb	Mar	Apr	May	June	July	Aug	Sept	Oct
Nov	-	80.4	70.7	69.8	66.7	59.6	68.1	60.7	70.5	77.9	77.6	69.9
Dec		-	65.2	72.9	71.8	71.2	63.4	62.6	67.4	78.1	81.5	76.1
Jan			-	68.4	57.8	50.0	64.2	50.6	69.2	70.6	75.0	62.4
Feb				-	69.0	63.6	70.6	55.4	63.4	60.7	67.4	66.0
March					-	75.8	71.7	60.0	62.9	68.8	72.7	71.2
April						-	68.8	61.5	53.3	66.0	72.0	68.6
May							-	59.1	64.4	63.8	63.9	68.6
June								-	58.8	56.5	71.6	72.0
July									-	65.9	66.0	66.7
Aug										-	83.2	73.6
Sept											-	78.9
Oct												-

Table 4. Phytoplankton community similarities (Sorenson’s index) 2003-04

	Nov	Dec	Jan	Feb	March	April	May	June	July	Aug	Sept	Oct
Nov	-	76.5	66.0	69.4	74.5	72.9	73.5	73.7	72.2	74.8	74.2	78.1
Dec		-	82.0	73.1	76.0	78.4	76.9	75.3	77.7	74.3	79.6	73.9
Jan			-	79.2	69.6	66.0	70.8	73.1	69.5	68.0	84.2	71.8
Feb				-	79.2	63.3	66.0	70.1	76.8	73.3	72.7	84.1
March					-	74.5	72.9	64.5	75.8	74.2	69.5	71.8
April						-	79.6	71.6	70.1	72.7	74.2	76.2
May							-	68.0	70.7	71.3	68.7	76.6
June								-	72.9	69.4	72.9	75.0
July									-	74.0	73.5	69.8
Aug										-	74.0	81.5
Sept											-	75.5
Oct												-